The effects of the Nordic hamstring exercise on sprint performance and eccentric knee flexor strength: A systematic review and meta-analysis of intervention studies among team sport players.
Level 1 - systematic review of randomized trials
Systematic review and meta-analysis of intervention studies
PubMed 33893033 · doi:10.1016/j.jsams.2021.03.009
What was done
Authors systematically searched electronic databases through June 20, 2020, to examine the effects of the Nordic hamstring exercise (NHE) versus control on sprint performance (5, 10, and 20 m) and eccentric knee flexor strength in team sport players. Random-effects meta-analyses were conducted across 17 intervention studies using mean difference (MD) for sprint time and standardized change of mean difference (SCMD) for eccentric knee flexor strength.
What was found
NHE interventions demonstrated a small overall benefit on sprint performance (MD: -0.04 s [-0.08, -0.01]). By distance, a significant improvement was observed for 10 m sprints (MD: -0.06 s [-0.10, -0.01]), but not for 5 m (MD: -0.02 s [-0.10, 0.06]) or 20 m (MD: -0.05 s [-0.30, 0.19]). For eccentric knee flexor strength, NHE demonstrated a significant improvement (SCMD: 0.83 [0.55, 1.12]) relative to control. Subgroup analysis showed moderate strength benefits in relatively untrained individuals, but less consistent improvements among well-trained players.
Why it matters
Beyond its common use for hamstring injury prevention, the Nordic hamstring exercise provides modest functional improvements in initial acceleration and substantial eccentric strength gains in less trained team sport athletes.
Limits
The included trials were characterized by some concerns or high risk of bias. Total participant sample size is not stated in the abstract. Sprint improvements were non-significant at 5 m and 20 m, and eccentric strength gains were inconsistent in well-trained cohorts.
Cited by
- supports Performing Nordic hamstring curls improves sprinting speed.