FitMet

Part 3 of a multi-part series.

While the measurement of VO_2max is important, its accurate measurement through a laboratory measure is cost prohibitive for physical education. This means that field tests are used to measure cardiovascular function. The field tests used by physical educators are calibrated with laboratory measures for accuracy. While they are not as accurate as laboratory measures, students and teachers can still benefit by using them to measure fitness.

Common field tests used to measure cardiovascular fitness include the mile run/walk, the Progressive Aerobic Cardiovascular Endurance Run (PACER), and the walk test for ages thirteen and older. The mile run/walk is not necessarily the most accurate measure of aerobic capacity. Instead, a multiple regression formula that is more accurate can be used. This formula takes into account various contributing variables to get a more accurate estimate of VO_2max. These variables include mile run/walk time, age, gender, and body mass index. The teacher or student can easily collect all of these data. As a result, the teacher can effortlessly calculate VO_2max for an entire group of students using a spreadsheet.

Boys & Girls

Differences can be seen in terms of VO_2max between boys and girls. The average VO_2max for girls at age five is approximately 50 ml/kg/min and steadily declines to about 42 ml/kg/min by age sixteen. For boys however, the average VO_2max at age five is 50 ml/kg/min. This average remains the same during the growing years and at age sixteen, the average is still 50 ml/kg/min.

Differences in mile run times can be seen as well. Average mile run times at age five are 15 minutes for five year old girls and steadily get better until they plateau at about age 13 with an average time of 10 minutes. Average mile run times in girls actually get a little slower at about age 16 with times closer to 11 minutes 30 seconds. In boys, however, average mile run times are about 14 minutes for five-year-olds and steadily get better until age 15 or 16 where the average is about 7 minutes.

It was stated earlier that VO_2max may be the single most important health related fitness measure according to Brooks et al. However, according to Rowland, mile run times and VO_2max may not be the best means of assessing changes in aerobic fitness in youth. Clearly, teachers should be cautious when examining longitudinal changes in VO_2max during the growing years. This is why the criterion reference standards used for the Healthy Fitness Zone for VO_2max in the Fitnessgram assessment decrease with increasing age while the criterion for boys remain the same.

Norms vs. Criterion Reference Standards

Norm-referenced assessments are designed to compare the performance of an individual with the performance of a normative group. Mastropaolo, et al. has suggested norm-reference standards for VO_2max.

The FITNESSGRAM is an example of a criterion-referenced standardized assessment used to measure health related physical fitness. It was developed by a panel of experts using a combination of empirical data, normative data, and judgment as the basis for the standards. For cardiovascular fitness, data pertaining to all-cause mortality rates were used in this decision process.

Improvements in Cardiovascular Fitness

You may be wondering what types of improvement in VO_2max you can expect as a physical educator. Rowland reports that in the prebubertal child, improvements of only 5% to 10% can be seen from a standard endurance training program of sufficient duration, intensity and frequency. Rowland also points out that most pediatric studies of VO_2max demonstrate increases that are no more than one-third of increases of 30% seen in adults. Rowland suggests that these results may be due to the methods used in the studies or possibly a biological mechanism such as blood volume or cellular aerobic capacity.