Physiological and kinematic effects of a soft exosuit on arm movements.
Michele Xiloyannis, Domenico Chiaradia, Antonio Frisoli and 1 others
PMID 30791919WHAT IT FOUND
The exosuit cut biceps muscle effort by 64.8% and delayed fatigue, but it slowed reaction times by 200 ms and reduced movement accuracy.
Therapists should not assume the device supports natural movement quality, as the suit interfered with tracking and smoothness.
Key findings
01The exosuit significantly reduced biceps muscle effort and biological torque required for movement.
02Wearing the device delayed the onset of muscle fatigue during isometric tasks.
03The suit reduced movement accuracy and smoothness, introducing a 200 ms delay in reaction time.
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
The study was very small (n=8) and involved only healthy, young, male participants of similar height and weight, limiting generalizability to clinical populations. Participants used the device for less than 10 minutes total, so the effects of longer-term use or adaptation are unknown. The baseline comparison was the unpowered suit, not a no-suit condition, though the authors argue the weight was negligible. The study tested only a single low load (1 kg dynamic, 3% body weight static), so performance with heavier or lighter objects is unknown. Movement was restricted to a single plane (elbow flexion/extension) in a controlled lab setting, not functional multi-joint movements.
Declared interests
Funded by the Rehabilitation Research Institute of Singapore. No other conflicts of interest were declared.
The easy way to misread this
Do not interpret the 64.8% reduction in muscle effort as evidence that the suit improves functional movement. The device significantly degraded movement accuracy and smoothness and added a 200 ms delay, meaning it assists strength/endurance at the cost of motor control quality.