Article

While a stable trunk and centre of mass (CoM) trajectory are required during
lifting, it is unclear how stability is controlled. Thirty healthy participants
(15M, 15F) performed repetitive, symmetric lifting at 10 cycles
per minute for 3
min with a load-in-hands equivalent to 10% of their maximum back strength. Short- and long-term maximum finite-time Lyapunov exponents (lambda(max-s) and
lambda(max-l)), describing responses to small (local) perturbations, estimated
the local dynamic stability of the foot, shank, thigh, pelvis, lower back, and
upper back segments. Instability (lambda(max-s)) significantly increased when
moving up the kinematic chain (p<0.001). Therefore, to maintain trunk equilibrium
and accurately regulate CoM trajectory during lifting, stability of the distal
(fixed) lower limb segments is prioritized. This is contrary to previous results
observed during gait, indicating that trunk control via kinematic chain stability
is accomplished differently for walking and lifting.
CI - Copyright (c) 2011 Elsevier B.V. All rights reserved.

Langue : ANGLAIS