Subjects -> HEALTH AND SAFETY (Total: 1541 journals)
    - CIVIL DEFENSE (22 journals)
    - DRUG ABUSE AND ALCOHOLISM (87 journals)
    - HEALTH AND SAFETY (722 journals)
    - HEALTH FACILITIES AND ADMINISTRATION (390 journals)
    - OCCUPATIONAL HEALTH AND SAFETY (108 journals)
    - PHYSICAL FITNESS AND HYGIENE (130 journals)
    - WOMEN'S HEALTH (82 journals)

PHYSICAL FITNESS AND HYGIENE (130 journals)                     

Showing 1 - 130 of 130 Journals sorted alphabetically
ACSMs Health & Fitness Journal     Full-text available via subscription   (Followers: 15)
Acta Facultatis Educationis Physicae Universitatis Comenianae     Open Access   (Followers: 4)
Acta Kinesiologiae Universitatis Tartuensis     Open Access   (Followers: 1)
ACTIVE : Journal of Physical Education, Sport, Health and Recreation     Open Access   (Followers: 31)
Adapted Physical Activity Quarterly     Hybrid Journal   (Followers: 5)
African Journal for Physical, Health Education, Recreation and Dance     Full-text available via subscription   (Followers: 7)
Ágora para la Educación Física y el Deporte     Open Access  
Al.Qadisiya journal for the Sciences of Physical Education     Open Access  
American Journal of Sexuality Education     Hybrid Journal   (Followers: 4)
Annals of Applied Sport Science     Open Access   (Followers: 11)
Annals of Work Exposures and Health     Hybrid Journal   (Followers: 11)
Applied Physiology, Nutrition and Metabolism     Hybrid Journal   (Followers: 33)
Apunts. Medicina de l'Esport     Full-text available via subscription   (Followers: 1)
Arab Journal of Nutrition and Exercise     Open Access   (Followers: 1)
Archives of Exercise in Health and Disease     Open Access   (Followers: 7)
Arquivos de Ciências do Esporte     Open Access  
Arquivos em Movimento     Open Access   (Followers: 1)
Arrancada     Open Access   (Followers: 1)
Athletic Training & Sports Health Care     Full-text available via subscription   (Followers: 24)
BMC Obesity     Open Access   (Followers: 8)
BMC Sports Science, Medicine and Rehabilitation     Open Access   (Followers: 35)
Childhood Obesity     Hybrid Journal   (Followers: 24)
Clinical Journal of Sport Medicine     Hybrid Journal   (Followers: 36)
Comparative Exercise Physiology     Hybrid Journal   (Followers: 25)
Cultura, Ciencia y Deporte     Open Access   (Followers: 2)
Eating and Weight Disorders - Studies on Anorexia, Bulimia and Obesity     Hybrid Journal   (Followers: 24)
eJRIEPS : Ejournal de la recherche sur l'intervention en éducation physique et sport     Open Access  
Environmental Health and Preventive Medicine     Open Access   (Followers: 4)
Éthique & Santé     Full-text available via subscription  
Fat Studies : An Interdisciplinary Journal of Body Weight and Society     Partially Free   (Followers: 3)
Fisioterapia em Movimento     Open Access  
Fitness & Performance Journal     Open Access   (Followers: 3)
Food Science and Human Wellness     Open Access   (Followers: 5)
Frontiers in Sports and Active Living     Open Access   (Followers: 2)
Gelanggang Pendidikan Jasmani Indonesia     Open Access  
German Journal of Exercise and Sport Research : Sportwissenschaft     Hybrid Journal   (Followers: 4)
Geron     Full-text available via subscription  
Global Journal of Health and Physical Education Pedagogy     Full-text available via subscription   (Followers: 2)
Health and Quality of Life Outcomes     Open Access   (Followers: 15)
Health Education Journal     Hybrid Journal   (Followers: 17)
Health Marketing Quarterly     Hybrid Journal   (Followers: 3)
Health Physics     Hybrid Journal   (Followers: 7)
Home Healthcare Now     Hybrid Journal   (Followers: 5)
Human Movement     Open Access   (Followers: 14)
Human Movement Science     Hybrid Journal   (Followers: 17)
IISE Transactions on Occupational Ergonomics and Human Factors     Hybrid Journal  
Indonesia Performance Journal     Open Access  
İnönü Üniversitesi Beden Eğitimi ve Spor Bilimleri Dergisi     Open Access  
International Journal for Vitamin and Nutrition Research     Hybrid Journal   (Followers: 12)
International Journal of Applied Exercise Physiology     Open Access   (Followers: 60)
International Journal of Athletic Therapy & Training     Hybrid Journal   (Followers: 15)
International Journal of Behavioral Nutrition and Physical Activity     Open Access   (Followers: 30)
International Journal of Men's Health     Full-text available via subscription   (Followers: 5)
International Journal of Obesity     Hybrid Journal   (Followers: 94)
International Journal of Obesity Supplements     Full-text available via subscription   (Followers: 8)
International Journal of Qualitative Studies on Health and Well-Being     Open Access   (Followers: 22)
International Journal of Spa and Wellness     Hybrid Journal  
International Journal of Sport, Exercise & Training Sciences     Open Access   (Followers: 2)
International Journal of Yoga     Open Access   (Followers: 17)
Isokinetics and Exercise Science     Hybrid Journal   (Followers: 12)
Journal of American College Health     Hybrid Journal   (Followers: 4)
Journal of Athlete Development and Experience     Open Access   (Followers: 1)
Journal of Bioenergetics and Biomembranes     Hybrid Journal   (Followers: 1)
Journal of Human Performance in Extreme Environments     Open Access   (Followers: 2)
Journal of Human Sport and Exercise     Open Access   (Followers: 19)
Journal of Motor Learning and Development     Hybrid Journal  
Journal of Physical Activity and Health     Hybrid Journal   (Followers: 10)
Journal of Physical Activity and Hormones     Open Access   (Followers: 1)
Journal of Physical Activity Research     Open Access   (Followers: 5)
Journal of Physical Education and Human Movement     Open Access  
Journal of Physical Education and Sport Sciences     Open Access   (Followers: 2)
Journal of Physical Education Health and Sport     Open Access   (Followers: 2)
Journal of Physical Education, Recreation & Dance     Full-text available via subscription   (Followers: 15)
Journal of Science in Sport and Exercise     Hybrid Journal   (Followers: 4)
Journal of Sport and Health Science     Open Access   (Followers: 22)
Journal of Sport Sciences and Fitness     Open Access   (Followers: 16)
Journal of Strength and Conditioning Research     Hybrid Journal   (Followers: 79)
Journal of Yoga & Physical Therapy     Open Access   (Followers: 9)
Jurnal Pendidikan Kesehatan Rekreasi     Open Access   (Followers: 4)
Kerbala Magazine of Physical Edu. Seiences     Open Access   (Followers: 2)
Kinesiology : International Journal of Fundamental and Applied Kinesiology     Open Access  
Kinesiology Review     Hybrid Journal   (Followers: 6)
Krankenhaus-Hygiene - Infektionsverhütung     Full-text available via subscription  
Measurement in Physical Education and Exercise Science     Hybrid Journal   (Followers: 7)
Médecine & Nutrition     Full-text available via subscription  
Mental Health and Physical Activity     Hybrid Journal   (Followers: 17)
MHSalud : Movimiento Humano y Salud     Open Access  
Obesity     Hybrid Journal   (Followers: 58)
Obesity Research & Clinical Practice     Full-text available via subscription   (Followers: 21)
Obesity Reviews     Hybrid Journal   (Followers: 26)
Obesity Science & Practice     Open Access   (Followers: 1)
Open Obesity Journal     Open Access   (Followers: 1)
Pain Management in General Practice     Full-text available via subscription   (Followers: 12)
PALAESTRA : Adapted Sport, Physical Education, and Recreational Therapy     Full-text available via subscription   (Followers: 4)
Physical Activity and Health     Open Access   (Followers: 2)
Physical Education & Sport Pedagogy     Hybrid Journal   (Followers: 12)
Preventing Chronic Disease     Free   (Followers: 2)
Psychology of Sport and Exercise     Hybrid Journal   (Followers: 21)
Quality in Sport     Open Access   (Followers: 1)
Race and Yoga     Open Access   (Followers: 5)
RBNE - Revista Brasileira de Nutrição Esportiva     Open Access   (Followers: 1)
RBONE - Revista Brasileira de Obesidade, Nutrição e Emagrecimento     Open Access  
RBPFEX - Revista Brasileira de Prescrição e Fisiologia do Exercício     Open Access  
Research Quarterly for Exercise and Sport     Hybrid Journal   (Followers: 1)
Retos : Nuevas Tendencias en Educación Física, Deportes y Recreación     Open Access  
Revista Andaluza de Medicina del Deporte     Open Access   (Followers: 2)
Revista Brasileira de Atividade Física & Saúde     Open Access  
Revista Brasileira de Ciências do Esporte     Open Access   (Followers: 1)
Revista Brasileira de Cineantropometria & Desempenho Humano     Open Access   (Followers: 1)
Revista Brasileira de Educação Física e Esporte     Open Access   (Followers: 2)
Revista da Educação Física : UEM     Open Access   (Followers: 1)
Revista Iberoamericana de Psicología del Ejercicio y el Deporte     Open Access  
Revista Internacional de Medicina y Ciencias de la Actividad Física y del Deporte : International Journal of Medicine and Science of Physical Activity and Sport     Open Access   (Followers: 1)
Revue phénEPS / PHEnex Journal     Open Access  
Scandinavian Journal of Sport and Exercise Psychology     Open Access   (Followers: 9)
SIPATAHOENAN : South-East Asian Journal for Youth, Sports & Health Education     Open Access  
Spor Bilimleri Dergisi / Hacettepe Journal of Sport Sciences     Open Access  
Sport and Fitness Journal     Open Access   (Followers: 5)
Sport Health     Full-text available via subscription   (Followers: 3)
Sport Sciences for Health     Hybrid Journal   (Followers: 5)
Sport- und Präventivmedizin     Hybrid Journal   (Followers: 3)
SPORTIVE : Journal Of Physical Education, Sport and Recreation     Open Access   (Followers: 5)
Sports     Open Access   (Followers: 2)
Sports Biomechanics     Hybrid Journal   (Followers: 29)
Sports Health: A Multidisciplinary Approach     Hybrid Journal   (Followers: 4)
Strength & Conditioning Journal     Hybrid Journal   (Followers: 64)
Timisoara Physical Education and Rehabilitation Journal     Open Access   (Followers: 5)
Turkish Journal of Sport and Exercise     Open Access  
Yoga Mimamsa     Open Access   (Followers: 2)
Здоровье человека, теория и методика физической культуры и спорта     Open Access  

           

Similar Journals
Journal Cover
Journal of Strength and Conditioning Research
Journal Prestige (SJR): 1.366
Citation Impact (citeScore): 2
Number of Followers: 79  
 
