Effects of a stretching protocol for the pectoralis minor on muscle length, function, and scapular kinematics in individuals with and without shoulder pain

Abstract

Study design: Parallel-group intervention with repeated measures.

Introduction: Shortening of the pectoralis minor (PM) may contribute to alterations in scapular kinematics.

Purpose of the study: To evaluate the effects of a stretching protocol on function, muscle length, and scapular kinematics in subjects with and without shoulder pain.

Methods: A sample of 25 patients with shoulder pain and 25 healthy subjects with PM tightness performed a daily stretching protocol for 6 weeks. Outcome measures included Disabilities of the Arm, Shoulder, and Hand questionnaire, PM length, and scapular kinematics.

Results: Disabilities of the Arm, Shoulder, and Hand scores decreased (P < .05) in the patient group at post-intervention. No differences (P > .05) were found for PM length in both groups. Scapular anterior tilt increased (P < .05) at 90° of flexion in the healthy group.

Discussion: This study demonstrated that a daily home stretching protocol significantly decreases pain and improves function in subjects with shoulder pain. The mechanism responsible for these improvements does not appear directly related to PM muscle length or scapula kinematics, suggesting that other neuromuscular mechanisms are involved.

Conclusion: The PM stretching protocol did not change the PM length or scapular kinematics in subjects with or without shoulder pain. However, pain and function of the upper limbs improved in patients with shoulder pain.

Level of evidence: 2b.

Keywords: Physical therapy; Scapula; Shortening; Shoulder impingement syndrome.