Spikes in acute:chronic workload ratio and injury rate in English Premier League football players

Summary of the article focused on relationship between training load and the risk of sustaing injury in male professional soccer (football) players.

Who

33 male field players from one club aged 25.4(±3.1) (English Premier League).

Design

3 years of data, 61 individual soccer seasons

Outcome measures

Sports injuries (“injury caused any absence from future football participation, that is, a time loss injury”, reported by club doctor and senior physiotherapist), their location, severity and type (overall, contact, non-contact)
workload (GPS), chronic workload (previous 4-week average of weekly workloads), ACWR (Acute:chronic workload ratio)
total distance covered [m], number of accelerations, number of decelarations, high-speed distance [m], low intensity distance [m], sprint distance [m]

ACWR – Acute:chronic workload ratio = a ratio of traning load acummulated over the recent week and the training load accumulated over the previous 4 weeks

Main results

In 61 individual soccer seasons, 132 injuries (13.3/1000 hours; 4820 days missed) were recorded. Knee injuries were the most common with 69% being non-contact. Ankle injuries were the most common of contact injuries. Game injuries were 5 times more common than practice injuries (33.7/1000 h vs 5.8/1000h).
The highest overall injury risk was related to ACWRs above 2.0 combined with a low chronic workload of accelerations, decelerations and low-intensity distance.
The risk of non-contact injury was 5-7 times higher for low chronic workloads combined with ACWRs above 2.14 for total distance, low-intensity distance, accelerations and decelerations when compared with lower ACWR (<2.14).
The risk for contact injuries was the highest with ACWR between 1.1 and 1.5 for total distance, decelerations and low-intensity distance. Also, weekly accumulation of total distance between 24,000 adn 30,500 meters and decelerations between 1300 and 1800 increase risk for contact injury.

High risk for different types of injuries in professional soccer:

CWR > 2.0 and low chronic workload of accelerations, decelerations and low-intensity distance

CWR > 2.14 and low chronic workload of total distance, low-intensity distance, accelerations and decelerations

ACWR 1.1-1.5 of total distance, decelerations, low-intensity distance

Take home message

For a clinician & coach

In professional soccer, a combination of very high acute:chronic workload ratios with low chronic workloads for low-intensity distance, accelerations and decelerations elicited the highest risk for non-contact and overall injury risk. The highest risk for contact injuries was when acute:chronic workload ratios were moderate for total distance covered, decelerations and low-intensity distance.

For a parent

Spikes in workload combined with low chronic loads are related to a higher risk of non-contact and overall injuries in professional soccer.

For an athlete

Spikes in workload combined with low chronic loads are related to a higher risk of non-contact and overall injuries in professional soccer.

Original article

Bowen L, Gross AS, Gimpel M, Bruce-Low S, Li FX. Spikes in acute: chronic workload ratio (ACWR) associated with a 5–7 times greater injury rate in English Premier League football players: a comprehensive 3-year study. British journal of sports medicine. 2020 54:731-738.