Trapezius muscle activity during wall slide exercise: Natural vs corrected head posture

Abstract

Background: Head posture affects muscle activation. However, the effect of head posture on trapezius muscle activation during wall slide exercise has not been investigated. Setting: A cross-sectional study. Purpose: To investigate the effect of head posture (natural head posture (NHP) and corrected head posture (CHP)) on trapezius muscle activation levels and ratios during wall slide exercise. Methods: Nineteen healthy participants (12 female and 7 male, Age = 24.84 ± 4.87 years, Body Mass Index = 22.29 ± 3.0 kg/m2) were asked to perform wall slide exercise with both NHP and CHP, separately. Muscle activations of the upper trapezius (UT), middle trapezius (MT), and lower trapezius (LT) were measured with a surface EMG Noraxon MiniDTS system in the ascending, stationary, and descending phases of the exercise. Results: All trapezius muscles demonstrated low muscle activation (<20 % Maximum Voluntary Isometric Contraction) in both head postures. The UT and MT muscle activations during the wall slide exercise were greater with CHP than with NHP (respectively, p = 0.001, p = 0.010). However, LT muscle activation, UT/MT, and UT/LT muscle activation ratios were similar in both head postures (p > 0.05). The UT muscle activation during the ascending phase was higher than the activation in the descending phase (p < 0.000). Also, MT and LT muscle activations during the ascending phase were higher than the stationary and descending phase (both, p < 0.000). Conclusion: Performing the wall slide exercise with CHP and focusing on the ascending phase may provide a more efficient shoulder rehabilitation program by increasing overall trapezius muscle activation and preserving the balance in trapezius muscles without changing muscle activation ratios.