Article

Ageing involves modifications of the locomotor system which is believed to
increase energy consumption. This study aimed at verifying whether neuromuscular
adaptation due to ageing, in conjunction with age-related modifications of the
muscle-tendon actuators, involves greater muscle-tendon workload. Ten young and 7
elderly healthy subjects were assessed using gait analysis while walking at
comparable speed. Planar models of muscle-driven locomotion, accounting for 14
muscles grouped into 9 equivalent actuators, were developed. Muscle-tendon forces
were estimated by using the inverse-dynamic based static optimization where cost
functions were tuned to capture the different muscle co-activation between
groups. Following this, tendon and muscle shortening/lengthening was computed,
and muscle-tendon work was estimated and compared between groups. Results showed
that both groups produced comparable muscle mechanical work, though shared
differently among muscles. In particular, young subjects showed a greater
workload of ankle plantaflexor muscles and older subjects used greater eccentric
energy at the knee extensors during stance phase. Moreover, young people used
more elastic energy than older people. These findings suggest that the
combination adaptation due to ageing, in conjunction with age-related
modifications of the muscle-tendon actuators, do not significantly increase the
overall energetic output of locomotion. Moreover, the motor control system
appears to be characterised by a degree of adaptation which allows older
individuals to achieve biomechanical efficiency comparable to younger subjects.
CI - Copyright (c) 2012 Elsevier B.V. All rights reserved.

Langue : ANGLAIS