  Hybrid Journal Hybrid journal (It can contain Open Access articles)
ISSN (Print) 1064-8011 - ISSN (Online) 1533-4287
Published by LWW Wolters Kluwer Homepage  [301 journals]
  • Comparision of Low and High Volume of Resistance Training on Body Fat and
           Blood Biomarkers in Untrained Older Women: A Randomized Clinical Trial
    • Authors: Cunha; Paolo M.; Tomeleri, Crisieli M.; Nascimento, Matheus A.; Mayhew, Jerry L.; Fungari, Edilaine; Cyrino, Letícia T.; Barbosa, Décio S.; Venturini, Danielle; Cyrino, Edilson S.
      Abstract: imageCunha, PM, Tomeleri, CM, Nascimento, MA, Mayhew, JL, Fungari, E, Cyrino, LT, Barbosa, DS, Venturini, D, and Cyrino, ES. Comparision of low and high volume of resistance training on body fat and blood biomarkers in untrained older women: a randomized clinical trial. J Strength Cond Res 35(1): 1–8, 2021—The purpose of this study was to compare the effects of resistance training (RT) performed with 2 different volumes on body fat and blood biomarkers in untrained older women. Sixty-five physically independent older women (≥60 years) were randomly assigned to one of 3 groups: low-volume (LV) training group, high-volume (HV) training group, and a control group. Both training groups performed RT for 12 weeks, using 8 exercises of 10–15 repetitions maximum for each exercise. The low-volume group performed only a single set per exercise, whereas the HV group performed 3 sets. Anthropometric, body fat (%), trunk fat, triglycerides (TG), total cholesterol, low-density lipoprotein cholesterol (LDL-c), high-density lipoprotein cholesterol, very LDL-c (VLDL-c), glucose (GLU), C-reactive protein (CRP), and composite Z-score were measured. The HV group obtained greater improvements compared with the LV group (p < 0.05) for TG (LV = −10.5% vs. HV = −16.6%), VLDL-c (LV = −6.5% vs. HV = −14.8%), GLU (LV = −4.7% vs. HV = −11.1%), CRP (LV = −13.2% vs. HV = −30.8%), % body fat (LV = −2.4% vs. HV = −6.1%), and composite Z-score (LV = −0.13 ± 0.30 vs. HV = −0.57 ± 0.29). Trunk fat was reduced (p < 0.05) only in the HV group (−6.8%). We conclude that RT performed in higher volume seems to be the most appropriate strategy to reduce body fat (%), trunk fat, improve blood biomarkers, and reduce composite Z-score in older women.
      PubDate: Fri, 01 Jan 2021 00:00:00 GMT-
       
  • Higher Peak Fat Oxidation During Rowing vs. Cycling in Active Men and
           Women
    • Authors: Astorino; Todd A.; Oriente, Chandler; Peterson, Jill; Alberto, Giannina; Castillo, Erica Elena; Vasquez-Soto, Ulices; Ibarra, Esmerelda; Guise, Victoria; Castaneda, Ivan; Marroquin, Joel R.; Dargis, Rachel; Thum, Jacob S.
      Abstract: imageAstorino, TA, Oriente, C, Peterson, J, Alberto, G, Castillo, EE, Vasquez-Soto, U, Ibarra, E, Guise, V, Castaneda, I, Marroquin, JR, Dargis, R, and Thum, JS. Higher peak fat oxidation during rowing vs. cycling in active men and women. J Strength Cond Res 35(1): 9–15, 2021—This study compared fat and carbohydrate oxidation (CHOOx) between progressive rowing and cycling. Initially, 22 active healthy adults (age = 27 ± 8 years) performed incremental cycling and rowing to volitional fatigue to assess maximal oxygen uptake (V̇o2max) and maximal heart rate (HRmax). The order of 2 subsequent sessions was randomized, performed 2 hours postmeal, and included a warm-up followed by three 8-minute stages of rowing or cycling at 60–65, 70–75, and 80–85 %HRmax. During exercise, power output was modified to maintain work rate in the desired range. Gas exchange data and blood samples were obtained to measure fat and CHOOx and blood lactate concentration. Fat oxidation (FOx) increased during exercise (p < 0.001) and there was a main effect of mode (p = 0.03) but no modeXintensity interaction (p = 0.33). Peak FOx was higher in response to rowing vs. cycling (0.23 ± 0.09 g·min−1 vs. 0.18 ± 0.07 g·min−1, p = 0.01). Carbohydrate oxidation increased during exercise (p < 0.001) but there was no effect of mode (p = 0.25) or modeXintensity interaction (p = 0.08). Blood lactate concentration was lower (p = 0.007) at the end of rowing vs. cycling (3.1 ± 1.0 mM vs. 3.9 ± 1.6 mM, d = 1.1). Prolonged rowing having equivalent calorie expenditure and intensity vs. cycling elicits higher peak FOx, which is likely attributed to greater muscle mass used during rowing.
      PubDate: Fri, 01 Jan 2021 00:00:00 GMT-
       
  • Activation of the Gluteus Maximus During Performance of the Back Squat,
           Split Squat, and Barbell Hip Thrust and the Relationship With Maximal
           Sprinting
    • Authors: Williams; Michael J.; Gibson, Neil V.; Sorbie, Graeme G.; Ugbolue, Ukadike C.; Brouner, James; Easton, Chris
      Abstract: imageWilliams, MJ, Gibson, N, Sorbie, GG, Ugbolue, UC, Brouner, J, and Easton, C. Activation of the gluteus maximus during performance of the back squat, split squat, and barbell hip thrust and the relationship with maximal sprinting. J Strength Cond Res 35(1): 16–24, 2021—The purpose of this research was to compare muscle activation of the gluteus maximus and ground reaction force between the barbell hip thrust, back squat, and split squat and to determine the relationship between these outcomes and vertical and horizontal forces during maximal sprinting. Twelve, male, team sport athletes (age, 25.0 ± 4.0 years; stature, 184.1 ± 6.0 cm; body mass, 82.2 ± 7.9 kg) performed separate movements of the 3 strength exercises at a load equivalent to their individual 3 repetition maximum. The ground reaction force was measured using force plates and the electromyography (EMG) activity of the upper and lower gluteus maximus and was recorded in each leg and expressed as percentage of the maximum voluntary isometric contraction (MVIC). Subjects then completed a single sprint on a nonmotorized treadmill for the assessment of maximal velocity and horizontal and vertical forces. Although ground reaction force was lower, peak EMG activity in the gluteus maximus was higher in the hip thrust than in the back squat (p = 0.024; 95% confidence interval [CI] = 4–56% MVIC) and split squat (p = 0.016; 95% CI = 6–58% MVIC). Peak sprint velocity correlated with both anterior-posterior horizontal force (r = 0.72) and peak ground reaction force during the barbell hip thrust (r = 0.69) but no other variables. The increased activation of gluteus maximus during the barbell hip thrust and the relationship with maximal running speed suggests that this movement may be optimal for training this muscle group in comparison to the back squat and split squat.
      PubDate: Fri, 01 Jan 2021 00:00:00 GMT-
       
  • Effect of Barbell Load on Vertical Jump Landing Force-Time Characteristics
    • Authors: Lake; Jason P.; Mundy, Peter D.; Comfort, Paul; McMahon, John J.; Suchomel, Timothy J.; Carden, Patrick
      Abstract: imageLake, JP, Mundy, PD, Comfort, P, McMahon, JJ, Suchomel, TJ, and Carden, P. Effect of barbell load on vertical jump landing force-time characteristics. J Strength Cond Res 35(1): 25–32, 2021—The aim of this study was to quantify the effect that barbell load has on the jump height and force-time characteristics of the countermovement jump (CMJ). Fifteen strength-trained men (mean ± SD: age 23 ± 2 years, mass 84.9 ± 8.1 kg, and height 1.80 ± 0.05 m) performed 3 CMJs with no additional load, and with barbell loads of 25, 50, 75, and 100% of body mass on 2 force plates recording at 1,000 Hz. Propulsion and landing force-time characteristics were obtained from force-time data and compared using analysis of variance and effect sizes. Jump height decreased significantly as load increased (26–71%, d = 1.80–6.87). During propulsion, impulse increased with load up to 75% of body mass (6–9%, d = 0.71–1.08), mean net force decreased (10–43%, d = 0.50–2.45), and time increased (13–50%, d = 0.70–2.57). During landing, impulse increased as load increased up to 75% of body mass (5 to 12%, d = 0.54–1.01), mean net force decreased (13–38%, d = 0.41–1.24), and time increased (20–47%, d = 0.65–1.47). Adding barbell load to CMJ significantly decreases CMJ height. Furthermore, CMJ with additional barbell load increases landing phase impulse. However, while mean net force decreases as barbell load increases, landing time increases so that jumpers are exposed to mechanical load for longer. Practitioners should exercise caution when implementing loaded CMJ to assess their athletes.
      PubDate: Fri, 01 Jan 2021 00:00:00 GMT-
       
  • High- vs. Low-Intensity Fatiguing Eccentric Exercise on Muscle Thickness,
           Strength, and Blood Flow
    • Authors: Hill; Ethan C.; Housh, Terry J.; Smith, Cory M.; Keller, Joshua L.; Schmidt, Richard J.; Johnson, Glen O.
      Abstract: imageHill, EC, Housh, TJ, Smith, CM, Keller, JL, Schmidt, RJ, and Johnson, GO. High- vs. low-intensity fatiguing eccentric exercise on muscle thickness, strength, and blood flow. J Strength Cond Res 35(1): 33–40, 2021—The purpose of this investigation was to examine the acute effects of equal volumes of fatiguing high- vs. low-intensity eccentric muscle actions on changes in muscle thickness, echo intensity, muscle blood flow, and adipose thickness. Eighteen men (mean ± SD = 23.2 ± 3.0 years) performed eccentric peak torque (PT) and maximal voluntary isometric contraction (MVIC) trials before (pretest), immediately after (posttest), and 5 minutes after (recovery) performing randomly ordered fatiguing eccentric, isokinetic (180°·s−1) muscle actions of the elbow flexors at 40% (72 repetitions) or 80% (36 repetitions) of eccentric PT. Muscle thickness, exercise-induced edema, muscle blood flow, and adipose thickness were also assessed via ultrasound at pretest, posttest, and recovery. There were no intensity-specific effects on the patterns of responses for eccentric PT, MVIC, muscle thickness, echo intensity, muscle blood flow, or adipose thickness. There were, however, effects across time that decreased from pretest to posttest and from pretest to recovery for eccentric PT (21.5 and 13.0%), MVIC (14.6 and 5.8%), and adipose thickness (10.0 and 6.0%), but increased for muscle thickness (7.6 and 5.9%), echo intensity (13.7 and 9.9%), and muscle blood flow (129.6 and 90.1%) (collapsed across 40 and 80%). These findings indicated that when matched for exercise volume, there were no intensity-related effects on the increases in muscle thickness, echo intensity, muscle blood flow, or the decreases in eccentric PT, MVIC, and adipose thickness after fatiguing eccentric muscle actions. Therefore, exercise volume, independent of exercise intensity and number of repetitions, may be a mediating factor of muscle fatigue and performance during eccentric muscle actions.
      PubDate: Fri, 01 Jan 2021 00:00:00 GMT-
       
  • Does Intra-abdominal Pressure Have a Causal Effect on Muscle Strength of
           Hip and Knee Joints'
    • Authors: Tayashiki; Kota; Kanehisa, Hiroaki; Miyamoto, Naokazu
      Abstract: imageTayashiki, K, Kanehisa, H, and Miyamoto, N. Does intra-abdominal pressure have a causal effect on muscle strength of hip and knee joints? J Strength Cond Res 35(1): 41–46, 2021—It remains unclear whether intra-abdominal pressure (IAP) has a causal effect on lower-limb muscle strength. This study aimed to clarify whether or not changes in IAP, induced by changing breathing state, influence muscle strength of hip and knee extensor and flexor. Eighteen healthy males (age: 22.0 ± 2.2 years, height: 1.71 ± 0.03 m, and body mass: 68.1 ± 6.1 kg) performed maximal voluntary isometric contractions (MVICs) of hip and knee extensor and flexor during breath-hold at full inspiration (inspiratory condition) or expiration (expiratory condition), or during normal breath-hold (normal condition). Intra-abdominal pressure was obtained by a pressure transducer placed in the rectum and determined at the time at which the developed torque reached to the maximum. The IAP during each MVIC was significantly greater in inspiratory condition than in expiratory condition (p < 0.05). The maximal torque of hip extensor was significantly greater in inspiratory condition than in expiratory condition (p < 0.05). By contrast, the maximal torque of each of hip flexor, knee extensor, and knee flexor was not different among the 3 breath-hold conditions. The IAP was significantly correlated with the maximal torque of hip extensor in each breath-hold condition. The current results suggest that a sufficient increase in IAP has a causal effect to specifically improve muscle strength of hip extensor.
      PubDate: Fri, 01 Jan 2021 00:00:00 GMT-
       
