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Journal Cover Journal of Sport and Health Science
   [15 followers]  Follow    
  This is an Open Access Journal Open Access journal
     ISSN (Print) 2095-2546
     Published by Elsevier Homepage  [2575 journals]
  • Sports medician and science in soccer

    • Abstract: Publication date: Available online 20 October 2014
      Source:Journal of Sport and Health Science
      Author(s): Donald T. Kirkendall , Bing Yu



      PubDate: 2014-11-12T10:57:39Z
       
  • Evaluation of the test–retest repeatability of the Injury Severity
           Perception score in patients with acute whiplash-associated disorder

    • Abstract: Publication date: Available online 27 October 2014
      Source:Journal of Sport and Health Science
      Author(s): Robert Ferrari
      Objective To determine the test–retest repeatability of the Injury Severity Perception (ISP) score in participants with acute whiplash-associated disorders. Methods Consecutive patients with whiplash-associated disorder, presenting in the acute stage to a primary care center, were asked to complete the ISP score. ISP was measured with a numerical rating scale that ranged from 0 to 10, on which subjects were asked to rate how severe (in terms of damage) they thought their injury was. The anchors were labeled ‘‘no damage’’ (0) and ‘‘severe, and maybe permanent damage” (10). The ISP questionnaire was administered to the participants at the time of recruitment and again 7 days later. Repeatability was evaluated by calculating percentage agreement and Cohen kappa statistic between the two time points of measurement. Results A total of 94 subjects (34 males, 60 females, mean age 40.6 ± 10.0 years, range 19–60years) were included. The mean ISP score was 4.9 ± 1.7 (range 2–9 out of 10) at the time of recruitment and 5.1 ± 2.1 (range 2–9 out of 10) 7 days later. The percentage agreement between the two repeat measures of the ISP was 86% and the kappa coefficient was 0.79. Conclusions This study suggests that the test–retest repeatability for the ISP is high and that it is thus likely to have a low risk of classification bias in prognostic studies. The ISP likely has adequate reliability for use in epidemiological research of whiplash-associated disorders.


      PubDate: 2014-11-12T10:57:39Z
       
  • Daily heart rate variability of Paralympic gold medallist swimmers: A
           17-week investigation

    • Abstract: Publication date: Available online 8 November 2014
      Source:Journal of Sport and Health Science
      Author(s): Rohan Edmonds , Anthony Leicht , Mark McKean , Brendan Burkett
      Objectives Heart rate variability (HRV) can be a simple, non-invasive method of gauging cardiac autonomic nervous system fluctuations across periodised training workloads and taper in elite athlete populations. The purpose of these three case studies was to examine daily cardiac autonomic variations in Paralympic athletes leading in to the Paralympic games. Methods Three Paralympic gold medallist swimmers were monitored daily for their resting HRV over a 17 week monitoring period leading up to the Paralympic games. Specific time- and frequency-domain measures, along with non-linear indices of HRV were calculated for all analyses. All HRV data were analysed individually using daily values, weekly average values, and average values for rest and training phases. Results A significant difference in HRV was seen for all variables between athlete 1 and athletes 2 and 3 (amputee disabilities) during the entire monitoring period. Conclusion Despite minimal long-term changes, both swimming classification and disability type significantly influence HRV during athlete monitoring. An increased understanding of individual responses to training, travel and other outside influences affecting Paralympic athletes could potentially lead to improved management and monitoring of training workloads for enhanced performance.


      PubDate: 2014-11-12T10:57:39Z
       
  • Women’s football: Player characteristics and demands of the game

    • Abstract: Publication date: Available online 7 October 2014
      Source:Journal of Sport and Health Science
      Author(s): Vanessa Martinez-Lagunas , Margot Niessen , Ulrich Hartmann
      The number of scientific investigations on women’s football specific to the topics of player characteristics and demands of the game have considerably increased in recent years due to the increased popularity of the women’s game worldwide, although they are not yet as numerous as in the case of men’s football. To date, only two scientific publications have attempted to review the main findings of studies published in this area. However, one of them was published about 20 years ago, when women’s football was still in its infancy and there were only a few studies to report on. The other review is more recent. Nonetheless, its main focus was on the game and training demands of senior elite female players. Thus, information on female footballers of lower competitive levels and younger age groups was not included. Consequently, an updated review is needed in this area. The present article therefore aims to provide an overview of a series of studies that have been published so far on the specific characteristics of female football players and the demands of match-play. Mean values reported in the literature for age (12-27 years), body height (155-174 cm), body mass (48-72 kg), percent body fat (13%-29%), maximal oxygen uptake (45.1-55.5 mL/kg/min), Yo-Yo Intermittent Recovery Test Level 1 (780-1379 m), maximum heart rate (189-202 bpm), 30-m sprint times (4.34-4.96 s), and counter-movement jump or vertical jump (28-50 cm) vary mostly according to the players’ competitive level and positional role. There are also some special considerations that coaches and other practitioners should be aware of when working with female athletes such as the menstrual cycle, potential pregnancy and lactation, common injury risks (particularly knee and head injuries) and health concerns (e.g., female athlete triad, iron deficiency, and anemia) that may affect players’ football performance, health or return to play. Reported mean values for total distance covered (4-13 km), distance covered at high-speed (0.2-1.7 km), average/peak heart rate (74%-87%/94%-99% HRmax), average/peak oxygen uptake (52%-77%/96%-98% VO2max), and blood lactate (2.2-7.3 mmol/L) during women’s football match-play vary according to the players’ competitive level and positional role. Methodological differences may account for the discrepancy of the reported values as well. Finally, this review also aims to identify literature gaps that require further scientific research in women’s football and to derive a few practical recommendations. The information presented in this report provides an objective point of reference about player characteristics and game demands at various levels of women’s football, which can help coaches and sport scientists to design more effective training programs and science-based strategies for the further improvement of players’ football performance, health, game standards, and positive image of this sport.


      PubDate: 2014-10-09T04:27:34Z
       
  • Physical contributors to glenohumeral internal rotation deficit in high
           school baseball players

    • Abstract: Publication date: Available online 23 September 2014
      Source:Journal of Sport and Health Science
      Author(s): Elizabeth E. Hibberd , Casey E. Shutt , Sakiko Oyama , J. Troy Blackburn , Joseph B. Myers
      Background Glenohumeral internal rotation deficit (GIRD) is a risk factor for shoulder and elbow injury in baseball players. Although this evidence forms a basis for recommending stretching, clinical measures of internal rotation range of motion (ROM) do not differentiate if GIRD is due to muscular, capsuloligamentous, or osseous factors. Understanding the contributions of these structures to GIRD is important for the development of targeted interventions. We hypothesize that the osseous component will have the greatest relative contribution to GIRD, followed by muscle stiffness and posterior capsule thickness. Methods Internal rotation ROM, muscle stiffness (teres minor, infraspinatus, and posterior deltoid), posterior capsule thickness, and humeral retrotorsion was evaluated on 156 baseball players. A side-to-side difference was calculated for each variable. Variables were entered into a multivariable linear regression to determine the significant predictors of GIRD. Results The regression model was statistically significant (R 2 = 0.134, F(1, 156) = 24.0 p < 0.01) with only humeral retrotorsion difference remaining as a significant predictor (β = -0.243, t 156 = -4.9, p < 0.01). A greater humeral retrotorsion side-to-side difference was associated with more GIRD. Conclusion Humeral retrotorsion accounted for 13.3% of the variance in GIRD. The stiffness of the superficial shoulder muscles and capsular thickness, as measured in this study were not predictors of GIRD. Factors not assessed in this study, such as deeper muscle stiffness, capsule/ligament laxity, and neuromuscular regulation of muscle stiffness may also contribute to GIRD. Since it is the largest contributor to GIRD, causes of changes in humeral retrotorsion need to be identified. The osseous component only accounted for 13.3% of the variance in GIRD, indicating a large contribution from soft tissues factors that were not addressed in this study. These factors need to be identified to develop evidence-based evaluations and intervention programs to decrease the risk of injury in baseball players.


