Author(s): SPENCER, M., MOEN, H.P., BYRKJEDAL, P.T., Institution: UNIVERSITY OF AGDER, Country: NORWAY, Abstract-ID: 1008

INTRODUCTION:
Traditionally, studies investigating body composition (via Dual-energy X-ray Absorptiometry; DXA) in professional football have not assessed changes related to external load markers in training or matches, via global navigation satellite systems (GNSS) integrated with inertial measurement unit (1). Recently, GNSS derived training load data has been associated with changes in body composition in the various phases of the football season (2). However, currently there is limited research examining the relationships between GNSS derived data in actual matches and measures of body composition. Therefore, the aim of this study was to investigate the association between body composition and external match load data variables in male professional footballers.
METHODS:
Thirteen professional male football players (24.7 ± 3.2 yrs, 184.2 ± 4.8 cm, 78.1 ± 4.3 kg) from one Norwegian club participated in this study. Body composition was measured with two DXA scans separated by 5 weeks and 7 official matches were played during this period. To be included in the analysis, participants needed to complete both DXA scans and play ≥ 3 matches with ≥ 60 minutes. DXA scan variables included: whole body and leg measures of total tissue mass, lean mass, fat free mass and fat mass %. The mean of the two scans was used in the analysis. External match load variables were presented relative to playing time (minutes per match) and included: total distance, peak speed, high (19.8-25.2 km/h) and sprint (>25.2 km/h) intensity running distance, PlayerLoadTM, and high intensity events (>2.5 m/s) consisting of accelerations, decelerations and change of directions. A nonparametric Bayesian correlation analysis was performed to investigate the relationships between DXA variables and external load match performance variables. The Kendall tau correlations in combination with Bayes Factors (BF) were calculated for each comparison (3).
RESULTS:
The mean (± SD) number of matches and playing time were 6.4 ± 2.0 and 86.6 ± 8.0 minutes respectively. Meaningful associations were only evident in leg variables and a measure of accumulative acceleration load. Specifically, there was moderate evidence (BF >3 to <10) for the association between legs lean mass and PlayerLoadTM/min (τ = -0.56), in addition to the association between legs total mass and PlayerLoadTM/min (τ = -0.56). The remaining BF comparisons between the selected body composition and external load match performance variables were deemed anecdotal.
CONCLUSION:
Our findings suggest that there are limited associations between selected body composition and external load match performance variables in a condensed, in-season period in one team of professional footballers. Further research, with larger data sets, is required to understand the potential relationships between body composition and external load match performance in male professional footballers.
1. Milanese et al. J Sports Sci, 2015
2. Varley et al. Bone Reports, 2023
3. van Doorn et al Am Stat, 2018