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 .
Effects of a second bout of maximal eccentric exercise on muscle damage and electromyographic activity
This study examined whether a second bout of maximal eccentric exercise performed 3 days after the first exercise bout would produce further changes in muscle damage and electromyographic activity ( EMG ) . Male students ( n=26 ) were r and omly assigned to experimental 70 ( EX70 ; n=9 ) , experimental 30 ( EX30 ; n=8 ) , and control ( CON ; n=9 ) groups . The initial exercise was 30 maximal voluntary isokinetic eccentric contractions ( MAX1 ) on non-dominant elbow flexors at 60 ° s−1 ( 1.05 rad s-1 ) . The EX70 and EX30 groups performed a second bout of 70 and 30 eccentric contractions ( MAX2 ) , respectively , 3 days after MAX1 . Upper arm circumference , range of motion , strength , integrated EMG ( IEMG ) , and mean power frequency ( MPF ) were measured before , immediately after , and once a day for 9 days after MAX1 . Plasma creatine kinase ( CK ) activity and muscle soreness were assessed before and for 9 days after MAX1 . Total work , work per contraction , IEMG , and MPF were also recorded during MAX1 and MAX2 . All indicators of muscle damage changed following MAX1 for each group ( P<0.05 ) , but no indicators of additional damage ( P>0.05 ) were apparent after MAX2 for either the EX70 or EX30 groups . IEMG ( P=0.03 ) and MPF ( P=0.04 ) were lower for MAX2 compared with MAX1 for both the EX30 and EX70 groups . It is concluded that performing a second bout of eccentric exercise with damaged muscles 3 days after the initial bout does not produce further damage or retard recovery , even when the second bout of exercise is more strenuous . EMG findings were consistent with reduced activation of fast-twitch motor units during the second eccentric bout . These results may be interpreted as evidence of a neural protective mechanism
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 .