  • Comparing Acceleration and Change of Direction Ability Between Backpedal
           and Cross-over Run Techniques for Use in American Football
    • Authors: Angelino; Domenic; McCabe, Thomas J.G.; Earp, Jacob E.
      Abstract: imageAngelino, D, McCabe, TJG, and Earp, JE. Comparing acceleration and change of direction ability between backpedal and cross-over run techniques for use in American football. J Strength Cond Res 35(1): 47–55, 2021—In American football, defensive backs guard receivers using either cross-over (CO) run or backpedal (BP) techniques, but the efficacy of these techniques is unknown. The purpose of this study was to compare linear acceleration (LA) and change of direction (CoD) ability when using CO and BP. Collegiate football defensive backs participated in LA (n = 13) and CoD (n = 7) testing. During LA, subjects performed CO, BP, and forward sprints with split times taken between 0–3 and 3–5 yd and ground reaction forces recorded 0 and 3 yd from the start. During CoD testing, subjects performed the CO or BP for 3 yd and then were given a cue to sprint to a gate 5 yd away in 1 of 4 directions (downfield, midfield, sideline, or upfield). In LA, CO was faster than BP between 0–3 yd (Δ −0.20 ± 0.02 seconds, p = 0.000) and 3–5 yd (Δ −0.12 ± 0.02 seconds, p = 0.000). At the start of the movement, CO demonstrated greater propulsive forces (p = 0.017). However, 3 yd from the start, CO demonstrated greater propulsive forces and reduced braking forces (p = 0.000 & 0.003). In CoD, CO was faster than BP when running in the downfield (Δ 0.21 ± 0.05 seconds, p = 0.044) and lateral directions (Δ 0.21 ± 0.08 seconds, p = 0.035), but similar in the upfield direction (Δ 0.01 ± 0.08, p = 0.986). Our results indicate that CO is superior to BP in LA, CoD ability, and movement efficiency and support the use of CO for defensive backs.
      PubDate: Fri, 01 Jan 2021 00:00:00 GMT-
       
  • Vertical and Horizontal Asymmetries Are Related to Slower Sprinting and
           Jump Performance in Elite Youth Female Soccer Players
    • Authors: Bishop; Chris; Read, Paul; McCubbine, Jermaine; Turner, Anthony
      Abstract: imageBishop, C, Read, P, McCubbine, J, and Turner, A. Vertical and horizontal asymmetries are related to slower sprinting and jump performance in elite youth female soccer players. J Strength Cond Res 35(1): 56–63, 2021—Interlimb asymmetries have been shown to be greater during vertical jumping compared with horizontal jumping. Notable interlimb differences have also been established at an early age in male youth soccer players. Furthermore, given the multiplanar nature of soccer, establishing between-limb differences from multiple jump tests is warranted. At present, a paucity of data exists regarding asymmetries in youth female soccer players and their effects on physical performance. The aims of this study were to quantify interlimb asymmetries from unilateral jump tests and examine their effects on speed and jump performance. Nineteen elite youth female soccer players performed a single-leg countermovement jump (SLCMJ), single, triple, and crossover hops for distance, and a 20-m sprint test. Test reliability was good to excellent (intraclass correlation coefficient = 0.81–0.99) and variability acceptable (coefficient of variation = 1.74–5.42%). A 1-way analysis of variance highlighted larger asymmetries from the SLCMJ compared with all other jump tests (p < 0.05). Pearson's correlations portrayed significant relationships between vertical asymmetries from the SLCMJ and slower sprint times (r = 0.49–0.59). Significant negative relationships were also found between horizontal asymmetries during the triple hop test and horizontal jump performance (r = −0.47 to −0.58) and vertical asymmetries during the SLCMJ and vertical jump performance (r = −0.47 to −0.53). The results from this study highlight that the SLCMJ seems to be the most appropriate jump test for identifying between-limb differences with values ∼12% showing negative associations with sprint times. Furthermore, larger asymmetries are associated with reduced jump performance and would appear to be direction specific. Practitioners can use this information as normative data to be mindful of when quantifying interlimb asymmetries and assessing their potential impact on physical performance in youth female soccer players.
      PubDate: Fri, 01 Jan 2021 00:00:00 GMT-
       
  • Sex Comparison of Knee Extensor Size, Strength, and Fatigue Adaptation to
           Sprint Interval Training
    • Authors: Bagley; Liam; Al-Shanti, Nasser; Bradburn, Steven; Baig, Osamah; Slevin, Mark; McPhee, Jamie S.
      Abstract: imageBagley, L, Al-Shanti, N, Bradburn, S, Baig, O, Slevin, M, and McPhee, JS. Sex comparison of knee extensor size, strength, and fatigue adaptation to sprint interval training. J Strength Cond Res 35(1): 64–71, 2021—Regular sprint interval training (SIT) improves whole-body aerobic capacity and muscle oxidative potential, but very little is known about knee extensor anabolic or fatigue resistance adaptations, or whether effects are similar for men and women. The purpose of this study was to compare sex-related differences in knee extensor size, torque-velocity relationship, and fatigability adaptations to 12-week SIT. Sixteen men and 15 women (mean [SEM] age: 41 [±2.5] years) completed measurements of total body composition assessed by dual energy X-ray absorptiometry, quadriceps muscle cross-sectional area (CSAQ) assessed by magnetic resonance imaging, the knee extensor torque-velocity relationship (covering 0–240°·s−1) and fatigue resistance, which was measured as the decline in torque from the first to the last of 60 repeated concentric knee extensions performed at 180°·s−1. Sprint interval training consisted of 4 × 20-second sprints on a cycle ergometer set at an initial power output of 175% of power at V̇o2max, 3 times per week for 12 weeks. Quadriceps muscle cross-sectional area increased by 5% (p = 0.023) and fatigue resistance improved 4.8% (p = 0.048), with no sex differences in these adaptations (sex comparisons: p = 0.140 and p = 0.282, respectively). Knee extensor isometric and concentric torque was unaffected by SIT in both men and women (p> 0.05 for all velocities). Twelve-week SIT, totaling 4 minutes of very intense cycling per week, significantly increased fatigue resistance and CSAQ similarly in men and women, but did not significantly increase torque in men or women. These results suggest that SIT is a time-effective training modality for men and women to increase leg muscle size and fatigue resistance.
      PubDate: Fri, 01 Jan 2021 00:00:00 GMT-
       
  • Moderate Load Resisted Sprints Do Not Improve Subsequent Sprint
           Performance in Varsity-Level Sprinters
    • Authors: Thompson; Kyle M.A.; Whinton, Alanna K.; Ferth, Shane; Spriet, Lawrence L.; Burr, Jamie F.
      Abstract: imageThompson, K, Whinton, AK, Ferth, S, Spriet, LL, and Burr, JF. Moderate load resisted sprints do not improve subsequent sprint performance in varsity-level sprinters. J Strength Cond Res 35(1): 72–77, 2021—Resisted sprint training (RST) is commonly used for performance enhancement in athletics and team sports to develop acceleration ability. Evidence suggests that RST may be effective as a short-term intervention to improve successive sprints. Although these improvements have been measured in team sport athletes, limited research has considered the acute effects of RST training in sprint-trained athletes. Therefore, the aim of the current study was to determine whether performing RST with varsity-level sprinters using sled-equivalent resistive loads of ∼45% body mass results in a potentiation effect, leading to improvements in subsequent maximal sprint performance over 0–5 m and 0–20 m. Competitive sprinters (n = 20) were randomly assigned to perform a pre/post maximal 20-m sprint separated by either 3 resisted (RST group) or unresisted (URS group) sprints. The RST or URS protocol was performed on 4 occasions separated by at least 7 days. No significant differences were observed between the RST and URS groups comparing changes in sprint times over 0–5 m (URS Δ
      PubDate: Fri, 01 Jan 2021 00:00:00 GMT-
       
  • Absolute Reliability and Concurrent Validity of the Stryd System for the
           Assessment of Running Stride Kinematics at Different Velocities
    • Authors: García-Pinillos; Felipe; Roche-Seruendo, Luis E.; Marcén-Cinca, Noel; Marco-Contreras, Luis A.; Latorre-Román, Pedro A.
      Abstract: imageGarcía-Pinillos, F, Roche-Seruendo, LE, Marcen-Cinca, N, Marco-Contreras, LA, and Latorre-Román, PA. Absolute reliability and concurrent validity of the Stryd system for the assessment of running stride kinematics at different velocities. J Strength Cond Res 35(1): 78–84, 2021—This study aimed to determine the absolute reliability and to evaluate the concurrent validity of the Stryd system for measuring spatiotemporal variables during running at different velocities (8–20 km·h−1) by comparing data with another widely used device (the OptoGait system). Eighteen trained male endurance runners performed an incremental running test (8–20 km·h−1 with 3-minute stages) on a treadmill. Spatiotemporal parameters (contact time [CT], flight time [FT], step length [SL], and step frequency [SF]) were measured using 2 different devices (Stryd and OptoGait systems). The Stryd system showed a coefficient of variation (CV) 0.7; ∼7–65%), whereas SL and SF were very similar between systems (ES < 0.1, with differences
      PubDate: Fri, 01 Jan 2021 00:00:00 GMT-
       
  • Improving the Signal-To-Noise Ratio When Monitoring Countermovement Jump
           Performance
    • Authors: Kennedy; Rodney A.; Drake, David
      Abstract: imageKennedy, RA and Drake, D. Improving the signal-to-noise ratio when monitoring countermovement jump performance. J Strength Cond Res 35(1): 85–90, 2021—Countermovement jump (CMJ) performance has been routinely used to monitor neuromuscular status. However, the protocol used to establish the criterion score is not well documented. The purpose of this study was to examine how the protocol used would influence of the sensitivity of CMJ variables in rugby union players. Fifteen male (age: 19.7 ± 0.5 years) rugby union players performed 8 CMJs on 2 occasions, separated by 7 days. The between-session coefficient of variation (CV) was calculated using 2 techniques for treating multiple trials, the average, and the trial with the best jump height (JH), and then compared with the smallest worthwhile change (SWC). The signal-to-noise ratio was measured as the group mean change in a variable divided by the CV. Using the average value across multiple trials is superior to the best trial method, based on lower CVs for all variables. Only the average performance across 6 or more trials was classified as ideal (CV < 0.5 × SWC) for peak velocity (PV). In addition, the signal-to-noise ratio for peak concentric power (PCP), PV, and JH were classified as good, irrespective of the treatment method. Although increasing the number of trials can reduce the random error, it may be pragmatic to simply take the average from 2 to 3 trials, facilitating a CV < SWC for PV, PCP, and JH. Due to its simplicity, JH may be considered the principal variable to monitor neuromuscular fatigue.
      PubDate: Fri, 01 Jan 2021 00:00:00 GMT-
       
