Six-Minute Walk Test in Individuals With Unilateral Lower Limb Amputations

Background: The 6-minute walk test (6MWT) is one of the common clinical tests to assess rehabilitation progress and needs in individuals with lower-limb amputation (iLLAs). However, the analysis of this test is mostly limited to the distance parameter. The first aim was to investigate effort intensity and spatiotemporal parameters of 6MWT in iLLAs using inertial measurement units (IMUs) and heart rate (HR) monitor, and second, to assess physical, physiological, and pain-related aspects of fatigue over 6MWT.

Methods: Eleven unilateral iLLAs (57.91±15.63 years old) participated in this study. To evaluate HR and spatiotemporal parameters over 6MWT, data were classified using 6 intervals of 1 minute each (I1-I6). The pain level of participants was estimated using the visual analog scale (VAS).

Results: Our results showed that the means of normalized HR gradually increased over 6MWT (I1: 61.59±10.73 HR_max%, I6: 70.15±12.26 HR_max%, P = .003). Variability of HR during the first interval of 6MWT was higher than the others (P < .05). The stance ratio of the gait cycle increased over 6MWT (P < .05). Cadence and speed decreased over 6MWT (P < .05). VAS score after 6MWT was significantly higher than before 6MWT (P = .016).

Conclusion: In this preliminary study, effort intensity over 6MWT gradually increased because of enhancement of HR. Deterioration of speed and cadence and enhancement of stance ratio over 6MWT imply potential physical aspects of fatigue and instability.

Level of evidence: Level III, retrospective comparative study.