Effects of robotic assistance on muscle activation and fatigue during overground walking in non-disabled individuals: an exploratory study.

The study was done in 15 non-disabled young adults, and the paper says the results are applicable only to individuals without disabilities until data in people with CNS lesions are available. The sample was small, and the paper says this limits firm conclusions about the lack of difference when returning from lower assistance to full assistance. The trial order was fixed: 100%, then 40%, then 100%. The first full-assistance trial differed from later trials, so early exposure to the device may explain more of the change than the assistance level itself. The intended reduction from 100% to 40% assistance may not have translated into an actual 60% change in what participants felt, because power can be lost at the exoskeleton-user interface. Instructions differed between the 100% and 40% trials, which could confound the comparison, although the authors note the pattern did not match the expected instruction effect. Baseline walking without the exoskeleton was done at a comfortable speed, not at the slower exoskeleton speed, so a same-speed natural walking comparison was not available. Only 100% and 40% assistance were tested, and levels below 40% were described as very challenging to control.

The funding sentence names only the Faculty of Medicine, Universite Laval.

Do not conclude that lower assistance reduces muscle activation compared with full assistance. The clearest differences were between the first full-assistance trial and later trials, not between lower assistance and the second full-assistance trial, and the study was done in non-disabled walkers.