The effect of pectoralis muscle training in tetraplegic subjects.
We have previously shown that subjects with traumatic tetraplegia use the clavicular portion of the pectoralis major to expire actively. To determine if we could improve the expiratory function of these subjects, we studied six patients in whom the pectoralis major was trained by repetitive, strenuous, isometric contractions for 6 wk. Six patients receiving conventional respiratory rehabilitation served as control subjects. Training of the pectoralis major produced marked increases in the maximal isometric muscle strength (mean +/- SE: 54.6 +/- 5.8%; p less than 0.005) and in expiratory reserve volume (46.6 +/- 9.9%; p less than 0.005). Functional residual capacity did not change, such that residual volume decreased by 14.1 +/- 2.9% (p less than 0.005). In contrast, the control patients did not develop any significant alterations. We conclude that unlike conventional rehabilitation, training the pectoralis major for strength improves expiratory function in tetraplegic subjects. Therefore, training of this muscle should increase the effectiveness of coughing and might reduce the prevalence of bronchopulmonary infections in such subjects.