      PubDate: 2014-09-26T02:22:45Z
       
  • Acute short-term dim light exposure can lower muscle strength endurance

    • Abstract: Publication date: Available online 23 September 2014
      Source:Journal of Sport and Health Science
      Author(s): Arnold G. Nelson , Joke Kokkonen , Megan Mickenberg
      Background Since it has been shown that spending 18 h under dim light conditions can result in reduced handgrip endurance, it was questioned whether or not a shorter exposure to dim light (i.e., 1 h) would have similar influence upon muscular endurance. Therefore this study compared the number of weighted knee extension lifts that could be done after spending 1 h in either dim or bright light. Methods Participants (5 women, 11 men, college students 19-26 years) performed knee extension lifts to exhaustion with a load approximating 40% of their body weight. The lifts to exhaustion were measured immediately following 1 h of exposure to each of the following three conditions: dark (DL), room light (RL) and room light plus 5 mg melatonin (RLM). A minimum of 48 h separated each condition, and all participants started the exposures in a rested fed condition. Results Average (±SD) number of knee extension lifts for RL (62.0 ± 22.0) was significantly (p < 0.05) greater than DL (51.4 ± 14.7) and RLM (57.8 ± 22.9). The number of RLM knee extension lifts was not significantly different from DL. Exposure to 1 h of dim light immediately prior to activity can result in a reduction in thigh muscle endurance. The decline in performance to short-term dim light exposure was similar to that found following longer-term exposure. Conclusion It appears that light intensity can influence muscle endurance, however, at this time this effect cannot be directly related to endogenous melatonin production.


      PubDate: 2014-09-26T02:22:45Z
       
  • Validity and reliability of eating disorder assessments used with
           athletes: A review

    • Abstract: Publication date: Available online 20 September 2014
      Source:Journal of Sport and Health Science
      Author(s): Zachary Pope , Yong Gao , Nicole Bolter , Mary Pritchard
      Background Prevalence of eating disorders (ED) among college-aged athletes has risen in recent years. Although measures exist for assessing ED, these measures have not been thoroughly reviewed in athletes. This study reviewed the validity and reliability evidence of the commonly used measures for assessing ED in athlete populations aged 18-26 years. Methods Databases were searched for studies of regarding ED on male and/or female athletes. Inclusion criteria stated the study (a) assessed ED in an athlete population 18-26 years of age and (b) investigated ED using a psychometric measure found valid and/or reliable in a non-athlete population and/or athlete population. Results Fifty studies met the inclusion criteria. Seven and 22 articles, respectively, studied eating disorder behaviors in male and female athletes whereas 21 articles studied ED in combined-gender samples. The five most commonly used measures were the Eating Attitudes Test (EAT), Eating Disorder Inventory (EDI), Bulimia Test-Revised (BULIT-R), Questionnaire for Eating Disorder Diagnosis (QEDD), and the Eating Disorder Examination Questionnaire (EDE-Q). Conclusion Only seven studies calculated validity coefficients within the study whereas 47 cited the validity coefficient. Twenty-six calculated a reliability coefficient whereas 47 cited the reliability of the eating disorder measures. Four studies found validity evidence for the EAT, EDI, BULIT-R, QEDD, and EDE-Q in an athlete population. Few studies reviewed calculated validity and reliability coefficients of eating disorder measures. Cross-validation of these measures in athlete populations is clearly needed.


      PubDate: 2014-09-22T02:19:50Z
       
  • An 8-week reactive balance training program in older healthy adults: A
           preliminary investigation

    • Abstract: Publication date: Available online 20 September 2014
      Source:Journal of Sport and Health Science
      Author(s): Max R. Paquette , Yuhua Li , Joseph Hoekstra , Joshua Bravo
      Background This preliminary study examined the effects of an 8-week supervised reactive balance training program on reaction time and foot speed, static balance and balance confidence in healthy older adults compared to an exercise control group. Methods Twenty-five older adults were randomly assigned to a reactive balance training group (QuickBoard; n = 12; 71.0 ± 8.6 years) or a stationary cycling group (control; n = 13; 70.2 ± 6.0 years). Both groups were tested for foot reaction time, foot speed, static balance, and balance confidence at baseline, 4-week, 8-week, and 4-week follow-up. Results Results indicated significant improvements in QuickBoard foot reaction time and speed in both groups with greater improvements in the QuickBoard group. However, no group difference was found in static balance performance. Conclusion Although the improvements in reaction time and foot speed may be beneficial for fall and trip prevention, the implications of the current findings for trip avoidance and performance of daily tasks are unclear.


      PubDate: 2014-09-22T02:19:50Z
       
  • Effect of different stretching strategies on the kinetics of vertical
           jumping in female volleyball athletes

    • Abstract: Publication date: Available online 6 September 2014
      Source:Journal of Sport and Health Science
      Author(s): Nicholas T. Kruse , Marcus W. Barr , Roger M. Gilders , Michael R. Kushnick , Sharon R. Rana
      Purpose The present study aimed to examine the effect of static stretching (SS) and a sport-specific dynamic stretching (DS) session at two specific post-stretch time intervals in highly trained female athletes (age 19.9 ± 1.60 years; height 1.80 ± 0.06 m; mass 76.87 ± 9.95 kg) on kinetic parameters of peak force, time-to-takeoff and rate of force development. Methods The data were collected over 3 days (randomized within subject design with control session). Following each stretch session (SS vs. DS vs. control) of equal duration (7 min total: 30 s per targeted muscle group) participants performed countermovement jumping on a force platform at 1 and 15 min after stretching. Results The DS session significantly improved upon kinetic variables of rate of force development, peak force and time-to-takeoff relative to SS at 1 min after stretching. No significant effect was found at 15 min. Conclusions Together these findings suggest that when training and competing to jump quickly and maximally the female athlete should incorporate DS instead of SS as part of their pre-competition warm-up, but conduct performance within 15 min of their warm-up to elicit maximal gains.


      PubDate: 2014-09-07T00:45:00Z
       
  • Fundamental movement skills training to promote physical activity in
           children with and without disability: A pilot study

    • Abstract: Publication date: Available online 28 August 2014
      Source:Journal of Sport and Health Science
      Author(s): Catherine M. Capio , Cindy H.P. Sit , Kathlynne F. Eguia , Bruce Abernethy , Richard SW. Masters
      Background A positive association between fundamental movement skills (FMS) and physical activity (PA) has been shown in previous research of children with and without disability. This pilot study explored a causal mechanism for such relationship, and hypothesized that when FMS proficiency is improved, enhanced PA uptake will be found in children with and without disability. It was further hypothesized that improving FMS proficiency will have a greater impact on children with disability than those without disability. Methods Participants include typically developing (TD) children without disability and children with cerebral palsy (CP), who were allocated to FMS training groups (CP-FMS n = 12; TD-FMS n = 13) and control groups (CP-C n = 12, TD-C n = 13). Training groups practiced five FMS (run, jump, kick, throw, catch) in weekly 45-min sessions for 4 weeks. Control groups had their regular physiotherapy (CP) or physical education (TD) sessions. FMS were evaluated using process- and product-oriented measures, and PA was measured using accelerometers, before and after training. Results It was verified that training groups gained improvements in FMS while control groups did not. No significant changes in weekday PA were found. Increased weekend moderate to vigorous physical activity (MVPA) was found in the CP-FMS group, while decreased weekend sedentary time was found in the CP-FMS and TD-FMS groups. The percentages of participants who exceeded the minimum detectable change (MDC90) in MVPA and sedentary time were larger in children with CP than in children without disability. Conclusion The findings suggest that improved FMS proficiency could potentially contribute to heightened PA and decreased sedentary time during weekends for children. Such effect of improved FMS proficiency on PA appears to be greater in those with physical disability than in those without disability. It is recommended that the findings of this pilot study should be further examined in future research.


      PubDate: 2014-09-01T23:39:19Z
       
  • Sport specificity background affects the principal component structure
           of vertical squat jump performance of young adult female athletes

    • Abstract: Publication date: September 2014
      Source:Journal of Sport and Health Science, Volume 3, Issue 3
      Author(s): Vassilios Panoutsakopoulos , Nikolaos Papachatzis , Iraklis A. Kollias
      Purpose Long-term training specificity is thought to alter performance in tests evaluating strength and power production capability. The aim of the present study was to provide additional information to the limited existing knowledge concerning the possible differences of the force/time profile of squat jumping among different groups of young female athletes. Methods One hundred and seventy-three adult women (20.1 ± 2.8 years, 1.71 ± 0.09 m, 65.6 ± 10.3 kg, mean ± SD for age, height, and mass, respectively) engaged in track and field (TF), volleyball (VO), handball (HA), basketball (BA), and physical education students (PE) executed maximal squat jumps (SQJ) on a force plate. Pearson's correlation was used to identify the relationship between SQJ performance, the anthropometric characteristics and the biomechanical parameters. Differences concerning the biomechanical parameters among groups were investigated with analysis of variance, while the force- (FPD) or time- (TPD) dependency of SQJ execution was examined using principal components analysis (PCA). Results SQJ was unrelated to body height but significantly correlated with body mass (r = −0.26, p = 0.001). TF jumped higher and produced larger peak body power output compared to all the other groups (p < 0.05). All athletes were superior to PE since they performed the SQJ with a longer (p < 0.05) vertical body center of mass trajectory during the propulsion phase. PCA results revealed that TF significantly differentiated than the other groups by relying on FPD. Conclusion Various different profiles of FPD and TPD were detected due to different sporting background in young female athletes. Since TF superiority in SQJ was relied on the larger power production and a greater FPD, female indoor team sport athletes are suggested to execute jumping exercises adopting the jumping strategies utilized by TF.