  • Self-selected Rest Interval Improves Vertical Jump Postactivation
           Potentiation
    • Authors: do Carmo; Everton C.; De Souza, Eduardo O.; Roschel, Hamilton; Kobal, Ronaldo; Ramos, Henrique; Gil, Saulo; Tricoli, Valmor
      Abstract: imagedo Carmo, EC, De Souza, EO, Roschel, H, Kobal, R, Ramos, H, Gil, S, and Tricoli, V. Self-selected rest interval improves vertical jump postactivation potentiation. J Strength Cond Res 35(1): 91–96, 2021—This study compared the effects of self-selected rest interval (SSRI) and fixed rest interval (FRI) strategies on postactivation potentiation (PAP) in countermovement jump (CMJ) performance. Twelve strength-trained men (age: 25.4 ± 3.6 years; body mass: 78.8 ± 10.5 kg; height: 175 ± 7.0 cm; half-squat 1 repetition maximum: 188.7 ± 33.4 kg) performed 3 experimental conditions: (a) FRI: CMJ test; 4-minute rest interval; 5 repetition maximum (5RM) back squat; 4-minute rest interval; and CMJ test, (b) SSRI: CMJ test; 4-minute rest interval; 5RM back squat; SSRI; and CMJ test, and (c) control: CMJ test; 8-minute rest interval and CMJ test. In SSRI, subjects were instructed to rest until they felt fully recovered and able to exercise at maximal intensity based on the perceived readiness scale. Significant changes in pre-post CMJ performance were observed in the SSRI condition (38.2 ± 4.6 cm vs. 40.5 ± 4.4 cm; p = 0.08; confidence interval [CI]: 0.72–3.82 cm; effect size [ES] = 0.93). There were significant differences in post-CMJ performance when SSRI was compared with FRI (40.5 ± 4.4 cm vs. 37.7 ± 5.1 cm; p = 0.02; CI: 0.43–5.08; ES = 1.13) and control (40.5 ± 4.4 cm vs. 37.4 ± 5.7 cm; p = 0.01; CI: 0.66–5.61; ES = 1.35). The average rest interval length for the SSRI condition was 5:57 ± 2:44 min:sec (CI: 4:24–7:30). Our results suggest that the use of SSRI was an efficient and practical strategy to elicit PAP on CMJ height in strength-trained individuals.
      PubDate: Fri, 01 Jan 2021 00:00:00 GMT-
       
  • Contributions of Lower-Body Strength Parameters to Critical Power and
           Anaerobic Work Capacity
    • Authors: Byrd; M. Travis; Wallace, Brian J.; Clasey, Jody L.; Bergstrom, Haley C.
      Abstract: imageByrd, MT, Wallace, BJ, Clasey, JL, and Bergstrom, HC. Contributions of lower-body strength parameters to critical power and anaerobic work capacity. J Strength Cond Res 35(1): 97–101, 2021—This study examined the contribution of lower-body strength and isokinetic peak torque measures to the prediction of critical power (CP) and anaerobic work capacity (AWC). Fourteen recreationally trained males (mean ± SD age: 22.4 ± 2.5 years; height: 177.9 ± 7.7 cm; body mass: 84.2 ± 12.4 kg) with anaerobic training experience participated in this study. The lower-body strength measures included 1 repetition max bilateral back squat (BSq), isokinetic peak torque at 30°·s−1 [PT30], and isokinetic peak torque at 240°·s−1 [PT240] of the dominant leg. The CP and AWC were determined from the 3-minute all-out CP cycle ergometer test (CP3MT), with the resistance set at 4.5% of the total body mass. The CP was defined as the mean power output over the final 30 seconds of the test, and the AWC was calculated using the equation, AWC = 150 seconds (P150 − CP), where P150 equals the mean power output for the first 150 seconds. Stepwise regression analyses indicated that only BSq contributed significantly to the prediction of AWC (AWC = 0.0527 [BSq] + 8.094 [standard error of estimate = 2.151 kJ; p = 0.012]), with a correlation of r2 = 0.423. None of the strength parameters significantly predicted CP. These findings indicated that BSq strength accounted for 42% of the variance in AWC, but lower-body strength was not related to CP. The current results indirectly support the unique metabolic characteristics of both CP and AWC in providing separate measures of an individual's aerobic and anaerobic capabilities, respectively.
      PubDate: Fri, 01 Jan 2021 00:00:00 GMT-
       
  • The Effectiveness of a Functional Movement Assessment and 4-Week Exercise
           Training Program for Female High School Athletes
    • Authors: Boucher; Brenda; Rich, Angela; Gobert, Denise; Gardner, Bret; Metzner, Paul; King, Chris; Buse, Michael
      Abstract: imageBoucher, BK, Rich, AJ, Gobert, D, Gardner, B, Metzner, P, King, C, and Buse, M. The effectiveness of a functional movement assessment and 4-week exercise training program for female high school athletes. J Strength Cond Res 35(1): 102–110, 2021—The extent to which young females participate in school-sponsored athletics has grown significantly over the past 2 decades. The number of females in high school sports increased for the 25th consecutive year in 2012–2013, reaching an all-time record. Unfortunately, sports-related injury rates for female athletes have also continued to rise. A body of research exists to suggest that dysfunctional movement may be linked to increased risk of injury, and training programs designed to improve movement patterns are effective to both enhance performance and reduce the risk of injury. Effective training programs incorporate corrective exercises to retrain dysfunctional movement patterns. The Functional Movement ScreenTM (FMSTM) is a tool developed to assess 7 fundamental movement patterns. The FMSTM has been used extensively with a wide range of athletes at various levels of performance. The aim of this study was to investigate the effectiveness of a movement-training program with female high school athletes using the FMSTM. The overall purpose was to assess the effectiveness of a 4-week corrective exercise-training program at improving FMSTM scores. Data analysis using Wilcoxon signed-rank test revealed a statistically significant change in total group FMSTM scores (Z = −2.214, p = 0.027) after the corrective exercise-training program. Mean total group FMSTM scores increased from 14.43 ± 1.90 (pretest) to 17.29 ± 1.38 (posttest). Findings suggest that positive outcomes to a corrective exercise-training program, which targets specific movement impairments, can be achieved in a relatively short period of time.
      PubDate: Fri, 01 Jan 2021 00:00:00 GMT-
       
  • Electrical Stimulation of the Antagonist Muscle During Cycling Exercise
           Interval Training Improves Oxygen Uptake and Muscle Strength
    • Authors: Hashida; Ryuki; Takano, Yoshio; Matsuse, Hiroo; Kudo, Mei; Bekki, Masafumi; Omoto, Masayuki; Nago, Takeshi; Kawaguchi, Takumi; Torimura, Takuji; Shiba, Naoto
      Abstract: imageHashida, R, Takano, Y, Matsuse, H, Kudo, M, Bekki, M, Omoto, M, Nago, T, Kawaguchi, T, Torimura, T, and Shiba, N. Electrical stimulation of the antagonist muscle during cycling exercise interval training improves oxygen uptake and muscle strength. J Strength Cond Res 35(1): 111–117, 2021—A hybrid training system (HTS) is a resistance exercise method that combines voluntary concentric muscle contractions and electrically stimulated eccentric muscle contractions. We devised an exercise technique using HTS on cycle ergometer (HCE). The purpose of this study was to compare cardiorespiratory function and muscle strength when cycling exercise is combined with electrical stimulation over an extended period. Twenty-nine healthy young men were divided into an HCE group (n = 14) and a volitional cycle ergometer (VCE alone) group (n = 15). All subjects performed 30-minute cycling exercise interval training sessions 3 times a week for 6 weeks. The V̇o2peak of both groups significantly increased compared with the pretraining period (HCE group: from 31.3 ± 4.4 [ml·kg−1·min−1] pretraining to 37.6 ± 6.7 [ml·kg−1·min−1] post-training [p = 0.0024] and VCE group: from 34.0 ± 7.1 [ml·kg−1·min−1] pretraining to 38.4 ± 8.2 [ml·kg−1·min−1] [p = 0.0057]). After the training, there was no significant difference of changes in V̇o2peak between the HCE and the VCE groups (p = 0.7107). In the VCE group, the maximal isokinetic torque of knee extension (60°·s−1) post-training did not significantly increase compared with the pretraining period (VCE group: from 2.4 ± 0.5 [N·m·kg−1] pretraining to 2.5 ± 0.4 [N·m·kg−1] [p = 0.4543]). By contrast, in the HCE group, the maximal isokinetic torque of knee extension (60°·s−1) post-training significantly increased compared with pretraining period (HCE group: from 2.5 ± 0.3 [N·m·kg−1] pretraining to 2.8 ± 0.3 [N·m·kg−1] [p < 0.0001]). The change in knee extension torque was significantly greater for the HCE group than for the VCE group (p = 0.0307). In conclusion, cardiopulmonary function and knee extension strength were improved by the use of HCE.
      PubDate: Fri, 01 Jan 2021 00:00:00 GMT-
       
  • Trunk Muscle Endurance in Individuals With and Without a History of
           Anterior Cruciate Ligament Reconstruction
    • Authors: Werner; David M.; Barrios, Joaquin A.
      Abstract: imageWerner, DM and Barrios, JA. Trunk muscle endurance in individuals with and without a history of anterior cruciate ligament reconstruction. J Strength Cond Res 35(1): 118–123, 2021—Anterior cruciate ligament (ACL) rupture is one of the most common knee injuries and often leads to surgery. Second injury after an ACL reconstruction (ACLR) is a major risk after rehabilitation, and may be linked to persistent postoperative deficits in muscular strength and endurance. Trunk muscle endurance has not been well studied after ACLR. Therefore, the purpose of this study was to compare trunk endurance using the established McGill testing battery in 20 individuals who had previously undergone ACLR at least 1 year before with 20 controls matched for sex frequency, limb dominance, age, body mass index, and activity level. Four static positional holds to failure were performed in random order, with time in seconds recorded as the primary dependent variable. Mann-Whitney U tests using an alpha level of 0.05 were conducted comparing hold times for all positions between groups. Effect sizes were also calculated between groups. Deficits in trunk extension endurance were observed in the surgical group. The results of this study suggest that contemporary rehabilitation schemes after ACLR do not fully address trunk endurance deficits. Health care professionals delivering postoperative rehabilitation after ACLR may consider direct assessment of trunk endurance and targeted exercise training to address potential deficits.
      PubDate: Fri, 01 Jan 2021 00:00:00 GMT-
       
  • Post-Exercise Ingestion of Low or High Molecular Weight Glucose Polymer
           Solution Does Not Improve Cycle Performance in Female Athletes
    • Authors: Mock; Meredith G.; Hirsch, Katie R.; Blue, Malia N.M.; Trexler, Eric T.; Roelofs, Erica J.; Smith-Ryan, Abbie E.
      Abstract: imageMock, MG, Hirsch, KR, Blue, MNM, Trexler, ET, Roelofs, EJ, and Smith-Ryan, AE. Postexercise ingestion of low or high molecular weight glucose polymer solution does not improve cycle performance in female athletes. J Strength Cond Res 35(1): 124–131, 2021—The current study sought to evaluate the effects of postexercise ingestion of a high molecular weight (HMW) glucose polymer solution compared with an isocaloric low molecular weight (LMW) solution or placebo (PLA) on subsequent cycling performance in female athletes. In a randomized, double-blind, placebo-controlled, cross-over design, 10 competitive female cyclists (Mean ± SD; Age = 25.7 ± 5.0 years; V̇o2peak = 49.7 ± 4.3 ml·kg−1·min−1) completed 3 testing sessions separated by 7–10 days. Visits consisted of a ride-to-exhaustion (RTE) at 75% V̇o2peak, followed by immediate consumption of 700 ml containing either: 1.2 g·kg−1 LMW (maltodextrin/dextrose/fructose); 1.2 g·kg−1 HMW (Vitargo); or 0.066 g·kg−1 PLA (noncaloric flavoring). After 2 hours of rest, subjects performed a 15-minute time trial (TT). Respiratory exchange ratio (RER) was assessed via indirect calorimetry during exercise. Total body water (TBW) was measured using bioelectrical impedance to assess fluid balance. When covaried for estrogen, there was no treatment effect on distance (km; p = 0.632) or power output (watts; p = 0.974) during the 15-minute TT. Respiratory exchange ratio was not significantly different during the LMW and HWM TTs (p> 0.999), but both were significantly higher than PLA (p = 0.039, p = 0.001, respectively). Changes in total body water pre-exercise to postexercise were not significantly different between trials (p = 0.777). Despite benefits of HMW on cycling performance previously reported in males, current results demonstrate no ergogenic effect of HMW or LMW in females. Sex differences in substrate utilization may account for the discrepancy, and further research involving performance nutrition for female athletes is merited.
      PubDate: Fri, 01 Jan 2021 00:00:00 GMT-
       
