Handgrip Strength Exercises Modulate Shoulder Pain, Function, and Strength of Rotator Cuff Muscles of Patients with Primary Subacromial Impingement Syndrome

BACKGROUND: Impingement syndrome was shown to be associated with shoulder pain in 44–70% of patients worldwide. It usually occurs due to imbalance and insufficient activation of the rotator cuff (RC) muscles. AIM: This study explores the relative effects of handgrip-strengthening exercises on shoulder function, pain, strength, and active range of motion as part of the treatment program for the patients with primary subacromial impingement syndrome. MATERIALS AND METHODS: A total of 58 patients aged 18-50 years with primary subacromial impingement syndrome were randomly enrolled to participate in this single-blind randomized clinical trial. Out of them, only forty patients have eligibly matched the inclusion criteria and randomly assigned to one of two groups to undergo a standardized therapeutic program consisting of two sessions a week for 8 weeks. The control group prescribed ultrasound therapy, ice, and stretching exercises, while the experimental group followed the same program with the addition of handgrip-strengthening exercises (HGSE). Both patients of conventional therapy (control) and handgrip-strengthening exercises (experimental group) were advised to adhere also to stretching and HGSE exercises once a day at home for eight weeks. The outcomes were the shoulder function, pain intensity, muscle strength, and active range of motion of the shoulder joint. RESULTS: Patients treated with conventional interventions plus handgrip-strengthening exercises showed the significant improvement over time in shoulder pain and function, strength of rotator cuff muscles, and pain-free range of motion forward flexion, abduction, and external and internal rotation through eight weeks in the experimental group compared to control patient group treated with conventional interventions. In addition, patients of both control and experimental groups showed no significant difference in the adherence to respective home-based stretching and HGSE exercises once a day at home for eight weeks. CONCLUSIONS: Adding handgrip-strengthening exercises to conventional intervention increases the efficacy of treatment for patients with primary subacromial impingement syndrome in terms of shoulder function, pain, muscle strength, and active range of motion.