Comparison of Trunk and Hip Extensor Activation According to Various Applications of Elastic Bands During Nordic Hamstring Exercise

Background: Nordic hamstring exercise (NHE) is a widely used eccentric strengthening exercise that reduces the risk of hamstring and anterior cruciate ligament injuries. During NHE, the ankles are fixed in a kneeling position, while the upper body falls forward as the knee extends, maximizing hamstring activation. However, compensatory movements, such as an increased hip joint angle, make optimal execution difficult. Assisted NHE (ANHE) using an elastic band facilitates controlled movement, maintains high hamstring activation, and allows intensity adjustments. Despite their benefits, research on exercise postures based on different elastic band application regions remains limited. Objects: This study aimed to compare trunk and hip extensors activation, the gluteus maximus vs. erector spinae (GM/ES) ratio, and subjective difficulty during NHE, chest-assisted NHE (C-ANHE), and pelvic-assisted NHE (P-ANHE). Methods: Twenty-two healthy males performed each exercise, starting from a kneeling position with the knee joint at 90° and extending 15° with isometric contraction. The muscle activations of the ES, GM, and the biceps femoris long head (BFlh) were measured using surface electromyography. The GM/ES ratio was calculated, and the Borg rating of perceived exertion (Borg RPE) (6–20) scale was examined. Results: ES (F = 141.38, p < 0.001), GM (F = 184.14, p < 0.001), and BFlh (F = 164.85, p < 0.001) activation differed significantly among the exercises. All muscles showed higher muscle activity during P-ANHE than during C-ANHE (p < 0.017). The GM/ES ratio was lower than 1 for all exercises but significantly higher in P-ANHE (0.66 ± 0.15) than in C-ANHE (0.57 ± 0.18) (p < 0.017). The Borg RPE score differed significantly among exercises (p < 0.001) and was higher in P-ANHE (15.10 ± 1.77) than in C-ANHE (11.86 ± 1.91) (p < 0.017). Conclusion: P-ANHE increased GM activation to a greater extent than C-ANHE, with moderate subjective difficulty. It is recommended as an ANHE variant for targeting the GM while considering ES activation.