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Journal of Strength and Conditioning Research
Journal Prestige (SJR): 1.366  Citation Impact (citeScore): 2 Number of Followers: 78  Hybrid journal (It can contain Open Access articles)ISSN (Print) 1064-8011 - ISSN (Online) 1533-4287 Published by LWW Wolters Kluwer  [330 journals]
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- Kinetics and Kinematics of the Push Press, Push Jerk, and Split Jerk
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Authors: Soriano; Marcos A.; Jiménez-Ormeño, Ester; Lake, Jason P.; McMahon, John J.; Gallo-Salazar, César; Mundy, Peter; Comfort, Paul
Abstract:
Soriano, MA, Jiménez-Ormeño, E, Lake, JP, McMahon, JJ, Gallo-Salazar, C, Mundy, P, and Comfort, P. Kinetics and kinematics of the push press, push jerk, and split jerk. J Strength Cond Res 38(8): 1359–1365, 2024—The aim of this study was to explore the kinetics and kinematics across incremental loads with the push press (PP), push jerk (PJ), and split jerk (SJ). Eighteen resistance-trained men performed the 1 repetition maximum (1RM) tests (visit 1) 3–7 days before an incremental loading protocol (60, 75, and 90% 1RM) of the 3 exercises (visit 2). Kinetics and kinematics were derived from force-time data and compared using a repeated-measures analysis of variance with load and exercise as within-subject factors. Dependent variables for the biomechanics assessment were categorized as output (power and impulse), driver (force and work), and strategy (displacement and duration) metrics. The interrepetition reliability was assessed using the intraclass correlation coefficient and coefficient of variation. The PP, PJ, and SJ 1RM performance were 89.7 ± 15.4, 95.6 ± 14.4, and 103.0 ± 16.9 kg, respectively. Driver, strategy, and outcome metrics displayed moderate-to-excellent (intraclass correlation coefficient: 0.58–0.98) reliability with acceptable variability (% coefficient of variation: 2.02–10.00). Increased load resulted in significantly large increases in force, work, displacement, duration, power, and impulse (p < 0.001, = 0.534–0.903). Exercise selection had a significant and large effect on power, impulse, work, and force (p < 0.016, = 0.387–0.534). There was a significant and large effect of load × exercise interaction on work, displacement, and duration (p < 0.019, = 0.158–0.220). Practitioners are encouraged to use heavier loads (90> 75> 60% 1RM) during the SJ exercise to maximize output, driver, and strategy kinetics and kinematics.
PubDate: Thu, 01 Aug 2024 00:00:00 GMT-
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- Efficacy of Supersets Versus Traditional Sets in Whole-Body Multiple-Joint
Resistance Training: A Randomized Controlled Trial-
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Authors: Iversen; Vegard Moe; Eide, Vemund Bakken; Unhjem, Bjørnar Jakobsen; Fimland, Marius Steiro
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Iversen, VM, Eide, VB, Unhjem, BJ, and Fimland, MS. Efficacy of supersets versus traditional sets in whole-body multiple-joint resistance training: A randomized controlled trial. J Strength Cond Res 38(8): 1372–1378, 2024—Time constraints often hinder exercise engagement, necessitating exploration of time-efficient resistance training methods. Superset training, where 2 exercises are performed successively with minimal rest, nearly halves session duration but is metabolically demanding, possibly reducing strength gains. In a randomized controlled trial with blinded test leaders, we examined the efficacy of supersets versus traditional sets in a full-body, multiple-joint resistance training workout on maximal strength in the trained exercises. Subjects took part in a 3-week introductory training phase before baseline testing to ensure they were thoroughly familiarized. Next, they were randomized to a superset- or a traditional-set group, performing 10 weeks of heavy multiple-joint resistance training twice per week. The exercise programs consisted of leg press, bench press, lat pull-down, and seated rows. The traditional training group had a 5.2-kg higher improvement in pull-down than the superset group (p = 0.033), and a close to significant 4.8-kg higher improvement in seated rows (p = 0.073). The improvements in leg press and bench press were quite similar for both groups (p = 0.507–0.527). There were no changes between groups in body composition outcomes (0.151–0.640), but both groups increased muscle mass and reduced fat mass (p < 0.05). In conclusion, superset training of multi-joint exercises hampered maximal strength gains somewhat compared with traditional-set training. However, there were very similar improvements in body composition, and strength gains were observed for all exercises in the superset group. Thus, whole-body, multiple-joint superset resistance training could be a viable time-saving approach.
PubDate: Thu, 01 Aug 2024 00:00:00 GMT-
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- Individuals Can be Taught to Sense the Degree of Vascular Occlusion:
Implications for Practical Blood Flow Restriction-
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Authors: Song; Jun Seob; Hammert, William B.; Kataoka, Ryo; Yamada, Yujiro; Kang, Anna; Loenneke, Jeremy P.
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Song, JS, Hammert, WB, Kataoka, R, Yamada, Y, Kang, A, and Loenneke, JP. Individuals can be taught to sense the degree of vascular occlusion: Implications for practical blood flow restriction. J Strength Cond Res 38(8): 1413–1418, 2024—It is currently unknown if individuals can be conditioned to a relative arterial occlusion pressure (AOP) and replicate that pressure at a later time point. The purpose of this study was to determine whether individuals can be taught to sense a certain relative pressure (i.e., target pressure) by comparing a conditioning method with a time-matched non-conditioning control. Fifty-eight subjects completed 2 visits in a randomized order: (a) conditioning condition and (b) time-matched control condition. The conditioning involved 11 series of inflations to 40% AOP for 12 seconds followed by cuff deflation for 22 seconds. The pressure estimations were taken at 5 and 30 minutes after each condition. Data are presented as mean differences (95% credible interval). The absolute error at 5 minutes was greater for the control compared with conditioning condition (7.1 [2.0–12.1] mm Hg). However, this difference in absolute error between conditioning and control was reduced at 30 minutes (2.9 [−1.3 to 7.1] mm Hg). The mean difference and 95% limits of agreement for the control were 8.2 (−42.4 to 58.5) mm Hg at 5 minutes and 0.02 (−43.5 to 43.5) at 30 minutes. The agreements for the conditioning were −6.2 (−32.4 to 20.0) mm Hg at 5 minutes and −11.2 (−36.6 to 14.3) mm Hg at 30 minutes. The results suggest that the individuals can be taught to sense the target pressure, but this effect only lasts a short amount of time. Future work is necessary to refine the conditioning method to extend the duration of this conditioning effect.
PubDate: Thu, 01 Aug 2024 00:00:00 GMT-
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- Predicting Sprint Performance From the Vertical and Horizontal Jumps in
National Football League Combine Athletes-
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Authors: Agar-Newman; Dana J.; MacRae, Fraser; Tsai, Ming-Chang; Klimstra, Marc
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Agar-Newman, DJ, MacRae, F, Tsai, M-C, and Klimstra, M. Predicting sprint performance from the vertical and horizontal jumps in National Football League Combine athletes. J Strength Cond Res 38(8): 1433–1439, 2024—Identifying fast athletes is an important part of the National Football League (NFL) Combine. However, not all athletes partake in the 36.58-m sprint, and relying on this single test may miss potentially fast athletes. Therefore, the purpose of this study was to determine whether sprinting times can be predicted using simple anthropometric and jumping measures. Data from the NFL Combine between the years 1999–2020 inclusive were used (n = 4,149). Subjects had a mean (±SD) height = 1.87 ± 0.07 m and body mass = 111.96 ± 20.78 kg. The cross-validation technique was used, partitioning the data into a training set (n = 2,071) to develop regression models to predict time over the 9.14-, 9.14- to 18.29-, 18.29- to 36.58-m, and 36.58-m segments using vertical jump, broad jump, height, and mass as the independent variables. The models were then evaluated against a test set (n = 2,070) for agreement. Statistically significant (p < 0.01) models were determined for 9.14-m time (adjusted R2 = 0.76, SEE = 0.05 seconds), 9.14- to 18.29-m time (adjusted R2 = 0.74, SEE = 0.04 seconds), 18.29- to 36.59-m time (adjusted R2 = 0.79, SEE = 0.07 seconds), and 36.58-m time (adjusted R2 = 0.84, SEE = 0.12 seconds). When evaluated against the test set, the models showed biases of −0.05, −0.04, −0.02, and −0.02 seconds and root-mean-square error of 0.07, 0.05, 0.07, and 0.12 seconds for the 9.14-, 9.14- to 18.29-, 18.29- to 36.58-m, and 36.58-m segments, respectively. However, 5–6% of the predictions lay outside of the limits of agreement. This study provides 4 formulae that can be used to predict sprint performance when the 36.58-m sprint test is not performed, and practitioners can use these equations to determine training areas of opportunity when working with athletes preparing for the NFL Combine.
