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 .
Responses of human elbow flexor muscles to electrically stimulated forced lengthening exercise.
This study developed an electrical stimulation model for human elbow flexors to examine eccentric exercise-induced muscle damage and adaptation . Male students ( n=17 ) were r and omly placed into one of two groups ; isometric ( ES-ISO , n=8 ) and eccentric ( ES-ECC , n=9 ) . The elbow joint was fixed at 90 degrees ( 1.57 rad ) and the elbow flexors stimulated percutaneously by an electronic muscle stimulator for 5 s through two electrodes placed over the muscles for ES-ISO . In ES-ECC , the muscles were stimulated similarly to the ES-ISO , but the elbow joint was forcibly extended from an elbow flexed ( 90 degrees 1.57 rad ) to a full-extended position ( 180 degrees , 3.14 rad ) in 3 s. Maximal voluntary isometric force , range of motion , upper arm circumference , muscle thickness by ultrasonography , muscle soreness , plasma creatine kinase and aspartate aminotransferase activities were assessed before and for 4 days after exercise . ES-ECC produced significantly larger changes in all criterion measures compared with ES-ISO ( P < 0.01 ) . These findings confirmed that eccentric muscle actions induced muscle damage , but isometric contractions result ed in little or no damage . Six subjects from the ES-ECC group repeated the same eccentric exercise ( ECC2 ) 2 weeks after the first bout ( ECC1 ) , and changes in the criterion measures were compared between the bouts . Changes in all criterion measures after ECC2 were significantly smaller than ECC1 ( P < 0.01 ) . These results suggest that the first eccentric exercise produced a protective effect against muscle damage in the subsequent eccentric exercise bout , which does not involve adaptations in the central nervous system
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 .