SONOGRAPHIC DETERMINATION OF FASCICLE LENGTH DURING AND AFTER ACTIVE MUSCLE STRETCH IN VIVO

Abstract

Although force enhancement (FE) is quite accepted in literature as a phenomenon showing enhanced force during and following muscle stretch compared to the corresponding isometric reference force there is a lack of data supporting those findings in voluntary activated large human muscles. Hahn et al. (2007) presented new results investigating the m. quadriceps femoris in vivo. As one theoretical option the absence of significant post eccentric FE was supposed to originate from a difference of external knee flexion angle and real fibre length changes. They note that there might be a discrepancy between test and reference muscle length that hides real FE after muscle stretch. In order to scrutinize this idea a new investigation focuses on fascicle length changes during and after muscle stretch via ultrasound diagnostics.