PubDate: Thu, 01 Aug 2024 00:00:00 GMT-
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- Seasonal Changes in Match Demands and Workload Distribution in Collegiate
Soccer Across Two Seasons-
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Authors: Floersch; Sean; Vidden, Chad; Askow, Andrew T.; Jones, Margaret T.; Fields, Jennifer B.; Jagim, Andrew R.
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Floersch, S, Vidden, C, Askow, AT, Jones, MT, Fields, JB, and Jagim, AR. Seasonal changes in match demands and workload distribution in collegiate soccer across two seasons. J Strength Cond Res 38(8): 1440–1446, 2024—The purpose of this study was to examine seasonal changes in match demands in a collegiate women's soccer team. Forty-eight NCAA Division III women soccer athletes (age: 19.5 ± 1.2 years; height: 1.67 ± 0.05 m; body mass: 64.8 ± 7.4 kg; fat-free mass: 50.0 ± 4.5 kg; body fat %: 22.6 ± 6.0) were equipped with wearable global positioning systems with inertial sensors and heart rate (HR) monitors during matches throughout the 2019 (n = 22) and 2021 seasons (n = 26). Players were classified by position: flank player (FP; n = 28), center midfielder (CM; n = 11), and center back fielder (CB; n = 9) and as starters (S, n = 17) or reserves (R, n = 31). Variables included HR, training load, total distance, high-speed distance, distance per minute, and weighted distance. Differences in match and practice session demands were analyzed using linear mixed-effects models with season (2 levels; 2019 and 2021) as a fixed factor, with alpha set to p = 0.05. Data across all matches and training sessions were collapsed and presented as mean ± SD for descriptive purposes and then grouped by session type (i.e., match or training) and position. Athletes traveled more distance at high speeds during match play in the 2021 season compared with 2019 (mean difference, 95% confidence intervals [CI]) (200, 95% CI: 104, 304 km; p < 0.05) but had a lower training load in 2021 compared with 2019 (−50, 95% CI: −63, −36; p < 0.05) during match play. For training sessions, mean HR (4, 95% CI: 2, 5 bpm), total distance (0.5, 95% CI: 0.4, 0.7), distance per minute (5.6, 95% CI: 4.5, 6.7 m·min−1), high-speed distance (43, 95% CI: 43, 18, 67 m), high accelerations (8.6, 95% CI: 5.4, 11.8 n), and high accelerations per minute (0.1, 95% CI: 0.1, 0.1 n·min−1) were all higher in 2021 compared with 2019 (p < 0.05). As a team, several differences in measures of external workload were found between seasons in both session types (training and matches). Variations in positional demands of match play appear to fluctuate by year.
PubDate: Thu, 01 Aug 2024 00:00:00 GMT-
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- Relative Strength and Physical Performance in US Army Male and Female
Soldiers-
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Authors: Grier; Tyson; Benedict, Timothy; Mahlmann, Olivia; Canham-Chervak, Michelle
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Grier, T, Benedict, T, Mahlmann, O, and Canham-Chervak, M. Relative Strength and Physical Performance in U.S. Army Male and Female Soldiers. J Strength Cond Res 38(8): 1479–1485, 2024—In occupations with high physical demands, strength relative to bodymass is an important measure as it signifies an individual's ability to control and move their body mass through space. The purpose of this investigation was to examine physical characteristics, training, and performance based on different magnitudes of relative strength. Subjects were 1,806 male and 319 female US Army soldiers. Sex, age, height, body mass, and physical training data were obtained by an electronic survey. Physical performance was measured by the Army Combat Fitness Test (ACFT), which includes a three-repetition maximum deadlift, standing power throw, hand release push-up, sprint-drag-carry, leg tuck, and two-mile run. The relative body mass deadlifted was calculated and categorized into 4 groups for men and 3 groups for women. An analysis of variance and post hoc least significant difference test were used to evaluate the differences in relative strength and physical performance. Overall, 33% of men deadlifted ≥1.5 times their body mass, while 30% of women deadlifted ≥1.25 times their body mass. Men and women deadlifting the highest percentage of their body mass (≥1.5 times for men and ≥1.25 times for women) outperformed those with lower relative strength within their own sex in all 6 ACFT events. In 4 of the 6 ACFT events, women who deadlifted ≥1.25 times their body mass had similar performance compared with men deadlifting 1 to 1.24 times their body mass and outperformed men deadlifting
PubDate: Thu, 01 Aug 2024 00:00:00 GMT-
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- Using Barbell Acceleration to Determine the 1 Repetition Maximum of the
Jump Shrug-
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Authors: Techmanski; Baylee S.; Kissick, Cameron R.; Loturco, Irineu; Suchomel, Timothy J.
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Techmanski, BS, Kissick, CR, Loturco, I, and Suchomel, TJ. Using barbell acceleration to determine the 1 repetition maximum of the jump shrug. J Strength Cond Res 38(8): 1486–1493, 2024—The purpose of this study was to determine the 1 repetition maximum (1RM) of the jump shrug (JS) using the barbell acceleration characteristics of repetitions performed with relative percentages of the hang power clean (HPC). Fifteen resistance-trained men (age = 25.5 ± 4.5 years, body mass = 88.5 ± 15.7 kg, height = 176.1 ± 8.5 cm, relative 1RM HPC = 1.3 ± 0.2 kg·kg−1) completed 2 testing sessions that included performing a 1RM HPC and JS repetitions with 20, 40, 60, 80, and 100% of their 1RM HPC. A linear position transducer was used to determine concentric duration and the percentage of the propulsive phase (P%) where barbell acceleration was greater than gravitational acceleration (i.e., a>−9.81 m·s−2). Two 1 way repeated measures ANOVA were used to compare each variable across loads, whereas Hedge's g effect sizes were used to examine the magnitude of the differences. Concentric duration ranged from 449.7 to 469.8 milliseconds and did not vary significantly between loads (p = 0.253; g = 0.20–0.39). The P% was 57.4 ± 7.2%, 64.8 ± 5.9%, 73.2 ± 4.3%, 78.7 ± 4.0%, and 80.3 ± 3.5% when using 20, 40, 60, 80, and 100% 1RM HPC, respectively. P% produced during the 80 and 100% 1RM loads were significantly greater than those at 20, 40, and 60% 1RM (p < 0.01, g = 1.30–3.90). In addition, P% was significantly greater during 60% 1RM compared with both 20 and 40% 1RM (p < 0.01, g = 1.58–2.58) and 40% was greater than 20% 1RM (p = 0.003, g = 1.09). A braking phase was present during each load and, thus, a 1RM JS load was not established. Heavier loads may be needed to achieve a 100% propulsive phase when using this method.
