Article

The neuromuscular mechanisms determining the mechanical behaviour of the
knee during landing impact remain poorly understood. It was hypothesised that
neuromuscular preparation is subject-specific and ranges along a continuum from
passive to active. METHODS: A group of healthy men (N=12) stepped-down from a
knee-high platform for 60 consecutive trials. Surface EMG of the quadriceps and
hamstrings was used to determine pre-impact onset timing, activation amplitude
and cocontraction for each trial. Partial least squares regression was used to
associate pre-impact preparation with post-impact knee stiffness and
coordination. RESULTS: The group analysis revealed few significant changes in
pre-impact preparation across trial blocks. Single-subject analyses revealed
changes in muscle activity that varied in size and direction between individuals.
Further, the association between pre-impact preparation and post-impact knee
mechanics was subject-specific and ranged along a continuum of strategies.
CONCLUSION: The findings suggest that neuromuscular preparation during step
landing is subject-specific and its association to post-impact knee mechanics
occurs along a continuum, ranging from passive to active control strategies.
Further work should examine the implications of these strategies on the
distribution of knee forces in vivo.
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Langue : ANGLAIS