Thoracolumbar co-contraction: a predisposing mechanism for back pain associated with large chest size?

This study investigated trunk co-contraction during prolonged standing in women with small and large chest sizes. Higher levels of trunk co-contraction were found for the large chest size group. Global flexor-extensors, latissimus dorsi, and the erector spinae (T4, T9, L1 levels) displayed higher co-contraction indices throughout the entire stand for the large group. The thoracolumbar patterns of co-contraction found suggest that chest size warrants further investigation in the development of back pain, particularly in prolonged standing.