Article

Ageing is associated with geometrical changes in muscle fascicles
that may lead to deteriorations in physical functions. The purpose of this study
was to study the effects of ageing on fibre orientation and strength of the
lumbar extensor muscles. METHODS: Fifty two healthy, 26 younger (10 males and 16
females, aged from 20 to 35) and 26 older (10 males and 16 females, aged from 65
to 90) volunteers participated in this study. Ultrasound images of the lumbar
extensor muscles were obtained with the participants in relaxed standing and half
flexion (50% of the range of trunk flexion). The fibre angles at the
mid-substance of the muscle were recorded. Lumbar extensor muscle strength was
measured in the upright posture with a load cell. FINDINGS: The mean lumbar
extensor fibre angles were found to significantly decrease in the half flexion
posture when compared to upright stance (P<0.01). Both the fibre angle and the
moment generation capability of the muscles decreased with ageing (P<0.01). There
was a moderate correlation between the fibre angles in the upright posture and
the muscle strength measured in this posture (r=0.40, P<0.01). INTERPRETATION:
Age-related changes in muscle geometry and posture may partly account for the
deterioration in muscle function in the elderly.
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Langue : ANGLAIS