We highly commend Dr Souza et al.1for their systematic review research.The authors conducted a detailed investigation into the effects of ischemic preconditioning(IPC)on athletic performance,comparing it with placebo ...We highly commend Dr Souza et al.1for their systematic review research.The authors conducted a detailed investigation into the effects of ischemic preconditioning(IPC)on athletic performance,comparing it with placebo and no-intervention conditions.The study found that while IPC demonstrated superior effects over the no-intervention group in certain metrics(e.g.,time to exhaustion),its performance did not significantly surpass that of the placebo group.This suggests that the potential benefits of IPC may partially stem from participants’psychological expectations,or placebo effects.The study also highlighted the significant impact of placebo interventions on athletic performance,emphasizing the importance of distinguishing between placebo and no-intervention conditions in experimental designs.展开更多
Background:Ischemic preconditioning(IPC)is purported to have beneficial effects on athletic performance,although findings are inconsistent,with some studies reporting placebo effects.The majority of studies have inves...Background:Ischemic preconditioning(IPC)is purported to have beneficial effects on athletic performance,although findings are inconsistent,with some studies reporting placebo effects.The majority of studies have investigated IPC alongside a placebo condition,but without a control condition that was devoid of experimental manipulation,thereby limiting accurate determination of the IPC effects.Therefore,the aims of this study were to assess the impact of the IPC intervention,compared to both placebo and no intervention,on exercise capacity and athletic performance.Methods:A systematic search of PubMed,Embase,SPORTDiscus,Cochrane Library,and Latin American and Caribbean Health Sciences Literature(LILACS)covering records from their inception until July 2023 was conducted.To qualify for inclusion,studies had to apply IPC as an acute intervention,comparing it with placebo and/or control conditions.Outcomes of interest were performance(force,number of repetitions,power,time to exhaustion,and time trial performance),physiological measurements(maximum oxygen consumption,and heart rate),or perceptual measurements(RPE).For each outcome measure,we conducted 3 independent meta-analyses(IPC vs.placebo,IPC vs.control,placebo vs.control)using an inverse-variance random-effects model.The between-treatment effects were quantified by the standardized mean difference(SMD),accompanied by their respective 95%confidence intervals.Additionally,we employed the Grading of Recommendations,Assessment,Development and Evaluation(GRADE)approach to assess the level of certainty in the evidence.Results:Seventy-nine studies were included in the quantitative analysis.Overall,IPC demonstrates a comparable effect to the placebo condition(using a low-pressure tourniquet),irrespective of the subjects'training level(all outcomes presenting p>0.05),except for the outcome of time to exhaustion,which exhibits a small magnitude effect(SMD=0.37;p=0.002).Additionally,the placebo exhibited effects notably greater than the control condition(outcome:number of repetitions;SMD=0.45;p=0.03),suggesting a potential influence of participants'cognitive perception on the outcomes.However,the evidence is of moderate to low certainty,regardless of the comparison or outcome.Conclusion:IPC has significant effects compared to the control intervention,but it did not surpass the placebo condition.Its administration might be influenced by the cognitive perception of the receiving subject,and the efficacy of IPC as an ergogenic strategy for enhancing exercise capacity and athletic performance remains questionable.展开更多
In order to help athletes optimize their performances in competitions while prevent overtraining and the risk of overuse injuries,it is important to develop science-based strategies for optimally designing training pr...In order to help athletes optimize their performances in competitions while prevent overtraining and the risk of overuse injuries,it is important to develop science-based strategies for optimally designing training programs.The purpose of the present study is to develop a novel method by the combined use of optimal control theory and a training-performance model for designing optimal training programs,with the hope of helping athletes achieve the best performance exactly on the competition day while properly manage training load during the training course for preventing overtraining.The training-performance model used in the proposed optimal control framework is a conceptual extension of the Banister impulse-response model that describes the dynamics of performance,training load(served as the control variable),fitness(the overall positive effects on performance),and fatigue(the overall negative effects on performance).The objective functional of the proposed optimal control framework is to maximize the fitness and minimize the fatigue on the competition day with the goal of maximizing the performance on the competition day while minimizing the cumulative training load during the training course.The Forward-Backward Sweep Method is used to solve the proposed optimal control framework to obtain the optimal solutions of performance,training load,fitness,and fatigue.The simulation results show that the performance on the competition day is higher while the cumulative training load during the training course is lower with using optimal control theory than those without,successfully showing the feasibility and benefits of using the proposed optimal control framework to design optimal training programs for helping athletes achieve the best performance exactly on the competition day while properly manage training load during the training course for preventing overtraining.The present feasibility study lays the foundation of the combined use of optimal control theory and training-performance models to design personalized optimal training programs in real applications in athletic training and sports science for helping athletes achieve the best performances in competitions while prevent overtraining and the risk of overuse injuries.展开更多
