Knee extensor power predicts six-minute walk test performance in people with transfemoral amputations.
Lindsay Slater, Suzanne Finucane, Levi J Hargrove
PMID 33866679WHAT IT FOUND
Knee extensor power strongly predicted walking distance and efficiency in people with transfemoral amputation.
Isometric strength correlated with distance but not metabolic cost. Power may be a better target than strength for improving community mobility and reducing walking effort.
Key findings
01Average knee extensor power had the strongest correlation with both distance walked and total oxygen consumed during the six-minute walk test.
02Average knee extensor power explained 77.2% of the variance in distance traveled during the six-minute walk test.
03Average knee extensor power explained 44.2% of the variance in total oxygen consumption during the six-minute walk test.
STILL TO COME
How it was doneWhat they foundWhat it means for PTsWhat it means for OTs
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What it does not show
Small sample size (n=11) limits generalizability. Participants were high-functioning (low fear of movement, high subjective function), so results may not apply to those with poorer baseline mobility or higher fear of movement. No participants had dysvascular amputations, which are common and may present different strength-walking relationships. Isokinetic power measurement via dynamometer may have inflated power metrics compared to camera-based systems. Cross-sectional design cannot prove that increasing power causes improved walking performance. More men than women participated, and sex differences in gait mechanics were not controlled for in analysis.
Declared interests
Research support from N.I.H., Extramural and Non-U.S. Gov't. No commercial conflicts declared in the provided text.
The easy way to misread this
Do not assume that isometric strength is the primary driver of walking efficiency. Isometric strength correlated with distance but not metabolic cost, whereas knee extensor power correlated with both. Focusing only on strength gains may miss the key predictor of reduced walking effort.