  • Total Sleep Deprivation and Recovery Sleep Affect the Diurnal Variation of
           Agility Performance: The Gender Differences
    • Authors: Romdhani; Mohamed; Hammouda, Omar; Smari, Khawla; Chaabouni, Yassine; Mahdouani, Kacem; Driss, Tarak; Souissi, Nizar
      Abstract: imageRomdhani, M, Hammouda, O, Smari, K, Chaabouni, Y, Mahdouani, K, Driss, T, and Souissi, N. Total sleep deprivation and recovery sleep affect the diurnal variation of agility performance: The gender differences. J Strength Cond Res 35(1): 132–140, 2021—This study aimed to investigate the effects of time-of-day, 24 and 36 hours of total sleep deprivation (TSD), and recovery sleep (RS) on repeated-agility performances. Twenty-two physical education students (11 male and 11 female students) completed 5 repeated modified agility T-test (RMAT) sessions (i.e., 2 after normal sleep night [NSN] [at 07:00 and 17:00 hours], 2 after TSD [at 07:00 hours, i.e., 24-hour TSD and at 17:00 hours, i.e., 36-hour TSD], and 1 after RS at 17:00 hours). The RMAT index decreased from the morning to the afternoon after NSN (p < 0.05, d = 1.05; p < 0.01, d = 0.73) and after TSD (p < 0.001, d = 0.92; d = 1.08), respectively, for total time (TT) and peak time (PT). This finding indicates a diurnal variation in repeated agility, which persisted after TSD. However, the diurnal increase in PT was less marked in the female group after NSN (2.98 vs. 6.24%). Moreover, TT and PT increased, respectively, after 24-hour TSD (p < 0.001; d = 0.84, d = 0.87) and 36-hour TSD (p < 0.001, d = 1.12; p < 0.01, d = 0.65). Female subjects' PT was less affected by 24-hour TSD (1.76 vs. 6.81%) compared with male subjects' PT. After 36-hour TSD, the amount of decrease was not different between groups, which increased the diurnal amplitude of PT only for male subjects. Total sleep deprivation suppressed the diurnal increase of PT and increased the diurnal amplitude of oral temperature only in women. Nevertheless, RS normalized the sleep-loss–induced performance disruption. Conclusively, sleep loss and RS differently affect repeated-agility performance of men and women during the day. Sleep extension postdeprivation could have potent restorative effect on repeated-agility performances, and female subjects could extract greater benefits.
      PubDate: Fri, 01 Jan 2021 00:00:00 GMT-
       
  • Effects of Active and Passive Warm-ups on Range of Motion, Strength, and
           Muscle Passive Properties in Ankle Plantarflexor Muscles
    • Authors: Takeuchi; Kosuke; Takemura, Masahiro; Nakamura, Masatoshi; Tsukuda, Fumiko; Miyakawa, Shumpei
      Abstract: imageTakeuchi, K, Takemura, M, Nakamura, M, Tsukuda, F, and Miyakawa, S. Effects of active and passive warm-ups on range of motion, strength, and muscle passive properties in ankle plantarflexor muscles. J Strength Cond Res 35(1): 141–146, 2021—The purpose of this study was to examine the effects of active and passive warm-ups on flexibility and strength of calf muscles. Fourteen healthy males (age: 23.1 ± 2.6 years, height: 172.7 ± 5.6 cm, and body mass: 64.5 ± 7.0 kg) performed 3 types of warm-ups respectively for 10 minutes in a random order: an active warm-up by pedaling a cycling ergometer, an active warm-up doing repeated isometric contractions, and a passive warm-up in a hot water bath. To assess flexibility, range of motion (ROM) of ankle dorsiflexion, passive torque of ankle plantarflexion, and muscle tendon junction (MTJ) displacement were measured and then muscle tendon unit (MTU) stiffness was calculated. After the flexibility assessment, peak torque during maximum voluntary isometric contraction was measured to assess the isometric strength. These data were compared before and after each warm-up. As a result, all 3 types of warm-ups increased ROM (p < 0.05) and passive torque at terminal ROM (p < 0.01), but there were no significant changes in MTU stiffness or MTJ displacement. The active warm-up by pedaling a cycling ergometer increased peak torque during isometric contraction (p < 0.05), whereas the other warm-ups did not show significant alterations. In conclusion, the active warm-up with aerobic exercise increased flexibility and strength of the calf muscles.
      PubDate: Fri, 01 Jan 2021 00:00:00 GMT-
       
  • Acute Effects of Ballistic vs. Passive Static Stretching Involved in a
           Prematch Warm-up on Vertical Jump and Linear Sprint Performance in Soccer
           Players
    • Authors: López Mariscal; Samuel; Sánchez Garcia, Víctor; Fernández-García, José C.; Sáez de Villarreal, Eduardo
      Abstract: imageLópez Mariscal, S, Sánchez Garcia, V, Fernández-García, JC, and Sáez de Villarreal, E. Acute effects of ballistic vs. passive static stretching involved in a prematch warm-up on vertical jump and linear sprint performance in soccer players. J Strength Cond Res 35(1): 147–153, 2021—The purpose of this study was to compare the effects of introducing passive static and ballistic stretching in a standard soccer match warm-up. The variables addressed were the counter movement jump (CMJ), Abalakov jump, and the 40-m linear sprint. The sample was composed of 33 male subjects, divided into 2 age groups. U16 and adult players formed the groups, to cross check whether there were differences between them. Each group was further subdivided into 2 groups regarding the type of stretching carried out during the stretching phase. Before the warm-up, the tests previously described were assessed. In the experimental phase, standard stretching was carried out, consisting of an initial phase in which players had to execute continuous running; a general phase in which players had to make articulate moves; a technical phase in which players had to execute exercises with the ball; a 5 vs. 5 small-sided game was carried out during the tactical phase; and in the final phase, activation exercises and sprints were carried out by the players. Eventually, the same variables were assessed again once the warm-up was finished. There were no statistically significant differences between the 2 types of stretching included in the prematch warm-up. It can be concluded that ballistic and passive static stretching (
      PubDate: Fri, 01 Jan 2021 00:00:00 GMT-
       
  • A Comparison of Training Modality and Total Genotype Scores to Enhance
           Sport-Specific Biomotor Abilities in Under 19 Male Soccer Players
    • Authors: Suraci; Bruce R.; Quigley, Charlie; Thelwell, Richard C.; Milligan, Gemma S.
      Abstract: imageSuraci, BR, Quigley, C, Thelwell, RC, and Milligan, GS. A comparison of training modality and total genotype scores to enhance sport-specific biomotor abilities in under 19 male soccer players. J Strength Cond Res 35(1): 154–161, 2021—Soccer-specific training (SST) and small-sided games (SSGs) have been shown to develop physical proficiency in soccer. Research on genetics and epigenetics in the prescription of training is limited. The aims of this study were to compare the impact of 3 different SST/SSG methods and investigate if a total genotype score (TGS) influences training response. Subjects (n = 30 male soccer players, mean ± SD; age 17.2 ± 0.9 years, stature = 172.6 ± 6.2 cm; body mass = 71.7 ± 10.1 kg) were stratified into a “power” (PG) or “endurance” (EG) gene profile group, where a 15 single nucleotide polymorphism panel was used to produce an algorithmically weighted TGS. Training 1 (T1—SSGs only), training 2 (T2—SSGs/SST), and training 3 (T3—SST only) were completed (in that respective order), lasting 8 weeks each, interspersed by 4-week washouts. Acceleration (10-m sprint) was improved by T2 only (1.84 ± 0.09 seconds vs. 1.73 ± 0.05 seconds; Effect Size [ES] = 1.59, p < 0.001). Speed (30-m sprint) was improved by T2 (4.46 ± 0.22 seconds vs. 4.30 ± 0.19 seconds; ES = 0.81, p < 0.001) and T3 (4.48 ± 0.22 seconds vs. 4.35 ± 0.21 seconds; ES = 0.58, p < 0.001). Agility (T-test) was improved by T1 (10.14 ± 0.40 seconds vs. 9.84 ± 0.42 seconds; ES = 0.73, p < 0.05) and T3 (9.93 ± 0.38 seconds vs. 9.66 ± 0.45 seconds; ES = 0.66, p < 0.001). Endurance (Yo-Yo level 1) was improved by T1 (1,682.22 ± 497.23 m vs. 2,028.89 ± 604.74 m; ES = 0.63, p < 0.05), T2 (1,904.35 ± 526.77 m vs. 2,299.13 ± 606.97 m; ES = 0.69, p < 0.001), and T3 (1,851.76 ± 490.46 m vs. 2,024.35 ± 588.13 m; ES = 0.35, p < 0.05). Power (countermovement jump) was improved by T3 only (36.01 ± 5.73 cm vs. 37.14 ± 5.62 cm; ES = 0.20, p < 0.05). There were no differences in T1, T2, and T3 combined when comparing PG and EG. The PG reported significantly (χ2(20) = 4.42, p = 0.035, ES = 0.48) better training responses to T3 for power than the EG. These results demonstrate the efficacy of SSGs and SSTs in developing biomotor abilities. Although these results refute talent identification through the use of a TGS, there may be use in aligning the training method to TGS to develop power-based qualities in soccer.
      PubDate: Fri, 01 Jan 2021 00:00:00 GMT-
       
  • Match Running Performance of Elite Soccer Players: V̇o2max and
           Players Position Influences
    • Authors: Metaxas; Thomas I.
      Abstract: imageMetaxas, TI. Match running performance of elite soccer players: V̇o2max and players position influences. J Strength Cond Res 35(1): 162–168, 2021—The aims of this study were (a) to assess the relationship between laboratory-measured V̇o2max with total distance covered in a soccer match, (b) to assess the relationship between laboratory-measured V̇o2max with the distance covered at a different running intensity in a soccer match, (c) to quantify different intensity running in various playing positions, and (d) to determine the differences of running performance between halves. Analyzed match running performance of the Greek elite (n = 14) soccer players using a global positioning system within the second division professional league. No correlation was found between V̇o2max and match running performance at any velocity. The players covered greater distances in the first half at all speed levels except walking. In the first half, they covered a greater distance than in the second half (1,533 vs. 1,297 m, p < 0.001; 879 vs. 708 m, p < 0.001; 433 vs. 359 m, p < 001; 185 vs. 152 m, p < 0.01; 81.4 vs. 65.5 m, p < 0.001) when jogging, running, high-intensity running, fast running, sprint and total, respectively. Wide players covered greater distances at fast running (p < 0.001) and sprint zone than the players who played at the axon of the field (348 vs. 297 and 186 vs. 113 m, respectively). In addition, midfielders covered a greater distance at high-intensity running zone and at fast running zone than the defenders and forwards (1,768 vs. 1,372 m, p < 0.01 and 1,768 vs. 1,361 m, p < 0.01; 686 vs. 878 m, p < 0.01 and 709 vs. 878 m, p < 0.05, respectively). The results demonstrate that match running performance and the distance covered depends on the tactical role of each player in the team. These data provide valuable information for coaches regarding the running profile of the Greek elite soccer players that could be used to design a more effective training program.
      PubDate: Fri, 01 Jan 2021 00:00:00 GMT-
       