      PubDate: 2014-09-01T23:39:19Z
       
  • Relationship between peak oxygen uptake and regional body composition in
           Japanese subjects

    • Abstract: Publication date: September 2014
      Source:Journal of Sport and Health Science, Volume 3, Issue 3
      Author(s): Kanae Oda , Nobuyuki Miyatake , Noriko Sakano , Takeshi Saito , Motohiko Miyachi , Izumi Tabata , Takeyuki Numata
      Purpose To investigate the link between peak oxygen uptake and regional body composition by dual energy X-ray absorptiometry (DEXA) in Japanese subjects. Methods A total of 93 men (42.2 ± 12.3 years old) and 106 women (43.5 ± 12.3 years old) were enrolled in this cross-sectional investigation study. Peak oxygen uptake was measured by the breath-by-breath method. Regional body composition i.e., body fat mass, lean body mass, and body fat percentage was evaluated using DEXA. In addition, metabolic risk parameters were also evaluated. Results Peak oxygen uptake was 37.6 ± 8.7 mL/kg/min in men and 31.1 ± 6.4 mL/kg/min in women, and decreased with age in both genders. Peak oxygen uptake was significantly correlated with total body fat percentage (men: r = −0.684, p < 0.0001; women: r = −0.681, p < 0.0001). These associations remained even after adjusting for age and total lean body mass. However, peak work rate was positively and significantly correlated with leg lean body mass. Conclusion Peak oxygen uptake was closely correlated with total body fat percentage in both genders. Aerobic exercise as well as leg resistance training might be useful for improving peak oxygen uptake in Japanese subjects.


      PubDate: 2014-09-01T23:39:19Z
       
  • Lower extremity injury in female basketball players is related to a large
           difference in peak eversion torque between barefoot and shod conditions

    • Abstract: Publication date: September 2014
      Source:Journal of Sport and Health Science, Volume 3, Issue 3
      Author(s): Jennifer M. Yentes , Max J. Kurz , Nicholas Stergiou
      Background The majority of injuries reported in female basketball players are ankle sprains and mechanisms leading to injury have been debated. Investigations into muscular imbalances in barefoot versus shod conditions and their relationship with injury severity have not been performed. The purpose of this study was to investigate the effects of wearing athletic shoes on muscular strength and its relationship to lower extremity injuries, specifically female basketball players due to the high incidence of ankle injuries in this population. Methods During pre-season, 11 female collegiate basketball players underwent inversion and eversion muscle strength testing using an isokinetic dynamometer in both a barefoot and shod conditions. The difference between conditions was calculated for inversion and eversion peak torque, time to peak torque as well as eversion-to-inversion peak torque percent strength ratio for both conditions. Lower extremity injuries were documented and ranked in severity. The ranked difference between barefoot and shod conditions for peak torque and time to peak torque as well as percent strength ratio was correlated with injury ranking using a Spearman rho correlation (ρ) with an α level of 0.05. Results The ranked differences in barefoot and shod for peak eversion and inversion torque at 120°/s were correlated with their injury ranking. Ranking of the athletes based on the severity of injuries that were sustained during the season was found to have a strong, positive relationship with the difference in peak eversion torque between barefoot and shod (ρ = 0.78; p = 0.02). Conclusion It is possible that a large discrepancy between strength in barefoot and shod conditions can predispose an athlete to injury. Narrowing the difference in peak eversion torque between barefoot and shod could decrease propensity to injury. Future work should investigate the effect of restoration of muscular strength during barefoot and shod exercise on injury rates.


      PubDate: 2014-09-01T23:39:19Z
       
  • Editorial board

    • Abstract: Publication date: September 2014
      Source:Journal of Sport and Health Science, Volume 3, Issue 3




      PubDate: 2014-09-01T23:39:19Z
       
  • Concussion management in soccer

    • Abstract: Publication date: Available online 7 August 2014
      Source:Journal of Sport and Health Science
      Author(s): Jason P. Mihalik , Robert C. Lynall , Elizabeth F. Teel , Kevin A. Carneiro
      Brain injuries in sports drew more and more public attentions in recent years. Brain injuries vary by name, type, and severity in the athletic setting. It should be noted, however, that these injuries are not isolated to only the athletic arena, as non-athletic mechanisms (e.g., motor vehicle crashes) are more common causes of traumatic brain injuries (TBI) among teenagers. Notwithstanding, as many as 1.6 and 3.8 million TBI result from sports each year in the United States alone. These injuries are extremely costly to the global health care system, and make TBI among the most expensive conditions to treat in children. This article serves to define common brain injuries in sport; describe their prevalence, what happens to the brain following injury, how to recognize and manage these injuries, and what you can expect as the athlete recovers. Some return-to-activity considerations for the brain-injured athlete will also be discussed.


      PubDate: 2014-08-11T21:54:16Z
       
  • Effect of turf on the cutting movement of female football players

    • Abstract: Publication date: Available online 7 August 2014
      Source:Journal of Sport and Health Science
      Author(s): Gerda Strutzenberger , Hue-Man Cao , Janina Koussev , Wolfgang Potthast , Gareth Irwin
      Purpose The globalisation of artificial turf and the increase in player participation has driven the need to examine injury risk in the sport of football. The purpose of this study was to investigate the surface-player interaction in female football players between natural and artificial turf. Methods Eight university level female football players performed an unanticipated cutting manoeuver at an angle of 30° and 60°, on a regulation natural grass pitch (NT) and a 3G artificial turf pitch (AT). An automated active maker system (CodaSport CXS System, 200Hz) quantified 3D joint angles at the ankle and knee during the early deceleration phase of the cutting, defined from foot strike to weight acceptance at 20% of the stance phase. Differences were statistically examined using a two-way (cutting angle, surface) ANOVA, with an α level of p < 0.05 and Cohen’s d effect size reported. Results A trend was observed on the AT, with a reduction in knee valgus and internal rotation, suggesting a reduced risk of knee injury. This findings highlight that AT is no worse than NT and may have the potential to reduce the risk of knee injury. The ankle joint during foot strike showed large effects for an increase dorsiflexion and inversion on AT. A large effect for an increase during weight acceptance was observed for ankle inversion and external rotation on AT. Conclusion These findings provide some support for the use of AT in female football, with no evidence to suggests that there is an increased risk of injury when performing on an artificial turf. The ankle response was less clear and further research is warranted. This initial study provides a platform for more detailed analysis, and highlights the importance of exploring the biomechanical changes in performance and injury risk with the introduction of AT.


      PubDate: 2014-08-11T21:54:16Z
       
  • Effects of small-volume soccer and vibration training on body composition,
           aerobic fitness, and muscular PCr kinetics for inactive women aged 20-45

    • Abstract: Publication date: Available online 7 August 2014
      Source:Journal of Sport and Health Science
      Author(s): Luke J. Connolly , Suzanne Scott , Magni Mohr , Giorgos Ermidis , Ross Julian , Jens Bangsbo , Sarah R. Jackman , Joanna L. Bowtell , Rosemary C. Davies , Susan J. Hopkins , Richard Seymour , Karen M. Knapp , Peter Krustrup , Jonathan Fulford
      Purpose The present study investigated the effects of 16 weeks of small-volume, small-sided soccer training (soccer group (SG) n = 13) and oscillating whole-body vibration training (vibration group (VG) n = 17) on body composition, aerobic fitness and muscle PCr kinetics in healthy inactive premenopausal women in comparison with an inactive control group (CO) (n = 14). Methods Training for SG and VG consisted of twice-weekly 15-min sessions with average heart rates (HR) of ∼155 and 90 bpm respectively. Pre- and post-measurements of body composition (DXA), phosphocreatine (PCr) on- and off-kinetics and HR measurements during standardised submaximal exercise were performed. Results After 16 weeks of training in SG, fat percentage was lowered (p = 0.03) by 1.7% ± 2.4 % from 37.5% ± 6.9% to 35.8% ± 6.2% and the PCr decrease in the quadriceps during knee-extension ramp exercise was attenuated (4% ± 8%, p = 0.04), with no changes in VG or CO (time-group effect: p = 0.03 and p = 0.03). Submaximal exercise HR was also reduced in SG after 16 weeks of training (7% ± 5% of HRmax, p = 0.01). Conclusion Short duration soccer training for 16 weeks appears to be sufficient to induce favourable changes in body composition and indicators of aerobic fitness and muscle oxidative capacity in untrained premenopausal women.


