Confiabilidade e validade do incremental shuttle walking test para avaliar indivíduos na fase crônica pós acidente vascular encefálico.

Abstract

Stroke is one of the main causes of disabilities worldwide, impacting on health and functionality, such as on cardiopulmonary fitness and on exercise capacity. The Cardiopulmonary Exercise Test (CPET) is the gold standard for the assessment of cardiopulmonary fitness (measured by peak oxygen consumption - VO2peak). However, its clinical applicability is limited due to factors as the necessity of expensive equipment acquisition. A clinical test that evaluates exercise capacity of individuals after stroke is the Six-minute Walking Test (6MWT), with self-selected speed. The Incremental Shuttle Walking Test (ISWT) is an incremental test and it has been used to assess exercise capacity. This test has already shown adequate concurrent validity to estimate cardiopulmonary fitness (compared to VO2peak, in mL.kg-1.min-1, of the CPET) in individuals with pulmonary diseases. Nevertheless, the concurrent validity of the ISWT to estimate cardiopulmonary fitness of individuals in the chronic phase after stroke has not been determined yet. Thus, the objectives of the present study were to investigate the test-retest and inter-rater reliabilities, and the construct validity of the ISWT compared to the 6MWT to assess exercise capacity, and the concurrent validity of ISWT compared to the CPET to estimate the cardiopulmonary fitness of individuals in the chronic phase after stroke. The standard error of measurement (SEM) and the minimal detectable change (MDC) to assess exercise capacity through the ISWT of individuals after stroke were also assessed. Fifty-one individuals (54±11 years) at the chronic phase after stroke were included. In the first day, participants performed the CPET and an ISWT. The ISWT was performed twice by the same examiner after 4-18 days, for test-retest reliability investigation. A third ISWT was conducted by a second independent examiner to determine inter-rater reliability. The 6MWT was also performed on the second day of data collection by the first examiner. The intra-class correlation coefficient (ICC) was used to investigate the test-retest and inter-rater reliabilities and the construct validity. Spearman’s correlation coefficient was used to determine the concurrent validity of the ISWT between the distance covered during the ISWT and the VO2peak of the CPET (α=0.05). The SEM and MDC for both reliabilities were determined. The test-retest reliability of the ISWT showed high magnitude correlation (ICC=0.88; p<0.001). The SEM for this correlation was 41.47, and the MDC was 114.63 meters. The inter-rater reliability of the ISWT presented very high magnitude (ICC=0.93; p<0.001). The SEM for this correlation was 23.35, and the MDC was 64.53 meters. The construct validity between the ISWT and the 6MWT was of high magnitude (ICC=0.82; p<0.001). The concurrent validity between the ISWT and the CPET showed low magnitude correlation (rho= 0.38; p=0.005). The ISWT demonstrated adequate test-retest, inter-rater reliability and construct validity for the assessment of exercise capacity of individuals at the chronic phase after stroke. The ISWT does not seem to estimate cardiopulmonary fitness of these individuals given the low magnitude correlation. It is important to develop other investigations regarding the ISWT as an alternative method to estimate cardiopulmonary fitness of these individuals.