  • Match-Play Running Demands and Technical Performance Among Elite Gaelic
           Footballers: Does Divisional Status Count'
    • Authors: McGahan; Jason H.; Mangan, Shane; Collins, Kieran; Burns, Con; Gabbett, Tim; O'Neill, Cian
      Abstract: imageMcGahan, JH, Mangan, S, Collins, K, Burns, C, Gabbett, T, and O'Neill, C. Match-play running demands and technical performance among elite Gaelic footballers: Does divisional status count? J Strength Cond Res 35(1): 169–175, 2021—The aim of the current study was to compare positional differences in running demands and technical performance variables among elite Gaelic football teams from separate divisions. Data were obtained from a division 1 (26.7 ± 2.9 years, 179.2 ± 21.3 cm, 89.9 ± 21.2 kg) and a division 3 (25.7 ± 3.5 years, 183.0 ± 4.7 cm, 84.4 ± 6.5 kg) team. Match-play running variables were collected using 4-Hz global positioning system (GPS) units (VX Sport; Visuallex Sport, Lower Hutt, New Zealand) (Match data sets; division 1: n = 107, division 3: n = 97). Selected variables assessed were high-speed running distance (HSR) (≥17 km·h−1), number of high-speed efforts (HSE) (≥17 km·h−1), relative high-speed distance (RHSD) (≥17 km·h−1; m·min−1), and percentage of time at high speed (%HS). Each variable was analyzed across the 5 positional groups in Gaelic football (full back, half back, midfield, half forward, full forward). The same 25 competitive games were analyzed using the GPS and the Sports Code video analysis system (Sports Code Elite V9; Sportstec, Warriewood, NSW, Australia). Technical performance variables selected for analysis were total kick/hand passes, tackles, shots, and percentage of time in possession. High-speed running distance running demands were differentiated between the divisions; the division 3 team demonstrated significantly greater HSR, HSE, RHSD, and %HS than the division 1 team (p ≤ 0.05). Positional-specific analysis found that the division 3 full back and midfield positional lines had significantly greater HSR, RHSD, and %HS than their division 1 counterparts. The division 1 team made a greater number of total tackles, with significantly more tackles in the middle third (p ≤ 0.05). The division 3 team performed a significantly greater number of hand passes and unsuccessful shots per game (p < 0.01). The results of this study indicate that overall technical proficiency, rather than high-speed running profiles, differentiate division 1 and 3 Gaelic football teams.
      PubDate: Fri, 01 Jan 2021 00:00:00 GMT-
       
  • Concurrent Validity of a Rugby-Specific Yo-Yo Intermittent Recovery Test
           (Level 1) for Assessing Match-Related Running Performance
    • Authors: Dobbin; Nick; Highton, Jamie; Moss, Samantha L.; Hunwicks, Richard; Twist, Craig
      Abstract: imageDobbin, N, Highton, J, Moss, SL, Hunwicks, R, and Twist, C. Concurrent validity of a rugby-specific Yo-Yo intermittent recovery test (level 1) for assessing match-related running performance. J Strength Cond Res 35(1): 176–182, 2021—This study investigated the concurrent validity of a rugby-specific high-intensity intermittent running test against the internal, external, and perceptual responses to simulated match play. Thirty-six rugby league players (age 18.5 ± 1.8 years; stature 181.4 ± 7.6 cm; body mass 83.5 ± 9.8 kg) completed the prone Yo-Yo Intermittent Recovery Test (Yo-Yo IR1), of which 16 also completed the Yo-Yo IR1, and 2 × ∼20 minute bouts of a simulated match play (rugby league match simulation protocol for interchange players [RLMSP-i]). Most likely reductions in relative total, low-speed and high-speed distance, mean speed, and time above 20 W·kg−1 (high metabolic power [HMP]) were observed between bouts of the RLMSP-i. Likewise, rating of perceived exertion (RPE) and percentage of peak heart rate (%HRpeak) were very likely and likely higher during the second bout. Pearson's correlations revealed a large relationship for the change in relative distance (r = 0.57–0.61) between bouts with both Yo-Yo IR1 tests. The prone Yo-Yo IR1 was more strongly related to the RLMSP-i for change in repeated sprint speed (r = 0.78 cf. 0.56), mean speed (r = 0.64 cf. 0.36), HMP (r = 0.48 cf. 0.25), fatigue index (r = 0.71 cf. 0.63), %HRpeak (r = −0.56 cf. −0.35), RPEbout1 (r = −0.44 cf. −0.14), and RPEbout2 (r = −0.68 cf. −0.41) than the Yo-Yo IR1, but not for blood lactate concentration (r = −0.20 to −0.28 cf. −0.35 to −0.49). The relationships between prone Yo-Yo IR1 distance and measures of load during the RLMSP-i suggest that it possesses concurrent validity and is more strongly associated with measures of training or match load than the Yo-Yo IR1 using rugby league players.
      PubDate: Fri, 01 Jan 2021 00:00:00 GMT-
       
  • Speed Demands of Women's Rugby Sevens Match Play
    • Authors: Misseldine; Nicole D.; Blagrove, Richard C.; Goodwin, Jon E.
      Abstract: imageMisseldine, ND, Blagrove, RC, and Goodwin, JE. Speed demands of women's rugby sevens match play. J Strength Cond Res 35(1): 183–189, 2021—The purpose of this study was to quantify the running speed demands of elite female rugby sevens match play, both absolute and relative to maximal ability, and determine the importance of maximal velocity running to performance. Individual maximal running velocity (Vmax) was established for 12 professional female rugby sevens athletes before the collection of global positioning system data during all 6 games of an international tournament. The subjective importance of each maximal velocity running effort was established using visual analogue scale ratings of video clips by coaches. Differences in velocity demands between backs and forwards were analyzed using a one-way multivariate analysis of variance, and differences in “sprint” distance using the typical-standard and female-adjusted sprint thresholds were compared using a paired-samples t-test. The mean peak velocity reached per game by all players was 90.6 ± 7.9% Vmax. Players covered 1,556 ± 233 m per game, with “sprinting” representing 6 ± 4% of this total distance using the typical-standard “sprint” threshold (5.6 m·s−1), but a significantly (p < 0.001) greater 12 ± 4% using the female-adjusted threshold (4.7 m·s−1). Despite similar total distances, backs reached significantly (p < 0.05) greater peak running velocity and covered more distance at sprint,>75% Vmax and>90% Vmax speeds when compared to forwards. More than half of the running efforts peaking at ≥90% Vmax were considered very influential to game outcomes. These findings suggest that maximal velocity running is important to female rugby sevens performance, and that high-speed demands are different for backs and forwards. Furthermore, the typical-standard sprint thresholds significantly underestimate the true running demands of female rugby sevens.
      PubDate: Fri, 01 Jan 2021 00:00:00 GMT-
       
  • Relationship Between Tennis Serve Velocity and Select Performance Measures
    • Authors: Hayes; Matthew J.; Spits, Dirk R.; Watts, David G.; Kelly, Vincent G.
      Abstract: imageHayes, MJ, Spits, DR, Watts, DG, and Kelly, VG. Relationship between tennis serve velocity and select performance measures. J Strength Cond Res 35(1): 190–197, 2021—The purpose of this study was to determine whether there was a relationship between tennis serve speed and isometric midthigh pull (IMTP) kinetic variables: countermovement jump (CMJ) height, shoulder internal and external rotation strength, and anthropometric measures in elite adolescent tennis players. Twenty-one elite junior tennis players from the Tennis Australia National Academy were recruited for this study (male, n = 12 and female, n = 9). Correlations between the performance variables and peak tennis serve speed were calculated using a Pearson's product-moment correlation coefficient. A significant positive correlation was found between peak serve speed and body height (r = 0.80, p < 0.01), IMTP peak force (r = 0.87, p < 0.01), CMJ height (r = 0.77, p ≤ 0.01), and impulse at 300 ms (r = 0.71, p ≤ 0.01). A significant, strong correlation was found between peak serve speed and impulse at 100 ms (r = 0.58, p ≤ 0.01), impulse at 200 ms (r = 0.64, p ≤ 0.01), internal rotation
      PubDate: Fri, 01 Jan 2021 00:00:00 GMT-
       
  • Kinematic Comparison of the Roundhouse Kick Between Taekwondo, Karate, and
           Muaythai
    • Authors: Diniz; Rossano; Del Vecchio, Fabrício B.; Schaun, Gustavo Z.; Oliveira, Henrique B.; Portella, Elisa G.; da Silva, Edson S.; Formalioni, Andressa; Campelo, Paula C.C.; Peyré-Tartaruga, Leonardo A.; Pinto, Stephanie S.
      Abstract: imageDiniz, R, Del Vecchio, FB, Schaun, GZ, Oliveira, HB, Portella, EG, da Silva, ES, Formalioni, A, Campelo, PCC, Peyré-Tartaruga, LA, and Pinto, SS. Kinematic comparison of the roundhouse kick between taekwondo, karate, and muaythai. J Strength Cond Res 35(1): 198–204, 2021—The roundhouse kick (RHK) is frequently executed in taekwondo, karate, and muaythai because of its high technical effectiveness during combat. The purpose of this study was to compare kinematic characteristics during RHK performance between taekwondo, karate, and muaythai athletes. Forty-seven male athletes (25.5 ± 4.7 years, 1.75 ± 0.1 m, and 75.8 ± 11.5 kg) volunteered to participate (taekwondo: 17; karate: 15; and muaythai: 15). Self-selected distance from target, mean and peak fifth metatarsus linear velocity (LV5mean; LV5peak), mean and peak hip (HAVmean; HAVpeak) and knee (KAVmean; KAVpeak) angular velocities, as well as target linear acceleration (TLA) were analyzed with a 3D video motion analysis system. Comparisons between modalities were performed with 1-way analysis of variances and Bonferroni's post hoc test (α = 0.05). Self-selected distance was lower in muaythai compared with taekwondo and karate (p < 0.001). Also, karate had greater LV5mean compared with muaythai (p = 0.001), and muaythai showed higher HAVmean than karate (p = 0.011). In addition, HAVpeak was greater in muaythai than in taekwondo and karate (p < 0.001). No differences were found for KAVmean, KAVpeak, and TLA. Although it is similarly described between modalities, RHK showed distinct kinematic characteristics between taekwondo, karate, and muaythai. Based on these results, coaches and athletes can improve their RHK technique according to the specificities of each combat sport. Specifically, it is suggested that combat strategies should aim to increase the distance from the opponent during combat for muaythai athletes, whereas taekwondo and karate athletes should focus on decreasing it.
      PubDate: Fri, 01 Jan 2021 00:00:00 GMT-
       
  • Energetics of Swimming With Hand Paddles of Different Surface Areas
    • Authors: Crocker; George H.; Moon, Joseph F.; Nessler, Jeff A.; Newcomer, Sean C.
      Abstract: imageCrocker, GH, Moon, JF, Nessler, JA, and Newcomer, SC. Energetics of swimming with hand paddles of different surface areas. J Strength Cond Res 35(1): 205–211, 2021—Hand paddles are one of the most common training aids used by the competitive swimmer, yet little is known regarding how hand paddle surface area affects the metabolic cost of transport (COT) while swimming. The purpose of this study was to determine how altering hand paddle size affects energy use during submaximal, front-crawl (i.e., freestyle) swimming. Twenty-six proficient, adult swimmers (13 men and 13 women) completed six 3-minute trials in a flume at a constant pace (102 cm·s−1; 1:38 per 100 m). Trials were performed in random order, using 1 of 5 pairs of hand paddles of different sizes or no paddles at all. Paddle surface areas were 201, 256, 310, 358, and 391 cm2 per hand. Without paddles, COT, arm cadence, and distance per stroke were 7.87 ± 1.32 J·kg−1·m−1, 29.4 ± 4.9 min−1, and 2.13 ± 0.34 m, which corresponded to a rate of oxygen consumption (V̇o2) of 23.3 ± 3.7 ml·kg−1·min−1 and a heart rate (HR) of 118 ± 17 b·min–1. The use of larger hand paddles decreased COT, cadence, V̇o2, and HR and increased distance traveled per stroke (all p < 0.001). However, the magnitude of the change of COT decreased as paddle size increased, indicating diminishing marginal return with increasing paddle surface area. The largest sized paddles increased COT per stroke compared with swimming without paddles (p = 0.001). Therefore, results from this study suggest that an optimal hand paddle size exists (210–358 cm2) for proficient, adult swimmers, which reduces COT without increasing COT per stroke.
      PubDate: Fri, 01 Jan 2021 00:00:00 GMT-
       
