Functional aerobic exercise capacity limitation in adolescent idiopathic scoliosis

BACKGROUND CONTEXT: Exercise limitation has been described in patients with adolescent idiopathic scoliosis (AIS); however, whether the walking performance is impaired in these patients should be elucidated. PURPOSE: Thus, we aimed to evaluate the physiologic responses to the incremental shuttle walk test (ISWT) in patients with AIS. STUDY DESIGN/SETTING: Cross-sectional study. PATIENT SAMPLE: Twenty-nine patients with AIS and 20 healthy adolescents aged between 11 and 18 years old. OUTCOME MEASURES: Oxygen uptake (VO2), incremental shuttle walk distance (ISWD), Delta VO2/Delta walking velocity, Delta HR/Delta VO2, Delta VE/Delta VCO2, and linearized Delta tidal volume (VT)/Delta lnVE, forced expiratory volume in the first second of expiration (FEV1), and forced vital capacity (FVC). METHODS: We performed two ISWTs, and the data used were acquired in the second test. We also evaluated the lung function and respiratory muscle strength through spirometry test and manovacuometry, respectively. All authors confirm that there are no conflicts of interest. To compare the means or medians of variables between patients and healthy subjects, we used the unpaired t test or Mann-Whitney U test, respectively. The correlations were assessed by Pearson or Spearman coefficients according to the distribution of the studied variables. The probability of alpha error was set at 5% for all analyses. RESULTS: Adolescent idiopathic scoliosis patients showed significant lower values of ISWD, VO2, and ventilation at the end of the ISWT, as well as lower FEV1 and FVC; they also presented significantly shallower slope of Delta VT/Delta lnVE, whereas VO2 related significantly with ISWD (r = 0.80), FVC (r = 0.78), FEV1 (r = 0.73), and Delta VT/Delta lnVE (r = 0.58). CONCLUSIONS: Adolescent idiopathic scoliosis correlated to walking limitation and was associated to reduced pulmonary function and worse breathing pattern during exercise. Our results suggest that walking-based aerobic exercises should be encouraged in these patients. (C) 2014 Elsevier Inc. All rights reserved.