Objectives The purpose of this study is to examine the effects of applying anodal tDCS(2 mA for 20 min)over the scalp from T3(anodal-tDCS)to Fp2(cathodal-tDCS)on the perceptual,physiological and performance responses ...Objectives The purpose of this study is to examine the effects of applying anodal tDCS(2 mA for 20 min)over the scalp from T3(anodal-tDCS)to Fp2(cathodal-tDCS)on the perceptual,physiological and performance responses during maximal incremental and constant-load exercise(CLE)in trained cyclists.Methods Eleven male cyclists performed maximal incremental exercise(MIE)on a cycle ergometer under either tDCS or sham,with power output,heart rate(HR),oxygen uptake(V̇O_(2)),ratings of perceived exertion(RPE)assessed throughout,and blood samples collected before and after MIE.On two separate occasions,nine subjects performed CLE at 62%of the peak power output followed by a 15 km time trial under either tDCS or sham(n=8 for the time trial).Results HR,V̇O_(2),RPE and blood samples were collected at regular intervals.There were no differences between tDCS and sham in any variable during the MIE.tDCS elicited a decreased HR(F_(4,8)=9.232;p=0.016;η_(p)^(2)=0.54),increased V̇O_(2)(F_(4,8)=8.920;p=0.015;η_(p)^(2)=0.50)and increased blood non-esterified fatty acids(F_(6,8)=11.754;p=0.009;η_(p)^(2)=0.60)and glycerol(F_(6,8)=6.603;p=0.037;η_(p)^(2)=0.49)concentrations during the CLE when compared to sham.tDCS also improved 15 km time trial performance by 3.6%(p=0.02;d=0.47)without affecting RPE,HR and blood lactate.Conclusions The application of tDCS over the temporal cortex in trained cyclists improved cycling performance during a self-paced time trial but did not enhance performance during maximal incremental exercise.These results are encouraging and merit further investigation of the ergogenic effects of tDCS in trained athletes.展开更多
1.Background When searching for the term“muscle power”on Google Scholar,about 3.7 million hits come up in 60 ms,and for the past 3 years,there were approximately 225 yearly peer-reviewed publications dealing with mu...1.Background When searching for the term“muscle power”on Google Scholar,about 3.7 million hits come up in 60 ms,and for the past 3 years,there were approximately 225 yearly peer-reviewed publications dealing with muscle power.Muscle power has been used to assess and predict athletic performance,to determine muscle rehabilitation following injury or disease,to measure functional decline as occurs in aging,and many other topics.展开更多
Personality traits and motivation have been predictive of athletic success. Conscientiousness, intrinsic motivation （IM）, and extrinsic motivation （EM） positively predict sport performance, while amotivation （AM...Personality traits and motivation have been predictive of athletic success. Conscientiousness, intrinsic motivation （IM）, and extrinsic motivation （EM） positively predict sport performance, while amotivation （AM） has a negative impact. This study examined the effects of both sport motivation and conscientiousness on athletic performance. Methods included a cross-sectional survey study of endurance athletes （N= 73）; including runners （56.1%）, swimmers （19.2%）, triathletes （6.8%）, rowers （2.7%）, and multi-sport athletes （15.1%）. Conscientiousness and motivation were assessed using questionnaires. Subjective ratings and objective scores of a recent performance（s） were collected. Regression analyses demonstrated that conscientiousness positively predicted IM and negatively predicted AM. AM negatively predicted subjective performance. IM and EM were not significant predictors of subjective performance. No variable significantly predicted objective performance. Results support the deleterious role of AM in performance. Compared to IM and EM, AM might be a more relevant construct when predicting performance in a sample of athletes with varying degrees of commitment. This construct may be of particular interest to clinicians due to its association with athletic burnout. Conscientiousness may serve as a protective factor against burnout.展开更多
Background:When recommending avoidance of static stretching prior to athletic performance,authors and practitioners commonly refer to available systematic reviews.However,effect sizes(ES)in previous reviews were extra...Background:When recommending avoidance of static stretching prior to athletic performance,authors and practitioners commonly refer to available systematic reviews.However,effect sizes(ES)in previous reviews were extracted in major part from studies lacking control conditions and/or prepost testing designs.Also,currently available reviews conducted calculations without accounting for multiple study outcomes,with ES:0.03 to 0.10,which would commonly be classified as trivial.Methods:Since new meta-analytical software and controlled research articles have appeared since 2013,we revisited the available literatures and performed a multilevel meta-analysis using robust variance estimation of controlled prepost trials to provide updated evidence.Furthermore,previous research described reduced electromyography activity—also attributable to fatiguing training routines—as being responsible for decreased subsequent performance.The second part of this study opposed stretching and alternative interventions sufficient to induce general fatigue to examine whether static stretching induces higher performance losses compared to other exercise routines.Results:Including 83 studies with more than 400 ES from 2012 participants,our results indicate a significant,small ES for a static stretch-induced maximal strength loss(ES=0.21,p=0.003),with high magnitude ES(ES=0.84,p=0.004)for stretching durations≥60 s per bout when compared to passive controls.When opposed to active controls,the maximal strength loss ranges between ES:0.17 to0.28,p<0.001 and 0.040 with mostly no to small heterogeneity.However,stretching did not negatively influence athletic performance in general(when compared to both passive and active controls);in fact,a positive effect on subsequent jumping performance(ES=0.15,p=0.006)was found in adults.Conclusion:Regarding strength testing of isolated muscles(e.g.,leg extensions or calf raises),our results confirm previous findings.Nevertheless,since no(or even positive)effects could be found for athletic performance,our results do not support previous recommendations to exclude static stretching from warm-up routines prior to,for example,jumping or sprinting.展开更多
