Electromyography activity of the abdominal muscles during exercises with and without aid from upper limbs in healthy individuals: A cross-sectional study.

INTRODUCTION: Individuals with pronounced abdominal muscle impairment often struggle to perform conventional abdominal strengthening exercises, particularly during the initial phases of rehabilitation. Identifying alternative exercise positions that minimize these challenges while maintaining adequate muscular engagement is essential for effective training and clinical practice. This study aimed to compare the EMG activity of the abdominal and shoulder extensors muscles during traditional curl-ups, modified curl-ups, and roll-ups with balls.

METHOD: Forty healthy participants (20 male, 20 female) aged 20-30 years were recruited for this study. Each participant performed three exercises: a traditional curl-up, a modified curl-up (with upper limb assistance), and a roll-up with a ball (a modified Pilates exercise). EMG activity was recorded for the bilateral latissimus dorsi, posterior deltoid, rectus abdominis, and external oblique muscles. An accelerometer was used to determine the movement onset and offset.

RESULTS: Integrated EMG activity for the abdominal and posterior deltoid muscles was similar across all exercises (p > 0.13). However, latissimus dorsi activity was significantly higher during the modified curl-up (p = 0.02). Statistical parametric mapping analysis revealed increased latissimus dorsi (p < 0.012, p < 0.007) and posterior deltoid activity (p < 0.001, p < 0.016) during the modified curl-up compared to the curl-up and roll-up with a ball.

CONCLUSION: The modified curl-up, which incorporates upper limb assistance, elicits comparable abdominal muscle activation to other exercises and may enhance lumbopelvic stabilization, making it a viable alternative in early rehabilitation.