Conclusion Overall , our findings do not support the presence of a secondary loss of strength following an acute muscle injury , and strongly suggest that strength , on average , recovers steadily over the first 3 days post-injury
Background An immediate loss of strength follows virtually all types of muscle injury but there is debate whether the initial strength loss is maximal or if a secondary loss of strength occurs during the first 3 days post-injury .
Objective The objective of this analysis was to conduct a systematic review and meta- analysis of the research literature to determine if a secondary loss of strength occurs after an injurious initiating event .
Manipulation of knee extensor force using percutaneous electrical myostimulation during eccentric actions: effects on indices of muscle damage in humans.
Percutaneous electrical myostimulation ( PES ) was used to manipulate the force produced by the knee extensor muscles during eccentric exercise , thereby providing a model to investigate the role of force in muscle damage . Two eccentric exercise bouts of equal work were performed by nine subjects , using fixed voltage PES at 20 Hz ( to produce moderate muscle forces ) and 100 Hz ( to produce high muscle forces ) . Muscle contractility , serum creatine kinase activity ( CK ) and muscle soreness ( MS ) were evaluated before , and up to 14 days after exercise . Data are presented as means+/-SEM , and were analysed using repeated measures analysis of variance ( ANOVA ) , t-tests and Wilcoxon tests . Peak forces were higher during the 100 Hz bout than the 20 Hz bout for repetitions 1 ( 472+/-60 vs 237+/-23 Newtons ) , 10 ( 381+/-26 vs 233+/-26 Newtons ) , 20 ( 310+/-24 vs 218+/-24 Newtons ) , all p < 0.01 , t-test and 30 ( 297+/-27 vs 204+/-21 Newtons ) , p < 0.05 , t-test . Following the 100 Hz bout , maximum voluntary contractile force ( MVC ) was lower ( p<0.01 , ANOVA ) , and CK was higher ( p<0.0001 , ANOVA ) than after the 20 Hz bout . Subjects also reported greater MS on days 2 to 6 ( p<0.05 , Wilcoxon test ) following the 100 Hz bout . Despite a decline in the stimulated 20:100 Hz tetanic force ratio after each bout ( p<0.01 , ANOVA ) there was no difference between bouts ( p>0.05 , ANOVA ) . The higher rise in CK and MS after the 100 Hz bout , together with the greater deficit in MVC , suggest that in humans , muscle force is a contributing factor to muscle injury during eccentric actions
Conclusion Overall , our findings do not support the presence of a secondary loss of strength following an acute muscle injury , and strongly suggest that strength , on average , recovers steadily over the first 3 days post-injury
Background An immediate loss of strength follows virtually all types of muscle injury but there is debate whether the initial strength loss is maximal or if a secondary loss of strength occurs during the first 3 days post-injury .
Objective The objective of this analysis was to conduct a systematic review and meta- analysis of the research literature to determine if a secondary loss of strength occurs after an injurious initiating event .