Pilot study on the improvement effects of scapulothoracic exercises on the respiratory functions in sedentary young female adult with forward shoulder posture: a randomized control trial

Introduction
Upper body muscular imbalance is a potential risk of various shoulder problems and respiratory functions. The combined pectoralis minor muscles and scapular stabilizer muscles could alleviate muscular imbalances in forward shoulder posture (FSP). However, there remains an unclear conclusion regarding the efficacy of these exercises on respiratory function, including chest mobility, lung capacity, and respiratory muscle strength in FSP.

Material and methods
In this randomized clinical trial, 28 female participants with FSP, aged 18-23 years, were divided into the control and exercise groups. The exercise programs were conducted 5 days/week for 8 weeks. The distance from the acromion process to the wall was measured as FSP. Pectoralis minor length (PL) were measured from coracoid process to the fourth costosternal joint, thoracic kyphosis (TK) was measured along the thoracic spines, chest expansion was measured from the amplitude of thoracic wall circumference during full expiration and inspiration, maximal respiratory muscle strength generated during respiration (MIP), and maximum respiratory muscle strength during expiration (MEP) were assessed at the pre- and post-exercise intervention.

Results
After the 8 weeks training program, an improvement in FSP was observed as decreased mean difference (p < 0.05) and TK (p < 0.003). The PL (p < 0.05) and lower part of chest expansion (p < 0.010) were restored when compared to those in the control group. The strength generated in respiration also improved in the exercise group (MIP, p < 0.013).

Conclusions
The 8-week pectoral muscle stretching and scapular stabilizer strengthening could reduce the FSP, improving chest mobility and respiratory muscle strength.