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 .
Changes in human skeletal muscle ultrastructure and force production after acute resistance exercise.
Muscle ultrastructure and contractile properties were examined before and after a single bout of resistance exercise ( 8 sets of 8 repetitions at 80 % of 1 repetition maximum ) . Eight untrained males performed the concentric ( Con ) phase of arm-curl exercise with one arm and the eccentric ( Ecc ) phase with the other arm . Needle biopsies were obtained from biceps brachii before exercise ( Base ) , immediately postexercise from each arm ( post-Con and post-Ecc ) , and 48 h postexercise from each arm ( 48 h-Con and 48 h-Ecc ) . Electron microscopy was used to quantify the presence of disrupted fibers in each sample . Analysis of variance revealed a greater ( P < or = 0.05 ) proportion of disrupted fibers in post-Con , post-Ecc , 48 h-Con , and 48 h-Ecc sample s compared with Base . Significantly more fibers were disrupted in post-Ecc ( 82 % ) and 48 h-Ecc ( 80 % ) sample s compared with post-Con ( 33 % ) and 48 h-Con ( 37 % ) , respectively . Voluntary and evoked strength measurements recovered to Base values within 24 h in the Con arm but remained depressed ( P < or = 0.05 ) for 72 - 96 h in the Ecc arm . These data indicate that both the raising and lowering phases of weightlifting produced myofibrillar disruption , with the greatest disruption occurring during the lowering phase
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 .