caa a22 4500 467939942 CHVBK 20180406153009.0 cr unu---uuuuu 170328e20060901xx s 000 0 eng 10.1007/s00421-006-0170-4 doi (NATIONALLICENCE)springer-10.1007/s00421-006-0170-4 The dependence of force enhancement on activation in human adductor pollicis [Elektronische Daten] [Ali Oskouei, Walter Herzog] It has been well recognized that the steady-state isometric force after active muscle/fiber stretch is greater than the corresponding isometric force for electrically stimulated muscles and maximal voluntary contractions (MVC). However, recent evidence obtained for sub-MVC suggests that force enhancement properties are different from those observed for electrically induced and MVC. Specifically, it appears that force enhancement is activation-dependent and that there is a subject-specific threshold for force enhancement in sub-MVC. To address these suggestions, the relationship between force enhancement and voluntary activation during stretch was investigated in 11 healthy subjects. Human adductor pollicis muscles were studied and force enhancement was measured while muscle activation during the steady-state isometric phase was controlled at a level of 30% of MVC. In order to study the effects of activation on force enhancement, subjects performed stretch contractions at 0, 10, 30, 60, and 100% of maximal voluntary effort while the steady-state isometric force after stretch, obtained at 30% of activation in all cases, was compared to the corresponding values measured in the isometric reference contractions. There was no force enhancement if muscle stretching occurred passively but all subjects showed force enhancement when muscle stretching occurred at maximal voluntary effort. When increasing the level of activation during the stretch phase, force enhancement increased, and the number of subjects who showed force enhancement increased as well. We conclude from these results that force enhancement during voluntary contractions is activation-dependent with a threshold that is subject-specific. Springer-Verlag, 2006 Skeletal muscle nationallicence Force enhancement nationallicence Muscle properties nationallicence Mechanisms of contraction nationallicence Force-length relation nationallicence Voluntary contraction nationallicence Activation nationallicence Oskouei Ali Human Performance Laboratory, University of Calgary, T2N 1N4, Calgary, Alta, Canada aut Herzog Walter Human Performance Laboratory, University of Calgary, T2N 1N4, Calgary, Alta, Canada aut European Journal of Applied Physiology Springer-Verlag 98/1(2006-09-01), 22-29 1439-6319 98:1<22 2006 98 421 https://doi.org/10.1007/s00421-006-0170-4 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s00421-006-0170-4 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Oskouei Ali Human Performance Laboratory, University of Calgary, T2N 1N4, Calgary, Alta, Canada aut NATIONALLICENCE 700 1- Herzog Walter Human Performance Laboratory, University of Calgary, T2N 1N4, Calgary, Alta, Canada aut NATIONALLICENCE 773 0- European Journal of Applied Physiology Springer-Verlag 98/1(2006-09-01), 22-29 1439-6319 98:1<22 2006 98 421 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer