Acute Effects of Thoracic-Spinal Elevation via a Novel Bench Press Pad on sEMG and Barbell Kinetics in Resistance-Trained Males

This study investigated the acute effects of thoracic-spinal elevation, applied via a novel Bench Press Assist Device (BPAD), on pectoralis major activation and barbell kinetics during submaximal bench pressing. Ten resistance-trained males (23 ± 3 y) completed a randomized, single-blind, crossover trial performing five repetitions at 70 % 1-RM under standard flat bench and BPAD conditions. Bilateral surface electromyography (sEMG) assessed pectoralis major activation, while a linear position transducer recorded mean and peak barbell velocity, concentric power, and range of motion (ROM). Compared with the flat-bench condition, the BPAD produced significant increases in mean and peak velocity, bilateral pectoralis major activation (all p < 0.001), and ROM (p = 0.005). Concentric power rose by approximately 9 % but did not reach statistical significance, likely reflecting the fixed external load and the force-velocity trade-off at submaximal intensities. The observed gains in velocity and muscle activation indicate that thoracic elevation enhances mechanical efficiency and neuromuscular engagement during pressing without altering load demands. By facilitating thoracic extension and scapular retraction, the BPAD may improve length-tension relationships and joint alignment, yielding a smoother bar path and greater bilateral muscle symmetry. These findings highlight posture-focused interventions as a simple means to refine pressing mechanics, increase movement efficiency, and potentially reduce shoulder stress, likely driven by improved scapulothoracic mechanics and neural coordination. Future research should examine chronic adaptations to repeated use of thoracic elevation and its applicability across sexes, training levels, and varied load intensities.