Effects of shoulder girdle dynamic stabilization exercise on hand muscle strength

Background: Shoulder girdle stabilization influences hand strength but the effects of functional training remain unknown. Objective: To determine the influence of shoulder girdle stabilization on hand muscle strength. Methods: Handgrip strength (with hand in neutral position, supination, pronation) and tripod pinch strength were measured in 20 healthy volunteers (10 in training/control groups) weekly over six weeks. The training consisted of six specific Dynamic Neuromuscular Stabilization (DNS) exercises performed five times per week. The exercises were designed to obtain maximum joint stability within the shoulder. Results: Using mixed effects models, the training group showed significant improvement relative to the control group on all measures of hand muscle strength (p < 0.05). The gains were particularly pronounced in handgrip strength in the neutral position (dominant hand: Estimate = 0.26, standard error [SE] = 0.04, p < 0.001; non-dominant hand: Estimate = 0.23, SE = 0.03, p < 0.001). That is, the training group gained about 0.25 standard deviations over the control group per session for a total of 1.5 standard deviations (about 27 Newtons) across all sessions. Conclusions: Shoulder girdle exercises based on DNS may generate clinically significant gains in hand muscle strength.