Knee Flexion Angle at Peak Torque Changes Following Eccentric Hamstring Resistance Training in Adults: A Systematic Review

OBJECTIVES: To quantify changes in knee flexion angle at peak torque (APT) following eccentric hamstring resistance training in adults, and to summarize exercises that may promote a shift in APT. DESIGN: Intervention systematic review LITERATURE SEARCH: PubMed, CINAHL, PeDro, Scopus, EMBASE, and Web of Science were systematically searched in April 2025. STUDY SELECTION CRITERIA: Prospective studies quantifying the relationship between eccentric hamstring strength and APT were included. Retrospective studies, preliminary work, conference abstracts, and non-English articles were excluded. DATA SYNTHESIS: Findings were synthesized qualitatively, using Joanna Briggs Institute and Physiotherapy Evidence Database tools for evaluating methodological quality of studies. The certainty of evidence was assessed using Grade of Recommendations, Assessment, Development, and Evaluations (GRADE) framework. RESULTS: Nineteen studies (427 participants, age 18–52 years) were included. The APT generally shifted toward longer muscle lengths after eccentric training, with 15 studies reporting this change and 9 groups showing significant shifts. The largest changes occurred with seated eccentric knee flexion (−17.3°± 11.7, p < 0.001) and the Nordic Hamstring Exercise (−13.5°± 4.8, p < 0.05). CONCLUSION: Eccentric training interventions, particularly the Nordic Hamstring Exercise and seated eccentric knee flexion, may contribute to shifts in hamstring peak torque toward more extended muscle lengths. The certainty of evidence was low for all comparisons.