2011 Annual Conference

Geelhoed, Michael

The purpose of this cross sectional study was to determine the correlation between body mass index (BMI) and three different performance-based tests.

Twenty-six students were randomly selected from a group of young athletes that participated in Vacation Plyo School, a three day plyometrics camp held in San Antonio, Texas. Subjects in the study consisted of 13 girls and 13 boys ranging from 12-18 years of age. The camp is an annual free event provided by local PT clinicians and DPT students to prepare athletes for the upcoming fall sports season. Ideally, camp organizers hope participation in camp will enhance athletic performance and prevent injuries commonly sustained in fall sports.

Students participating in the study were asked to perform three different performance-based tests which included: 1) 40 yard dash, 2) Standing broad jump, and 3) Vertical leap. Each test was measured accordingly in seconds or inches. These performance-based tests were chosen because of their recognition in the literature to be relevant to the fall sports that most of these subjects compete in. Anthropometric measures were also taken to compute their BMI. 

A Pearson coefficient of correlation was used to evaluate the relationship between the subjects’ BMI and their respective performance-based tests results.

The correlation coefficient for the BMI versus the 40 yard dash was 0.39, with a standard deviation of ±0.54. The correlation coefficient for BMI versus the broad jump was -0.13 with a standard deviation of ±10.53. The correlation coefficient for BMI versus vertical leap was -0.27 with a standard deviation of ±4.00. The standard deviation of BMI alone was ±4.27.

BMI can be indicative of how an athlete will perform on performance based-tests. With a higher BMI, the athlete’s performance decreased. Underweight individuals also demonstrated a slight decrease in performance, especially female athletes. When data was separated between males and females, male data showed a linear positive correlation for BMI versus the 40 yard dash. This concluded that the leaner the male, the faster he ran. The female data revealed decreased performance for exceedingly high or low BMI. However, there was an optimal range at which female performance was best. For the broad jump, there was a slight negative correlation for both males and females. This revealed that as BMI increased, the athlete’s performance decreased. This negative inverse relationship was also observed on the vertical leap test. Performance decreased as BMI increased for males and females alike. For all tests, we found a small correlation between the variables.

Maintaining an ideal body mass index for an athlete can enhance athletic performance. Education on BMI should be provided to young athletes, along with nutrition and exercise counseling in order to achieve ideal BMI, and therefore maximize athletic performance.