      PubDate: 2014-08-11T21:54:16Z
       
  • Chinese-translated Behavioral Regulation in Exercise Questionnaire-2:
           Evidence from university students in Mainland China and Hong Kong.

    • Abstract: Publication date: Available online 1 August 2014
      Source:Journal of Sport and Health Science
      Author(s): Jing Dong Liu , Pak-Kwong Chung , Chun-Qing Zhang , Gangyan Si
      Purpose The study further examined the psychometric properties of the Chinese-translated Behavioral Regulation in Exercise Questionnaire-2 (C-BREQ-2) among Chinese university students from Mainland China and Hong Kong. Methods University students from Mainland China (n = 191) and Hong Kong (n = 194) participated in this study. Factorial validity, discriminant validity, nomological validity, internal reliability, and measurement invariance across sample of the C-BREQ-2 were examined. Results Confirmatory factor analysis provided support for the factorial validity of the 18-item, 5-factor structure C-BREQ-2. Examination of the 95% confidence interval of the inter-factor correlations suggested that the C-BREQ-2 assesses related but distinct constructs, which provided support for its discriminant validity. The internal consistency reliability of the C-BREQ-2 was found acceptable. Examination of the pattern of inter-factor correlations between different regulations suggested that a simplex-like pattern was displayed, which provided evidence for the nomological validity of C-BREQ-2. The results from multi-group confirmatory factor analysis suggested that the factor loadings and factor variances/covariances of the C-BREQ-2 measurement model were invariant across the Chinese University students in Mainland China and Hong Kong. Conclusion The current study provided further psychometric evidence for the C-BREQ-2, which makes the further application and research of self-determination theory (SDT) based motivation in relation to exercise and physical activity in the Mainland Chinese context possible.


      PubDate: 2014-08-05T21:14:53Z
       
  • Anterior cruciate ligament injuries in soccer: Loading mechanisms, risk
           factors, and prevention programs

    • Abstract: Publication date: Available online 30 July 2014
      Source:Journal of Sport and Health Science
      Author(s): Boyi Dai , Dewei Mao , William E. Garrett , Bing Yu
      Anterior cruciate ligament (ACL) injuries are common in soccer. Understanding ACL loading mechanisms and risk factors for ACL injury is critical for designing effective prevention programs. The purpose of this review is to summarize the relevant literature on ACL loading mechanisms, ACL injury risk factors, and current ACL injury prevention programs for soccer players. Literature has shown that tibial anterior translation due to shear force at the proximal end of tibia is the primary ACL loading mechanism. No evidence has been found showing that knee valgus moment is the primary ACL loading mechanism. ACL loading mechanisms are largely ignored in previous studies on risk factors for ACL injury. Identified risk factors have little connections to ACL loading mechanisms. The results of studies on ACL injury prevention programs for soccer players are inconsistent. Current ACL injury prevention programs for soccer players are clinically ineffective due to low compliance. Future studies are urgently needed to identify risk factors for ACL injury in soccer that is connected to ACL loading mechanisms, and have cause-and-effect relationships with injury rate, and develop new prevention programs to improve compliance.


      PubDate: 2014-07-31T20:49:39Z
       
  • The relative age effect has no influence on match outcome in youth soccer

    • Abstract: Publication date: Available online 31 July 2014
      Source:Journal of Sport and Health Science
      Author(s): Donald T. Kirkendall
      Purpose In age-restricted youth sport, the over-selection of athletes born in the first quarter of the year and under-selection of athletes born in the last quarter of the year has been called the relative age effect (RAE). Its existence in youth sports like soccer is well established. Why it occurs has not been identified, however, one thought is that older players, generally taller and heavier, are thought to improve the team’s chances of winning. To test this assumption, birth dates and match outcome were correlated to see if teams with the oldest mean age had a systematic advantage against teams with younger mean ages. Methods Player birth dates and team records (n = 5943 players on 371 teams; both genders; U11-U16) were obtained from the North Carolina Youth Soccer Association for the highest level of statewide youth competition. Results The presence of an RAE was demonstrated with significant oversampling from players born in the 1st vs. the 4th quarter (overall: 29.6% vs. 20.9% respectively, p < 0.0001). Mean team age was regressed on match outcomes (winning %, points/match, points/goal, and goals for, against, and goal difference), but there was no evidence of any systematic influence of mean team age and match outcomes, except possibly in U11 males. Conclusion Selecting players based on physical maturity (and subsequently, on age) does not appear to have any systematic influence on match outcome or season record in youth soccer suggesting that the selection process should be focused on player ability and not on physical maturation.


      PubDate: 2014-07-31T20:49:39Z
       
  • Principle and practices of training for soccer

    • Abstract: Publication date: Available online 31 July 2014
      Source:Journal of Sport and Health Science
      Author(s): Ryland Morgans , Patrick Orme , Liam Anderson , Barry Drust
      The complexity of the physical demands of soccer requires the completion of a multi-component training programme. The development, planning, and implementation of such a programme is difficult due partly to the practical constraints related to the competitive schedule at the top level. The effective planning and organisation of training is therefore crucial to the effective delivery of the training stimulus for both individual players and the team. The aim of this article is to provide an overview of the principles of training that can be used to prepare players for the physical demands of soccer. Information relating to periodisation is supported by an outline of the strategies used to deliver the acute training stress in a soccer environment. The importance of monitoring to support the planning process is also reviewed.


      PubDate: 2014-07-31T20:49:39Z
       
  • Effects of carbohydrate supplements on exercise-induced menstrual
           dysfunction and ovarian subcellular structural changes in rats

    • Abstract: Publication date: Available online 30 June 2014
      Source:Journal of Sport and Health Science
      Author(s): Can Zhao , Xiao-Li Liu , Run-Xiao Hong , He Li , Rena Li , Ren-Wei Wang
      Background Exercise-associated menstrual dysfunction (EAMD) is a common health problem in female athletes as a part of female athlete triad (FAT), a condition related to low energy availability. In this study, we explored the possibility that carbohydrate supplements can improve the status of EAMD and prevent exercise-induced ovarian injury in a FAT rat model. This research aimed to provide experimental evidence with regard to the relationship of energy intervention and EAMD. Methods Forty-five female Sprague–Dawley rats (2 months old) were randomly divided into five experimental groups: control group (C), 9-week exercise as model for EAMD (E), post-EAMD recovery group (R), oligosaccharide intervention group (O), and glucose intervention group (G). All rats were sacrificed at the end of 9 weeks. Serum samples were collected for measuring gonadotropin releasing hormone, follicle stimulating hormone, luteinizing hormone, 17β-estradiol and progesterone levels. The ovaries were taken for investigation of exercise- and carbohydrate-induced follicular subcellular structure changes. Results Exercise induced irregular menstrual cycles and ovary subcellular structural damages, such as swollenness of mitochondrial in rats from groups E and R. Both glucose and oligosaccharide supplements restored well-differentiated mitochondria in the ovarian follicular cells, and a significant improvement of endoplasmic reticulum and Golgi in swollenness in theca cells in groups O and G compared to groups C, E, and R. There was no difference in mitochondria subcellular structural changes between groups O and G. Group E showed attenuation of serum levels of 17β-estradiol and progesterone compared to C. There were no differences of 17β-estradiol serum levels among groups O, G, and R, while group G showed a lower level of progesterone than C. Conclusion Female adult rats with 9-week continuous exercise can cause menstrual dysregulation as a model for EAMD. Post-EAMD intervention with glucose and oligosaccharide intake can normalize the menstrual cycle, restore the follicular subcellular structure, and reverse the exercise-induced reduction of ovary sex hormones. It suggests a positive feedback of hypothalamus–pituitary–ovarian axis might be involved in the molecular mechanisms of energy intake in treating EAMD.


      PubDate: 2014-07-25T20:28:35Z
       
  • Women's health in exercise and aging: What do we know?

