Gait characteristics and influence of fatigue during the 6-minute walk test in patients with post-polio syndrome.

Objective: To evaluate gait in patients with post-polio syndrome, using the 6-minute walk test (6MWT) combined with three-dimensional kinematic analysis.
Design: Descriptive study.
Subjects: Eighteen patients and 11 healthy controls.
Methods: Kinematic data were obtained during a 6MWT by a Vicon motion capture system. Distance, heart rate, leg tiredness, dyspnoea and exertion were also recorded.
Results: Patients with post-polio syndrome showed larger increases in leg tiredness (p < 0.001) and dyspnoea (p < 0.05) as a result of the 6MWT than did controls. Walking speed decreased by 14.1% in patients vs 4.7% in controls (p < 0.05). Fourteen out of 18 patients displayed plantar-flexed ankle at initial contact (1/11 controls). At foot-off, the patients had a flexed hip (extended in controls) and a more flexed knee. Walking speed in patients correlated with hip angle at foot-off, at the start (r = -0.60, p < 0.001) and the end of the 6MWT (r = -0.74, p < 0.001), being higher the more the hip was extended.
Conclusion: The 6MWT is fatiguing for patients with post-polio syndrome, and this was reflected in the kinematic data. Walking speed was negatively correlated with the increased hip flexion, but not with the ankle plantar-flexion at foot-off in the patients with post-polio syndrome. The three-dimensional results underscore the importance of hip function in this patient group.