Purpose: The oxidative stress (OS) hypothesis of overtraining syndrome argues that increased production of free radicals through exercise cause muscle fatigue and damage resulting in lower athletic performance. Severa...Purpose: The oxidative stress (OS) hypothesis of overtraining syndrome argues that increased production of free radicals through exercise cause muscle fatigue and damage resulting in lower athletic performance. Several studies have investigated OS immediately before and after exercise bouts in a training macrocycle. Our study aimed to compare OS of endurance athletes between a competition macrocycle and the immediate post-season recovery macrocycle. In addition, we aimed to identify athletes who experienced an unexplainable drop in athletic performance during the competition season in order to compare their OS to those who experienced no drop in performance. Methods: Fifteen members of the University of Alaska Fairbanks cross country ski team volunteered for this study. Blood samples were taken in early February (“mid-season”) and late April (“post-season”). Participants completed questionnaires regarding physical activity and athletic performance at the time of the blood draws. Plasma was analyzed for 4-hydroxynonenal<sup> </sup>(HNE), nitrotyrosine,<sup> </sup>nitric oxide (NOX), and superoxide dismutase (SOD). Significance was determined by Wilcoxon and Mann-Whitney tests. Results: Participants displayed significantly higher (p Conclusion: Signs of oxidative stress and mitigation during the post-season recovery macrocycle were higher in athletes who reported experiencing a drop in athletic performance during the competition season macrocycle.展开更多
Purpose:The aim of this study was to review,systematically,evidence concerning the link between the ACTN3 R577X polymorphism and the rates and severity of non-contact injuries and exercise-induced muscle damage in ath...Purpose:The aim of this study was to review,systematically,evidence concerning the link between the ACTN3 R577X polymorphism and the rates and severity of non-contact injuries and exercise-induced muscle damage in athletes and individuals enrolled in exercise training programs.Methods:A computerized literature search was performed in the electronic databases PubMed,Web of Science,and SPORTDiscus,from inception until November 2020.All included studies compared the epidemiological characteristics of non-contact injury between the different genotypes of the ACTN3 R577X polymorphism.Results:Our search identified 492 records.After the screening of titles,abstracts,and full texts,13 studies examining the association between the ACTN3 genotypes and the rate and severity of non-contact injury were included in the analysis.These studies were performed in 6 different countries(Spain,Japan,Brazil,China,the Republic of Korea,and Italy)and involved a total participant pool of 1093 participants.Of the studies,2 studies involved only women,5 studies involved only men,and 6 studies involved both men and women.All the studies included were classified as highquality studies(≥6 points in the Physiotherapy Evidence Database(PEDro)scale score).Overall,evidence suggests there is an association between the ACTN3 R577X genotype and non-contact injury in 12 investigations.Six studies observed a significant association between A CTN3 R577X polymorphism and exercise induced muscle damage:2 with non-contact ankle injury,3 with non-contact muscle injury,and 1 with overall non-contact injury.Conclusion:The present findings support the premise that possessing the ACTN3 XX genotype may predispose athletes to a higher probability of some non-contact injuries,such as muscle injury,ankle sprains,and higher levels of exercise-induced muscle damage.展开更多
BACKGROUND Evidence regarding the effectiveness of using orthotics in improving comfort,increasing running speed and helping to reduce injury rate during running is limited and mixed.Alongside the increasing popularit...BACKGROUND Evidence regarding the effectiveness of using orthotics in improving comfort,increasing running speed and helping to reduce injury rate during running is limited and mixed.Alongside the increasing popularity of running is the increasing rate of running-related injuries(RRIs).Further research into whether orthotics could be used to help reduce RRIs would be highly beneficial for those affected.Additionally,there is a need to clarify whether orthotics use increases comfort during running and helps improve running speed.AIM To investigate whether running with Aetrex Orthotics improves comfort and performance and reduces injury whilst running.METHODS Runners were recruited on a voluntary basis if they were 18 or older with no serious health conditions,ongoing foot pain or deformity,previous foot surgery in their lifetime or any surgery in the past 6 mo.Participants were randomly assigned to either an intervention group or a control group.All participants were asked to complete runs and provide quantitative data regarding comfort during running,running time and distance,and any RRIs over an 8-wk study period.Participants in the intervention group ran with Aetrex L700 Speed Orthotics,whilst participants in the control group ran without orthotics.Other than the addition of orthotics for participants in the intervention group,all participants were asked to run as they usually would.This report presents preliminary data from the first 47 participants recruited for this study.Running speed was calculated from running distance and time and given in miles per hour.For each outcome variable,the mean for each group,effect size and 95%confidence interval were calculated,and a t-test was performed to determine if between-group differences were statistically significant.RESULTS Data for all three primary outcomes was provided from a total of 254 runs by the 23 participants in the intervention group and a total of 289 runs by the 24 participants in the control group.Participants in the intervention group reported higher comfort scores(8.00±1.41 vs 6.96±2.03,P≤0.0001),faster running speeds(6.27±1.03 vs 6.00±1.54,P=0.013),and lower RRI rates(0.70±1.01 vs 1.21±1.53,P=0.18)than those in the control group.These findings were statistically significant for comfort and running speed but not for RRI rate,with statistical significance considered if P<0.05.No adjustments were made for group differences in age,gender,tendency for RRIs or usual running speed.CONCLUSION This preliminary report provides evidence for orthotics use in increasing comfort levels and running speed,but no significant difference in RRI rate.展开更多
