A p value ≤ 0.05 was deemed to be statistically significant. A

paired t-test with Bonferroni correction was used (with p = 0.05/6 = 0.0083) for the pair-wise comparison in muscle activity and marker displacement in the frontal and sagittal planes for the two feedback conditions. Nineteen participants were recruited from the Department of Physical Therapy, Yonsei University, ABT 199 Korea. The characteristics of the participants are presented in Table 1. All participants completed all aspects of the testing procedure according to the random allocation of testing conditions. For the upper trapezius muscle, the main effects were significant for shoulder flexion angle (p < 0.001) and feedback (p = 0.017), as was the interaction effect (p = 0.003). Visual feedback increased activation of the upper trapezius at both 60°

and 90° of shoulder flexion ( Table 2). After Bonferroni correction, however, the effect of visual feedback was significant only at the 60° shoulder flexion angle (p = 0.008). For the lower trapezius muscle, the main effect for shoulder flexion angle was significant (p = 0.001), but neither the main http://www.selleckchem.com/products/DAPT-GSI-IX.html effect for the visual-feedback condition (p = 0.152) nor the interaction effect (p = 0.150) was significant. The data are presented in Table 2. For the serratus anterior muscle, the main effects were significant for shoulder flexion angle (p < 0.001) and feedback

(p < 0.001), as was the interaction effect (p = 0.045). Visual feedback significantly increased activation of serratus anterior at both 60° and 90° of shoulder flexion ( Table 2). After Bonferroni correction, the effect of visual feedback remained significant at both 60° and 90° of shoulder flexion (p < 0.001). Measurement of displacement of the acromial marker in the frontal plane showed that the average movement was superior for all combinations of flexion angle and feedback. The main effects were significant for shoulder flexion angle (p < 0.001) and feedback and (p < 0.001), as was the interaction effect (p = 0.001). Visual feedback significantly increased the superior displacement of the acromion ( Table 3). After Bonferroni correction, the effect of feedback remained significant only at 60° of shoulder flexion (p < 0.001). Measurement of displacement of the acromial marker in the sagittal plane showed that the average movement was anterior with feedback and posterior without feedback. The main effect was significant for the visual feedback (p = 0.000), but neither the main effect for shoulder flexion angle (p = 0.100) nor the interaction (p = 0.268) was significant. After Bonferroni correction, the effect of visual feedback on anterior movement of the acromion during shoulder flexion remained significant at both 60° and 90° of shoulder flexion (p < 0.001).