Effect of high vs. low volume of the Nordic hamstring curl on hamstring muscle architecture and eccentric strength in soccer players: A Systematic review and Meta-analysis

Jozef Cholp^*Erika Zemková

• Comenius University, Bratislava, Slovakia

Hamstring strain injuries (HSI) are the most prevalent injury in professional soccer, representing a persistent challenge for players and practitioners. The Nordic hamstring exercise (NHE) is the most extensively studied intervention for reducing HSI risk, primarily through its effects on modifiable factors such as eccentric hamstring strength and muscle architecture. However, uncertainty remains regarding the minimal effective dosage of NHE to achieve meaningful adaptations. This systematic review and meta-analysis aimed to (1) examine the effects of low- versus high-volume NHE on eccentric strength and hamstring muscle architecture in soccer players, and (2) highlight gaps in the literature for future research. A systematic search of PubMed, Web of Science, and Scopus identified 11 eligible studies. Data were pooled using a random-effects model, with Hedges’ g effect sizes and 95% confidence intervals (CI) calculated. High-volume NHE protocols (≈2–3 sets of 8–12 repetitions, 2–3 times per week) significantly improved eccentric strength (g = 0.77, CI 0.49–1.06, p < 0.001), fascicle length (g = 0.43, CI 0.20–0.65, p < 0.001), and muscle thickness (g = 0.48, CI 0.28–0.68, p < 0.001). No significant effect was observed for pennation angle (g = -0.16, p = 0.16). In contrast, low-volume NHE (≈1–2 sets of 3–5 repetitions, 1–2 times per week) significantly improved eccentric strength (g = 0.46, CI 0.06–0.87, p < 0.05), but did not induce meaningful changes in fascicle length, pennation angle, or muscle thickness. For eccentric torque, neither high- nor low-volume NHE produced significant effects (g ≈ 0.04, p = 0.74). Control groups demonstrated trivial or negative adaptations across all outcomes. These findings indicate that while both low- and high-volume NHE can enhance eccentric hamstring strength, high-volume training provides superior benefits for hamstring muscle architecture, particularly fascicle length and muscle thickness, which are key factors in HSI prevention. Nonetheless, outcomes may vary depending on playing level, prior NHE experience, and adherence to training. Moreover, inconsistencies in isokinetic dynamometry protocols highlight the need for standardized assessment methods to improve comparability across studies. Future research should explore the potential of low-volume NHE to induce structural adaptations in players with different training backgrounds and competitive levels.