Date of Award

1997

Degree Name

Exercise Science

College

College of Science

Type of Degree

M.S.

Document Type

Thesis

First Advisor

Dr. Terry Shepherd

Second Advisor

Dr. William Marley

Third Advisor

Dr. Wayne Taylor

Fourth Advisor

Leonard J. Deutsch

Abstract

Participation by children in organized sport continues to increase. A 1994 survey of 10,000 households by the National Sporting Goods Association (1994) found that approximately 40,000 children between the ages of 7-17 years participate in an organized sport or recreational activity annually. In the realm of organized sports, especially endurance activities, there continues to be interest in how cardiovascular fitness is attained and how it can be maximized. Measurement of cardiovascular fitness is an important piece to that puzzle.

The most common and most descriptive measure for children and adults, is the maximal oxygen uptake or max (Astrand & Rodahl, 1977, p.318; Bar-Or, 1983, p.3; McArdle et al., 1994, p. 125; Pollock, 1973). This refers specifically to the amount of oxygen required by the cells to produce energy for physical work at the body’s maximal level (McArdle et al., 1994, p.66). Individual components of max are cardiac output (consisting of stroke volume and heart rate) and the arterio-venous oxygen difference (see Definition of Terms). It seems therefore, that an improvement in the efficiency of any of these factors would improve max and, in turn, cardiovascular fitness levels.

The relationship between cardiovascular fitness and each of its’ individual components has been extensively reviewed for adults (American College of Sports Medicine, 1990; Andrew et al., 1966; Astrand &Rodahl, 1977, p.394; Clausen, 1977; Pollock, 1973; Rowell, 1986; Saltin, 1990; Scheuer & Tipton, 1977). The frequency, intensity and duration of exercise necessary for improving maximal oxygen consumption and therefore cardiovascular fitness for adults is also well established (American College of Sports Medicine, 1990; Pollock, 1973). The type of endurance training recommended to improve max (American College of Sports Medicine, 1990) causes adaptions in all the previously mentioned components of maximal submaximal and maximal exercise (Andrew et al., 1966; Astrand & Rodahl, 1977, p.394; Clausen, 1977; McArdle et al., 1994, p.263-264; Rowell, 1986; Saltin, 1990; Scheuer & Tipton, 1977). A decrease in the heart rate at rest and during submaximal exercise has also been reported and is considered a hallmark of aerobic fitness (American College of Sports Medicine, 1990; Andrew et al., 1966; Astrand &Rodahl, 1977, p.394; McArdle et al., 1994, p.366; Saltin, 1990; Scheuer, 1977). The decrease in heart rate associated with endurance training is related to stroke volume increases to support the increase in cardiac output during exercise and to maintain cardiac output at rest (Astrand &Rodahl, 1977, p.394; Clausen, 1977; McArdle et al., 1994, p.264; Rowell, 1986; Saltin, 1990; Scheuer & Tipton, 1977). Increases in arterio-venous oxygen difference have also been found to occur with endurance training in adults (Andrew et al., 1966; Astrand &Rodahl, 1977, p.394; Clausen, 1977; McArdle et al., 1994, p.366; Pollock, 1973; Rowell, 1986; Saltin, 1990; Scheuer & Tipton, 1977). Additional anatomical and physiological changes in the structure and function of the heart itself are improvements in the myocardial thickness, left ventricular volume, and thus cardiac contractility that occurs with endurance training in adults (Adams, 1978; Demaria et al., 1978; Ehsani, et al., 1978; Gilbert et al., 1977; McArdle et al., 1994, p.366).

Subject(s)

Physical fitness for children – Research.

Cardiovascular fitness.

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