Reverse Nordic Curl Does Not Generate Superior Eccentric Activation of the Quadriceps Muscle Than Bodyweight Squat-Based Exercises

Abstract

Context: The quadriceps femoris is consistently ranked among the muscles most prone to sustain strain injuries in sports involving kicking and sprinting actions. Given the documented preventive effect of Nordic hamstring curl programs against hamstring strain injuries, incorporating exercises that induce eccentric overload on the quadriceps could potentially help mitigate strain injuries within this muscle group. The Reverse Nordic Curl (RNC) has emerged as a viable field-based exercise for eccentrically working the quadriceps. This study aimed to compare quadriceps muscle eccentric activation during the RNC with 3 bodyweight squat-based exercises: single-leg squat (SLS), Bulgarian squat, and forward lunge. Design: Cross-sectional study. Methods: Twenty-three healthy volunteers (15 men) were monitored for rectus femoris, vastus lateralis, and vastus medialis electromyographic signal, as well as knee range of motion, while performing 10 repetitions of each exercise. Electromyography data acquired during eccentric phases were normalized by maximum voluntary isometric contraction of the knee extensors. The exercises were compared based on the electromyography and knee range of motion values. Results: RNC generated a similar rectus femoris and vastus medialis eccentric activation compared with the squat-based exercises (P > .05 for all), and a lower vastus lateralis activation than SLS (P < .001). Among the bodyweight squat-based exercises, SLS generated greater eccentric activation than forward lunge and Bulgarian squat for the 3 muscles (P < .05 for all). RNC was performed with lower knee-flexion range of motion than bodyweight squat-based exercises (P < .001). Conclusions: RNC did not produce superior eccentric quadriceps activation compared to bodyweight squat-based exercises, even proving to be less demanding for the vastus lateralis compared to the SLS. These findings may assist practitioners in selecting exercises to elicit quadriceps eccentric stimulus, with a focus on preventing strain injuries.