Shoulder muscle activation during standard climbing movement: an EMG analysis in individuals with shoulder pain

The shoulder joint is one of the most mobile joints in the body, consisting of a complex structure that provides stability, mobility, and support. These characteristics must be preserved and maintained to ensure proper joint functionality. However, its high degree of mobility makes the shoulder particularly susceptible to injuries and dislocations which could make climbing impractical. This preliminary study aimed to evaluate shoulder muscle activation using surface electromyography (sEMG) during two standard climbing movements in individuals with shoulder pain. It also examined the effects of physiotherapy treatment and analyzed the influence of the pathology on muscle function. Eight participants (3 females and 5 males, mean age 29.9 ± 6.1 years) experiencing persistent shoulder joint pain were recruited from a local climbing gym. The medial deltoid, pectoralis major, latissimus dorsi, upper trapezius, lower trapezius, and anterior serratus were analyzed, as they are the primary muscles involved in shoulder movement during climbing. The protocol included recording the maximum voluntary contraction (MVC) for each muscle, followed by the execution of two standard climbing movements (frontal and flagging) three times per side before and after physiotherapy treatment. The percentage of muscle relative to the MVC was evaluated for three positions identified in each task. The subjects were divided into four groups according to the shoulder condition (healthy and painful) before and after physiotherapy treatment. The results showed some significant differences (p=0.02) in the lower trapezius, pectoralis major, and latissimus dorsi. In response to pain, the body compensates through motor and postural adaptations to minimize strain on the affected shoulder while preserving movement efficiency. Physiotherapy treatment altered muscle activation on both sides, enhancing the engagement of key muscles involved in climbing movements. Despite the limited sample size and some non-significant differences, the findings suggest a beneficial impact on shoulder biomechanics.