Serratus Anterior and Lattisimus Dorsi Muscle Activation in Hypopressive Exercises Performed in Open Versus Closed Kinetic Chain: A Cross-Sectional Study

This study aimed to describe and compare the serratus anterior (SA) and latissimus dorsi (LD) muscle activity between six pairs of closed and open kinetic chain HE. While previous studies have analyzed abdominal and pelvic muscle activity during HE, no research has examined the neuromuscular activation of the muscles SA and LD in different HE positions using open versus closed kinetic chains. Twenty-five healthy adults (mean age, 42.9±8.4 years; BMI, 22.1±2.4 kg/m²) with prior HE experience participated. Participants performed three open-chain and three closed-chain HE positions. Surface electromyography recorded SA and LD activity, normalized to maximum voluntary isometric contraction (MVIC). SA showed greater activation than LD across all positions. SA activity was moderate (20–40% MVIC), while LD activity was mild (<20%). Significant differences were observed for left SA (p<0.001, ε²=0.09), left LD (p=0.04, ε²=0.04), and right LD (p=0.01, ε²=0.05). Significant differences were observed for left SA in standing versus kneeling (p<0.01) and kneeling versus seated (p<0.01), and for right LD in kneeling versus seated (p<0.05). No differences were found between standing and kneeling for any muscle. Closed kinetic chain HE elicits greater SA and LD activation than open-chain variations. SA activation during closed-chain HE performed on a wall is moderate, while LD activation remains low.