Age-related differences in pre-movement antagonist muscle co-activation and reaction-time performance

Ivan Bautmans (1, 2, 3, 4) , Stijn Vantieghem (1, 4) , Ellen Gorus (1, 2, 3) , Yuri-Reva Grazzini (1) , Yves Fierens (5) , Annelies Pool-Goudzwaard (4) , Tony Mets (1, 2, 3, 4)

1 VUB - Vrije Universiteit Brussel
2 Gerontology department
3 Geriatrics department
4 SOMT-research department
5 Radiology department

Multiple causes contribute to the prolonged reaction-times (RT) observed in elderly persons. The involvement of antagonist muscle co-activation remains unclear. Here the Mm. Biceps and Triceps Brachii activation in 64 apparently healthy elderly (80±6years) and 60 young (26±3years) subjects were studied during a simple RT-test (moving a finger using standardized elbow-extension from one pushbutton to another following a visual stimulus). RT was divided in pre-movement-time (PMT, time for stimulus processing) and movement-time (MT, time for motor response completion). RT-performance was significantly worse in elderly compared to young; the slowing was more pronounced for MT than PMT (respectively 101±10ms and 41±6ms slower, p<0.01). Elderly subjects showed significantly higher (p<0.01) antagonist muscle co-activation during the PMT-phase, which was significantly related to worse MT and RT (p<0.01). During the MT-phase, antagonist muscle co-activation was similar for both groups. It can be concluded that increased antagonist muscle co-activation in elderly persons occurs in an early phase, already before the start of the movement. These findings provide further understanding of the underlying mechanisms of age-related slowing of human motor performance.

Mots clés: Antagonist Co-contraction; Electromyography; Ageing; Reaction Time; Skeletal Muscle

Domaines: Gériatrie et gérontologie

Ivan Bautmans, Stijn Vantieghem, Ellen Gorus, Yuri-Reva Grazzini, Yves Fierens, et al.. Age-related differences in pre-movement antagonist muscle co-activation and reaction-time performance. Experimental Gerontology, 2011, ⟨10.1016/j.exger.2011.03.002⟩. ⟨hal-00715435⟩