Effect of Nordic Hamstring Exercise Training on Knee Flexors Eccentric Strength and Fascicle Length: A Systematic Review and Meta-Analysis

Context : Nordic hamstring exercise (NHE) has been widely employed to prevent strain injuries. However, it is still not clear which adaptations are responsible for the NHE preventive effects. Objectives The aim of this study was investigate effects on knee flexors eccentric strength and fascicle length. Evidence Acquisition search strategy included MEDLINE, PEDro, Cochrane CENTRAL from inception April 2020. Randomized clinical trials that have analyzed training and/or length were included. Synthesis From 1932 studies identified, 12 in systematic review, 9 presented suitable data meta-analysis. All demonstrated increments response (10%–15% 16%–26% tests performed isokinetic dynamometer device, respectively), as well significant enhancement biceps femoris long head (12%–22%). Meta-analysis showed effective increase assessed with both (0.68; 95% confidence interval, 0.29 1.06) (1.11; 0.62 1.61). also (0.97; 0.46 1.48). Conclusions potential increasing