Health, Exercise, and Sports Sciences ETDs

Publication Date

7-17-1972

Abstract

Despite the mass of scientific data relating to the study of vigorous exercise, the literature contains little information on the minimum stress required for improvement in aerobic function. In view of the fact that the work intensity-duration relationship is far from elucidated, and considering the important implications of the concept of minimum exercise, particularly for cardiac patients and the elderly, it is imperative that further research be conducted. The present study was undertaken to describe the effects of three different work regimens of low to moderate intensity and duration. Twenty-three healthy male students at The University of New Mexico enrolled in Developmental Activities classes were randomly placed into one of three training groups: walking for forty minutes at a heart rate of approximately 130 BPM (N=8), jogging for ten minutes at a heart rate of approximately 160 BPM (N=7), and running for five minutes at a heart rate of approximately 175 BPM (N=8). An additional ten healthy male subjects volunteered to act as an inactive control group (N=10). Training took place three days per week on a 440 yard grass track for eight weeks. Pace was modulated by the work heart rate of each participant. After each lap, training heart rates were estimated from the time for ten beats after the temporary cessation of work. Training pace was monitored by observing movement time between flags placed at fifty-five yard intervals. Multiple trials on a double-stage (360 and 720 kgm/min) bicycle ergometer test were administered in order to determine steady state work heart rates at each power load. Rest heart rate prior to the test and recovery heart rate for five minutes following the submaximal test also were recorded. In addition, utilization of the Astrand-Ryhming Nomogram enabled prediction of max VO2 from the work heart rate at the 720 kgm/min power load. The results indicated improvement ranging from 2.6 to 7.0 percent in predicted max VO2 and work heart rates among all three experimental groups. On all of the criterion variables, excluding rest heart rate, the running group showed the largest improvements, followed by the joggers and walkers. Similar trends in improvement were noted by increases in training pace necessary to maintain the prescribed work heart rate. Stepwise regression analyses made it possible to examine the predicted improvements in the initially high and low fitness subjects. The results of these analyses showed marked predicted improvements in aerobic function among the less fit subjects in each experimental group. The better fit subjects, on the other hand, showed predicted deteriorations or no change. Hence, this study provides some evidence that reduced heart rate and increased max VO2 may ensue if moderate activities are continued for sufficient durations. This finding fails to confirm Karvonen's minimal intensity theory.53 Although the findings of this study tend to support the work of both Durnin et al.25 and Cooper,20 who emphasized the relationship between intensity and duration, the exact nature of which still must be determined. In this study, it was found that simple intensity­duration formulas are not sufficient for the prescription of exercise. Initial level of fitness was found to be a third crucial variable. Thus, all three variables are essential components in program design: intensity, duration, and initial fitness level.

Document Type

Dissertation

Language

English

Degree Name

Health Education

Level of Degree

Doctoral

Department Name

Health, Exercise, and Sports Sciences

First Committee Member (Chair)

Hemming Axel Atterbom

Second Committee Member

Marvin LeRoy Riedesel

Third Committee Member

Mary Bierman Harris

Fourth Committee Member

Martin Burlingame

Fifth Committee Member

Lawrence F. Locke

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