Background:Soccer match-play is typically contested over 90 min;however,in some cup and tournament scenarios,when matches are tied,they proceed to an additional 30 min,which is termed "extra-time^(ET).This system...Background:Soccer match-play is typically contested over 90 min;however,in some cup and tournament scenarios,when matches are tied,they proceed to an additional 30 min,which is termed "extra-time^(ET).This systematic review sought to appraise the literature available on 120-min of soccer-specific exercise,with a view to identifying practical recommendations and future research opportunities.Methods:The review was conducted according to the PRISMA guidelines.Independent researchers performed a systematic search of PubMed,CINAHL,and PsycINFO in May 2019,with the following keywords entered in various combinations:"soccer","football","extra-time","extra time","extratime","120 minutes","120 min","additional 30 minutes",and "additional 30 min".Results:The search yielded an initial 73 articles.Following the screening process,11 articles were accepted for analyses.Articles were subsequently organized into the following 5 categories:movement demands of ET,performance responses to ET,physiological and neuromuscular response during ET,nutritional interventions,and recovery and ET.The results highlighted that during competitive match-play,players cover5%-12% less distance relative to match duration(i.e.,meters per minute) during ET compared to the preceding 90 min.Reductions in technical performance(i.e.,shot speed,number of passes and dribbles) were also observed during ET.Additionally,carbohydrate provision may attenuate and improve dribbling performance during ET.Moreover,objective and subjective measures of recovery may be further compromised following ET when compared to 90 min.Conclusion:Additional investigations are warranted to further substantiate these findings and identify interventions to improve performance during ET.展开更多
Purpose The purpose of this study was to examine the influence of muscle length and fatigue on maximal force,submaximal force steadiness,and electromyographic(EMG)activity of the biceps brachii.Methods Force and EMG r...Purpose The purpose of this study was to examine the influence of muscle length and fatigue on maximal force,submaximal force steadiness,and electromyographic(EMG)activity of the biceps brachii.Methods Force and EMG responses were measured before and after a fatigue protocol consisting of maximal intermit-tent contractions of the elbow flexors until task failure(n=20).The protocol was performed on two separate occasions in a randomized order.During one visit,the elbow joint was at 90°(EF90)and for the other,it was extended to 120°(EF120).Results The results show a large effect size for greater force loss following fatigue at long muscle length(P=0.067,n^(2)_(p)=0.166).The fatigue-based decreases in force steadiness were not different between muscle lengths(P=0.502,n^(2)_(p)=0.024).Force steadiness was lower at long muscle length before and after fatigue(P<0.01,d=0.691).Following fatigue,muscle excitation decreased and increased during maximal and submaximal force tasks,respectively,yet there were no length-dependent EMG responses.Conclusions The novel findings show fatigue at long muscle length likely affects force loss to a greater degree than fatigue-based decreases in force steadiness.These data show lower elbow flexion force steadiness when the biceps brachii is in a lengthened position.展开更多
文摘Background:Soccer match-play is typically contested over 90 min;however,in some cup and tournament scenarios,when matches are tied,they proceed to an additional 30 min,which is termed "extra-time^(ET).This systematic review sought to appraise the literature available on 120-min of soccer-specific exercise,with a view to identifying practical recommendations and future research opportunities.Methods:The review was conducted according to the PRISMA guidelines.Independent researchers performed a systematic search of PubMed,CINAHL,and PsycINFO in May 2019,with the following keywords entered in various combinations:"soccer","football","extra-time","extra time","extratime","120 minutes","120 min","additional 30 minutes",and "additional 30 min".Results:The search yielded an initial 73 articles.Following the screening process,11 articles were accepted for analyses.Articles were subsequently organized into the following 5 categories:movement demands of ET,performance responses to ET,physiological and neuromuscular response during ET,nutritional interventions,and recovery and ET.The results highlighted that during competitive match-play,players cover5%-12% less distance relative to match duration(i.e.,meters per minute) during ET compared to the preceding 90 min.Reductions in technical performance(i.e.,shot speed,number of passes and dribbles) were also observed during ET.Additionally,carbohydrate provision may attenuate and improve dribbling performance during ET.Moreover,objective and subjective measures of recovery may be further compromised following ET when compared to 90 min.Conclusion:Additional investigations are warranted to further substantiate these findings and identify interventions to improve performance during ET.
文摘Purpose The purpose of this study was to examine the influence of muscle length and fatigue on maximal force,submaximal force steadiness,and electromyographic(EMG)activity of the biceps brachii.Methods Force and EMG responses were measured before and after a fatigue protocol consisting of maximal intermit-tent contractions of the elbow flexors until task failure(n=20).The protocol was performed on two separate occasions in a randomized order.During one visit,the elbow joint was at 90°(EF90)and for the other,it was extended to 120°(EF120).Results The results show a large effect size for greater force loss following fatigue at long muscle length(P=0.067,n^(2)_(p)=0.166).The fatigue-based decreases in force steadiness were not different between muscle lengths(P=0.502,n^(2)_(p)=0.024).Force steadiness was lower at long muscle length before and after fatigue(P<0.01,d=0.691).Following fatigue,muscle excitation decreased and increased during maximal and submaximal force tasks,respectively,yet there were no length-dependent EMG responses.Conclusions The novel findings show fatigue at long muscle length likely affects force loss to a greater degree than fatigue-based decreases in force steadiness.These data show lower elbow flexion force steadiness when the biceps brachii is in a lengthened position.
