Effect of Body Composition and Mass Adjustments on Workload Estimation in NCAA Division I Football Players

Abstract

PURPOSE: Global Positioning Systems (GPS) and accelerometer integrated wearable technology (IWT) is often used to quantify an athlete’s work output. Differences in body composition may impact an athlete’s workload. This study examined the relationship between IWT determined total workload (TWL) and body composition measurements between 9 football positions. METHODS: TWL was measured in 78 NCAA Division I football athletes [9 Safeties (S), 6 Cornerbacks (CB), 12 Wide Receivers (WR), 5 Running Backs (RB), 5 Quarterbacks (QB), 6 Tight Ends (TE), 13 Linebackers (LB), 13 Defensive Linemen (DL), and 9 Offensive Linemen (OL)] using IWT during summer training sessions (June-July). Body fat percentage (BF%) and total upper body – lean lower mass ratio (TULLR) were determined using dual X-ray absorptiometry. Average TWL for the measured period was multiplied by BF%, BMI, and TULLR to obtain relative values for each player. An ANOVA was used to test the effect of position on each workload variable. When position had a significant effect, a Tukey test determined positional differences. RESULTS: Position had an effect on TWL (p<0.001) with S having a higher TWL than OL. When TWL was adjusted for BF% OL had significantly (p<0.025) higher TWL than all positions. There were no differences in TWL by position when adjusted for BMI (p=0.174) or TULLR (p=0.107). Table 1 presents the positional comparisons for each measure of TWL. CONCLUSION: Data from this study suggests that adjustments of TWL influences the interpretation of positional differences. Given that TWL is estimated based on changes in acceleration, the amount, and composition, of the athlete’s mass is critical to understanding the actual work being performed. Based on the observed variance in physiological response to similar TWL, future studies should examine relative player loads based on body mass and composition.Table 1: Total Workload and Relative Adjustments mean (±SD)