Association of Pectoralis Minor Muscle Extensibility, Shoulder Mobility, and Duration of Manual Wheelchair Use

Abstract

Objective To assess the relation of pectoralis minor muscle (PMm) length and extensibility to shoulder pain, shoulder girdle motion, and duration of manual wheelchair (MWC) use, and to compare differences in muscle length, muscle extensibility, peak humeral elevation, and pain among groups based on duration of wheelchair use. Design Cross-sectional cohort study. Setting Laboratory setting. Participants Individuals with spinal cord injury (SCI) who used an MWC for daily community and home mobility (N=22; 18 men; mean age, 41.7y; duration wheelchair use, 14.6y). Participants were stratified into groups based on duration of wheelchair use: <5 years (n=6), 5 to 15 years (n=8), and >15 years (n=8). Interventions Not applicable. Main Outcome Measures Clinical measures of PMm length and extensibility, shoulder girdle motion, and shoulder pain (Wheelchair User's Shoulder Pain Index). Results Significant high correlations were found among duration of wheelchair use, passive PMm length, passive PMm extensibility, and peak humerothoracic elevation. Moderate correlation of peak humerothoracic elevation to pain was found. Individuals with >15 years wheelchair use had reduced PMm extensibility and reduced peak humerothoracic elevation than those with <5 years duration of use. Conclusions To our knowledge, this is the first investigation to identify the association of reduced PMm extensibility with reduced shoulder girdle mobility, pain, and duration of wheelchair use in individuals with SCI.