Abstract
Contribution of mono- and biarticular muscles to extending knee joint moments in runners and cyclists.
Savelberg HH, Meijer K.
Department of Human Movement Science, Nutrition and Toxicology Research Institute Maastricht, Faculty of Health Sciences, Universiteit Maastricht, NL-6200 MD Maastricht, The Netherlands. hans.savelberg@bw.unimaas.nl
Motor actions are governed by coordinated activation of mono- and biarticular muscles. This study considered differences in mono- and biarticular knee extensors between runners and cyclists in the context of adaptations to task-specific movement requirements. Two hypotheses were tested: 1) the length-at-use hypothesis, which is that muscle adapts to have it operate around optimal length; and 2) the contraction-mode hypothesis, which is that eccentrically active muscles prefer to operate on the ascending limb of the length-force curve. Ten runners and ten cyclists performed maximal, isometric knee extensions on a dynamometer at five knee and four hip joint angles. This approach allowed the separation of the contribution of mono- and biarticular extensors. Three major differences occurred: 1) compared with runners, monoarticular extensors of cyclists reach optimal length at larger muscle length; 2) in runners, optimal length of the biarticular extensor is shifted to larger lengths; and 3) the moment generated by monoarticular extensor was larger in cyclists. Mono- and biarticular extensors respond to different adaptation triggers in runners and cyclists. Monoarticular muscles seem to adapt to the length-at-use, whereas biarticular muscles were found to be sensitive to the contraction-mode hypothesis
Savelberg HH, Meijer K.
Department of Human Movement Science, Nutrition and Toxicology Research Institute Maastricht, Faculty of Health Sciences, Universiteit Maastricht, NL-6200 MD Maastricht, The Netherlands. hans.savelberg@bw.unimaas.nl
Motor actions are governed by coordinated activation of mono- and biarticular muscles. This study considered differences in mono- and biarticular knee extensors between runners and cyclists in the context of adaptations to task-specific movement requirements. Two hypotheses were tested: 1) the length-at-use hypothesis, which is that muscle adapts to have it operate around optimal length; and 2) the contraction-mode hypothesis, which is that eccentrically active muscles prefer to operate on the ascending limb of the length-force curve. Ten runners and ten cyclists performed maximal, isometric knee extensions on a dynamometer at five knee and four hip joint angles. This approach allowed the separation of the contribution of mono- and biarticular extensors. Three major differences occurred: 1) compared with runners, monoarticular extensors of cyclists reach optimal length at larger muscle length; 2) in runners, optimal length of the biarticular extensor is shifted to larger lengths; and 3) the moment generated by monoarticular extensor was larger in cyclists. Mono- and biarticular extensors respond to different adaptation triggers in runners and cyclists. Monoarticular muscles seem to adapt to the length-at-use, whereas biarticular muscles were found to be sensitive to the contraction-mode hypothesis
Original language | English |
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Pages (from-to) | 2241-2248 |
Number of pages | 8 |
Journal | Journal of Applied Physiology |
Volume | 94 |
Issue number | 6 |
DOIs | |
Publication status | Published - 1 Jan 2003 |