The effect of stretching the pectoralis major, sternocleidomastoid, and iliopsoas muscles on 800 m swimming performance in master swimmers

Muscle mechanical properties and mobility-related characteristics are often considered important contributors to swimming performance, influencing stroke mechanics, movement efficiency, and injury prevention. However, the specific contribution of targeted stretching exercises for upper and lower body muscles to swimming performance remains unclear, especially in master-level athletes. It was hypothesized that adding targeted stretching exercises for the Pectoralis major, Sternocleidomastoid, and Iliopsoas muscles to regular swimming training would enhance 800-m swimming performance and induce favorable changes in muscle mechanical properties compared with standard training alone. Level II-Randomized controlled trial. Thirty volunteer master swimmers were randomly assigned to two groups: an Experimental Group (n = 15) and a Control Group (n = 15). The Experimental Group performed daily targeted stretching of the Pectoralis major, Sternocleidomastoid, and Iliopsoas muscles for six weeks, in addition to their regular swimming training. The Control Group continued standard training without additional stretching. Pre- and post-intervention assessments included 800-m swim times and muscle mechanical and viscoelastic properties assessed using the MyotonPRO device.Statistical analyses compared within- and between-group changes, with significance set at p < 0.05. Both groups showed statistically significant improvements in 800-m swim times after six weeks of training (p < 0.05). However, no significant difference was found between the groups(p > 0.05). MyotonPRO measurements revealed no statistically significant changes in muscle mechanical properties in either group (p > 0.05). Regular swimming training improved 800-m performance in master swimmers. The addition of targeted stretching exercises for the Pectoralis major, Sternocleidomastoid, and Iliopsoas muscles did not result in additional improvements in performance or measurable changes in muscle mechanical properties. Although stretching is commonly incorporated into swimming training programs, the present findings suggest that adding daily stretching of the pectoralis major, sternocleidomastoid, and iliopsoas muscles to regular swimming training does not provide additional short- to medium-term improvements in 800 m swimming performance or muscle mechanical properties in master swimmers. Clinical trial number: NCT05991999, trial registration: 2023-08-05.