Preferred walking speed is a widely-used performance measure for people with mobility issues . Often these speeds are measured walking in a straight line and walking over short distances . However, daily walking involves walking for bouts of different distances and walking with turning. Here, we observe walking for short distances and walking in circles in subjects with unilateral lower-limb amputation using a Jaipur Foot prosthetic leg. We find that the preferred walking speeds are lower for unilateral amputees for short distances , but the distance-dependence of preferred walking speed is less steep than for non-amputees. In circle walking, unilateral amputees slow down when walking in circles of smaller radii and above-knee amputees in particular walk faster when the prosthetic leg is outside the circle. Using simple mathematical models, we show that the observed preferred walking speeds are predicted by minimal energy costwith increased costs for walking, changing speeds , and turning for amputees compared to non-amputees. These results predict that the cost of changing speeds and turning may be substantial in amputees but still not as high as the constant-speed cost. These findings will inform prosthesis design and rehabilitation therapy to better assist changing speeds and turning tasks in amputee walking  .
Preferred walking speed is a widely-used performance measure for people with mobility issues , but is usually measured in straight line walking for fixed distances or durations . However, daily walking involves walking for bouts of different distances and walking with turning. Here, we studied walking for short distances and walking in circles in unilateral lower-limb amputees wearing an above or below-knee passive prosthesis, specifically, a Jaipur foot prosthesis. Analogous to earlier results in non-amputees, we found that their preferred walking speeds are lower for short distances and lower for circles of smaller radii . Using inverse optimization, we estimated the cost of changing speeds and turning such that the observed preferred walking speeds in our experiments minimizes the total energy cost. The inferred costs of changing speeds and turning were much larger than for non-amputees. These findings could inform prosthesis design and rehabilitation therapy to better assist changing speeds and turning tasks in amputee walking . Further, measuring the preferred speed for a range of distances and radii is a more robust subject-specific measure of walking performance .
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. Often these speeds are measured walking in a straight line and walking over short distances
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observe
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subjects with
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amputation using a Jaipur Foot prosthetic leg. We find that the
amputees wearing an above or below-knee passive prosthesis, specifically, a Jaipur foot prosthesis. Analogous to earlier results in non-amputees, we found that their
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unilateral amputees for short distances , but the distance-dependence of preferred walking speed is less steep than for non-amputees. In circle walking, unilateral amputees slow down when walking in
short distances and lower for
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and above-knee amputees in particular walk faster when the prosthetic leg is outside the circle. Using simple mathematical models, we show
. Using inverse optimization, we estimated the cost of changing speeds and turning such
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are predicted by minimal energy costwith increased costs for walking, changing speeds , and turning for amputees compared to
in our experiments minimizes the total energy cost. The inferred costs of changing speeds and turning were much larger than for
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results predict that the cost of changing speeds and turning may be substantial in amputees but still not as high as the constant-speed cost. These findings will
findings could
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. Further, measuring the preferred speed for a range of distances and radii is a more robust subject-specific measure of walking performance