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 .
Effect of lengthening contraction velocity on muscle damage of the elbow flexors.
PURPOSE This study investigated the effect of lengthening contraction velocity on exercise-induced muscle damage . METHODS Sixteen men were placed into two groups performing either 30 ( N = 8) or 210 ( N = 8) maximal lengthening contractions of the elbow flexors on an isokinetic dynamometer .  Dominant and nondominant arms were r and omly assigned for a slow-velocity ( S : 30 degrees.s(-1 ) ) or a fast-velocity ( F : 210 degrees.s(-1 ) ) exercise separated by 14 d. Maximal voluntary strength of isometric contractions ( iMVC ) and isokinetic concentric contractions ( cMVC ) , range of motion ( ROM ) , upper-arm circumference , muscle soreness , and serum creatine kinase ( CK ) activity were measured before , immediately after , and 1 - 120 h after exercise . Changes in these measures over time were compared by a two-way repeated- measures ANOVA to examine the effect of velocity in the same number of contractions ( S30 vs F30 ; S210 vs F210 ) or the effect of contraction number at the same velocity ( S30 vs S210 ; F30 vs F210 ) . RESULTS A significant ( P < 0.05 ) interaction effect was evident only for iMVC between S30 and F30 , but it was evident for iMVC , cMVC , ROM , and CK between S210 and F210 . Changes in most of the measures were significantly ( P < 0.05 ) smaller after 30 contractions ( S30 and F30 ) than after 210 contractions ( S210 and F210 ) . CONCLUSION These results suggest that the effect of contraction velocity on the magnitude of muscle damage after 30 contractions is minor ; however , when 210 lengthening contractions were performed , the effect of contraction velocity became conspicuous . It is concluded that fast-velocity lengthening contractions are likely to induce greater muscle damage than slow-velocity contractions ; however , muscle fatigue seems to be a confounding factor for the velocity effect
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 .