PubDate: Thu, 01 Aug 2024 00:00:00 GMT-
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- The Use of Free Weight Squats in Sports: A Narrative Review—Squatting
Movements, Adaptation, and Sports Performance: Physiological-
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Authors: Stone; Michael H.; Hornsby, Guy; Mizuguchi, Satoshi; Sato, Kimitake; Gahreman, Daniel; Duca, Marco; Carroll, Kevin; Ramsey, Michael W.; Stone, Margaret E.; Haff, G. Gregory
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Stone, MH, Hornsby, G, Mizuguchi, S, Sato, K, Gahreman, D, Duca, M, Carroll, K, Ramsey, MW, Stone, ME, and Haff, GG. The use of free weight squats in sports: a narrative review—squatting movements, adaptation, and sports performance: physiological. J Strength Cond Res 38(8): 1494–1508, 2024—The squat and its variants can provide numerous benefits including positively affecting sports performance and injury prevention, injury severity reduction, and rehabilitation. The positive benefits of squat are likely the result of training-induced neural alterations and mechanical and morphological adaptations in tendons, skeletal muscles, and bones, resulting in increased tissue stiffness and cross-sectional area (CSA). Although direct evidence is lacking, structural adaptations can also be expected to occur in ligaments. These adaptations are thought to beneficially increase force transmission and mechanical resistance (e.g., resistance to mechanical strain) and reduce the likelihood and severity of injuries. Adaptations such as these, also likely play an important role in rehabilitation, particularly for injuries that require restricted use or immobilization of body parts and thus lead to a consequential reduction in the CSA and alterations in the mechanical properties of tendons, skeletal muscles, and ligaments. Both volume and particularly intensity (e.g., levels of loading used) of training seem to be important for the mechanical and morphological adaptations for at least skeletal muscles, tendons, and bones. Therefore, the training intensity and volume used for the squat and its variations should progressively become greater while adhering to the concept of periodization and recognized training principles.
PubDate: Thu, 01 Aug 2024 00:00:00 GMT-
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- Comparison of Force, Neuromuscular, and Metabolic Responses During
Sustained, Isometric Handgrip Holds to Failure Anchored to Low and High
Perceptual Intensities in Men: An Exploratory Study-
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Authors: Kwak; Minyoung; Succi, Pasquale J.; Benitez, Brian; Mitchinson, Clara J.; Samaan, Michael A.; Abel, Mark G.; Bergstrom, Haley C.
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Kwak, M, Succi, PJ, Benitez, B, Mitchinson, C, Samaan, MA, Abel, MG, and Bergstrom, HC. Comparison of force, neuromuscular, and metabolic responses during sustained, isometric handgrip holds to failure anchored to low and high perceptual intensities in men: An exploratory study. J Strength Cond Res 38(8): e405–e416, 2024—This study examined the responses of force alterations, relative to critical force (CF), neuromuscular parameters, and muscle oxygenation (SmO2) for isometric handgrip holds to failure (HTF) anchored to ratings of perceived exertion (RPE) of 3 and 7. Twelve men completed pre-maximal voluntary isometric contractions (pre-MVIC), submaximal HTF at 4 percentages of pre-MVIC, HTF at RPE = 3 and 7, and post-MVIC. Mechanomyograpic (MMG) signals and SmO2 were recorded during the RPE HTF. Analyses included paired-samples t-tests and repeated-measures ANOVAs at an alpha level of p ≤ 0.05. Time to task failure was not different between RPE 3 (478.7 ± 196.6 s) and RPE 7 (495.8 ± 173.8 s). Performance fatigability (PF) and MMG amplitude (AMP) were greater for RPE 7 (PF: 37.9 ± 12.9%; MMG AMP: 15.7 ± 7.4% MVIC) than RPE 3 (PF: 30.0 ± 14.5%; MMG AMP: 10.2 ± 6.5% MVIC), but MMG mean power frequency (MPF) was greater for RPE 3 (146.2 ± 31.1% MVIC) than RPE 7 (128.8 ± 23.0% MVIC). There were RPE-dependent decreases in force (p ≤ 0.01) across 3 discernable phases during the HTF. There were decreases in MMG AMP across time for both RPEs, but there were no significant changes in MMG MPF or SmO2. There were overall similar motor unit control strategies and local metabolic demand between RPEs. The majority of the HTF performed below CF at RPE 3 and 7 indicated CF did not reflect the highest sustainable force. When prescribing isometric exercise anchored to RPE, practitioners should be aware of the magnitude of force loss and relative intensity of the task to be sure desired training loads are met.
PubDate: Thu, 01 Aug 2024 00:00:00 GMT-
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- High-Speed Efforts of Elite Association Football Referees in National and
International Matches-
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Authors: Amatori; Stefano; Helsen, Werner F.; Baldari, Carlo; Serra, Tommaso; Belli, Annalisa; Guidetti, Laura; Rocchi, Marco B. L.; Sisti, Davide; Perroni, Fabrizio
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Amatori, S, Helsen, WF, Baldari, C, Serra, T, Belli, A, Guidetti, L, Rocchi, MBL, Sisti, D, and Perroni, F. High-speed efforts of elite association football referees in national and international matches. J Strength Cond Res 38(8): e417–e422, 2024—Field referees (FRs) need to move throughout the pitch to identify any infringements of the game's laws. Their performance depends on technical, tactical, physical, physiological, and mental factors. This retrospective study aimed to examine and assess the physical and physiological parameters as a function of time in elite association football referees during official matches. Global positioning system (match time, distance in different intensity ranges [low-intensity, high-speed, very high-speed running, and sprinting], average and peak speed, distance in accelerations or decelerations) and heart rate (average and peak) data from 212 national and international football matches were analyzed. A linear mixed-model analysis was performed to assess the differences between halves and between the three 15-minute sections of each half-time for all the physical and physiological variables collected. A significant effect of match half was found for the game time (p < 0.001) and the standing time (p = 0.005), both higher in the second half, and for the average speed (p = 0.017), which was lower in the second half. Total distance (p < 0.001), low-intensity distance (p = 0.004), and average speed (p = 0.007) all showed a reduction as a function of time. More than 7.800 high-speed intervals were detected. Accelerative actions within 3 seconds characterized most of the high-speed efforts of an FR during a match. Significant differences emerged in the way the match intensity is distributed across the match, analyzed both in halves (first vs. second) and 15-minute intervals within each half. It is important to emphasize the importance of high-speed training with a focus on a faster transition from low- to high-speed running to keep up with the play to get into an appropriate position and subsequently make the correct decisions.
PubDate: Thu, 01 Aug 2024 00:00:00 GMT-
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- How Do Young Soccer Players Train' A 5-Year Analysis of Weekly Training
Load and its Variability Between Age Groups in an Elite Youth Academy-
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Authors: Connolly; Darragh R.; Stolp, Sean; Gualtieri, Antonio; Ferrari Bravo, Duccio; Sassi, Roberto; Rampinini, Ermanno; Coutts, Aaron J.