  • Tethered Swimming Test: Reliability and the Association With Swimming
           Performance and Land-Based Anaerobic Performance
    • Authors: Nagle Zera; Jacquelyn; Nagle, Elizabeth F.; Nagai, Takashi; Lovalekar, Mita; Abt, John P.; Lephart, Scott M.
      Abstract: imageNagle Zera, J, Nagle, EF, Nagai, T, Lovalekar, M, Abt, JP, and Lephart, SM. Tethered swimming test: reliability and the association with swimming performance and land-based anaerobic performance. J Strength Cond Res 35(1): 212–220, 2021—The purpose of this study was 3-fold: (a) to examine the test-retest reliability of a 30-second maximal tethered freestyle swimming test (TST), (b) to assess the validity of the TST by examining the association with sprint swimming performance, and (c) to examine the associations between a swim-specific and land-based measure of anaerobic performance. A total of 29 male and female swimmers were recruited to participate in the study. Each subject completed a Wingate Anaerobic cycling test (WAnT), 2 or 4 TST, and a 22.9 m (25 yd), 45.7 m (50 yd), and 91.4 m (100 yd) maximal freestyle performance swims (PS). Mean and peak force (Fmean and Fpeak) were recorded for both the WAnT and TST, and average swimming velocity and time were recorded for the PS. In addition, physiological and perceptual measures were recorded immediately postexercise for all tests. The results of the present investigation showed strong intersession and intrasession reliability (R = 0.821–0.975; p < 0.001) for force parameters of the TST. Moderate correlations were found between Fmean and PS time and velocity of all distances, with slightly weaker correlations between Fpeak and the 22.9 m (time and velocity) and 45.7 m (velocity) PS. Finally, moderate correlations were found for Fmean and Fpeak of the TST and WAnT. This study demonstrated that the TST is a reliable measure, with moderate association with swimming performance, producing similar physiological responses compared with free swimming. Therefore, future research should focus on investigating the potential benefits of using the TST as a regular assessment tool as a part of a competitive swimming training program to track adaptations and inform training decisions.
      PubDate: Fri, 01 Jan 2021 00:00:00 GMT-
       
  • Effect of Ischemic Preconditioning on Maximal Swimming Performance
    • Authors: Williams; Natalie; Russell, Mark; Cook, Christian J.; Kilduff, Liam P.
      Abstract: imageWilliams, N, Russell, M, Cook, CJ, and Kilduff, LP. Effect of ischemic preconditioning on maximal swimming performance. J Strength Cond Res 35(1): 221–226, 2021—The effect of ischemic preconditioning (IPC) on swimming performance was examined. Using a randomized, crossover design, national- and international-level swimmers (n = 20; 14 men, 6 women) participated in 3 trials (Con, IPC-2h, and IPC-24h). Lower-body IPC (4 × 5-minute bilateral blood flow restriction at 160–228 mm Hg and 5-minute reperfusion) was used 2 hours (IPC-2h) or 24 hours (IPC-24h) before a self-selected (100 m, n = 15; 200 m, n = 5) swimming time trial (TT). The Con trial used a sham intervention (15 mm Hg) 2 hours before exercise. All trials required a 40-minute standardized precompetition swimming warm-up (followed by 20-minute rest; replicating precompetition call room procedures) 1 hour before TT. Capillary blood (pH, blood gases, and lactate concentrations) was taken immediately before and after IPC, before TT and after TT. No effects on TT for 100 m (P = 0.995; IPC-2h: 64.94 ± 8.33 seconds; IPC-24h: 64.67 ± 8.50 seconds; Con: 64.94 ± 8.24 seconds), 200 m (P = 0.405; IPC-2h: 127.70 ± 10.66 seconds; IPC-24h: 129.26 ± 12.99 seconds; Con: 130.19 ± 10.27 seconds), or combined total time (IPC-2h: 84.27 ± 31.52 seconds; IPC-24h: 79.87 ± 29.72 seconds; Con: 80.55 ± 31.35 seconds) were observed after IPC. Base excess (IPC-2h: −13.37 ± 8.90 mmol·L−1; Con: −13.35 ± 7.07 mmol·L−1; IPC-24h: −16.53 ± 4.65 mmol·L−1), pH (0.22 ± 0.08; all conditions), bicarbonate (IPC-2h: −11.66 ± 3.52 mmol·L−1; Con: −11.62 ± 5.59 mmol·L−1; IPC-24h: −8.47 ± 9.02 mmol·L−1), total carbon dioxide (IPC-2h: −12.90 ± 3.92 mmol·L−1; Con: −11.55 ± 7.61 mmol·L−1; IPC-24h: 9.90 ± 8.40 mmol·L−1), percentage oxygen saturation (IPC-2h: −0.16 ± 1.86%; Con: +0.20 ± 1.93%; IPC-24h: +0.47 ± 2.10%), and blood lactate (IPC-2h: +12.87 ± 3.62 mmol·L−1; Con: +12.41 ± 4.02 mmol·L−1; IPC-24h: +13.27 ± 3.81 mmol·L−1) were influenced by swimming TT (P < 0.001), but not condition (all P> 0.05). No effect of IPC was seen when applied 2 or 24 hours before swimming TT on any indices of performance or physiological measures recorded.
      PubDate: Fri, 01 Jan 2021 00:00:00 GMT-
       
  • Predisposing Risk Factors for Stress Fractures in Collegiate Cross-Country
           Runners
    • Authors: Griffin; Kaci L.; Knight, Kathy B.; Bass, Martha A.; Valliant, Melinda W.
      Abstract: imageGiffin, KL, Knight, KB, Bass, MA, and Valliant, MW. Predisposing risk factors and stress fractures in collegiate cross-country runners. J Strength Cond Res 35(1): 227–232, 2021—The purpose of this study was to explore factors associated with increased stress fractures in collegiate cross-country runners. Subjects in this study were 42 male and female cross-country runners at a Division I university. Each athlete completed a questionnaire regarding smoking status, vitamin/mineral intake, previous stress fracture history, birth control usage, menstrual status, and demographic information. Nutritional assessment using a 3-day food record and measurements of whole body, lumbar spine, and hip bone mineral densities (BMDs) were also conducted on each athlete. Results indicated that 40% of the female and 35% of the male runners reported a history of stress fracture, and that all of them did not meet the recommended daily energy intake or adequate intakes for calcium or vitamin D required for their amount of training. Two-tailed t-test found statistically higher incidences of lumbar spine BMD in male and female runners whose daily calcium and vitamin D intakes were below minimum requirements as well as for women whose caloric intake was below the required level. When data on the lumbar spine was evaluated, 31% of subjects (31.8% of the male and 30% of the female runners) were identified as having osteopenia and 4.8% with osteoporosis. Results warrant a need for future longitudinal studies.
      PubDate: Fri, 01 Jan 2021 00:00:00 GMT-
       
  • Influence of Different Treadmill Inclinations on V̇o2max and Ventilatory
           Thresholds During Maximal Ramp Protocols
    • Authors: Silva; Sidney C.; Monteiro, Walace D.; Cunha, Felipe A.; Farinatti, Paulo
      Abstract: imageSilva, SC, Monteiro, WD, Cunha, FA, and Farinatti, P. Influence of different treadmill inclinations on V̇o2max and ventilatory thresholds during maximal ramp protocols. J Strength Cond Res 35(1): 233–239, 2021—Ramp protocols for cardiopulmonary exercise testing (CPET) lack precise recommendations, including optimal treadmill inclination. This study investigated the impact of treadmill grades applied in ramp CPETs on maximal oxygen uptake (V̇o2max), ventilatory thresholds (VT1/VT2), and V̇o2 vs. workload relationship. Twenty-one healthy men (age 33 ± 8 years; height 176.6 ± 5.8 cm; body mass 80.4 ± 8.7 kg; and V̇o2max 44.9 ± 5.7 ml·kg−1·min−1) and 12 women (age 29 ± 7 years; height 163.3 ± 6.7 cm; body mass 56.6 ± 6.3 kg; and V̇o2max 39.4 ± 4.9 ml·kg−1·min−1) underwent ramp CPETs with similar speed increments and different treadmill grades: CPET0%, CPET2%, CPET3.5%, and CPET5.5%. The V̇o2max was similar across protocols (42.8–43.2 ml·kg−1·min−1, p = 0.76), albeit duration of CPETs shortened when treadmill inclination increased (CPET0% 12.7 minutes; CPET2% 9.1 minutes; CPET3.5% 8.0 minutes; and CPET5.5% 6.6 minutes; p < 0.01). The %V̇o2max corresponding to VT1 was slightly lower in CPET0% (63.6%) and higher in CPET5.5% (75.8%) vs. CPET2% (67.8%) and CPET3.5% (69.5%; p < 0.05), whereas VT2 was not affected by treadmill inclination (95.1–95.8% V̇o2max; p> 0.05). V̇o2max and ventilatory thresholds were similar in CPETs performed with different treadmill inclinations and similar initial/final speeds. However, linear regressions between workload and V̇o2 were closer to the identity line in CPETs performed with smaller (CPET0% and CPET2%) than with greater (CPET3.5% and CPET5.5%) inclinations. These data suggest that in healthy young adults, ramp CPETs performed with inclinations of 0–2% degree should be preferred over protocols with greater inclinations.
      PubDate: Fri, 01 Jan 2021 00:00:00 GMT-
       
  • The Golf Movement Screen Is Related to Spine Control and X-Factor of the
           Golf Swing in Low Handicap Golfers
    • Authors: Gould; Zachariah I.; Oliver, Jon L.; Lloyd, Rhodri S.; Neil, Rich; Bull, Mark
      Abstract: imageGould, ZI, Oliver, JL, Lloyd, RS, Neil, R, and Bull, M. The golf movement screen is related to spine control and x-factor of the golf swing in low handicap golfers. J Strength Cond Res 35(1): 240–246, 2021—The aim of the study was to investigate the association between the golf movement screen (GMS), x-factor, which is the separation between the upper torso and pelvis rotation, and biomechanical movements of the pelvis, thorax, and spine during the backswing and impact of a golf shot in low handicap golfers. In total, 62 golfers were involved in this study (n = 40 male, n = 22 female); the mean age of the sample was 15.4 ± 2.4 years. For the GMS, all subjects were assessed on their movement ability over a total of 10 different exercises. After a thorough warm-up routine of practice swings, each golfer then performed a single trial for biomechanical analysis. Biomechanical data were collected using an electromagnetic tracking system. Four of the 10 exercises had a significant correlation with x-factor (r = 0.25–0.33; p < 0.05). Four exercises had moderate correlations with spine rotation at the top of backswing. Spine side bend had a significant correlation with 9 of the 10 exercises and total GMS score (r = 0.26–0.53, p < 0.05). Movements of the pelvis and thorax at the top of backswing had minimal associations with the GMS. At impact, trunk inclination, thoracic rotation, and squat had small to moderate significant relationships with biomechanical movements (p < 0.05). Movement competency, as measured by the GMS, is associated with important aspects of swing mechanics. In particular, golfers who achieve better scores in the GMS have better spine control and can create a greater x-factor during the golf swing.
      PubDate: Fri, 01 Jan 2021 00:00:00 GMT-
       
  • Balance Training Reduces Postural Sway and Improves Sport-specific
           Performance in Visually Impaired Cross-Country Skiers
    • Authors: Kurz; Alexander; Lauber, Benedikt; Franke, Steffen; Leukel, Christian
      Abstract: imageKurz, A, Lauber, B, Franke, S, and Leukel, C. Balance training reduces postural sway and improves sport-specific performance in visually impaired cross-country skiers. J Strength Cond Res 35(1): 247–252, 2021—Balance training is highly effective in reducing sport injuries and causes improvements in postural stability and rapid force production. So far, the positive effects of balance training have been described for healthy athletes. In the present experiments, we questioned whether athletes with disabilities of the visual system can also benefit from balance training. Fourteen visually impaired cross-country skiers participated in this randomized controlled study. The intervention group (N = 7) completed 8 sessions of balance training over a period of 4 weeks (2 times per week), whereas a waiting control group (N = 7) received no training during that time. After training, postural sway was significantly reduced in the intervention group but not in the waiting control group. In addition, sport-specific performance, which was assessed by a standardized Cooper's 12-minute test on roller skis or rollerblades, increased in the intervention group. The change in postural sway from the premeasurement to the postmeasurement correlated with the change in sport-specific performance in all subjects. Our results indicate that balance training is useful for improving postural stability and sport-specific performance in visually impaired cross-country skiers. We propose that balance training should therefore be implemented as part of the training routine in athletes with disabilities of the visual system.
      PubDate: Fri, 01 Jan 2021 00:00:00 GMT-
       
