Biomedical subjects

A L Rowell

Publications and source records attributed to A L Rowell.

3 recordsLinked to original sources

PubMed1997

Responses to exercise at the velocity associated with VO2max.

The purpose of this study was to assess the significance of the velocity at which an individual achieves VO2max in an incremental treadmill test (Vmax) and the time that this velocity can be sustained (Tmax) to evaluate the rationale for using Vmax and Tmax in the prescription of endurance exercise training. Mean (+/- SD) values for VO2max, and Vmax in 13 female track athletes were 52.1 +/- 5.1 ml.kg.min-1 and 271 +/- 18 m.min-1, respectively. Then each athlete performed an exhaustive run at her Vmax. In these runs, VO2max was achieved after 234 +/- 49 s and was maintained for 56 +/- 48 s (range, 10-155 s) which was the last 18 +/- 13% (range, 4-47%) of the total exercise bout. Only one of the 13 subjects reached VO2max in the first 60% of the constant velocity test. Thus, while VO2max was attained during exhaustive exercise at Vmax, the amount of time that it was sustained was quite small (less than 60 s) and highly variable. It was concluded that Vmax is a suitable intensity to elicit VO2max in training. But 60% (or less) of Tmax is not an appropriate duration for training at this intensity because it is too short a time to allow most athletes to reach VO2max.

Adult↗

PubMed1996

Significance of time to exhaustion during exercise at the velocity associated with VO2max.

In theory, time to exhaustion at the velocity associated with VO2max (tLIM at vVO2max) together with the anaerobic threshold (AT) should provide information about the anaerobic capacity of an individual. The primary purpose of this study was to test that hypothesis, using oxygen deficit as a criterion for anaerobic capacity. A second purpose was to identify factors that might explain the large inter-individual variability reported in tLIM at vVO2max. Subjects were 13 female track athletes who performed incremental treadmill tests to determine VO2max and AT and constant velocity tests at vVO2max to determine tLIM and oxygen deficit. Correlations between oxygen deficit and tLIM at vVO2max and [(tLIM at vVO2max).(VO2max-AT)], a compound variable derived based on the critical power concept, were 0.51 (p < 0.05, one-tailed) and 0.67 (p < 0.01). To identify factors related to the inter-individual variability in tLIM at vVO2max, correlations between tLIM and AT, oxygen deficit, and [oxygen deficit/(VO2max-AT)] were calculated. Intra-individual differences in AT explained 44% of the variability in tLIM at vVO2max, oxygen deficit explained 26% of the variance, and the compound variable explained only 36%. It was concluded that (a) alone, or in combination with AT, tLIM at vVO2max cannot be used to estimate anaerobic capacity and (b) factors other than anaerobic capacity and AT contribute to the relatively large intra-individual variability in tLIM at vVO2max (CV = 21%). Determinants of tLIM at vVO2max must be elucidated if this measure is to be of use to sport scientists.

Adult↗

PubMed1996

Running velocity at VO2max.

Several authors have defined velocities which may, as a group, be described as the velocity associated with VO2max. Although several names, definitions, and abbreviations have been introduced, in this paper we shall use vVO2max for them all. These vVO2max have been reported to be an indicator of performance in distance running events. However, protocols for data collection and definitions used in the calculation of vVO2max have differed between studies. The purpose of this investigation was to compare values of vVO2max obtained using five definitions that have been described in the literature. vVO2max was determined in 22 women track athletes as (a) the speed at which VO2max was attained in a speed-incremented 0%-slope treadmill test, (b) the highest speed in the test that could be sustained for 1 min, (c) the ratio of VO2max to the oxygen cost of submaximal running (C), (d) the ratio of (VO2max - VO2 at rest) to (C - VO2 at rest), and (e) the velocity determined by extrapolation of the submaximal velocity:VO2 relationship. Results of ANOVA suggested that there were significant differences among the values derived using the different methods (F4.84 = 7.80, P < 0.001). Correlations among the various pairs of values ranged from 0.68 to 1.00. It is concluded that there are five distinct parameters described by the five definitions. The value of each of these parameters is influenced by VO2max and the energy cost of running. In theory, three of the parameters have an anaerobic component; two do not.

Adult↗