Nordic Exercise Versus Hold-Relax Stretching for Hamstring Flexibility in Soccer Players

Abstract

Background: Reduced hamstring flexibility may impair movement performance and increase susceptibility to hamstring-related problems in soccer players. Nordic Exercise and Hold-Relax Stretching are commonly used to improve hamstring flexibility, but comparative evidence remains limited.
Objective: To evaluate the effects of Nordic Exercise and Hold-Relax Stretching on hamstring flexibility and compare their effectiveness in young soccer players.
Methods: This quasi-experimental pretest-posttest nonrandomized study involved 14 male soccer players aged 18–23 years with reduced hamstring flexibility. Thirty players were screened, and 14 eligible participants were allocated to either a Nordic Exercise group (n=7) or a Hold-Relax Stretching group (n=7). Both interventions were performed three times weekly for four weeks. Hamstring flexibility was assessed using the Active Knee Extension (AKE) test. Paired-sample t-tests were used for within-group comparisons, and independent-sample t-tests were used for between-group comparisons.
Results: Nordic Exercise significantly improved hamstring flexibility, with mean AKE scores decreasing from 37.86±6.96° to 27.86±5.96° (mean change=9.71±7.91°; p=0.016), representing a 25.6% improvement. Hold-Relax Stretching also significantly improved hamstring flexibility, with mean AKE scores decreasing from 39.71±6.49° to 32.00±5.13° (mean change=7.71°; p<0.001), representing a 19.4% improvement. Post-intervention AKE scores were lower in the Nordic Exercise group than in the Hold-Relax Stretching group (27.85±5.95° vs 32.00±5.13°), although the difference was not statistically significant (p=0.189).
Conclusion: Both Nordic Exercise and Hold-Relax Stretching significantly improved hamstring flexibility in young soccer players. Neither intervention demonstrated superior effectiveness during the four-week intervention period.