Secular Trends in the Physical Fitness of American Youth, Young Adults and Army Recruits

Abstract

Abstract : This paper reviews the literature and existing databases for information on secular trends in the physical fitness of young Americans and describes changes in fitness during Basic Combat Training (BCT). The VO2max of male youth and new Army recruits has not changed while that of female youth and new recruits has improved slightly from at least 1975 to 1998. Performance has declined on endurance running tasks in a similar time period. It may be that youth and recruits are not as proficient at applying their physiological capability to performance tasks like timed runs, possibly because of factors such as reduced experience with ruining, lower motivation, and/or environmental factors. Limited data on Army recruits demonstrate an increase in strength from 1978 to 1998 that is consistent with an increase in the frequency of self-reported youth strength training and an estimated increase in fat-free body mass over the same time period. Data on muscular endurance is not consistent. Among young Americans there is strong evidence that body weight and body mass index (BMI) have progressively increased since about 1980 and this increase continues into the 2000s. Available evidence suggests that the increases in BMI and body weight are associated with an increase in caloric intake. Most physical fitness trends can be modeled using linear regression and there is little reason to think the trends cited above will not continue into the future. During BCT, men improved their push-up, sit-up, and 2-mile run performance by an average of 56%, 47%, and 17%, respectively; women improved an average of 189%, 77% and 18%, respectively. To track future trends in BMI, cardiorespiratory endurance, and muscular endurance in the Army, appropriate surveillance systems should be developed to systematically collect Army Physical Fitness Test data.