The Effect of Different Upper Extremity Plyometric Exercises on Scapulothoracic Muscle Activations in Female Volleyball Players.

Uzun, S, Kahraman, MY, Sanli, G, Tatar, Y, and Gercek, N. The effect of different upper extremity plyometric exercises on scapulothoracic muscle activations in female volleyball players. J Strength Cond Res XX(X): 000-000, 2026-This study investigated the EMG activity ratios of the scapulothoracic musculature during selected upper extremity plyometric exercises to identify those most effective for promoting scapular stabilization in female volleyball players. Thirty-five female volleyball players (age: 17.34 ± 2.36 years, height: 174.79 ± 6.88 cm, body mass: 63.09 ± 6.92 kg) participated. Surface EMG was recorded from the upper trapezius (UT), middle trapezius (MT), and lower trapezius (LT), and serratus anterior (SA) during 8 bilateral plyometric exercises categorized as open-kinetic chain and closed-kinetic chain (CKC). EMG data were normalized to maximal voluntary isometric contractions, and UT/MT, UT/LT, and UT/SA activation ratios were calculated to evaluate scapular stabilization. Significant differences (p < 0.01) and a large effect size (η2 = 0.254) were found in activation ratios across the exercises. The Supine Med-Ball Chest Pass demonstrated the lowest overall activation ratios among the exercises (UT/MT = 138.21%, UT/LT = 77.59%, UT/SA = 22.59%). In addition, Ground Med-Ball Throw and Wall Med-Ball Chest Pass exercises demonstrated lower UT/SA ratios (39.22 and 45.21%, respectively; p < 0.001), suggesting reduced UT activation and increased SA engagement. Conversely, plyometric push-up variations showed higher UT/SA ratios (112.77 and 103.81%; p < 0.001), indicating a less favorable scapular muscle activation profile. Exercises performed in the supine position and at lower shoulder flexion angles elicited superior scapular stabilization muscle activation patterns compared with those performed in standing and higher overhead arm positions. Open-kinetic chain exercises generally demonstrated more favorable muscle activation ratios than CKC exercises. These findings may guide practitioners in selecting plyometric exercises that promote favorable scapular muscle activation patterns to improve scapular control in volleyball players.