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Connolly, DR, Stolp, S, Gualtieri, A, Ferrari Bravo, D, Sassi, R, Rampinini, E, and Coutts, AJ. How do young soccer players train' A 5-year analysis of weekly training load and its variability between age groups in an elite youth academy. J Strength Cond Res 38(8): e423–e429, 2024—The aim of this study was to quantify the session rating of perceived exertion (sRPE), duration, and training load accrued across typical training weeks undertaken by youth soccer players. Differences between starters, nonstarters, and variations in training load variables were also investigated. Data were collected from 230 elite youth players in 4 age groups (U15, U16, U17, and U19) during 5 competitive seasons. Mixed models were used to describe variation between age groups and compare starters with nonstarters, with season as a fixed covariate effect. Week-to-week variation in training load was expressed as the percentage coefficient of variation. The main findings may be used to highlight a significant effect of age and playing status on training intensity, duration, and internal training load. Weekly training load increased progressively from the U15 to U17, with significant differences between each age group (p < 0.03). Lower mean weekly perceived intensity (sRPE) was noted in U15 when compared with the older age groups (4.2 vs. 4.6–4.9 arbitrary unit for U16 to U19, p < 0.001). Low weekly training load variation was observed across the different phases of the season in each age group, with the preseason exhibiting the greatest variance (3.6–6.2%). Differences in the training load are likely more attributable to changes in training duration rather than sRPE. Control of session duration seems to play an important role when aiming to control load in the academy environment, and practitioners should closely monitor the differences in duration and load being recorded between starters and nonstarters.
PubDate: Thu, 01 Aug 2024 00:00:00 GMT-
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- Effects of Shoulder Corrective Training Program on Pitching Loads and
Sonographic Morphology in Elbow Joint in Youth Baseball Players-
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Authors: Chen; Po-Tsun; Lin, Yu-Chun; Chang, Hsiao-Yun; Chiu, Chih-Hao; Chen, Cheng-Yu; Chen, Poyu; Lin, Yang-Hua
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Chen, P-T, Lin, Y-C, Chang, H-Y, Chiu, C-H, Chen, C-Y, Chen, P, and Lin, Y-H. Effects of shoulder corrective training program on pitching loads and sonographic morphology in elbow joint in youth baseball players. J Strength Cond Res 38(8): e440–e447, 2024—We assessed the effects of a 12-week shoulder corrective training program for shoulder flexibility and strengthening on pitching loads and sonographic morphology of the elbow joints in youth baseball players. Seventeen subjects were recruited and underwent evaluations before and after the training program. We found that following training, subjects demonstrated significantly increased ranges of shoulder internal rotation (38.9 ± 12.9° vs. 69.2 ± 10.8°, p < 0.001), external rotation (91.2 ± 14.6° vs. 107.3 ± 9.5°, p = 0.004), and horizontal adduction (21.5 ± 8.0° vs. 32.7 ± 7.3°, p = 0.002); improved strength in the shoulder internal rotators (8.7 ± 1.6 kg vs. 9.8 ± 2.1 kg, p = 0.04), external rotators (6.5 ± 1.9 kg vs. 7.5 ± 2.8 kg, p = 0.04), middle trapezius (12.7 ± 2.1 kg vs. 14.3 ± 2.4 kg, p = 0.04), and middle deltoid muscles (10.8 ± 3.3 kg vs. 14.8 ± 3.2 kg, p = 0.001); and decreased thickness of the ulnar collateral ligament (6.1 ± 0.6 mm vs. 4.8 ± 0.7 mm, p = 0.002). Although there was no substantial change in elbow torque and arm speed, significantly increased ball speed (51.2 ± 4.6 mph vs. 54.1 ± 4.5 mph, p < 0.001) and decreased arm slot (63.8 ± 11.9° vs. 53.0 ± 12.7°, p = 0.02) were observed. We suggest that adequate corrective training should be performed regularly to minimize or mitigate adverse soft tissue changes at the elbow in youth baseball players. Balanced shoulder strength and flexibility may decrease medial elbow stress during pitching. Future studies should consider the kinetic and kinematic effects of other corrective training programs on the shoulder or elbow joint during pitching.
PubDate: Thu, 01 Aug 2024 00:00:00 GMT-
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- Validation of Bioelectrical Impedance Devices for the Determination of
Body Fat Percentage in Firefighters-
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Authors: Jagim; Andrew R.; Luedke, Joel; Erickson, Jacob L.; Fields, Jennifer B.; Jones, Margaret T.
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Jagim, AR, Luedke, J, Erickson, JL, Fields, JB, and Jones, MT. Validation of bioelectrical impedance devices for the determination of body fat percentage in firefighters. J Strength Cond Res 38(8): e448–e453, 2024—To cross-validate bioelectrical impedance devices for the determination of body fat percentage (BF%) in firefighters. Twenty-eight structural firefighters were evaluated (female, n = 2; male, n = 26 [mean ± SD] age: 38.2 ± 8.3 years; height: 180.2 ± 7.5 cm; body mass: 86.7 ± 20.8 kg; body mass index: 25.8 ± 7.8 kg·m−2) using multifrequency bioelectrical impedance analysis (MFBIA) hand-to-foot device, and single-frequency BIA foot scale (F2FBIA), and a single-frequency handheld BIA device (HHBIA). Dual X-ray absorptiometry served as the criterion. Validity metrics were examined to establish each method's performance. Body fat % values produced by MFBIA (r = 0.913), F2FBIA (r = 0.695), and HHBIA (r = 0.876) were strongly associated (p < 0.001) with criterion BF% measures. However, MFBIA, F2FBIA, and HHBIA all significantly (p < 0.001) underestimated BF% when compared with the criterion measure. Constant error ranged between 4.0 and 5.5% across all BIA devices. Despite strong associations between the BIA devices included in the current study and the criterion measure, all BIA devices underestimated BF%, which resulted in an overestimation of fat-free mass. In addition, proportional bias was observed in which BF% was overestimated at lower values and underestimated at higher values.
PubDate: Thu, 01 Aug 2024 00:00:00 GMT-
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- A Review of the Validity and Reliability of Accelerometer-Based Metrics
From Upper Back–Mounted GNSS Player Tracking Systems for Athlete
Training Load Monitoring-
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Authors: Dawson; Laura; Beato, Marco; Devereux, Gavin; McErlain-Naylor, Stuart A.
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Dawson, L, Beato, M, Devereux, G, and McErlain-Naylor, SA. A review of the validity and reliability of accelerometer-based metrics from upper back–mounted GNSS player tracking systems for athlete training load monitoring. J Strength Cond Res 38(8): e459–e474, 2024—Athlete load monitoring using upper back–mounted global navigation satellite system (GNSS) player tracking is common within many team sports. However, accelerometer-based load monitoring may provide information that cannot be achieved with GNSS alone. This review focuses on the accelerometer-based metrics quantifying the accumulation of accelerations as an estimation of athlete training load, appraising the validity and reliability of accelerometer use in upper back–mounted GNSS player tracking systems, the accelerometer-based metrics, and their potential for application within athlete monitoring. Reliability of GNSS-housed accelerometers and accelerometer-based metrics are dependent on the equipment model, signal processing methods, and the activity being monitored. Furthermore, GNSS unit placement on the upper back may be suboptimal for accelerometer-based estimation of mechanical load. Because there are currently no feasible gold standard comparisons for field-based whole-body biomechanical load, the validity of accelerometer-based load metrics has largely been considered in relation to other measures of training load and exercise intensity. In terms of convergent validity, accelerometer-based metrics (e.g., PlayerLoad, Dynamic Stress Load, Body Load) have correlated, albeit with varying magnitudes and certainty, with measures of internal physiological load, exercise intensity, total distance, collisions and impacts, fatigue, and injury risk and incidence. Currently, comparisons of these metrics should not be made between athletes because of mass or technique differences or between manufacturers because of processing variations. Notable areas for further study include the associations between accelerometer-based metrics and other parts of biomechanical load-adaptation pathways of interest, such as internal biomechanical loads or methods of manipulating these metrics through effective training design.
