Article

Standing up, standing, and walking functions can be restored to people with
spinal cord injury by contracting the paralyzed hip, knee, and ankle muscles with
electrical stimulation. Restoring these functions using electrical stimulation
requires controlled activation to provide coordinated movements. However, the
stand-to-sit (STS) maneuver involves eccentric contractions of the quadriceps to
control lowering of the body to the seated position, which is difficult to
achieve with stimulation alone and presents unique challenges to lower-limb
neuroprostheses. In this study, we examined the biomechanics of the STS maneuver
in five nondisabled individuals and five users of an implanted neuroprosthesis.
Neuroprosthesis users relied heavily on their upper limbs during STS, with peak
supporting forces approximately 25% body weight, and exhibited an average
vertical acceleration at the impact six times higher than that of the nondisabled
subjects (p < 0.001). Sitting with stimulation resulted in impact forces at
initial contact with the seating surface averaging 1.4 times body weight and
representing an average of twice the impact forces of the nondisabled subjects (p
< 0.001). These results indicate a need for additional interventions to better
control descent, minimize impact, and gently transition from standing to sitting
to achieve a more natural movement and reduce the risk of injury.

Langue : ANGLAIS