Feasibility of whole-body gait kinematics to assess the validity of the six-minute walk test over a 10-m walkway in the elderly

Abstract Background The six-minute walk test (6MWT) assesses the functional exercise capacity and its impairments due to chronic cardiorespiratory and/or musculoskeletal conditions, particularly in the elderly. The clinimetric properties and clinical utility of the 6MWT are well-described, but little is known about the gait kinematics during this test. This study evaluated the feasibility of a study protocol based on whole-body gait kinematics to assess the validity of the 6MWT over a 10-m walkway in the elderly. Methods Eight elderly healthy participants (7 women, aged 61–77 years) underwent the 6MWT over a 10-m rectilinear walkway. The data were collected using infrared cameras and a spherical marker covered with retroreflective tape firmly attached to a helmet worn by the participant during the 6MWT. Results The total distance measured by the assessor was significantly smaller than both its kinematics (P = 0.012) and model-predicted (P = 0.017) counterparts. The total distance measured by the kinematics was also smaller than the predicted one (P = 0.025). A large bias toward underestimating the 6MWD, as measured by the assessor (mean = −32, SD = 6.3 m), was observed along with a high determination coefficient (R2 = 99.2%). Most of the participants presented a negative trend for the average speed as a function of half-turns. Discussion Analysis of whole-body gait kinematics is feasible using motion capture systems and can be used to assess the validity of the 6MWT over a 10-m walkway in the elderly. The 6MWD, as measured by the assessor, underestimates the actual covered distance in the 6MWT but not the functional exercise capacity.