    • Abstract: Publication date: Available online 1 July 2014
      Source:Journal of Sport and Health Science
      Author(s): Rena Li



      PubDate: 2014-07-25T20:28:35Z
       
  • Exercise training and antioxidant supplementation independently improve
           cognitive function in adult male and female GFAP-APOE mice

    • Abstract: Publication date: Available online 26 June 2014
      Source:Journal of Sport and Health Science
      Author(s): Kiran Chaudhari , Jessica M. Wong , Philip H. Vann , Nathalie Sumien
      Purpose The purpose of this study was to determine if antioxidant supplementation, moderate exercise, and the combination of both treatments could ameliorate cognitive performance in adult mice and whether the apolipoprotein E (APOE) genotype as well as sex could influence the functional outcomes of the treatments. Methods For a period of 16 weeks, separate groups of male and female mice expressing either the human APOE3 or APOE4 isoforms were fed either a control diet (NIH-31) or the control diet supplemented with vitamins E and C (1.12 IU/g diet α-tocopheryl acetate and 1.65 mg/g ascorbic acid). The mice were further separated into a sedentary group or a group that followed a daily exercise regimen. After 8 weeks on the treatments, the mice were administered a battery of functional tests including tests to measure cognitive and affective function. Results There was no effect of genotype or treatment on the learning performance in the Morris water maze. In the discriminated avoidance task, APOE4 mice performed better in learning the discrimination component of the task. Overall, exercise improved performance of APOE4 and APOE3 mice on various aspects of the active avoidance task. Antioxidant supplementation improved performance only in the APOE4 mice. On the test for anxiety, APOE4 mice spent more time in the open arms and supplementation with antioxidant reversed that effect. Conclusion Exercise was the most effective treatment at improving cognitive function in both genotypes and sex, while antioxidants seemed to be effective only in the APOE4. In young adult mice only non-spatial learning and memory were improved. The combination of the two treatments did not yield further improvement in cognition, and there was no antagonistic action of the antioxidant supplementation on the beneficial effects of exercise.


      PubDate: 2014-07-25T20:28:35Z
       
  • Sex differences in exercise and drug addiction: A mini review of animal
           studies

    • Abstract: Publication date: Available online 28 June 2014
      Source:Journal of Sport and Health Science
      Author(s): Yuehui Zhou , Chenglin Zhou , Rena Li
      Growing literature has demonstrated that exercise may be an effective prevention and treatment option for drug addiction. In the past few years, many studies have suggested that there were sex differences in all phases of drug addiction. However, very limited research has investigated sex differences in the effectiveness of exercise intervention in drug addiction and rehabilitation. In this mini review, we summarize the effect of sex on the results of using exercise to prevent and treat drug addiction. The studies we consider span various animal models and use multiple types of exercise to examine the effectiveness of exercise on the neurobiological mechanism of exercise rehabilitation. We believe that exercise as an adjuvant intervention strategy can be applied better in drug addiction prevention and recovery.


      PubDate: 2014-07-25T20:28:35Z
       
  • Women and exercise in aging

    • Abstract: Publication date: Available online 4 May 2014
      Source:Journal of Sport and Health Science
      Author(s): Kristina L. Kendall , Ciaran M. Fairman
      Aging is associated with physiological declines, notably a decrease in bone mineral density (BMD) and lean body mass, with a concurrent increase in body fat and central adiposity. Interest in women and aging is of particular interest partly as a result of gender specific responses to aging, particularly as a result of menopause. It is possible that the onset of menopause may augment the physiological decline associated with aging and inactivity. More so, a higher incidence of metabolic syndrome (an accumulation of cardiovascular disease risk factors including obesity, low-density lipoprotein cholesterol, high blood pressure, and high fasting glucose) has been shown in middle-aged women during the postmenopausal period. This is due in part to the drastic changes in body composition, as previously discussed, but also a change in physical activity (PA) levels. Sarcopenia is an age related decrease in the cross-sectional area of skeletal muscle fibers that consequently leads to a decline in physical function, gait speed, balance, coordination, decreased BMD, and quality of life. PA plays an essential role in combating physiological decline associated with aging. Maintenance of adequate levels of PA can result in increased longevity, and a reduced risk for metabolic disease along with other chronic diseases. The aim of this paper is to review relevant literature, examine current PA guidelines, and provide recommendations specific to women based on current research.


      PubDate: 2014-07-25T20:28:35Z
       
  • Why women see differently from the way men see? A review of sex
           differences in cognition and sports

    • Abstract: Publication date: Available online 23 May 2014
      Source:Journal of Sport and Health Science
      Author(s): Rena Li
      The differences of learning and memory between males and females have been well documented and confirmed by both human and animal studies. The sex differences in cognition started from early stage of neuronal development and last through entire life span. The major biological basis of the gender-dependent cognitive activity includes two major components: sex hormone and sex-related characteristics, such as sex-determining region of the Y chromosome (SRY) protein. However, the knowledge of how much biology of sex contributes to normal cognitive function and elite athletes in various sports are still pretty limited. In this review, we will be focusing on sex differences in spatial learning and memory – especially the role of male- and female-type cognitive behaviors in sports.


      PubDate: 2014-07-25T20:28:35Z
       
  • Editorial board

    • Abstract: Publication date: June 2014
      Source:Journal of Sport and Health Science, Volume 3, Issue 2




      PubDate: 2014-07-25T20:28:35Z
       
  • Metabolic response to 6-week aerobic exercise training and dieting in
           previously sedentary overweight and obese pre-menopausal women: A
           randomized trial

    • Abstract: Publication date: Available online 1 June 2014
      Source:Journal of Sport and Health Science
      Author(s): Petri Wiklund , Markku Alen , Eveliina Munukka , Shu Mei Cheng , Bo Yu , Satu Pekkala , Sulin Cheng
      Background The aim of this study was to compare 6 weeks short-term moderate intensity aerobic exercise and dieting on serum metabolomics and cardio-metabolic risk factors in pre-menopausal women. Methods Ninety previously inactive overweight and obese (BMI 25–35 kg/m2) women (age 41.5 ± 7.6 years) were randomized to either a 6-week Nordic walking exercise program (EX, n = 45) or dietary counseling group (DI, n = 45). Body composition, serum glucose, insulin and lipids were measured. Serum low-molecular-weight metabolites and lipid constituents were analyzed by nuclear magnetic resonance spectroscopy. Measurements were done at baseline and 7 days after the last training session. Results Six weeks aerobic exercise program yielded reductions in serum free fatty acids (−34.7%, 95% confidence interval (CI), −50 to −18, p < 0.001), glucose (−9.6%, 95%CI, −15 to −4, p < 0.001) and homeostasis model assessment of insulin resistance (HOMA-IR) (−28.7%, 95% CI, −48 to −10, p = 0.005) without changes in body weight or fat mass. Diet counseling resulted in loss of body weight (1.5%, 95%CI, −2.3 to −0.7, p = 0.001) but no changes in free fatty acids, fasting glucose, or HOMA-IR were found. Conclusion Our results indicate that small weight loss does not produce measurable health benefits, whereas short-term regular aerobic exercise can improve glucose and lipid metabolism even in the absence of weight loss in previously sedentary overweight and obese women.


      PubDate: 2014-07-25T20:28:35Z
       
  • Muscle capacity and physical function in older women: What are the impacts
           of resistance training?

    • Abstract: Publication date: Available online 4 June 2014
      Source:Journal of Sport and Health Science
      Author(s): Anne O. Brady , Chad R. Straight
      The number of older adults (individuals ≥65 years), particularly women, in our society is increasing and understanding the impact of exercise on muscle capacity (e.g., strength and power) and subsequently physical function is of utmost importance to prevent disability and maintain independence. Muscle capacity declines with age and this change negatively impacts physical function in older women. Exercise, specifically resistance training, is recommended to counteract these declines; however, the synergistic relationships between exercise, muscle capacity, and physical function are poorly understood. This review will summarize the literature regarding age-related changes in the aforementioned variables and review the research on the impact of resistance training interventions on muscle capacity and physical function in older women. Recommendations for future research in this area will be discussed.


      PubDate: 2014-07-25T20:28:35Z
       
  • Surgical menopause enhances hippocampal amyloidogenesis following global
           cerebral ischemia

    • Abstract: Publication date: Available online 12 June 2014
      Source:Journal of Sport and Health Science
      Author(s): Erin L. Scott , Quan-Guang Zhang , Yan Dong , Dong Han , Rui-Min Wang , Ratna K. Vadlamudi , Darrell W. Brann
      Background Prematurely menopausal women have a doubled lifetime risk of dementia and a 5-fold increased risk of mortality from neurological disorders, but the molecular mechanisms underlying these risks remain unclear. We hypothesized that ischemia-induced amyloidogenesis may be enhanced in the hippocampus following prolonged loss of ovarian 17β-estradiol (E2), which could contribute to these phenomena. Methods To investigate, the current study used a rat model of premature surgical menopause (10-week bilateral ovariectomy) with E2 therapy either initiated immediately (short-term E2 deprivation (STED)) or delayed to the end of the ovariectomy period (long-term E2 deprivation (LTED)). One week after continuous, subcutaneous E2 therapy, we subjected animals to 10-min global cerebral ischemia (GCI) to assess the effect of LTED on ischemia-induced amyloidogenesis in the hippocampal CA1. Results The present study revealed that while hippocampal β-amyloid (Aβ) is not typically enhanced following GCI, there is a rapid, robust elevation of endogenous Aβ in LTED females after GCI. In STED females, we observed that GCI attenuates and E2 maintains ADAM 10 expression in the hippocampal CA1, and concurrently, GCI increases and E2 decreases BACE1 levels in the same region. Intriguingly, however, we observed a loss of E2 regulation of ADAM 10, ADAM 17, and BACE1 levels in the hippocampal CA1 of LTED females, which provides mechanistic evidence for the enhanced post-ischemic Aβ load following LTED. We also observed loss of E2 regulation of tau hyperphosphorylation in LTED females subjected to GCI. Conclusion Collectively, these studies partially explain the enhanced risk of dementia and mortality from neurological disorders seen in prematurely menopausal women and support timely initiation of E2 therapy to yield maximum neurological benefit.


