Kinematic evaluation of patients with chronic obstructive pulmonary disease during the 6-min walk test

A better understanding of gait kinematics during the 6-min walk test (6MWT) may facilitate the development of rehabilitation strategies for patients with chronic obstructive pulmonary disease (COPD).

To evaluate gait kinematics during the 6MWT in patients with COPD.

Thirty-six patients with COPD and 19 healthy controls underwent a full-body kinematic analysis during the 6MWT. Data were collected using a system with four infrared cameras to capture the movement of a spherical marker covered with retroreflective tape attached to a helmet worn during the test.

The walking distances measured by the assessor and by kinematics analysis were lower in the group of patients (P = 0.036 and P = 0.013, respectively). Moreover, the walking distances measured by kinematics analysis were greater than those measured by the assessor for both groups (P < 0.001). In the kinematics analysis of the complete test, the mean and maximum speeds were higher for the controls than for the patients (P = 0.007 and P = 0.044, respectively). In the half-turn analysis, acceleration, speed, and deceleration peaks (maximal absolute values) were lower for the patients than for the controls (P = 0.002, P = 0.012 and P = 0.006, respectively).

Patients with COPD show worse functional capacity due to lower gait speed and acceleration-deceleration peaks after turnings as compared to healthy individuals during the 6MWT. Assessors can accurately predict the 6MWD measured by kinematics, though they underestimate this distance.