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 .
Comparison of eccentric knee extensor muscle actions at two muscle lengths on indices of damage and angle-specific force production in humans.
In this study , we investigated the effects of knee extensor length during eccentric exercise on indices of muscle damage and adaptation .  Subjects ( n = 7 ) performed two bouts of 75 maximal voluntary eccentric muscle actions at a knee joint angular velocity of 1.57 rad s(-1 ) . One bout was performed at a short muscle length ( bout S ) with a knee joint range of motion of 2.79 to 1.40 radians ( 160 degrees to 80 degrees ) , and a second with the contralateral knee extensors at a long muscle length ( bout L ) with a range of motion of 2.01 to 0.7 radians ( 120 degrees to 40 degrees ) . The maximum voluntary contractile force ( MVC ) was measured before and 5 min after exercise , and again on days 3 , 5 , 7 , 10 and 12 , at knee angles of 160 degrees , 120 degrees and 80 degrees . Muscle soreness was measured before exercise and on each day after exercise . Serum creatine kinase activity was measured before exercise and on days 3 , 5 , 7 , 10 and 12 post-exercise . The MVC declined after each bout ( P < 0.01 ) , with a greater decline after bout L ( P < 0.05 ) . Muscle soreness was higher relative to bout S on days 1 , 2 , 3 , 5 and 6 ( P < 0.05 ) . Although serum creatine kinase activity was elevated after both exercise bouts ( P < 0.01 ) , there was no difference between bouts . Functional muscle damage markers and muscle soreness suggest greater damage after bout L. Post-exercise angle-specific force decrements suggest a transient increase in muscle length after bout L but not bout
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 .