      PubDate: 2014-07-25T20:28:35Z
       
  • The acute effects of vibration stimulus following FIFA 11+ on agility and
           reactive strength in collegiate soccer players

    • Abstract: Publication date: Available online 24 June 2014
      Source:Journal of Sport and Health Science
      Author(s): Ross Cloak , Alan Nevill , Julian Smith , Matthew Wyon
      Purpose The aim of this study was to assess the effects of combining the FIFA 11+ and acute vibration training on reactive strength index (RSI) and 505 agility. Methods Seventy-four male collegiate soccer players took part in the study and were randomly assigned to FIFA 11+ with acute vibration group (FIFA + WBV), FIFA 11+ with isometric squat group (FIFA + IS) or a control group consisting of the FIFA 11+ alone (Con). The warm-up consisted of the FIFA 11+ and was administered to all participants. The participants in the acute vibration group were exposed to 30 s whole body vibration in squat position immediately post warm-up. The isometric group completed an isometric squat for 30 s immediately post warm-up. Results RSI significantly improved pre- to post- intervention amongst FIFA + WBV (p < 0.001) due to a decrease in contact time (p < 0.001) in comparison to FIFA + IS and Con, but 505 agility was not affected. Conclusion The results of this study suggest the inclusion of an acute bout of WBV post FIFA 11+ warm-up produces a neuromuscular response leading to an improvement in RSI. Future research is required to examine the exact mechanisms behind these improvements amongst other populations and over time course of the performance.


      PubDate: 2014-07-25T20:28:35Z
       
  • Correlates of subjectively and objectively measured physical activity in
           young adolescents

    • Abstract: Publication date: Available online 11 July 2014
      Source:Journal of Sport and Health Science
      Author(s): Kelly Kavanaugh , Justin B. Moore , Leisha Johnson Hibbett , Andrew T. Kaczynski
      Background Many studies examining individual-level correlates in youth utilize self-report rather than objective measures of physical activity (PA). This utilization of self-report may result in associations that are not present when examining objectively measured PA. The present study investigates the relationship between hypothesized correlates of PA with objectively and subjectively measured PA. Methods Participating children (n = 232, 101 males, mean age = 12.3 years) provided a minimum of four monitored days of PA (via accelerometer) and completed a survey assessing moderate-to-vigorous physical activity (MVPA), sport competence, appearance, enjoyment, and self-efficacy. Height and weight were measured and body mass index (BMI) was calculated. Results Hierarchical regression models controlling for sex, race, and BMI Z-score showed that only sex and BMI Z-score were significant correlates of objective MVPA while only sex was a significant correlate of objective total PA. However, in a separate model examining the relationship with subjective MVPA, enjoyment of PA and self-efficacy for PA were the only significant correlates of self-reported PA. Conclusion Measuring MVPA via self-report versus accelerometry produces considerably different results in a sample of young adolescents. Future studies should use caution when selecting outcome measures if the intent is to identify modifiable correlates of MVPA in youth.


      PubDate: 2014-07-25T20:28:35Z
       
  • Stress hormonal analysis in elite soccer players during a season

    • Abstract: Publication date: Available online 14 July 2014
      Source:Journal of Sport and Health Science
      Author(s): Yiannis Michailidis
      Purpose The purpose of this study was to evaluate the changes in some hormonal parameters (cortisol, testosterone, ratio of testosterone/cortisol) in professional soccer players during a season. Methods Fifteen professional players from a soccer club of the first division of the Greek soccer league participated. All sport medical examinations were conducted four times: before the re-building period, post re-building period, mid-season, and after finishing the competition phase. Results For testosterone, significant differences were observed between the end season and post re-building period (11.6%; p < 0.05) and mid-season (12.1%; p < 0.05). The cortisol concentration increased at mid-season by approximately 23%, and this change differed significantly from all other measurements for this hormone. The T/C ratio increased at the post re-building period and decreased at the middle of the season. Conclusion These hormones and their ratios could be used as stress and recovery state indicators. Coaches can use these parameters in combination with other indicators to optimize workloads, and to avoid overreaching and overtraining.


      PubDate: 2014-07-25T20:28:35Z
       
  • Introduction: The past, present, and future of research on running
           barefoot and in minimal shoes

    • Abstract: Publication date: Available online 22 April 2014
      Source:Journal of Sport and Health Science
      Author(s): Daniel E. Lieberman , Irene S. Davis , Benno M. Nigg



      PubDate: 2014-05-04T21:30:03Z
       
  • Strike type variation among Tarahumara Indians in minimal sandals versus
           conventional running shoes

    • Abstract: Publication date: Available online 24 April 2014
      Source:Journal of Sport and Health Science
      Author(s): Daniel E. Lieberman
      Purpose This study examined variation in foot strike types, lower extremity kinematics, and arch height and stiffness among Tarahumara Indians from the Sierra Tarahumara, Mexico. Methods High speed video was used to study the kinematics of 23 individuals, 13 who habitually wear traditional minimal running sandals (huaraches), and 10 who habitually wear modern, conventional running shoes with elevated, cushioned heels and arch support. Measurements of foot shape and arch stiffness were taken on these individuals plus an additional sample of 12 individuals. Results Minimally shod Tarahumara exhibit much variation with 40% primarily using midfoot strikes, 30% primarily using forefoot strikes, and 30% primarily using rearfoot strikes. In contrast, 75% of the conventionally shod Tarahumara primarily used rearfoot strikes, and 25% primarily used midfoot strikes. Individuals who used forefoot or midfoot strikes landed with significantly more plantarflexed ankles, flexed knees, and flexed hips than runners who used rearfoot strikes. Foot measurements indicate that conventionally shod Tarahumara also have significantly less stiff arches than those wearing minimal shoes. Conclusion These data reinforce earlier studies that there is variation among foot strike patterns among minimally shod runners, but also support the hypothesis that foot stiffness and important aspects of running form, including foot strike, differ between runners who grow up using minimal versus modern, conventional footwear.


      PubDate: 2014-05-04T21:30:03Z
       
  • Barefoot running survey: Evidence from the field

    • Abstract: Publication date: Available online 24 April 2014
      Source:Journal of Sport and Health Science
      Author(s): David Hryvniak , Jay Dicharry , Robert Wilder
      Background Running is becoming an increasingly popular activity among Americans with over 50 million participants. Running shoe research and technology has continued to advance with no decrease in overall running injury rates. A growing group of runners are making the choice to try the minimal or barefoot running styles of the pre-modern running shoe era. There is some evidence of decreased forces and torques on the lower extremities with barefoot running, but no clear data regarding how this corresponds with injuries. The purpose of this survey study was to examine factors related to performance and injury in runners who have tried barefoot running. Methods The University of Virginia Center for Endurance Sport created a 10-question survey regarding barefoot running that was posted on a variety of running blogs and FaceBook pages. Percentages were calculated for each question across all surveys. Five hundred and nine participants responded with over 93% of them incorporating some type of barefoot running into their weekly mileage. Results A majority of the participants (53%) viewed barefoot running as a training tool to improve specific aspects of their running. However, close to half (46%) viewed barefoot training as a viable alternative to shoes for logging their miles. A large portion of runners initially tried barefoot running due to the promise of improved efficiency (60%), an attempt to get past injury (53%) and/or the recent media hype around the practice (52%). A large majority (68%) of runners participating in the study experienced no new injuries after starting barefoot running. In fact, most respondents (69%) actually had their previous injuries go away after starting barefoot running. Runners responded that their previous knee (46%), foot (19%), ankle (17%), hip (14%), and low back (14%) injuries all proceeded to improve after starting barefoot running. Conclusion Prior studies have found that barefoot running often changes biomechanics compared to shod running with a hypothesized relationship of decreased injuries. This paper reports the result of a survey of 509 runners. The results suggest that a large percentage of this sample of runners experienced benefits or no serious harm from transitioning to barefoot or minimal shoe running.


