Muscle Activity During a Single Set of Resistance Training to Failure in Women With Chronic Neck and Shoulder Pain Before and After 10 Weeks Training

Background: Resistance training to failure is an advanced method often used by healthy individuals. Little is known about this type of training in individuals with musculoskeletal pain. Purpose: This study investigates the effect of 10 weeks’ elastic resistance training on neck and shoulder muscle activity during a single set to failure. Study design: This was an observational cohort study. Methods: Sixteen untrained, female office workers with chronic neck and shoulder pain performed 10 weeks of elastic resistance exercise as a single set of lateral raise to failure during workdays. Electromyography (EMG) amplitude and median power frequency (MPF) from the splenius and the upper trapezius muscles were analyzed. Results: EMG amplitude increased and MPF decreased linearly from the first to the last repetition during the set, before and after the 10 weeks of training. For the first few repetitions of exercise, muscle activity was higher after 10 weeks than before the intervention (91% vs.74%, P = 0.03). However, during the last repetitions, similar high levels of EMG amplitude were noted both before and after the 10 weeks (129% vs.127%, P = 0.81). The MPF before and after the training intervention was 79 and 77 Hz (P = 0.69), respectively, during the first repetitions, and 66 and 69 Hz (P = 0.62) during the last repetitions of exercise. The increase in EMG and decrease in MPF – which were similar before and after 10 weeks – are good indicators of acute muscle fatigue. Conclusion: The results indicate that untrained women with neck-shoulder pain are capable of training to failure, and concur with previous results showing rapid benefits in terms of muscle strength and pain reductions from this type of training.