BACKGROUND Running is a hugely popular sport.Unfortunately,running-related injury(RRI)rates are high,particularly amongst amateur and recreational runners.Finding ways to reduce RRI rates and maximise comfort and perf...BACKGROUND Running is a hugely popular sport.Unfortunately,running-related injury(RRI)rates are high,particularly amongst amateur and recreational runners.Finding ways to reduce RRI rates and maximise comfort and performance for runners is important.Evidence regarding whether orthotics can successfully improve these parameters is limited and contradicting.Further research is required to provide runners with clearer guidance on the usefulness of orthotics.AIM To investigate the effect of Aetrex Orthotics on comfort,speed and RRI rates during recreational running.METHODS One hundred and six recreational runners were recruited on a voluntary basis via running clubs and social media pages and randomised into either the intervention or control group.Participants in the intervention group ran with Aetrex L700 Speed Orthotics inserted in their usual running shoes,whilst participants in the control group ran in their usual running shoes with no orthotics.The study ran for an 8-wk period.Participants provided data relating to running comfort,distance,and time during weeks 3-6.Participants provided data relating to any RRIs they sustained during all 8 wks.Running distance and time were used to calculate running speed in miles per hour(mph).For each outcome variable,95%confidence intervals and P values were calculated to assess the statistical significance between the groups.For comfort and speed data,univariate multi-level analysis was performed,and for outcome variables with significant between group differences,multi-level multivariate analysis was performed to evaluate any confounding effects of gender and age.RESULTS Ninety-four participants were included in the final analysis(drop-out rate=11%).Comfort and speed from 940 runs and 978 injury data reports were analysed.Participants who ran with orthotics reported,on average,speeds 0.30 mph faster(P=0.20)and comfort scores 1.27 points higher(P≤0.001)than participants who ran with no orthotics.They were also 2.22 times less likely to sustain an injury(P=0.08)than participants who ran with no orthotics.However,findings were only significant for comfort and not for speed or injury rates.Age and gender were found to be significant predictors of comfort.However,the improvements in comfort reported by participants who ran with orthotics were still significant after adjusting for age and gender.CONCLUSION This study found orthotics to improve comfort and speed and prevent RRIs whilst running.However,these findings were only statistically significant for comfort.展开更多
Swimrun was established in Sweden in 2006.In competition athletes alternate between running and swimming multiple times.It has grown from only being hosted in Sweden to now being a global sport.The swimrun race expose...Swimrun was established in Sweden in 2006.In competition athletes alternate between running and swimming multiple times.It has grown from only being hosted in Sweden to now being a global sport.The swimrun race exposes athletes to environments that require a unique set of skills.For example,participants have to negotiate ocean currents and waves.The environmental conditions change between the runs and the swims.Athletes may be exposed to hot temperatures when running in wetsuits(25℃and hotter)and cold water(colder than 16℃)when swimming.This sudden change in environmental conditions imposes a poorly defined physiological stress on the participants.Research on the demands of swimrun is scarce.More research is needed to improve athlete safety during events.Also,research is needed to provide insight into enhancing training methods and performance.展开更多
Background This study aimed to(i)provide normative data for measures of physical fitness(PF)(i.e.,muscle strength,muscle power,linear sprint speed)in 8-to 14-year-old Tunisian children and(ii)to examine sex and age gr...Background This study aimed to(i)provide normative data for measures of physical fitness(PF)(i.e.,muscle strength,muscle power,linear sprint speed)in 8-to 14-year-old Tunisian children and(ii)to examine sex and age group differences in these measures.Methods A total of 597 subjects(aged 8~14)participated in this study,the normative data for handgrip strength,jump height,and linear sprint speed were generated and collected,and the two-way analysis of variance(ANOVA)was used to identify the presence of the main effect of age,sex,an age×sex interaction for all tests.Results The two-way ANOVA showed credible age by sex interactions for all measures of PF[Effect Size(ES)ranged from 0.28 to 0.68;P<0.05].The findings indicated a main effect of age in handgrip strength,countermovement jump(CMJ)height,and linear sprint speed(all P<0.05),regardless of sex.Post hoc analyses showed early increases in handgrip strength for boys from 8 to 14 years.For CMJ height,an increase in performance was observed from 10 to 11 years(ES=0.23)and 12 to 13 years(ES=0.14)(all P<0.05).For linear sprint speed,performance enhancement was observed from 10 to 11 years(ES=1.00).In girls,an increase in handgrip strength was noted from 9 to 12 years(ES=1.00).However,the changes across age were less convincing for CMJ height and linear sprint speed tests,suggesting that differences for girls were not sup-ported by the collected data.Boys outperformed girls in all measures of PF(P<0.05).A summary of the estimated centiles of 10-and 30-m sprint speed,grip strength,and CMJ height for boys and girls allows a particular child’s test values to be compared to the norms for the group.Conclusions In summary,this study provides normative data that can be used as a tool to classify sprint speed,strength,and jump height performance in children of both sexes aged 8-14 years.展开更多
文摘We highly commend Dr Souza et al.1for their systematic review research.The authors conducted a detailed investigation into the effects of ischemic preconditioning(IPC)on athletic performance,comparing it with placebo and no-intervention conditions.The study found that while IPC demonstrated superior effects over the no-intervention group in certain metrics(e.g.,time to exhaustion),its performance did not significantly surpass that of the placebo group.This suggests that the potential benefits of IPC may partially stem from participants’psychological expectations,or placebo effects.The study also highlighted the significant impact of placebo interventions on athletic performance,emphasizing the importance of distinguishing between placebo and no-intervention conditions in experimental designs.
