Activation of upper limb muscles in subjects with scapular dyskinesis during bench-press and dumbbell fly on stable and unstable surfaces.

BACKGROUND: Scapular dyskinesis has been associated with shoulder dysfunctions, and changes in electromyographic (EMG) activity have been reported during the execution of some exercises. OBJECTIVE: To compare upper limb muscles EMG of asymptomatic subjects with and without scapular dyskinesis during bench-press and dumbbell fly exercise performed on different surface stability conditions. METHODS: Twenty-eight physically active men were allocated into two groups: Control group (n= 14) and Dyskinesis group (n= 14). The participants performed six repetitions lasting three seconds of the bench press and dumbbell fly exercises with 50% of one-repetition maximum (1RM) on a bench and a Swiss ball. The EMG activity of the pectoralis major, serratus anterior, upper and lower trapezius, anterior deltoid, biceps and triceps muscles were recorded. RESULTS: No differences were found between groups, regardless of exercise or surface type. Inserting the unstable surface in the supine exercise promoted a slight increase in upper trapezius EMG activity for the control [4.32 (95% CI: 1.04 to 7.60)] and dyskinesis [3.30 (95% CI: 0.34 to 6.27)] groups. CONCLUSIONS: There is no difference in upper limb muscle EMG activity between subjects with and without scapular dyskinesis. In addition, inserting unstable surfaces did not modify EMG activity.

Additional Functional Performance Gains After 24-Week Unstable Strength Training With Cognitive Training in Community-Dwelling Healthy Older Adults: A Randomized Trial.

The authors investigated the effects of unstable strength training (UST) without or with cognitive training (C+UST) on functional performance in community-dwelling older adults. A total of 50 participants were randomly assigned (1:1) to either 24 weeks of thrice-weekly UST (n = 25) or C+UST (n = 25). All participants performed moderate-intensity strength exercises using unstable surfaces, and C+UST participants simultaneously received cognitive training in addition to UST. Primary outcomes included measures of functional performance: single- and dual-task timed up and go tests. Secondary outcomes included dynamic balance, mobility, handgrip strength, flexibility, quality of life, and concern about falling. The authors observed similar improvements on functional performance through the interventions. The C+UST group experienced additional gains at completion (single-task timed up and go: -0.90 s, 95% confidence interval [-2.38, -0.03]; dual-task timed up and go: -4.80 s, 95% confidence interval [-8.65, -0.95]) compared with the UST group. Moreover, significant differences were observed in mobility (sitting-rising test: -1.34, 95% confidence interval [-2.00, -0.20]) at 24 weeks. Both exercise modes improved single-task functional performance, while adding cognitive-training-optimized dual-task functional performance gains.