PubDate: Mon, 08 Jul 2024 00:00:00 GMT-
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- A New Training Load Quantification Method at Supramaximal Intensity and
Its Application in Injuries Among Members of an International Volleyball
Team-
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Authors: Bouzigues; Théo; Maurelli, Olivier; Imbach, Frank; Prioux, Jacques; Candau, Robin
Abstract:
Bouzigues, T, Maurelli, O, Imbach, F, Prioux, J, and Candau, R. A new training load quantification method at supramaximal intensity and its application in injuries among members of an international volleyball team. J Strength Cond Res 38(8): 1453–1463, 2024—The quantification of training loads (TLs) is essential for optimizing jump performance and reducing the occurrence of injuries. This study aimed to (a) propose a new method for quantifying TLs in explosive exercises, (b) determine the nature of the relationship between TLs dynamics and injury occurrence, and (c) assess a TLcritical for training schedule purposes, above which the risk of injury occurrence becomes unacceptable. This study was conducted with 11 male volleyball players on a national team during a 5-month international competitive period. The proposed new method for quantifying TLs is based on a weighting factor applied to relative jumping intensities, determined by the number of sustainable jumps and their intensities measured by G-Vert accelerometer. The relationship between TLs dynamics and injury occurrence was assessed using a variable dose-response model. A high coefficient of determination was found between the maximum number of jumps possible and their intensities (r2 = 0.94 ± 0.14, p < 0.001), indicating a strong physiological relationship between jumping intensities and the constraints imposed. The occurrence of injury was dependent on TLs dynamics for 2 players (r2 = 0.26 ± 0.01; p < 0.001). The TLcritical corresponded to 11 jumps over 80% of maximum jump height during games and approximately 130 jumps at
PubDate: Tue, 25 Jun 2024 00:00:00 GMT-
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- 4–6 Repetition Maximum (RM) and 1-RM Prediction in Free-Weight Bench
Press and Smith Machine Squat Based on Body Mass in Male Athletes-
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Authors: Dhahbi; Wissem; Padulo, Johnny; Russo, Luca; Racil, Ghazi; Ltifi, Mohamed-Amine; Picerno, Pietro; Iuliano, Enzo; Migliaccio, Gian Mario
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Dhahbi, W, Padulo, J, Russo, L, Racil, G, Ltifi, M-A, Picerno, P, Iuliano, E, and Migliaccio, GM. Four- to 6-repetition maximum and 1-repetition maximum estimation in free-weight bench press and smith machine squat based on body mass in male athletes. J Strength Cond Res 38(8): 1366–1371, 2024—This study aimed to explore the feasibility and face validity of predicting maximum strength 1 repetition maximum (1-RM) and 4–6 RM in athletes across different sports specialties, based on the relationship between muscle strength and BM. One hundred fifteen male athletes, aged 23.63 ± 6.77 years and participating in diverse sports specialties, were included in this study. Muscle strength was assessed using the 4–6 RM and 1-RM tests in free-weight bench press (BP) and Smith machine squat (SQ) exercises, whereas BM was measured using a portable digital scale. A linear regression equation based on muscle strength and BM was performed. The 4–6 RM and 1-RM scores showed excellent intersession relative reliability (intraclass correlation coefficient(2,1): 0.946–0.989) and absolute reliability (CV: 3.4–4.7%) in both BP and SQ exercises. In addition, the magnitude of the relationship and the coefficients used to estimate the 4–6 RM and 1RM, based on BM, differed among the subjects when they are grouped according to their sports specialties (R2 ranged from non-significant to 0.998). Overall, the 4–6 RM test showed a stronger correlation with BM (R: 0.655 for SQ and R: 0.683 for BP) than the 1RM (R: 0.552 for SQ and R: 0.629 for BP), and the general (i.e., not sport-specific) 4 to 6-RM prediction equations should be preferred over sport-specific ones because they are statistically more robust due to the larger sample size. In conclusion, the 4–6 RM can be predicted from BM with high reliability, a moderate association, and a prediction error that, when considering the 4–6 RM as a starting point for estimating of the 1RM, can be considered entirely acceptable in practical settings.
PubDate: Tue, 18 Jun 2024 00:00:00 GMT-
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- Analysis of Concentric and Eccentric Power in Flywheel Exercises Depending
on the Subjects' Strength Level and Body Mass-
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Authors: Asencio; Pablo; García-Valverde, Adrián; Albaladejo-García, Carlos; Beato, Marco; Moreno, Francisco J.; Sabido, Rafael
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Asencio, P, García-Valverde, A, Albaladejo-García, C, Beato, M, Moreno-Hernández, FJ, and Sabido, R. Analysis of concentric and eccentric power in flywheel exercises depending on the subjects’ strength level and body mass. J Strength Cond Res 38(8): 1394–1400, 2024—The objective of this study is to describe how flywheel exercise mechanical outputs are affected by the athletes' body mass (BM) and strength level and by the exercise type. Forty-six recreational athletes came to a laboratory 3 times. On the first day, descriptive data, squat (1 repetition maximum: 1RM) and flywheel familiarization were performed. After a second day of familiarization, subjects performed a randomized flywheel exercise-testing protocol of squat and split squat exercises. The variables used for data analysis were peak concentric power and peak eccentric power, eccentric/concentric ratio, and their relationship with 1RM/BM. Subjects were assigned to a stronger or weaker group according to their 1RM/BM ratio. Group differences were found in absolute values of eccentric overload (EOL) (p < 0.01; effect size [ES] = 0.51) and EOL/BM (p < 0.01; ES = 0.46) only in the split squat. Absolute power values in the concentric phase showed differences between inertial load (p < 0.01; ES = 0.41). The stronger group did not present significant differences between inertial loads during squat (p < 0.01; ES = 0.46), but they showed different ratios with light inertias in comparison with the weaker group (p < 0.01; ES = 0.46). There were significant differences between groups with light inertias in split squat (nondominant) and squat exercises (p < 0.05; ES = 0.29) in the eccentric and concentric phases (p < 0.116; ES = 0.20). Squat and split squat exercises present different profiles depending on the training level. In conclusion, it is recommended that practitioners perform a test to understand the inertial load–power profile (concentric, eccentric, and their ratio) for each exercise and also consider the user's strength level for selection of the inertial load and for the exercise to use in training.
PubDate: Tue, 04 Jun 2024 00:00:00 GMT-
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- Acute Upper-Body and Lower-Body Neuromuscular Fatigue Effect on Baseball
Pitchers' Velocity: A Pilot Study-
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Authors: Tremblay; Mathieu; Anderson Sirois, Samuel; Verville, William; Auger, Mathis; Abboud, Jacques; Descarreaux, Martin
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Tremblay, M, Anderson Sirois, S, Verville, W, Auger, M, Abboud, J, and Descarreaux, M. Acute upper-body and lower-body neuromuscular fatigue effect on baseball pitchers’ velocity: A pilot study. J Strength Cond Res 38(8): 1447–1452, 2024—The purpose of this pilot study was to explore the acute effect of upper-body and lower-body neuromuscular fatigue protocols on baseball pitchers' velocity. Sixteen baseball pitchers were recruited, and a crossover design was used to meet the study purpose. Pitchers were tested twice, 7 days apart, with their upper-body and lower-body explosiveness, pitching velocity, and muscle soreness perception of their throwing arm (forearm flexors, biceps, anterior deltoid, and upper trapezius muscles) assessed before and after an upper-body and lower-body neuromuscular fatigue protocol. Two-way analysis of variances and paired t tests (p < 0.05) were used to identify and compare prescores and postscores. Following both fatigue protocols, results revealed a significant decrease in time for pitching velocity (p = 0.005, ηp2 = 0.462), and increases in muscle soreness perception of the forearm flexors (p = 0.005, ηp2 = 0.470), anterior deltoid (p = 0.045, ηp2 = 0.274), and upper trapezius (p = 0.023, ηp2 = 0.339) muscles. Paired t test results showed a significant decrease in preneuromuscular and postneuromuscular fatigue protocol in the upper-body (p < 0.01) and lower-body (p < 0.01) explosiveness scores. These pilot study results show the impact of different exercise protocols on pitchers' explosiveness, velocity, and muscle soreness perception emphasizing the need for further investigation into the acute effect of exercise targeting the upper or lower-body on pitching performance, specifically at the pitcher's position.
