Pas, H. I., Reurink, G., Tol, J. L., Weir, A., Winters, M., & Moen, M. H. (2015). Efficacy of rehabilitation (lengthening) exercises, platelet-rich plasma injections, and other conservative interventions in acute hamstring injuries: an updated systematic review and meta-analysis. Br J Sports Med, 49(18), 1197-1205. doi:10.1136/bjsports-2015-094879