2011 Annual Conference

Lin, Suh-Jen

The six-minute walk test is a field exercise test which measures how far a person can walk in 6 minutes. During the walk test, a person can speed up or slow down as needed which provides us an opportunity to look into gait patterns in naturally varying speeds of walking over ground. However, gait patterns during the walk test have not been reported before. The purpose of this study was to explore gait characteristics during the walk test, specifically the relationship between step length and velocity, in individuals with amputation. We hypothesized that with increasing speed of walking, (1) the step length of both legs would increase, and (2) the step length of the prosthetic leg would be greater than that of the sound leg.

Fourteen individuals (5 women, 9 men) with unilateral lower-limb amputation participated in the study (age: 53±8.3 yrs, length of prosthesis experience ≥ 6 months). Seven healthy age-matched individuals served as the control group. Informed consent was obtained.

For the walk test, participants were instructed to walk as far as possible in 6 minutes on a hallway to cover the maximal distance. The temporal-spatial gait data were captured by an instrumented walkway (GaitRite) during each lap of walking.

The gait data were then exported for further analysis. Step length and velocity were charted with trends analyzed for each participant and grouped together if they had similar trends. Linear regression analysis was conducted for the step length and velocity for each group.

Gait patterns during the six-minute walk test appeared to fall into three categories. Category 1 (n=7): data were typical for people with amputation and supported both hypotheses. Category 2 (n=5): data were only consistent with hypothesis (1), showing a symmetrical gait pattern similar to that in the control group. Category 3 (n=2): data were only consistent with hypothesis (2). Possible factors such as a longer experience in prosthesis use and a better fitness level might contribute to the more symmetrical gait patterns observed for the Category 2 data. Further studies with a larger sample size are needed to confirm our observations.

During the six-minute walk test, changes in step length at naturally varying velocities were not typically observed in individuals with lower-limb amputation.

In addition to the distance of walking, it is important to document the gait patterns when applying the six-minute walk test as an outcome measure for individuals with lower-limb amputation.