  • Positive Pressure Ventilation Improves Exercise Performance and Attenuates
           the Fall of Postexercise Inspiratory Muscular Strength in Rower Athletes
    • Authors: Gonçalves; Thiago R.; Soares, Pedro Paulo da S.
      Abstract: imageGonçalves, TR and Soares, PP. Positive pressure ventilation improves exercise performance and attenuates the fall of postexercise inspiratory muscular strength in rower athletes. J Strength Cond Res 35(1): 253–259, 2021—Positive pressure ventilation (PPV) can increase exercise performance in cyclists, but its effects are unclear in other exercise modes, especially those using large muscle mass. The aim of this study was to compare the exercise performance and postexercise inspiratory muscles' strength with and without PPV (NO-PPV) during rowing. Nine male rowers (19 ± 1 year) participated in 3 experimental days (M1, M2, and M3) separated by 1 week. In M1, rowers performed a 2,000-m test (2k) on a rowing ergometer to obtain average power (W2k). In M2 and M3, the rowers performed 4 minutes' workouts at 55, 65, 75, and 85% W2k, respectively, separated by 1 minute of recovery, with PPV and NO-PPV application in randomized order. Blood lactate (La) was measured during intervals. After submaximal exercises, with 10 minutes of “cool down,” the rowers performed a maximal performance test of 4 minutes (4-minute all-out rowing). Traveled distance was computed and correlated with maximal inspiratory pressure (MIP) changes from pretest to posttest (∆). Positive pressure ventilation application increased the traveled distance in relation to NO-PPV exercise (1,210.7 ± 45.5 vs. 1,199.8 ± 43.4 m, p ≤ 0.05). The ∆MIP (cmH2O) was lower in PPV as compared to NO-PPV exercise (−19.1 ± 10.2 vs. −26.3 ± 7.9 cmH2O, p ≤ 0.05). The [La] showed no significant difference between PPV and NO-PPV exercises (p> 0.05). Therefore, the PPV during whole-body rowing exercise improved the exercise performance and attenuated the inspiratory postexercise fatigue. These findings suggest that inspiratory muscles' strength plays a role during high-intensity exercise with large muscle mass.
      PubDate: Fri, 01 Jan 2021 00:00:00 GMT-
       
  • Normative Reference Values for Handgrip Strength in Chilean Children at
           8–12 Years Old Using the Empirical Distribution and the Lambda, Mu, and
           Sigma Statistical Methods
    • Authors: Garcia-Hermoso; Antonio; Cofre-Bolados, Cristian; Andrade-Schnettler, Rodrigo; Ceballos-Ceballos, Rodrigo; Fernández-Vergara, Omar; Vegas-Heredia, Eddie D.; Ramírez-Vélez, Robinson; Izquierdo, Mikel
      Abstract: imageGarcia-Hermoso, A, Cofre-Bolados, C, Andrade-Schnettler, R, Ceballos-Ceballos, R, Fernández-Vergara, O, Vegas-Heredia, ED, Ramírez-Vélez, R, and Izquierdo, M. Normative reference values for handgrip strength in Chilean children at 8–12 years old using the empirical distribution and the lambda, mu, and sigma statistical methods. J Strength Cond Res 35(1): 260–266, 2021—The aim of this study was 2-fold (a) to provide sex- and age-specific handgrip reference standards for Chilean children aged 8–12 years and (b) to compare the levels of handgrip strength of Chilean children with those of children from other countries. This cross-sectional study enrolled 2,026 schoolchildren (boys n = 1,334 and girls n = 692, mean age 10.18 [1.16] years old). Handgrip strength was measured using a hand dynamometer with an adjustable grip. Relative handgrip strength was calculated by dividing handgrip strength by body mass (handgrip strength kg per mass kg). Smoothed centile curves and tables for the 10th, 20th, 30th, 40th, 50th, 60th, 70th, 80th, and 90th centiles were calculated using Cole's lambda, mu, and sigma method. The results indicate that mean handgrip strength was greater among boys than girls. Handgrip strength peaked at 16.25 (5.03) kg in boys and 14.90 (4.32) kg in girls. In addition, relative handgrip strength peaked at 0.38 (0.08) in boys and 0.34 (0.07) in girls. Chilean children of both sexes scored higher than their South American counterparts from Colombia and Peru but showed lower handgrip strength than European and Australian children. Our results provide, for the first time, sex- and age-specific handgrip reference standards for Chilean children aged 8–12.9 years. These normative reference values could help identify the levels of handgrip strength that need attention to provide appropriate feedback and advice to children about how to best improve their overall physical fitness.
      PubDate: Fri, 01 Jan 2021 00:00:00 GMT-
       
  • Reduced Electromyographic Fatigue Threshold After Performing a Cognitive
           Fatiguing Task
    • Authors: Ferris; Justine R.; Tomlinson, Mary A.; Ward, Tayler N.; Pepin, Marie E.; Malek, Moh H.
      Abstract: imageFerris, JR, Tomlinson, MA, Ward, TN, Pepin, ME, and Malek, MH. Reduced electromyographic fatigue threshold after performing a cognitive fatiguing task. J Strength Cond Res 35(1): 267–274, 2021—Cognitive fatigue tasks performed before exercise may reduce exercise capacity. The electromyographic fatigue threshold (EMGFT) is the highest exercise intensity that can be maintained without significant increase in the electromyography (EMG) amplitude vs. time relationship. To date, no studies have examined the effect of cognitive fatigue on the estimation of the EMGFT. The purpose of this study, therefore, was to determine whether cognitive fatigue before performing exercise reduces the estimated EMGFT. Eight healthy college-aged men were recruited from a university student population and visited the laboratory on multiple occasions. In a randomized order, subjects performed either the cognitive fatigue task (AX continuous performance test) for 60 minutes on one visit (experimental condition) or watched a video on trains for 60 minutes on the other visit (control condition). After each condition, subjects performed the incremental single-leg knee-extensor ergometry test while the EMG amplitude was recorded from the rectus femoris muscle and heart rate was monitored throughout. Thereafter, the EMGFT was calculated for each subject for each visit and compared using paired samples t-test. For exercise outcomes, there were no significant mean differences for maximal power output between the 2 conditions (control: 51 ± 5 vs. fatigue: 50 ± 3 W), but there was a significant decrease in EMGFT between the 2 conditions (control: 31 ± 3 vs. fatigue: 24 ± 2 W; p = 0.013). Moreover, maximal heart rate was significantly different between the 2 conditions (control: 151 ± 5 vs. fatigue: 132 ± 6; p = 0.027). These results suggest that performing the cognitive fatiguing task reduces the EMGFT with a corresponding reduction in maximal heart rate response.
      PubDate: Fri, 01 Jan 2021 00:00:00 GMT-
       
  • The Effects of Below-Knee Medical Compression Stockings on Pulse Wave
           Velocity of Young Healthy Volunteers
    • Authors: Szolnoky; Gyozo; Gavallér, Henriette; Gönczy, Anna; Bihari, Imre; Kemény, Lajos; Forster, Tamás; Nemes, Attila
      Abstract: imageSzolnoky, G, Gavallér, H, Gönczy, A, Bihari, I, Kemény, L, Forster, T, and Nemes, A. The effects of below-knee medical compression stockings on pulse wave velocity of young healthy volunteers. J Strength Cond Res 35(1): 275–279, 2021—The effects of graduated medical compression stockings (MCS) on cardiovascular responses are poorly investigated. A simple study was undertaken to investigate whether the application of below-knee leg MCSs with different pressures could influence aortic pulse wave velocity (PWV) as the gold standard for aortic stiffness measurement evaluated by arteriography. Ten volunteers underwent PWV measurement at baseline, then in below-knee compression class (ccl) 1 (18–21 mm Hg), 2 (23–32 mm Hg) and 3 (34–46 mm Hg) MCSs in a consecutive manner. Baseline PWV (mean value: 7.86 ± 1.70 m·s−1) was significantly reduced by ccl 1 MCSs (mean value: 6.55 ± 0.88 m·s−1, p = 0.04). ccl 2 and ccl 3 stockings also notably decreased baseline PWV (mean values: 6.63 ± 0.65 m·s−1, p = 0.058 and 6.62 ± 1.00 m·s−1, p = 0.067; respectively). The application of low compression MCSs (ccl 1) leads to a significant decrease in PWV indicating a beneficial cardiovascular influence.
      PubDate: Fri, 01 Jan 2021 00:00:00 GMT-
       
  • Relationship Between Reactive Strength Index Variants in Rugby League
           Players
    • Authors: McMahon; John J.; Suchomel, Timothy J.; Lake, Jason P.; Comfort, Paul
      Abstract: imageMcMahon, JJ, Suchomel, TJ, Lake, JP, and Comfort, P. Relationship between reactive strength index variants in rugby league players. J Strength Cond Res 35(1): 280–285, 2021—Two reactive strength index (RSI) variants exist, the RSI and RSI modified (RSImod), which are typically calculated during the drop jump (DJ) and countermovement jump (CMJ), respectively. Both RSI variants have been used to monitor athletes' ability to complete stretch-shortening cycle actions quickly, but they have never been compared. The purpose of this study was to determine whether they yield relatable information about reactive strength characteristics. Male professional rugby league players (n = 21, age = 20.8 ± 2.3 years, height = 1.82 ± 0.06 m and body mass = 94.3 ± 8.4 kg) performed 3 DJs (30 cm) and CMJs on a force plate. Reactive strength index and RSImod were subsequently calculated by dividing jump height (JH) by ground contact time (GCT) and time to take-off (TTT), respectively. All variables were highly reliable (intraclass correlation coefficient ≥0.78) with acceptable levels of variability (coefficient of variation ≤8.2%), albeit larger variability was noted for DJ variables. Moreover, there was a large relationship between RSI and RSImod (r = 0.524, p = 0.007), whereas very large relationships were noted between JHs (r = 0.762, p < 0.001) and between GCT and TTT (ρ = 0.705, p < 0.001). In addition, RSI (0.90 ± 0.22) was largely and significantly (d = 2.57, p < 0.001) greater than RSImod (0.47 ± 0.08). The DJ-derived RSI yields much larger values than the CMJ-derived RSImod and although a large relationship was noted between them, it equated to just 22% shared variance. These results suggest that the 2 RSI variants do not explain each other well, indicating that they do not assess entirely the same reactive strength qualities and should not be used interchangeably.
      PubDate: Fri, 01 Jan 2021 00:00:00 GMT-
       
  • Classic Powerlifting Performance: A Systematic Review: Erratum
    • Abstract: No abstract available
      PubDate: Fri, 01 Jan 2021 00:00:00 GMT-
       
  • Effect of COL5A1, GDF5, and PPARA Genes on a Movement Screen and
           Neuromuscular Performance in Adolescent Team Sport Athletes: Erratum
    • Abstract: No abstract available
      PubDate: Fri, 01 Jan 2021 00:00:00 GMT-
       
  • Validity of Combination Use of Activity Record and Accelerometry to
           Measure Free-Living Total Energy Expenditure in Female Endurance Runners:
           An Erratum
    • Abstract: No abstract available
      PubDate: Fri, 01 Jan 2021 00:00:00 GMT-
       
 
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