基金partially supported by the State Funding Agency of Minas Gerais,Brazil(FAPEMIG),Process No.APQ-01811-21supported by Alexander von Humboldt-Stiftung(AvH)/Coordena??o de Aperfei?oamento de Pessoal de Nível Superior(CAPES)+1 种基金National Council for Scientific and Technological Development-CNPq(Process No.308138/2022-8)supported by National Council for Scientific and Technological Development-CNPq(Process No.BPD-00905-22).
文摘Background:Ischemic preconditioning(IPC)is purported to have beneficial effects on athletic performance,although findings are inconsistent,with some studies reporting placebo effects.The majority of studies have investigated IPC alongside a placebo condition,but without a control condition that was devoid of experimental manipulation,thereby limiting accurate determination of the IPC effects.Therefore,the aims of this study were to assess the impact of the IPC intervention,compared to both placebo and no intervention,on exercise capacity and athletic performance.Methods:A systematic search of PubMed,Embase,SPORTDiscus,Cochrane Library,and Latin American and Caribbean Health Sciences Literature(LILACS)covering records from their inception until July 2023 was conducted.To qualify for inclusion,studies had to apply IPC as an acute intervention,comparing it with placebo and/or control conditions.Outcomes of interest were performance(force,number of repetitions,power,time to exhaustion,and time trial performance),physiological measurements(maximum oxygen consumption,and heart rate),or perceptual measurements(RPE).For each outcome measure,we conducted 3 independent meta-analyses(IPC vs.placebo,IPC vs.control,placebo vs.control)using an inverse-variance random-effects model.The between-treatment effects were quantified by the standardized mean difference(SMD),accompanied by their respective 95%confidence intervals.Additionally,we employed the Grading of Recommendations,Assessment,Development and Evaluation(GRADE)approach to assess the level of certainty in the evidence.Results:Seventy-nine studies were included in the quantitative analysis.Overall,IPC demonstrates a comparable effect to the placebo condition(using a low-pressure tourniquet),irrespective of the subjects'training level(all outcomes presenting p>0.05),except for the outcome of time to exhaustion,which exhibits a small magnitude effect(SMD=0.37;p=0.002).Additionally,the placebo exhibited effects notably greater than the control condition(outcome:number of repetitions;SMD=0.45;p=0.03),suggesting a potential influence of participants'cognitive perception on the outcomes.However,the evidence is of moderate to low certainty,regardless of the comparison or outcome.Conclusion:IPC has significant effects compared to the control intervention,but it did not surpass the placebo condition.Its administration might be influenced by the cognitive perception of the receiving subject,and the efficacy of IPC as an ergogenic strategy for enhancing exercise capacity and athletic performance remains questionable.
基金funded by the National Science and Technology Council,grant number NSTC 113-2221-E-002-136-.
文摘In order to help athletes optimize their performances in competitions while prevent overtraining and the risk of overuse injuries,it is important to develop science-based strategies for optimally designing training programs.The purpose of the present study is to develop a novel method by the combined use of optimal control theory and a training-performance model for designing optimal training programs,with the hope of helping athletes achieve the best performance exactly on the competition day while properly manage training load during the training course for preventing overtraining.The training-performance model used in the proposed optimal control framework is a conceptual extension of the Banister impulse-response model that describes the dynamics of performance,training load(served as the control variable),fitness(the overall positive effects on performance),and fatigue(the overall negative effects on performance).The objective functional of the proposed optimal control framework is to maximize the fitness and minimize the fatigue on the competition day with the goal of maximizing the performance on the competition day while minimizing the cumulative training load during the training course.The Forward-Backward Sweep Method is used to solve the proposed optimal control framework to obtain the optimal solutions of performance,training load,fitness,and fatigue.The simulation results show that the performance on the competition day is higher while the cumulative training load during the training course is lower with using optimal control theory than those without,successfully showing the feasibility and benefits of using the proposed optimal control framework to design optimal training programs for helping athletes achieve the best performance exactly on the competition day while properly manage training load during the training course for preventing overtraining.The present feasibility study lays the foundation of the combined use of optimal control theory and training-performance models to design personalized optimal training programs in real applications in athletic training and sports science for helping athletes achieve the best performances in competitions while prevent overtraining and the risk of overuse injuries.
