The Study
Data from a number of studies performed in various countries have shown that, in addition to physical activity levels, ethnicity may contribute to differences in aerobic fitness among adolescent females. The purpose of this study, led by James M. Pivarnik, professor of kinesiology at Michigan State University, was to compare aerobic fitness and treadmill performance in black and white adolescent girls. The sample consisted of 40 black and 53 white girls whose socioeconomic backgrounds were similar and who ranged in age from 11-16 years (13.5 = average). Girls with a preexisting medical condition that might limit their exercise performance did not participate in the study. A sexual maturity evaluation for breast and pubic hair development was part of the physical exam given participants prior to entering the study. Girls were measured for weight, height, body mass and percent fat; each participated in an exercise test on a motorized treadmill to determine her aerobic fitness level. Oxygen consumption and carbon dioxide production were measured continuously during the exercise period, as was heart rate. Statistical measures were used to analyze the data.

The Findings
While the groups did not differ in age, percent body fat and standing height, the black girls were heavier and were at a more advanced stage of sexual maturity compared with the white girls. Oxygen consumption and treadmill time to exhaustion of black adolescent girls were found to be significantly lower than those found in whites. Differences in aerobic fitness may have been related to anatomical (including sexual maturity), physiological and/or behavioral factors.

What It Means to You
As you assess the aerobic fitness of all students in your school, you may want to pay particular attention to the fitness of your black adolescent females and examine the availability of suitable exercise programs for them. While ethnic differences may contribute to aerobic fitness - or the lack of it - the physical activity patterns of black female students may also be contributing to the disparity of their fitness with white female students. (The 1995 Youth Risk Behavior Survey reported that black female students in grades 9-12 were the least likely to be vigorously active three or more times per week.) Since studies have shown a decline in girls' aerobic fitness during adolescence when their body fat stores are increasing, this may be particularly important for black females who are at high risk for developing cardiovascular disease.

For More Information
Consult Pivarnik, J.M. et. al, "Ethnicity Affects Aerobic Fitness in U.S. Adolescent Girls," (1995), Medicine and Science in Sports and Exercise, The American College of Sports Medicine, vol. 27, p. 1635-1638.

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