PubDate: Tue, 04 Jun 2024 00:00:00 GMT-
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- Relationships Between Physical Ability Test Performance and Fitness in
Recruits From a Southeastern U.S. Police Department-
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Authors: Lockie; Robert G.; Orr, Robin M.; Sanchez, Kristine J.; Gonzales, Stephen M.; Viramontes, Erika; Kennedy, Kelly; Dawes, J. Jay
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Lockie, RG, Orr, RM, Sanchez, KJ, Gonzales, SM, Viramontes, E, Kennedy, K, and Dawes, JJ. Relationships between physical ability test performance and fitness in recruits from a southeastern U.S. police department. J Strength Cond Res 38(8): 1472–1478, 2024—Police recruit occupational ability may be predicted by a physical ability test (PAT). This study determined relationships between a department-specific PAT and fitness test performance among police recruits. Retrospective analysis was conducted on recruit data (1,069 men and 404 women) from one department collected during 2005–2009 and 2016–2020. The following data were provided: grip strength; sit-and-reach; 60-second push-ups; 60-second sit-ups; 2.4-km run; and the PAT. The PAT involved exiting a vehicle and opening the trunk; running ∼201 m; completing an obstacle course; dragging a 68-kg dummy 31 m; completing an obstacle course and running ∼201 m; dry firing a weapon 6 times with each hand; and trunk item placement and vehicle reentry. Relationships between the PAT and fitness tests were measured by partial correlations and stepwise linear regression, both controlling for sex. The PAT was completed in a mean time of 4:16 ± 1:07 minutes:seconds. The PAT significantly (p < 0.001) related to all fitness tests. Moderate relationships were found for push-ups (r = −0.35), sit-ups (r = −0.41), and the 2.4-km run (r = −0.43). Small relationships were found with grip strength (r = −0.19) and the sit-and-reach (r = −0.17). The final regression model, which included sex and all fitness tests except the sit-and-reach, explained ∼53% of the variance. Sex and the 2.4-km run explained ∼47% of the variance. Aerobic fitness appeared to have the greatest impact on PAT performance, which may have related to the PAT design and duration. Tasks completed in succession, and the use of a relatively light dummy, may stress aerobic fitness and muscular endurance to a greater extent.
PubDate: Tue, 04 Jun 2024 00:00:00 GMT-
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- Physiological and Locomotor Profiling Enables to Differentiate Between
Sprinters, 400-m Runners, and Middle-Distance Runners-
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Authors: Thron; Maximiliane; Woll, Alexander; Doller, Lukas; Quittmann, Oliver Jan; Härtel, Sascha; Ruf, Ludwig; Altmann, Stefan
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Thron, M, Woll, A, Doller, L, Quittmann, OJ, Härtel, S, Ruf, L, and Altmann, S. Physiological and locomotor profiling enables to differentiate between sprinters, 400-m runners, and middle-distance runners. J Strength Cond Res 38(8): 1419–1427, 2024—Different approaches exist for characterizing athletes, e.g., physiological and locomotor profiling. The aims of this study were to generate and compare physiological and locomotor profiles of male and female runners and to evaluate relationships between the different approaches. Thirty-four highly trained adolescent and young adult female and male athletes (n = 11 sprinters; n = 11,400-m runners; n = 12 middle-distance runners) performed two 100-m sprints on a running track to determine maximal sprinting speed (MSS) and maximal lactate accumulation rate (ċLamax). A cardiopulmonary exercise test was performed on a treadmill to determine maximal aerobic speed (MAS) and maximal oxygen uptake (V̇o2max). Anaerobic speed reserve (ASR) was calculated as the difference between MSS and MAS. Group comparisons were conducted with a 2-way ANOVA (discipline × sex; p < 0.05) and Bonferroni post hoc tests and Cohen's d as effect size. Parameters were correlated by Pearson's correlation coefficients. Maximal aerobic speed and V̇o2max were higher in 400-m and middle-distance runners compared with sprinters (p ≤ 0.02; −2.24 ≤ d ≤ −1.29). Maximal sprinting speed and ċLamax were higher in sprinters and 400-m runners compared with middle-distance runners (0.03 ≤ p ≤ 0.28; 0.73 ≤ d ≤ 1.23). Anaerobic speed reserve was highest in sprinters and lowest in middle-distance runners (p ≤ 0.03; 1.24 ≤ d ≤ 2.79). High correlations were found between ASR and MAS, MSS, and ċLamax (p < 0.01; −0.55 ≤ r ≤ 0.91) and between ċLamax and MSS (p < 0.01; r = 0.74). Our results indicate that athletes of different sprinting and running disciplines show differing physiological and locomotor profiles, and that the parameters of these approaches are related to each other. This can be of interest for assessing strengths and weaknesses (e.g., for talent identification) or training prescription in these disciplines.
PubDate: Fri, 24 May 2024 00:00:00 GMT-
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- Low-Load and High-Load Resistance Exercise Completed to Volitional Fatigue
Induce Increases in Postexercise Metabolic Responses With More Prolonged
Responses With the Low-Load Protocol-
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Authors: Grisebach; Daniel; Bornath, Derek P. D.; McCarthy, Seth F.; Jarosz, Claudia; Hazell, Tom J.
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Grisebach, D, Bornath, DPD, McCarthy, SF, Jarosz, C, and Hazell, TJ. Low-load and high-load resistance exercise completed to volitional fatigue induce increases in post-exercise metabolic responses with more prolonged responses with the low-load protocol. J Strength Cond Res 38(8): 1386–1393, 2024—Comparisons of high-load with low-load resistance training (RT) exercise have demonstrated no differences in postexercise metabolism when volume is matched. This important limitation of matching or equating volume diminishes benefits of the low-load RT protocol. Therefore, the purpose of this study was to determine the effects of acute low-load high volume and high-load low volume RT protocols completed to volitional fatigue on postexercise metabolism. Eleven recreationally active resistance-trained male subjects (24 ± 2 years; BMI: 25.3 ± 1.5 kg·m−2) completed 3 experimental sessions: (a) no-exercise control (CTRL); (b) RT at 30% 1 repetition maximum (1RM; 30% 1RM); and (c) RT at 90% 1RM (90% 1RM) with oxygen consumption (V̇o2) measurements 2 hours postexercise. The RT sessions consisted of 3 sets of back squats, bench press, straight-leg deadlift, military press, and bent-over rows to volitional fatigue completed sequentially with 90 seconds of rest between sets and exercises. Changes were considered important if p < 0.100 with a ≥medium effect size. V̇o2 1 hour postexercise was elevated following 30% 1RM (25%; p = 0.003, d = 1.40) and 90% 1RM (14%; p = 0.010, d = 1.15) vs. CTRL and remained elevated 2 hours postexercise following 30% 1RM (16%; p = 0.010, d = 1.15) vs. CTRL. Total O2 consumed postexercise increased following 30% 1RM and 90% 1RM (∼17%; p < 0.044, d> 0.91) vs. CTRL. Fat oxidation was elevated 1 hour postexercise following 30% 1RM and 90% 1RM (∼155%; p < 0.001, d> 2.97) and remained elevated 2 hours postexercise following 30% 1RM compared with CTRL and 90% 1RM (∼69%; p < 0.030, d> 1.03). These data demonstrate beneficial changes to postexercise metabolism following high- and low-load RT sessions, with more prolonged effects following the low-load RT protocol completed to volitional fatigue.
