Article

A decline in walking capacity and high energy cost can limit mobility
following stroke. Mechanical energy exchange between lower limb and trunk
segments can reflect gait inefficiencies, but reveals little about active energy
flow between adjacent segments through muscle actions. This study evaluated
mechanical energy expenditures (MEEs) during walking in stroke and healthy groups
to understand movement control and explore the impact of walking speed on
mechanical energy exchanges. METHODS: Thirteen adults with hemiparesis and six
healthy controls walked at self-selected speed. Power curves for each lower limb
joint were segmented into concentric and eccentric sources of muscle power and
transfer/no-transfer modes to calculate MEEs during stance. FINDINGS: MEEs were
lower in the stroke group on the affected side compared to the less affected side
and compared to controls. Specifically, the affected plantarflexors transferred
less energy distally via concentric action in late stance compared to the less
affected side. However, the stroke group generated greater energy at the ankle in
the absence of transfer compared to controls. Less concentrically transferred
energy through midstance and absorbed in late stance was evident by the knee
extensors bilaterally in stroke. At the hip, the total energy (no transfer) was
reduced on the affected side. Classifying stroke subjects by walking speed
(<.6m/s, >.6m/s) revealed disruptions in harnessing energy through motion and
transfer energy across segments in the slower group. INTERPRETATION: The limited
ability of those with stroke to exploit intersegmental energy transfer to
optimize efficiency may limit endurance and functional independence.
CI - Copyright (c) 2014 Elsevier B.V. All rights reserved.

Langue : ANGLAIS