Impact of body weight on performance of a weight-supported motor fitness test in men.

The impact of body weight on test scores is a common issue in applied measurement. Dimensional analysis suggests that heavier participants are disadvantaged in weight-supported tasks. The purpose of this study was to evaluate the impact of body weight on performance scores for a military obstacle course. Three cohorts of male participants completed the Indoor Obstacle Course Test (IOCT). In cohort 1 (N = 2,191), height and weight were measured. In cohort 2 (N = 134), skinfold measurements were also performed. In cohort 3 (N = 44), all aforementioned measurements were performed, as well as upper- and lower-body tests for aerobic power, anaerobic power, muscular strength, and muscular endurance. The R2 between IOCT scores and body weight was 0.06 and that between IOCT scores and percentage of body fat was 0.08. All cohort analyses suggested that, for male subjects, body weight had only a small impact on the performance score distribution and the IOCT is fit for purpose as a fair repeatable system for assessment of physical performance.

Cross-sectional area and muscular strength: a brief review.

A brief review is provided on the relationship of strength to muscle cross-sectional area (CSA). It is commonly believed that maximal force and CSA are strongly related. Studies examining varying levels of training status display discordant data suggesting complex relationships between training status, CSA and peak force. It has been reported that trained participants had a significantly larger force to CSA ratio (F/CSA) than untrained males and females. Therefore, it is difficult to attribute all force changes due to training to CSA changes. In general, studies of CSA and strength suggest that sex differences may exist. For example, recreationally trained female weightlifters produced higher F/CSA than males at lower velocities of contraction. Definitive conclusions regarding sex differences, force production and CSA are difficult because of limited studies and equivocal results among these studies. Some studies have also examined the impact of aging on F/CSA. These studies seem to follow the same pattern as studies on sex differences and training status, with data suggesting that F/CSA varies unpredictably across ages and that differences may be attributed to factors other than age alone. In the papers reviewed, the relationship between force and CSA is neither consistent nor simple. Although some of the discrepancies between studies could be attributed to methodological variations, this does not seem likely to explain all differences. The F/CSA relationship seems complex, and future studies are required to elucidate the relationships among key factors in the expression of strength.