文摘Objectives The purpose of this study is to examine the effects of applying anodal tDCS(2 mA for 20 min)over the scalp from T3(anodal-tDCS)to Fp2(cathodal-tDCS)on the perceptual,physiological and performance responses during maximal incremental and constant-load exercise(CLE)in trained cyclists.Methods Eleven male cyclists performed maximal incremental exercise(MIE)on a cycle ergometer under either tDCS or sham,with power output,heart rate(HR),oxygen uptake(V̇O_(2)),ratings of perceived exertion(RPE)assessed throughout,and blood samples collected before and after MIE.On two separate occasions,nine subjects performed CLE at 62%of the peak power output followed by a 15 km time trial under either tDCS or sham(n=8 for the time trial).Results HR,V̇O_(2),RPE and blood samples were collected at regular intervals.There were no differences between tDCS and sham in any variable during the MIE.tDCS elicited a decreased HR(F_(4,8)=9.232;p=0.016;η_(p)^(2)=0.54),increased V̇O_(2)(F_(4,8)=8.920;p=0.015;η_(p)^(2)=0.50)and increased blood non-esterified fatty acids(F_(6,8)=11.754;p=0.009;η_(p)^(2)=0.60)and glycerol(F_(6,8)=6.603;p=0.037;η_(p)^(2)=0.49)concentrations during the CLE when compared to sham.tDCS also improved 15 km time trial performance by 3.6%(p=0.02;d=0.47)without affecting RPE,HR and blood lactate.Conclusions The application of tDCS over the temporal cortex in trained cyclists improved cycling performance during a self-paced time trial but did not enhance performance during maximal incremental exercise.These results are encouraging and merit further investigation of the ergogenic effects of tDCS in trained athletes.
文摘1.Background When searching for the term“muscle power”on Google Scholar,about 3.7 million hits come up in 60 ms,and for the past 3 years,there were approximately 225 yearly peer-reviewed publications dealing with muscle power.Muscle power has been used to assess and predict athletic performance,to determine muscle rehabilitation following injury or disease,to measure functional decline as occurs in aging,and many other topics.
文摘Personality traits and motivation have been predictive of athletic success. Conscientiousness, intrinsic motivation （IM）, and extrinsic motivation （EM） positively predict sport performance, while amotivation （AM） has a negative impact. This study examined the effects of both sport motivation and conscientiousness on athletic performance. Methods included a cross-sectional survey study of endurance athletes （N= 73）; including runners （56.1%）, swimmers （19.2%）, triathletes （6.8%）, rowers （2.7%）, and multi-sport athletes （15.1%）. Conscientiousness and motivation were assessed using questionnaires. Subjective ratings and objective scores of a recent performance（s） were collected. Regression analyses demonstrated that conscientiousness positively predicted IM and negatively predicted AM. AM negatively predicted subjective performance. IM and EM were not significant predictors of subjective performance. No variable significantly predicted objective performance. Results support the deleterious role of AM in performance. Compared to IM and EM, AM might be a more relevant construct when predicting performance in a sample of athletes with varying degrees of commitment. This construct may be of particular interest to clinicians due to its association with athletic burnout. Conscientiousness may serve as a protective factor against burnout.
文摘Background:When recommending avoidance of static stretching prior to athletic performance,authors and practitioners commonly refer to available systematic reviews.However,effect sizes(ES)in previous reviews were extracted in major part from studies lacking control conditions and/or prepost testing designs.Also,currently available reviews conducted calculations without accounting for multiple study outcomes,with ES:0.03 to 0.10,which would commonly be classified as trivial.Methods:Since new meta-analytical software and controlled research articles have appeared since 2013,we revisited the available literatures and performed a multilevel meta-analysis using robust variance estimation of controlled prepost trials to provide updated evidence.Furthermore,previous research described reduced electromyography activity—also attributable to fatiguing training routines—as being responsible for decreased subsequent performance.The second part of this study opposed stretching and alternative interventions sufficient to induce general fatigue to examine whether static stretching induces higher performance losses compared to other exercise routines.Results:Including 83 studies with more than 400 ES from 2012 participants,our results indicate a significant,small ES for a static stretch-induced maximal strength loss(ES=0.21,p=0.003),with high magnitude ES(ES=0.84,p=0.004)for stretching durations≥60 s per bout when compared to passive controls.When opposed to active controls,the maximal strength loss ranges between ES:0.17 to0.28,p<0.001 and 0.040 with mostly no to small heterogeneity.However,stretching did not negatively influence athletic performance in general(when compared to both passive and active controls);in fact,a positive effect on subsequent jumping performance(ES=0.15,p=0.006)was found in adults.Conclusion:Regarding strength testing of isolated muscles(e.g.,leg extensions or calf raises),our results confirm previous findings.Nevertheless,since no(or even positive)effects could be found for athletic performance,our results do not support previous recommendations to exclude static stretching from warm-up routines prior to,for example,jumping or sprinting.
