### Abstract

We hypothesized that the history of contraction would affect the in vivo quadriceps torque-velocity relationship. We examined the quadriceps torque-velocity relationship of the human knee extensors at the descending and ascending limb of the torque-position relationship by initiating the knee extension at a knee angle position of 1.39 rad (80°) or 0.87 rad (50°) over a 0.52 rad (30°) range of motion under conditions of constant or linearly increasing velocity. Maximal voluntary isometric knee extension torque (M_{0}) was measured at 1.87 rad, 0.87 rad, and 0.35 rad, and concentric torque was measured. The subjects carried out ten maximal knee extensions at ten distinct velocities, each velocity ranging between 0.52 rad·s^{-1} to 5.24 rad·s^{-1} in steps of 0.52 rad·s^{-1}. Peak concentric torque was measured and mean torque calculated from the respective torque-time curves. Peak or mean torque, computed from the individual torque-time curves, and velocity data were fitted to the Hill equation under the four experimental conditions and the curve parameters computed. The M_{0} was similar at 0.87 rad and 1.39 rad, but it was significantly lower at 0.35 rad. In the low-velocity domain of the torque-velocity curve where a plateau normally occurs, peak torque was always lower than M_{0}. Peak and mean torque were significantly greater under linearly increasing velocity conditions and the 1.39 rad starting knee position. Mean torque but not peak torque data could be well fitted to the Hill equation and the two computations resulted in significantly different Hill curve parameters including the concavity ratio, peak power, and maximal angular velocity. We concluded that the history of contraction significantly modifies the in vivo torque-velocity relationship of the human quadriceps muscle. Muscle mechanics and not neural factors may have accounted for the inconsistencies in the human torque-velocity relationships reported previously.

Original language | English |
---|---|

Pages (from-to) | 393-402 |

Number of pages | 10 |

Journal | European Journal of Applied Physiology |

Volume | 87 |

Issue number | 4-5 |

DOIs | |

Publication status | Published - Dec 1 2002 |

### Keywords

- Constant acceleration
- Constant speed
- Hill equation
- Knee extensors
- Muscle mechanics

### ASJC Scopus subject areas

- Orthopedics and Sports Medicine
- Public Health, Environmental and Occupational Health
- Physiology (medical)

## Fingerprint Dive into the research topics of 'Contraction history affects the in vivo quadriceps torque-velocity relationship in humans'. Together they form a unique fingerprint.

## Cite this

*European Journal of Applied Physiology*,

*87*(4-5), 393-402. https://doi.org/10.1007/s00421-002-0633-1