Description

The latissimus dorsi (LD) originates from the spinous processes of the lower six thoracic vertebrae and the thoracolumbar fascia/iliac crest, and-together with the teres major-attaches to the medial lip of the intertubercular groove of the humerus. Functionally, LD contributes to shoulder adduction, internal rotation, and extension, linking the upper limb to the trunk. Alongside the rotator cuff, prevention of superior translation of the humeral head may be provided by the glenohumeral adductors (pectoralis major and LD) acting as humeral head depressors via a medio-inferior vector created by their tendon orientation. From an osteokinematic perspective, LD may protect against subacromial pain by facilitating inferior glide of the humeral head on the glenoid.

Selecting an appropriate strengthening exercise is critical to restore muscle performance and functional arm elevation in patients with shoulder injury or dysfunction. The literature emphasizes exercises targeting activation of the rotator cuff and scapulothoracic muscles that contribute to functional elevation. Surface electromyography (sEMG) is commonly used to guide exercise selection and progression by quantifying a muscle's contribution across different exercises, thereby enabling evidence-based advancement in strengthening programs.

However, much of the existing LD literature centers on lateral pull-down variations, with limited data for rehabilitation-relevant tasks such as low row, inferior glide, bent-over row (with trunk flexion), seated press-up, and body-lifting. Focusing on a single exercise limits clinical decision-making for shoulder rehabilitation (exercise selection and progression). Therefore, to support a scientific, evidence-based progression for LD strengthening in rehabilitation, this study was planned to obtain comprehensive sEMG data across multiple exercises.

Aim: To examine LD EMG activation levels during different exercises and determine between-exercise differences.