      PubDate: 2014-05-04T21:30:03Z
       
  • Muscle activity and kinematics of forefoot and rearfoot strike runners

    • Abstract: Publication date: Available online 24 April 2014
      Source:Journal of Sport and Health Science
      Author(s): A.N. Ahn , C. Brayton , T. Bhatia , P. Martin
      Background Forefoot strike (FFS) and rearfoot strike (RFS) runners differ in their kinematics, force loading rates, and joint loading patterns, but the timing of their muscle activation patterns are less clear. Methods Forty recreational and highly trained runners ran at four speeds barefoot and shod on a motorized treadmill. “Barefoot” runners wore thin, five-toed socks and shod runners wore neutral running shoes. Subjects were instructed to run comfortably at each speed with no instructions about foot strike patterns. Results Eleven runners landed with an FFS when barefoot and shod and eleven runners landed with an RFS when barefoot and shod. The 18 remaining runners shifted from an FFS when barefoot to an RFS when shod (shifters). Shod shifters ran with a lower stride frequency and greater stride length than all other runners. All FFS runners landed with more plantarflexed ankles and more vertical lower legs at the beginning of stance compared to RFS runners. All FFS runners activated their plantarflexor muscles 11% earlier and 10% longer than RFS runners. Conclusion This earlier and longer relative activation of the plantarflexors likely enhances the capacity for the passive structures of the foot and ankle to store elastic energy, and may also enhance the performance of the active muscle by increasing the storage of elastic strain energy in the cross-bridges and activated titin.


      PubDate: 2014-05-04T21:30:03Z
       
  • The effect of minimal shoes on arch structure and intrinsic foot muscle
           strength

    • Abstract: Publication date: Available online 2 May 2014
      Source:Journal of Sport and Health Science
      Author(s): Elizabeth E. Miller , Katherine K. Whitcome , Daniel E. Lieberman , Heather L. Norton , Rachael E. Dyer
      Background This prospective study explored the effects of endurance running (ER) in minimal versus standard running shoes on the foot’s superficial layer intrinsic muscles and the function of the longitudinal arch. Our hypothesis was that running in minimal shoes would cause hypertrophy in these muscles and lead to higher, stronger, stiffer arches. Methods The hypothesis was tested using a sample of 33 healthy runners randomized into two groups, a control group shod in traditional running footwear and an experimental group shod in minimal support footwear, whose feet were scanned in an MRI before and after a 12-week training regime. Running kinematics as well as arch stiffness and height were also assessed before and after the treatment period. Results Analysis of anatomical cross-sectional areas and muscle volumes indicate that the flexor digitorum brevis muscle became larger in both groups by 11% and 21%, respectively, but only the minimally shod runners had significant areal and volumetric increases of the abductor digiti minimi of 18% and 22%, respectively, and significantly increased longitudinal arch stiffness (60%). Conclusion These results suggest that endurance running in minimal support footwear with 4 mm offset or less makes greater use of the spring-like function of the longitudinal arch, thus leading to greater demands on the intrinsic muscles that support the arch, thereby strengthening the foot.


      PubDate: 2014-05-04T21:30:03Z
       
  • Reduction in ground reaction force variables with instructed barefoot
           running

    • Abstract: Publication date: Available online 19 April 2014
      Source:Journal of Sport and Health Science
      Author(s): Cynthia D. Samaan , Michael J. Rainbow , Irene S. Davis
      Backgound Barefoot (BF) running has recently increased in popularity with claims that it is more natural and may result in fewer injuries due to a reduction in impact loading. However, novice BF runners do not necessarily immediately switch to a forefoot strike pattern. This may increase mechanical parameters such as loading rate, which has been associated with certain running-related injuries, specifically, tibial stress fractures, patellofemoral pain, and plantar fasciitis. The purpose of this study was to examine changes in loading parameters between typical shod running and instructed BF running with real-time force feedback. Methods Forty-nine patients seeking treatment for a lower extremity injury ran on a force-sensing treadmill in their typical shod condition and then BF at the same speed. While BF they received verbal instruction and real-time feedback of vertical ground reaction forces. Results While 92% of subjects (n = 45) demonstrated a rearfoot strike pattern when shod, only 2% (n = 1) did during the instructed BF run. Additionally, while BF 47% (n = 23) eliminated the vertical impact transient in all eight steps analyzed. All loading variables of interest were significantly reduced from the shod to instructed BF condition. These included maximum instantaneous and average vertical loading rates of the ground reaction force (p < 0.0001), stiffness during initial loading (p < 0.0001), and peak medial (p = 0.001) and lateral ground reaction forces (p < 0.0001) and impulses in the vertical (p < 0.0001), medial (p = 0.047), and lateral (p < 0.0001) directions. Conclusion As impact loading has been associated with certain running-related injuries, instruction and feedback on the proper forefoot strike pattern may help reduce the injury risk associated with transitioning to BF running.


      PubDate: 2014-05-04T21:30:03Z
       
  • Foot strike patterns and hind limb joint angles during running in Hadza
           hunter-gatherers

    • Abstract: Publication date: Available online 25 April 2014
      Source:Journal of Sport and Health Science
      Author(s): Herman Pontzer , Kelly Suchman , David A. Raichlen , Brian M. Wood , Audax Z.P. Mabulla , Frank W. Marlowe
      Background Investigations of running gait among barefoot and populations have revealed a diversity of foot strike behaviors, with some preferentially employing a rear-foot strike (RFS) as the foot touches down while others employ a mid-foot strike (MFS) or fore-foot strike (FFS). Here, we report foot strike behavior and joint angles among traditional Hadza hunter-gatherers living in Northern Tanzania. Methods Hadza adults (n = 26) and juveniles (n = 14) ran at a range of speeds (adults: mean 3.4 ± 0.7 m/s, juveniles: mean 3.2 ± 0.5) over an outdoor trackway while being recorded via high-speed digital video. Foot strike type (RFS, MFS, or FFS) and hind limb segment angles at foot strike were recorded. Results Hadza men preferentially employed MFS (86.7% of men), while Hadza women and juveniles preferentially employed RFS (90.9% and 85.7% of women and juveniles, respectively). No FFS were recorded. Speed, the presence of footwear (sandals versus barefoot), and trial duration had no effect on foot strike type. Conclusion Unlike other habitually barefoot populations which prefer FFS while running, Hadza men preferred MFS, and Hadza women and juveniles preferred RFS. Sex and age differences in foot strike behavior among Hadza adults may reflect differences in running experience, with men learning to prefer MFS as they accumulate more running experience.


      PubDate: 2014-05-04T21:30:03Z
       
  • The effect of shoe type on gait in forefoot strike runners during a 50-km
           run

    • Abstract: Publication date: Available online 19 April 2014
      Source:Journal of Sport and Health Science
      Author(s): Mark E. Kasmer , Nicholas C. Ketchum , Xue-cheng Liu
      Purpose To observe the relative change in foot-strike pattern, pressure characteristics, surface EMG (sEMG) recordings, and stride characteristics in forefoot strike runners wearing both minimalist and traditional shoes during a 50-km run. Methods Four experienced minimalist runners were enrolled in this study. Each runner ran a 50-km simulated run in both minimalist shoes and traditional shoes. Pressure data, sEMG recordings, and limited 3D motion capture data were collected during the initial 0.8 km and final 0.8 km for each trial. Results Three runners in the traditional shoe type condition and one runner in the minimalist shoe type condition demonstrated a more posterior initial contact area (midfoot strike (MFS) pattern) after the 50-km run, which was supported by increased activity of the tibialis anterior in the pre-contact phase (as per root mean square (RMS) values). In addition, in both pre- and post-run conditions, there were increased peak pressures in the minimalist shoe type, specifically in the medial forefoot. Muscle fatigue as defined by a decreased median frequency observed in isometric, constant force contractions did not correspond with our hypothesis in relation to the observed foot strike change pattern. Finally, step rate increased and step length decreased after the 50-km run in both shoe type conditions. Conclusion More runners adopted a more posterior initial contact area after the 50-km run in the traditional shoe type than in the minimalist shoe type. The runners who adopted a more posterior initial contact area were more closely associated with an increased median frequency of the medial gastrocnemius, which suggests there may be a change in motor unit recruitment pattern during long-distance, sustained velocity running. The increased peak pressures observed in the medial forefoot in the minimalist shoe type may predispose to metatarsal stress fractures in the setting of improper training.


