Tactile cues change trunk and scapular muscle activity, scapular winging, and thoracic kyphosis during knee push-up plus in subjects with scapular winging: The cross-sectional study

Serratus anterior muscle weakness causes scapular winging, characterized by scapular downward rotation and scapular anterior tipping in the resting position. Knee push-up plus (KPP), a modified push-up plus that is generally used in early rehabilitation programs, is performed to elicit SA activation. However, excessive thoracic kyphosis can easily occur as a compensatory movement during KPP. Therefore, the aim of this study was to examine the effect of tactile cues during KPP on activities of the thoracic erector spinae, rectus abdominis, lower trapezius, serratus anterior, and upper trapezius; scapular winging; and thoracic kyphosis in subjects with scapular winging. Thirteen men with scapular winging performed KPP exercises under 3 different tactile cue conditions (no cue, to the thoracic spinous process [TSP], and to the interscapular region [ISR]). Electromyography was used to collect the muscle activity; in addition, a scapulometer and ImageJ software were used to measure the amount of scapular winging and thoracic kyphosis, respectively. One-way repeated-measures analysis of variance and Bonferroni correction were used to assess for statistical significance. The activity of the thoracic erector spinae, rectus abdominis, serratus anterior, and upper trapezius had significant difference among three conditions (P < .05). Lower trapezius activity was no significantly different among 3 conditions. Degrees of scapular winging and thoracic kyphosis had also significant difference among 3 conditions (P < .05). These results suggest that the tactile cue to the TSP and ISR in KPP exercise can be an effective method for decreasing scapular winging as well as correcting compensatory thoracic kyphosis during the KPP in subjects with scapular winging.