PubDate: Wed, 22 May 2024 00:00:00 GMT-
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- Acute Responses to Traditional and Cluster-Set Squat Training With and
Without Blood Flow Restriction-
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Authors: Cornejo-Daza; Pedro J.; Sánchez-Valdepeñas, Juan; Páez-Maldonado, Jose; Rodiles-Guerrero, Luis; Boullosa, Daniel; León-Prados, Juan A.; Wernbom, Mathias; Pareja-Blanco, Fernando
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Cornejo-Daza, PJ, Sánchez-Valdepeñas, J, Páez-Maldonado, J, Rodiles-Guerrero, L, Boullosa, D, León-Prados, JA, Wernbom, M, and Pareja-Blanco, F. Acute responses to traditional and cluster-set squat training with and without blood flow restriction. J Strength Cond Res 38(8): 1401–1412, 2024—To compare the acute responses to different set configurations (cluster [CLU] vs. traditional [TRA]) under distinct blood flow conditions (free vs. restricted) in full-squat (SQ). Twenty resistance-trained males performed 4 protocols that differed in the set configuration (TRA: continuous repetitions; vs. CLU: 30 seconds of rest every 2 repetitions) and in the blood flow condition (FF: free-flow; vs. blood flow restriction [BFR]: 50% of arterial occlusion pressure). The relative intensity (60% 1RM), volume (3 sets of 8 repetitions), and resting time (2 minutes) were equated. Mean propulsive force (MPF), velocity (MPV) and power (MPP), and electromyography (EMG) parameters were recorded during each repetition. Tensiomyography (TMG), blood lactate, countermovement jump (CMJ) height, maximal voluntary isometric contraction, in SQ, and movement velocity against the load that elicited a 1 m·s−1 velocity at baseline (V1-load) in SQ were assessed at pre- and post-exercise. The CLU protocols allowed a better maintenance of MPF, MPV, MPP, and EMG median frequency during the exercise compared to TRA (clu-time interaction, p < 0.05). The TRA protocols experienced greater impairments post-exercise in TMG- and EMG-derived variables (clu-time interaction, p < 0.05) and SQ and CMJ performance (clu-time interaction, p = 0.08 and p < 0.05, respectively), as well as higher blood lactate concentrations (clu-time interaction, p < 0.001) than CLU. Moreover, BFR displayed decreases in TMG variables (bfr-time interaction, p < 0.01), but BFR-CLU resulted in the greatest reduction in twitch contraction time (p < 0.001). Cluster sets reduced fatigue during and after the training session and BFR exacerbated impairments in muscle mechanical properties; however, the combination of both could improve contraction speed after exercise.
PubDate: Tue, 21 May 2024 00:00:00 GMT-
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- Cardiovascular Demand Differences Between Male and Female US Marine
Recruits During Progressive Loaded Hikes-
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Authors: Schram; Ben; Orr, Robin; Niederberger, Brenda; Givens, Andrea; Bernards, Jake; Kelly, Karen R.
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Schram, B, Orr, R, Niederberger, B, Givens, A, Bernards, J, and Kelly, KR. Cardiovascular demand differences between male and female US Marine recruits during progressive loaded hikes. J Strength Cond Res 38(8): e454–e458, 2024—Despite having to carry the same occupational load, female soldiers tend to be lighter than male soldiers. The aim of this study was to determine the differences in cardiovascular load between female and male US Marine recruits during progressive load carriage hikes. United States Marine Corps recruits (565 male recruits; 364 female recruits) completed 6 loaded hikes over 6 weeks (1: 10 kg, 30 minutes; 2: 10 kg, 45 minutes; 3: 15 kg, 30 minutes, 4: 15 kg, 45 minutes; 5: 20 kg, 30 minutes; 6: 20 kg, 45 minutes) during which cardiovascular response was measured. Average heart rate (HRavg), HR maximum (HRmax), and pace were measured via a wrist-worn physiological monitor. Independent sample t-tests were conducted to compare between sexes, with significance set at 0.008 after adjusting for multiple comparisons. The average female recruit had significantly lower body mass (BM) compared with the average male recruit (p < 0.001) and thus carried a significantly heavier relative load. (10 kg ∼17%, 15 kg ∼25%, 20 kg ∼33%, p < 0.001). There were no significant differences in pace in any hike, and no significant differences were found in HRavg or HRmax when comparing female and male Marines during Hike 1. For female Marines, HRavg was significantly higher compared with male Marines during Hike 2 (+6.5 b·min–1, p < 0.001) and Hike 3 (+7.4 b·min–1, p < 0.001), and both HRavg and HRmax were significantly higher in Hike 4 (+11.9 b·min–1, +8.4 b·min–1, p < 0.001), Hike 5 (+7.7 b·min–1, +7.9 b·min–1, p < 0.001), and Hike 6 (+6.9 b·min–1, +7.1 b·min–1, p < 0.001), respectively. Female Marines endured greater cardiovascular demand compared with male Marines during load carriage events when carrying loads greater than 15 kg (∼25% BM).
PubDate: Fri, 26 Apr 2024 00:00:00 GMT-
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- Inter-Repetition Rest Impact on the Estimated Repetitions in Reserve at
Various Loads and Proximities to Neuromuscular Failure-
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Authors: Ruiz-Alias; Santiago A.; Ramirez-Campillo, Rodrigo; Leando Quidel-Catrilelbún, Maurio Elías; García-Pinillos, Felipe; Pérez-Castilla, Alejandro
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Ruiz-Alias, SA, Ramirez-Campillo, R, Leando Quidel-Catrilelbún, ME, García-Pinillos, F, and Pérez-Castilla, A. Inter-repetition rest impact on the estimated repetitions in reserve at various loads and proximities to neuromuscular failure . J Strength Cond Res 38(8): 1379–1385, 2024—The repetitions in reserve (RIR) estimation method allows for monitoring resistance training set volume. However, a significant bias is commonly observed when ending the set further from neuromuscular failure and using lower relative loads. Is unclear if implementing an IRR could improve its estimation validity. This study aimed to determine if the RIR estimation is influenced by the IRR at different relative loads and proximities to neuromuscular failure during the back squat (BQ) and bench press (BP) exercises. After a familiarization session, 19 male subjects (age, 21–26 years) completed an experimental session for each IRR configuration: IRR0 (without rest), IRR3 (3 seconds of rest), and SSIRR (self-selected rest [up to 5 seconds]). In each session, single sets to neuromuscular failure were performed at 3 relative loads (65% 1 repetition maximum [1RM], 75% 1RM, 85% 1RM) for BQ and BP exercises. Using the Estimated Repetitions to Failure scale, subjects estimated the RIR associated with a score of “5” and “2” (i.e., RIR-5 and RIR-2). The results revealed no interactions between the RIR estimation and IRR for BQ (RIR-5: p = 0.812; RIR-2: p = 0.084) or BP (RIR-5: p = 0.884; RIR-2: p = 0.944). Subjects provided valid estimations, with overestimation (BQ RIR-5: 0%; BQ RIR-2: 2.9%; BP RIR-5: 1.1%; BP RIR-2: 2.3%) or underestimation (BQ RIR-5: 14.9%; BQ RIR-2: 4%; BP RIR-5: 15.2% BP RIR-2: 8.2%) in few sets. In conclusion, the RIR estimation method seems valid, and the IRR (0–5 seconds) does not influence its validity at 65–85% 1RM loads nor proximities to neuromuscular failure (RIR-2, RIR-5).
