RESPIRATORY MUSCLE STRENGTH AND ENDURANCE IN INDIVIDUALS WITH TETRAPLEGIA

The purpose of this study was to assess the strength and endurance cap acity of the respiratory muscles in individuals with tetraplegia and t o compare these properties to those in able-bodied subjects. In additi on, the relationship between respiratory muscle properties and respira tory function, ie, ventilation and gas exchange, was examined. Fifteen individuals with tetraplegia (TP) and 15 able-bodied controls (AB) pa rticipated in this study. Respiratory muscle strength was assessed by measuring static inspiratory (Pi-max) and expiratory (Pe-max) mouth pr essure, whereas inspiratory endurance capacity (Pendu) was determined using an incremental ventilatory threshold loading test. Results were significantly lower in TP compared to AB: Pi-max (5.9 vs 8.4 kPa), Pe- max (5.6 vs 12.3 kPa), Pendu (2.7 vs 6.9 kPa), vital capacity (3.1 vs 5.51) and rest oxygen uptake (0.21 vs 0.29 ml/min) and significant cor relations were found between the respiratory muscle properties and the respiratory function. Of note is the fact that the ratio Pendu/Pi-max was significantly lower in TP (0.49) compared to AB (0.82). This impl ies that the capacity to generate pressure during the endurance test w as not fully used in TP, probably due to an early onset of muscle fati gue and an altered force-length relationship of the diaphragm muscle. Results of this study demonstrate a limited ability in individuals wit h tetraplegia to ventilate.