Accumulated workloads and the acute:chronic workload ratio relate to injury risk in elite youth football players. Issue 5 (22nd July 2016)

• Record Type: Journal Article
• Authors: Bowen, Laura; Gross, Aleksander Stefan; Gimpel, Mo; Li, François-Xavier
• Is Part Of: British journal of sports medicine. Volume 51:Issue 5(2017)
• Page Start: 452
• Page End: 459
• Publication Date: 2016-07-22
• Subjects: Global positioning system -- Injury -- Football -- Adolescent -- Training load; Sports medicine -- Periodicals; 617.1027
• DOI: 10.1136/bjsports-2015-095820
• Languages: English
• ISSNs: 0306-3674

Abstract

Abstract : Aim: The purpose of this study was to investigate the relationship between physical workload and injury risk in elite youth football players. Methods: The workload data and injury incidence of 32 players were monitored throughout 2 seasons. Multiple regression was used to compare cumulative (1, 2, 3 and 4-weekly) loads and acute:chronic (A:C) workload ratios (acute workload divided by chronic workload) between injured and non-injured players for specific GPS and accelerometer-derived variables:total distance (TD), high-speed distance (HSD), accelerations (ACC) and total load. Workloads were classified into discrete ranges by z-scores and the relative risk was determined. Results: A very high number of ACC (≥9254) over 3 weeks was associated with the highest significant overall (relative risk (RR)=3.84) and non-contact injury risk (RR=5.11). Non-contact injury risk was significantly increased when a high acute HSD was combined with low chronic HSD (RR=2.55), but not with high chronic HSD (RR=0.47). Contact injury risk was greatest when A:C TD and ACC ratios were very high (1.76 and 1.77, respectively) (RR=4.98). Conclusions: In general, higher accumulated and acute workloads were associated with a greater injury risk. However, progressive increases in chronic workload may develop the players' physical tolerance to higher acute loads and resilience to injury risk.