Citation

Bobbert MF, Casius LJR, van der Zwaard S, Jaspers RT. J. Appl. Physiol. (APS Bethesda) 2019; ePub(ePub): ePub.

Affiliation

Vrije Universiteit Amsterdam.

Copyright

(Copyright © 2019, American Physiological Society)

DOI

10.1152/japplphysiol.00674.2018

PMID

31854247

Abstract

Fascicle length of m. vastus lateralis in cyclists has been shown to correlate positively with peak sprint cycling power normalized for lean body mass. We investigated whether vasti morphology affects sprint cycling power via the force‑length and force‑velocity relationships. We simulated isokinetic sprint cycling at pedaling rates ranging from 40 to 150 rpm with a forward dynamic model of the human musculoskeletal system actuated by eight leg muscles. Input of the model was muscle stimulation over time, which was optimized to maximize the average power output over a pedal cycle. This was done for a reference model and for models in which the vasti had equal volume but different morphology. It was found that models with longer muscle fibers but reduced physiological cross-sectional area of the vasti produced a higher sprint cycling power. This was partly explained by better alignment of the peak power - pedaling rate curve of the vasti with the corresponding curves of the other leg muscles. The highest sprint cycling power was achieved in a model in which the increase in muscle fiber length of the vasti was accompanied by a concomitant shift in optimum knee angle. It was concluded that muscle mechanics can partly explain the positive correlations between fascicle length of m. vastus lateralis and normalized peak sprint cycling power. It should be investigated whether muscle fiber length of the vasti and optimum knee angle are suitable training targets for athletes who want to concurrently improve their sprint and endurance cycling performance.

Language: en

Keywords

forward dynamic simulation model; muscle architecture; muscle fiber length; muscle power; optimum knee angle