Blood flow and oxygen uptake increase with total power during five different knee-extension contraction rates.

Journal Article (Journal Article)

Controversies exist regarding quantification of internal power (IP) generated by the muscles to overcome energy changes of moving body segments when external power (EP) is performed. The aim was to 1) use a kinematic model for estimation of IP during knee extension, 2) validate the model by independent calculation of IP from metabolic variables (IP(met)), and 3) analyze the relationship between total power (TP = EP + IP) and physiological responses. IP increased in a curvilinear manner (5, 7, 13, 21, and 34 W) with contraction rate (45, 60, 75, 90, and 105 contractions/min), but it was independent of EP. Correspondingly, IP(met) was 5, 7, 10, 19, and 28 W, supporting the kinematic model. Heart rate, pulmonary oxygen uptake, and leg blood flow plotted vs. TP fell on the same line independent of contraction rate, and muscular mechanical efficiency as well as delta efficiency remained remarkably constant across contraction rates. It is concluded that the novel metabolic validation of the kinematic model supports the model assumptions, and physiological responses proved to be closely related to TP, supporting the legitimacy of IP estimates.

Full Text

Duke Authors

Cited Authors

  • Sjøgaard, G; Hansen, EA; Osada, T

Published Date

  • November 2002

Published In

Volume / Issue

  • 93 / 5

Start / End Page

  • 1676 - 1684

PubMed ID

  • 12381753

International Standard Serial Number (ISSN)

  • 8750-7587

Digital Object Identifier (DOI)

  • 10.1152/japplphysiol.00259.2002


  • eng

Conference Location

  • United States