Warren, G. L., Farthing, A. K., Piaro, B. B., Coley, S. R., Satterfied, C. W., Vlahos, C. D., & Lewis, J. E. (2012). Does a secondary loss of strength occur following induction of muscle injury? Presentation 2937 at the 59th Annual Meeting of the American College of Sports Medicine, San Francisco, California; May 29-June 2, 2012.

This paper reported on a systematic review and meta-analysis of the research literature to determine if a secondary loss of strength occurs after muscle injury. Searches were performed using four electronic databases (i.e., PubMed, CINAHL, Cochrane Library, and OpenSigle). Search terms included: skeletal muscle AND (injur* OR damag*) AND (strength OR force OR torque). Peer-reviewed articles (N = 106) were deemed suitable for analysis.

For all studies, a moderate increase in strength was found to occur between immediately post-injury and days 1, 2, and/or 3 post-injury. Strength was also found to increase progressively from day 1 to day 3 post-injury. Because the heterogeneity of between-study effect size was large, moderator variables that could potentially explain this heterogeneity were probed using subgroup analysis or meta-regression. There was no significant difference in overall effect size between studies using humans and those using animals. Additionally, there were no significant differences among studies using different muscle groups. The only moderator variable showing a significant effect was gender. Studies using females exhibited a slower rate of strength recovery after injury compared to studies using males only.

Implication. In the literature, there is no support for a secondary loss of strength following muscle injury. Actually, data indicate that a significant increase in strength occurs over the first three days after injury with females showing a slower recovery rate.

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