      PubDate: 2014-05-04T21:30:03Z
       
  • Impact shock frequency components and attenuation in rearfoot and forefoot
           running

    • Abstract: Publication date: Available online 18 April 2014
      Source:Journal of Sport and Health Science
      Author(s): Allison H. Gruber , Katherine A. Boyer , Timothy R. Derrick , Joseph Hamill
      Background The forefoot running footfall pattern has been suggested to reduce the risk of developing running related overuse injuries due to a reduction of impact related variables compared with the rearfoot running footfall pattern. However, only time-domain impact variables have been compared between footfall patterns. The frequency content of the impact shock and the degree to which it is attenuated may be of greater importance for injury risk and prevention than time-domain variables. Therefore, the purpose of this study was to determine the differences in head and tibial acceleration signal power and shock attenuation between rearfoot and forefoot running. Methods Nineteen habitual rearfoot runners and 19 habitual forefoot runners ran on a treadmill at 3.5 m/s using their preferred footfall patterns while tibial and head acceleration data were collected. The magnitude of the first and second head acceleration peaks, and peak positive tibial acceleration were calculated. The power spectral density of each signal was calculated to transform the head and tibial accelerations in the frequency domain. Shock attenuation was calculated by a transfer function of the head signal relative to the tibia. Results Peak positive tibial acceleration and signal power in the lower and higher ranges were significantly greater during rearfoot than forefoot running (p < 0.05). The first and second head acceleration peaks and head signal power were not statistically different between patterns (p > 0.05). Rearfoot running resulted in significantly greater shock attenuation for the lower and higher frequency ranges as a result of greater tibial acceleration (p < 0.05). Conclusion The difference in impact shock frequency content between footfall patterns suggests that the primary mechanisms for attenuation may differ. The relationship between shock attenuation mechanisms and injury is not clear but given the differences in impact frequency content, neither footfall pattern may be more beneficial for injury, rather the type of injury sustained may vary with footfall pattern preference.


      PubDate: 2014-05-04T21:30:03Z
       
  • Comparison of foot strike patterns of barefoot and minimally shod runners
           in a recreational road race

    • Abstract: Publication date: Available online 18 April 2014
      Source:Journal of Sport and Health Science
      Author(s): Peter Larson
      Background Previous studies of foot strike patterns of distance runners in road races have typically found that the overwhelming majority of shod runners initially contact the ground on the rearfoot. However, none of these studies has attempted to quantify foot strike patterns of barefoot or minimally shod runners. This study classifies foot strike patterns of barefoot and minimally shod runners in a recreational road race. Methods High-speed video footage was obtained of 169 barefoot and 42 minimally shod distance runners at the 2011 New York City Barefoot Run. Foot strike patterns were classified for each runner, and frequencies of forefoot, midfoot, and rearfoot striking were compared between the barefoot and minimally shod groups. Results A total of 59.2% of barefoot runners were forefoot strikers, 20.1% were midfoot strikers, and 20.7% were rearfoot strikers. For minimally shod runners, 33.3% were forefoot strikers, 19.1% were midfoot strikers, and 47.6% were rearfoot strikers. Foot strike distributions for barefoot and minimally shod runners were significantly different both from one another and from previously reported foot strike distributions of shod road racers. Conclusion Foot strike patterns differ between barefoot and minimally shod runners, with forefoot striking being more common, and rearfoot striking less common in the barefoot group.


      PubDate: 2014-05-04T21:30:03Z
       
  • Can minimal running shoes imitate barefoot heel-toe running patterns?
           A comparison of lower leg kinematics

    • Abstract: Publication date: Available online 13 April 2014
      Source:Journal of Sport and Health Science
      Author(s): Tobias Hein , Stefan Grau
      Background Numerous studies about the interaction between footwear (and barefoot) and kinematic and kinetic outcomes have been published over the last few years. Recent studies however lead to the conclusion that the assumed interactions depend mainly on the subjects' experience of barefoot (BF) walking/running, the preferred running strike pattern, the speed, the hardness of the surface, the thickness of the midsole material and the runners' level of ability. The aim of the present study was to investigate lower leg kinematics of BF running and running in a minimal running shoe (MRS) to assess comparability of BF kinematics in both conditions. To systematically compare both conditions we monitored the influencing variables described above in our measurement setup. We hypothesized that running in an MRS does not alter lower leg kinematics compared to BF running. Methods Thirty-seven subjects, injury-free and active in sports, ran BF on an EVA foam runway, and also ran shod wearing Nike Free 3.0 on a tartan indoor track. Lower-leg 3D kinematics was measured to quantify rearfoot and ankle movements. Skin markers were used in both shod and BF running. Results All runners revealed rearfoot strike pattern when running barefoot. Differences between BF and MRS running occurred particularly during the initial stance phase of running, both in the sagittal and the frontal planes. BF running revealed a flatter foot placement, a more plantar flexed ankle joint and less inverted rearfoot at touchdown compared to MRS running. Conclusion Barefoot running does not change the landing automatically to forefoot running, especially after a systematic exclusion of surface and other influencing factors. The Nike Free 3.0 mimics some BF features. Nevertheless, changes in design of the Nike Free should be considered in order to mimic BF movement even more closely.


      PubDate: 2014-05-04T21:30:03Z
       
  • Participation in some sports, not running, increases risk of knee and hip
           osteoarthritis

    • Abstract: Publication date: Available online 12 April 2014
      Source:Journal of Sport and Health Science
      Author(s): Songning Zhang



      PubDate: 2014-05-04T21:30:03Z
       
  • Editorial board

    • Abstract: Publication date: March 2014
      Source:Journal of Sport and Health Science, Volume 3, Issue 1




      PubDate: 2014-05-04T21:30:03Z
       
  • Tai Ji Quan: an overview of its history, health benefits, and cultural
           value

    • Abstract: Publication date: Available online 30 December 2013
      Source:Journal of Sport and Health Science
      Author(s): Guo Yucheng , Qiu Pixiang , Liu Taoguang
      Tai Ji Quan is considered to be a part of traditional Chinese Wushu (a martial art) and comprises various styles that have evolved historically from the Chen, Yang, Wǔ, Wú, and Sun families (schools). Recent simplification of the original classic styles has made Tai Ji Quan easier to adopt in practice. Thus, the traditional legacy of using Tai Ji Quan for self-defense, mindful nurturing of well-being, and fitness enhancement has been expanded to more contemporary applications that focus on promoting physical and mental health, enhancing general well-being, preventing chronic diseases, and being an effective clinical intervention for diverse medical conditions. As the impact of Tai Ji Quan on physical performance and health continues to grow, there is a need to better understand its historical impact and current status. This paper provides an overview of the evolution of Tai Ji Quan in China, its functional utility, and the scientific evidence of its health benefits, as well as how it has been a vehicle for enhancing cultural understanding and exchange between East and West.


      PubDate: 2013-12-31T05:11:24Z
       
  • Tai Ji Quan: From traditional applications to contemporary practice

    • Abstract: Publication date: Available online 26 December 2013
      Source:Journal of Sport and Health Science
      Author(s): Fuzhong Li , Peter Harmer



      PubDate: 2013-12-31T05:11:24Z
       
  • Transforming traditional Tai Ji Quan techniques into integrative movement
           therapy—Tai Ji Quan: Moving for Better Balance

    • Abstract: Publication date: Available online 26 December 2013
      Source:Journal of Sport and Health Science
      Author(s): Fuzhong Li
      Tai Ji Quan, developed as a martial art, has traditionally served multiple purposes, including self-defense, competition/performance, and health promotion. With respect to health, the benefits historically and anecdotally associated with Tai Ji Quan are now being supported by scientific and clinical research, with mounting evidence indicating its potential value in preventing and managing various diseases and improving well-being and quality of life in middle-aged and older adults. The research findings produced to date have both public health significance and clinical relevance. However, because of its roots in the martial arts, transforming traditional Tai Ji Quan movements and training approaches into contemporary therapeutic programs and functional applications is needed to maximize its ultimate utility. This paper addresses this issue by introducing Tai Ji Quan: Moving for Better Balance, a functional therapy that involves the use of Tai Ji Quan principles and Yang-style-based movements to form an innovative, contemporary therapeutic approach that integrates motor, sensory, and cognitive components to improve postural control, gait, and mobility for older adults and those who have neurodegenerative movement impairments. It provides a synergy of traditional and contemporary Tai Ji Quan practice with the ultimate goal of improving balance and gait, enhancing performance of daily functional tasks, and reducing incidence of falls among older adults.


      PubDate: 2013-12-31T05:11:24Z
       
 
 
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