Force Enhancement of Quadriceps Femoris in Vivo and Its Dependence on Stretch-Induced Muscle Architectural Changes

• Autores: Wolfgang Seiberl, Daniel Hahn, Florian Kreuzpointner, Ansgar Schwirtz, Uwe Gastmann
• Localización: Journal of applied biomechanics, ISSN-e 1543-2688, ISSN 1065-8483, Vol. 26, Nº. 3, 2010, págs. 256-264
• Idioma: inglés
• Texto completo no disponible (Saber más ...)
• Resumen

  • The purpose of this study was to investigate if force enhancement (FE) in vivo is influenced by stretch-induced changes of muscle architecture. Therefore, 18 subjects performed maximum voluntary isometric (100° knee flexion angle) and isometric-eccentric-isometric stretch contractions (80°�100°; omega = 60°·s�1) whereby pennation angle and fascicle length of vastus lateralis was determined using ultrasonography. We found significant (2-way repeated ANOVA; alpha = 0.05) enhanced torque of 5�10% after stretch as well as significant passive FE but no significant differences in muscle architecture between isometric and stretch contractions at final knee angle. Furthermore, EMG recordings during a follow-up study (n = 10) did not show significant differences in activation and mean frequency of contraction conditions. These results indicate that FE in vivo is not influenced by muscle architectural changes due to stretch