‘Internal workload’ is believed to be an important risk factor for injury in elite football players. A recent study from the BJSM has attempted to investigate the association between workload and non-contact injuries in the UEFA Champions League and whether it is possible to predict non-contact injuries.1
The acute:chronic workload ratio (a measure of a change in a player’s training and match volume) has been used in other sporting codes as a measure of training load. It has also been identified as a possible tool that could be used to predict injury. This measure is also widely used, and discussed in football, but there is limited evidence relating to its efficacy. Workload is generally measured using session RPE (s-RPE). This measure is calculated for a training session by asking the player to report their rating of perceived exertion (RPE) for a given session or match and multiplying this by the duration of activity. The values for each session are added together to have a figure for each week (acute workload). This is then compared with the sum of the s-RPE over several weeks (chronic workload). In this way the acute:chronic workload ratio can be calculated.
In this study the RPE was collected 30 minutes after every session for all players in five elite European teams. Players were asked to rate the intensity of their session using the question “How was your workout”. Chronic workloads were calculated as rolling averages over two, three and four weeks. The acute:chronic workload was then calculated (1:2, 1:3 and 1:4 weeks).
Acute:chronic ratios measured over 1:3 and 1:4 weeks demonstrated an association with non-contact injuries in the subsequent week. Unfortunately, a high workload ratio as a stand-alone maker, was not useful at predicting subsequent injury.
1. McCall A, Dupont D & Ekstrand J. Internal workload and non-contact injury: a one-season study of five teams from the UEFA Elite Club Injury Study. Br J Sports Med Published Online First: 06 April 2018. doi: 10.1136/bjsports-2017-098473.