Ankle resistance with a unilateral soft exosuit increases plantarflexor effort during pushoff in unimpaired individuals.
Krithika Swaminathan, Sungwoo Park, Fouzia Raza and 5 others
PMID 34961521WHAT IT FOUND
Resisting ankle push-off with a soft exosuit increased calf muscle effort in healthy walkers.
Higher resistance shifted weight to the other leg, reducing training specificity. Medium resistance best targeted the ankle, but the optimal force varied between individuals.
Key findings
01Ankle resistance increased biological torque at all tested force levels, with significant increases in soleus activity at medium and higher forces.
02High resistance caused users to shift weight away from the resisted leg to the unresisted leg, while medium resistance maintained specificity.
03The resistance level that maximized ankle targeting without engaging other joints varied across individuals, though medium was best overall.
STILL TO COME
How it was doneWhat they foundWhat it means for PTs
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What it does not show
The study was conducted on healthy young adults, so the response in people with stroke or other neuromotor disorders may differ significantly. The sample size was small (n=10), and one participant did not complete the highest resistance condition. Walking speed was fixed at 1.25 m/s, which may not reflect the slower, more variable speeds used in clinical rehabilitation. The exosuit applied resistance to only one leg, and all participants wore it on the left leg regardless of dominance. Exploratory comparisons with elastic bands and explicit instructions involved only two participants.
Declared interests
Research supported by the NIH and U.S. Government (Non-P.H.S.). No specific commercial conflicts of interest were declared in the provided text.
The easy way to misread this
Do not assume that higher resistance leads to better training outcomes for the ankle. The study showed that high resistance caused participants to shift weight to the unresisted leg, reducing the specificity of the intervention to the target joint.