Accumulated workloads and the acute:chronic workload ratio relate to injury risk in elite youth football players

Br J Sports Med. 2017 Mar;51(5):452-459. doi: 10.1136/bjsports-2015-095820. Epub 2016 Jul 22.


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.

Keywords: Adolescent; Football; Global positioning system; Injury; Training load.

MeSH terms

  • Acceleration
  • Adolescent
  • Athletic Injuries / epidemiology*
  • Humans
  • Incidence
  • Male
  • Risk Factors
  • Running
  • Soccer / injuries*
  • Workload*