EFFECT OF AEROBIC TRAINING ON VENTILATORY MUSCLE ENDURANCE OF SPINAL-CORD INJURED MEN

The functional consequences of ventilatory muscle impairment of spinal cord injured (SCI) subjects has been evaluated through spirometric an d maximal respiratory pressure tests. Nevertheless, underlying functio nal abnormalities may be evident only under dynamic conditions, such a s with a ventilatory muscle endurance test (VME). In order to evaluate the VME of thoracic SCI men and the effect of physical training on it we evaluated 12 SCI subjects (Group I) and 12 able-bodied controls (G roup II). The subjects were submitted to clinical evaluation, spiromet ry, maximum voluntary ventilation in 12 s (MVV-12sec) and a test of VM E-the highest time of sustained ventilation at 70% of the maximum volu ntary ventilation in isocapnic conditions (MW-70% time). Gr. II was ev aluated before and after an arm cranking aerobic training program (30 min/session, three times/week, 6 weeks) with training target heart rat e corresponding to ventilatory anaerobic threshold. On the initial eva luation, Gr. I subjects presented a significantly reduced forced vital capacity (FVC), forced expiratory volume in 1 s (FEV1) and MVV-12 sec when compared to controls (P < 0.05). Also, the VME was severely redu ced in Group I (median, ranges; 1.15, 0.61-12.22) when compared to Gro up II (14.60, 1.20-15.00) - P < 0.001. When Gr. I subjects were separa ted by the level of lesion, the VME was lower in high injured (T1-T7) than intermediate (TS-TIO) and low injured patients (T11-T12) - P < 0. 05. After aerobic training, Group I subjects incremented significantly the FVC (P < 0.05) and the VME (P < 0.001), so that MVV-70% time valu es posttraining were not different from the initial values of the Gr. II. In conclusion, (i) the VME of thoracic SCI men was severely reduce d when compared to able-bodied controls; (ii) a 6-weeks arm cranking a erobic training program was efficient to normalize the VME of SCI subj ects.