文摘Purpose: The oxidative stress (OS) hypothesis of overtraining syndrome argues that increased production of free radicals through exercise cause muscle fatigue and damage resulting in lower athletic performance. Several studies have investigated OS immediately before and after exercise bouts in a training macrocycle. Our study aimed to compare OS of endurance athletes between a competition macrocycle and the immediate post-season recovery macrocycle. In addition, we aimed to identify athletes who experienced an unexplainable drop in athletic performance during the competition season in order to compare their OS to those who experienced no drop in performance. Methods: Fifteen members of the University of Alaska Fairbanks cross country ski team volunteered for this study. Blood samples were taken in early February (“mid-season”) and late April (“post-season”). Participants completed questionnaires regarding physical activity and athletic performance at the time of the blood draws. Plasma was analyzed for 4-hydroxynonenal<sup> </sup>(HNE), nitrotyrosine,<sup> </sup>nitric oxide (NOX), and superoxide dismutase (SOD). Significance was determined by Wilcoxon and Mann-Whitney tests. Results: Participants displayed significantly higher (p Conclusion: Signs of oxidative stress and mitigation during the post-season recovery macrocycle were higher in athletes who reported experiencing a drop in athletic performance during the competition season macrocycle.
文摘Purpose:The aim of this study was to review,systematically,evidence concerning the link between the ACTN3 R577X polymorphism and the rates and severity of non-contact injuries and exercise-induced muscle damage in athletes and individuals enrolled in exercise training programs.Methods:A computerized literature search was performed in the electronic databases PubMed,Web of Science,and SPORTDiscus,from inception until November 2020.All included studies compared the epidemiological characteristics of non-contact injury between the different genotypes of the ACTN3 R577X polymorphism.Results:Our search identified 492 records.After the screening of titles,abstracts,and full texts,13 studies examining the association between the ACTN3 genotypes and the rate and severity of non-contact injury were included in the analysis.These studies were performed in 6 different countries(Spain,Japan,Brazil,China,the Republic of Korea,and Italy)and involved a total participant pool of 1093 participants.Of the studies,2 studies involved only women,5 studies involved only men,and 6 studies involved both men and women.All the studies included were classified as highquality studies(≥6 points in the Physiotherapy Evidence Database(PEDro)scale score).Overall,evidence suggests there is an association between the ACTN3 R577X genotype and non-contact injury in 12 investigations.Six studies observed a significant association between A CTN3 R577X polymorphism and exercise induced muscle damage:2 with non-contact ankle injury,3 with non-contact muscle injury,and 1 with overall non-contact injury.Conclusion:The present findings support the premise that possessing the ACTN3 XX genotype may predispose athletes to a higher probability of some non-contact injuries,such as muscle injury,ankle sprains,and higher levels of exercise-induced muscle damage.
基金Supported by Aetrex,Inc.414 Alfred Avenue Teaneck,NJ 07666,USA。
文摘BACKGROUND Evidence regarding the effectiveness of using orthotics in improving comfort,increasing running speed and helping to reduce injury rate during running is limited and mixed.Alongside the increasing popularity of running is the increasing rate of running-related injuries(RRIs).Further research into whether orthotics could be used to help reduce RRIs would be highly beneficial for those affected.Additionally,there is a need to clarify whether orthotics use increases comfort during running and helps improve running speed.AIM To investigate whether running with Aetrex Orthotics improves comfort and performance and reduces injury whilst running.METHODS Runners were recruited on a voluntary basis if they were 18 or older with no serious health conditions,ongoing foot pain or deformity,previous foot surgery in their lifetime or any surgery in the past 6 mo.Participants were randomly assigned to either an intervention group or a control group.All participants were asked to complete runs and provide quantitative data regarding comfort during running,running time and distance,and any RRIs over an 8-wk study period.Participants in the intervention group ran with Aetrex L700 Speed Orthotics,whilst participants in the control group ran without orthotics.Other than the addition of orthotics for participants in the intervention group,all participants were asked to run as they usually would.This report presents preliminary data from the first 47 participants recruited for this study.Running speed was calculated from running distance and time and given in miles per hour.For each outcome variable,the mean for each group,effect size and 95%confidence interval were calculated,and a t-test was performed to determine if between-group differences were statistically significant.RESULTS Data for all three primary outcomes was provided from a total of 254 runs by the 23 participants in the intervention group and a total of 289 runs by the 24 participants in the control group.Participants in the intervention group reported higher comfort scores(8.00±1.41 vs 6.96±2.03,P≤0.0001),faster running speeds(6.27±1.03 vs 6.00±1.54,P=0.013),and lower RRI rates(0.70±1.01 vs 1.21±1.53,P=0.18)than those in the control group.These findings were statistically significant for comfort and running speed but not for RRI rate,with statistical significance considered if P<0.05.No adjustments were made for group differences in age,gender,tendency for RRIs or usual running speed.CONCLUSION This preliminary report provides evidence for orthotics use in increasing comfort levels and running speed,but no significant difference in RRI rate.
