## Abstract

To examine a method to save time and money with empirical equations representing the relationship between oxygen uptake (VO_{2}), walking speed (v), step frequency (SF), and step length (SL), we recorded the VO_{2} and SF of 7 young male volunteers walking at an increasing speed from 16.7 to 131.7 m min^{-1} with 5 m min^{-1} increments every 1 min, and at a decreasing speed from 106.7 m min^{-1} for 5 min to 16.7 m min^{-1} with 5 m min^{-1} decrements every 1 min on a level treadmill. SL was also computed by dividing walking speed by SF. The VO_{2} during decremental-speed walking was significantly greater compared to that during incremental-speed walking at corresponding speeds. The SF and SL could be expressed as a function of speed by SF=√13.18v and SL=0.076√ v, respectively, regardless of the different modes of walking with respect to speed. To estimate the VO_{2} during walking at different speeds, the results of the increments and decrements were combined by averaging them with respect to speed (VO_{2} = 1.454 × 10^{-4}v^{2}-6.5 × 10^{-3}v+ 0.663, r=0.999, n=7). In a mathematical model of the cardiorespiratory system, the average values of VO_{2} at a given speed, even though there were on- and off-phase responses, could be predicted within 7.4% of the theoretical steady-state value. These results suggest that the VO_{2} against walking speed can be estimated by averaging the responses between the increments and decrements of moderate speeds. This could improve exercise tests for VO_{2} estimates in terms of time and money. In addition, by using the close relationship between SF and v, VO_{2} can be also expressed as a function of SF.

Original language | English |
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Pages (from-to) | 219-225 |

Number of pages | 7 |

Journal | Therapeutic Research |

Volume | 30 |

Issue number | 2 |

Publication status | Published - 2009 |

Externally published | Yes |

## Keywords

- Step frequency
- Step length
- Walking exercise
- Walking speed

## ASJC Scopus subject areas

- Medicine(all)