PubDate: Thu, 25 Apr 2024 00:00:00 GMT-
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- The Modified Reactive Strength Index Is a Valid Measure of Lower-Body
Explosiveness in Male and Female High School Athletes-
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Authors: Witte; Brandon C.; Schouten, Tyler C.; Westphal, Jessica A.; VanZile, Adam W.; Jones, Daniel D.; Widenhoefer, Tricia L.; Dobbs, Ward C.; Jagim, Andrew R.; Luedke, Joel A.; Almonroeder, Thomas G.
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Witte, BC, Schouten, TC, Westphal, JA, VanZile, AW, Jones, DD, Widenhoefer, TL, Dobbs, WC, Jagim, AR, Luedke, JA, and Almonroeder, TG. The modified reactive strength index is a valid measure of lower-body explosiveness in male and female high school athletes. J Strength Cond Res 38(8): 1428–1432, 2024—The modified reactive strength index (mRSI) is a commonly used metric to quantify lower-body explosiveness during countermovement jump (CMJ) performance. However, few studies have attempted to examine its validity as a measure of explosiveness, particularly among high school athletes. The purpose of this study was to examine the validity of the mRSI as a measure of lower-body explosiveness among a relatively large sample of male and female high school athletes from various sports. As part of this study, male (n = 132) and female (n = 43) high school athletes performed CMJs, while ground reaction forces were recorded using a force platform. The vertical ground reaction force data collected during the CMJs were used to derive the following variables: peak force (PF), peak power, time to PF, time to take-off, peak rate of force development, and the mRSI. Principal component analysis was applied and reduced these variables into 2 components related to “force” and “speed.” The mRSI loaded on both the force (loading = 0.82) and speed (loading = −0.46) components, indicating that it incorporates elements of both force and speed, although it loaded more strongly on the force component than the speed component. The observed pattern of cross-loading suggests that the mRSI is generally a valid measure of lower-body explosiveness for male and female high school athletes.
PubDate: Thu, 25 Apr 2024 00:00:00 GMT-
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- Longitudinal Internal Training Load and Exposure in a High-Performance
Basketball Academy-
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Authors: Lever; Jonathon R.; Duffield, Rob; Murray, Andrew; Bartlett, Jonathan D.; Fullagar, Hugh H.K.
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Lever, JR, Duffield, R, Murray, A, Bartlett, JD, and Fullagar, HHK. Longitudinal internal training load and exposure in a high-performance basketball academy. J Strength Cond Res 38(8): 1464–1471, 2024—This study describes the longitudinal training exposure (session counts) and internal training load (Rating of Perceived Exertion [RPE] and Session Rating of Perceived Exertion [sRPE]) of youth basketball players at a high-performance academy, based on the training year, training term, and playing position. Historical internal training load and training exposure data were collated from 45 male high-performance youth basketball athletes between 2015 and 2019. Data included session duration, RPE, sRPE, training type, and date. Linear mixed models and pairwise comparisons were performed on the weekly means and categorized by training year (year 1, year 2, year 3), term (term 1, term 2, term 3, term 4), and playing position (Backcourt, Frontcourt). Linear mixed models indicate that the individual athlete had the greatest influence on variance in training load and exposure. Significant differences were observed for increased session count, duration, and sRPE (p < 0.001) in year 2 compared with year 1. These measures also increased within each year whereby term 3 and term 4 (p < 0.001) were significantly greater than term 1 and term 2. No significant differences were observed between playing position (p> 0.05). Training exposure and internal training load increase in year 2 from year 1 for high-performance youth basketball academy athletes. Differences between training load and exposure for terms (i.e., training blocks) suggest the phase of season influences training prescription, while playing position has limited effect.
PubDate: Thu, 25 Apr 2024 00:00:00 GMT-
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- Observe, Practice, and Improve' Enhancing Sidestep Cutting Execution in
Talented Female Soccer Players: A Four-Week Intervention Program With
Video Instruction-
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Authors: Nijmeijer; Eline M.; Kempe, Matthias; Elferink-Gemser, Marije T.; Benjaminse, Anne
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Nijmeijer, EM, Kempe, M, Elferink-Gemser, MT, and Benjaminse A. Observe, practice and improve' Enhancing sidestep cutting (SSC) execution in talented female soccer players: A four-week intervention program with video instruction. J Strength Cond Res 38(8): e430–e439, 2024—Implicit learning has the potential to improve movement execution and reduce injury risk. Previous research showed beneficial effects of short-term interventions with implicit learning in male athletes. However, research on long-term interventions in female athletes is lacking. The aim of this study was to examine the effects of a 4-week intervention with video instruction on movement execution of SSC, a task that is highly related with anterior cruciate ligament (ACL) injury risk, in female athletes. Twenty talented adolescent female soccer players were part of the control (CTRL, n = 10) or video instruction (VIDEO, n = 10) group. All subjects practiced 4 weeks and received general task instructions. In addition, the VIDEO group received expert video instruction during practice. Lower extremity kinematics and kinetics and vertical ground reaction force of SSC were examined during baseline, immediate post, and 1-week retention tests. After nonlinear registration, differences between each subject and the expert she had seen were determined. These differences were analyzed with SPM1D 2-way ANOVA. No interaction effects between time and group were found (p> 0.05). Main effects of time were found in the frontal plane. In particular, smaller deviations of subjects compared with the seen expert of the knee adduction (p = 0.005, 97.9–100% stance phase [SP]) and hip abduction (p = 0.005, 11.5–13.8% SP) and adduction (p < 0.001, 33.4–87.7% SP) moments were found in immediate post compared with baseline. These frontal plane short-term improvements, replicating earlier findings in both sexes, may lower ACL injury risk. The large observed interindividual differences over time may have concealed the long-term effects of video instruction at the group level.
PubDate: Thu, 25 Apr 2024 00:00:00 GMT-
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- The Impact of Exercise-Induced Muscle Damage on Various Cycling
Performance Metrics: A Systematic Review and Meta-Analysis-
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Authors: Devantier-Thomas; Baily; Deakin, Glen B.; Crowther, Fiona; Schumann, Moritz; Doma, Kenji
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Devantier-Thomas, B, Deakin, GB, Crowther, F, Schumann, M, and Doma, K. The impact of exercise-induced muscle damage on various cycling performance metrics: a systematic review and meta-analysis. J Strength Cond Res 38(8): 1509–1525, 2024—This systematic review and meta-analysis examined the impact of exercise-induced muscle damage (EIMD) on cycling performance. The primary outcome measure was cycling performance, whereas secondary outcome measures included creatine kinase (CK), delayed-onset muscle soreness (DOMS), and muscular contractions. Data were extracted and quantified through forest plots to report on the standardized mean difference and p values. The meta-analysis showed no significant change in oxygen consumption at 24–48 hours (p> 0.05) after the muscle damage protocol, although ventilation and rating of perceived exertion significantly increased (p < 0.05) during submaximal cycling protocols. Peak power output during both sprint and incremental cycling performance was significantly reduced (p < 0.05), but time-trial and distance-trial performance showed no change (p> 0.05). Measures of CK and DOMS were significantly increased (p < 0.05), whereas muscular force was significantly reduced following the muscle-damaging protocols (p < 0.05), confirming that cycling performance was assessed during periods of EIMD. This systematic review showed that EIMD affected both maximal and submaximal cycling performance. Therefore, coaches should consider the effect of EIMD on cycling performance when implementing unaccustomed exercise into a cycling program. Careful consideration should be taken to ensure that additional training does not impair performance and endurance adaptation.
PubDate: Fri, 19 Jan 2024 00:00:00 GMT-
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