基金Supported by Aetrex,Inc.414 Alfred Avenue Teaneck,NJ 07666,USA。
文摘BACKGROUND Running is a hugely popular sport.Unfortunately,running-related injury(RRI)rates are high,particularly amongst amateur and recreational runners.Finding ways to reduce RRI rates and maximise comfort and performance for runners is important.Evidence regarding whether orthotics can successfully improve these parameters is limited and contradicting.Further research is required to provide runners with clearer guidance on the usefulness of orthotics.AIM To investigate the effect of Aetrex Orthotics on comfort,speed and RRI rates during recreational running.METHODS One hundred and six recreational runners were recruited on a voluntary basis via running clubs and social media pages and randomised into either the intervention or control group.Participants in the intervention group ran with Aetrex L700 Speed Orthotics inserted in their usual running shoes,whilst participants in the control group ran in their usual running shoes with no orthotics.The study ran for an 8-wk period.Participants provided data relating to running comfort,distance,and time during weeks 3-6.Participants provided data relating to any RRIs they sustained during all 8 wks.Running distance and time were used to calculate running speed in miles per hour(mph).For each outcome variable,95%confidence intervals and P values were calculated to assess the statistical significance between the groups.For comfort and speed data,univariate multi-level analysis was performed,and for outcome variables with significant between group differences,multi-level multivariate analysis was performed to evaluate any confounding effects of gender and age.RESULTS Ninety-four participants were included in the final analysis(drop-out rate=11%).Comfort and speed from 940 runs and 978 injury data reports were analysed.Participants who ran with orthotics reported,on average,speeds 0.30 mph faster(P=0.20)and comfort scores 1.27 points higher(P≤0.001)than participants who ran with no orthotics.They were also 2.22 times less likely to sustain an injury(P=0.08)than participants who ran with no orthotics.However,findings were only significant for comfort and not for speed or injury rates.Age and gender were found to be significant predictors of comfort.However,the improvements in comfort reported by participants who ran with orthotics were still significant after adjusting for age and gender.CONCLUSION This study found orthotics to improve comfort and speed and prevent RRIs whilst running.However,these findings were only statistically significant for comfort.
文摘Swimrun was established in Sweden in 2006.In competition athletes alternate between running and swimming multiple times.It has grown from only being hosted in Sweden to now being a global sport.The swimrun race exposes athletes to environments that require a unique set of skills.For example,participants have to negotiate ocean currents and waves.The environmental conditions change between the runs and the swims.Athletes may be exposed to hot temperatures when running in wetsuits(25℃and hotter)and cold water(colder than 16℃)when swimming.This sudden change in environmental conditions imposes a poorly defined physiological stress on the participants.Research on the demands of swimrun is scarce.More research is needed to improve athlete safety during events.Also,research is needed to provide insight into enhancing training methods and performance.
文摘Background This study aimed to(i)provide normative data for measures of physical fitness(PF)(i.e.,muscle strength,muscle power,linear sprint speed)in 8-to 14-year-old Tunisian children and(ii)to examine sex and age group differences in these measures.Methods A total of 597 subjects(aged 8~14)participated in this study,the normative data for handgrip strength,jump height,and linear sprint speed were generated and collected,and the two-way analysis of variance(ANOVA)was used to identify the presence of the main effect of age,sex,an age×sex interaction for all tests.Results The two-way ANOVA showed credible age by sex interactions for all measures of PF[Effect Size(ES)ranged from 0.28 to 0.68;P<0.05].The findings indicated a main effect of age in handgrip strength,countermovement jump(CMJ)height,and linear sprint speed(all P<0.05),regardless of sex.Post hoc analyses showed early increases in handgrip strength for boys from 8 to 14 years.For CMJ height,an increase in performance was observed from 10 to 11 years(ES=0.23)and 12 to 13 years(ES=0.14)(all P<0.05).For linear sprint speed,performance enhancement was observed from 10 to 11 years(ES=1.00).In girls,an increase in handgrip strength was noted from 9 to 12 years(ES=1.00).However,the changes across age were less convincing for CMJ height and linear sprint speed tests,suggesting that differences for girls were not sup-ported by the collected data.Boys outperformed girls in all measures of PF(P<0.05).A summary of the estimated centiles of 10-and 30-m sprint speed,grip strength,and CMJ height for boys and girls allows a particular child’s test values to be compared to the norms for the group.Conclusions In summary,this study provides normative data that can be used as a tool to classify sprint speed,strength,and jump height performance in children of both sexes aged 8-14 years.
