Table 2 Characteristics of included studies
Study | Follow-up | Population | Injury definition | Workload | |
|---|---|---|---|---|---|
Internal | External | ||||
Bacon and Mauger [26] 2017 UK | 2 seasons | N = 41 Mean age 17.8 ± 1.1 yrs | Overuse injuries—no definition described | n.a. | Total distance (m); weekly and whole season training/match averages High speed running (m); weekly and whole season training/match averages |
Bowen et al. [27] 2017 UK | 2 seasons | N = 32 Mean age 17.3 ± 0.9 yrs | A non-contact/contact injury was defined as one that caused any absence from future football participation | n.a. | Total distance (m); this includes walking, jogging, fast running, and sprinting High speed distance (m); total distance > 20 km/h Total load (au); acceleration along x, y, and z axes Accelerations (n); a change in GPS speed data for at least half a second with maximum acceleration in the period of at least 0.5 m/s/s |
Brink et al. [28] 2010 Netherlands | 2 seasons | N = 53 Mean age 15–18 yrs | Any physical complaint sustained by a player that results from a soccer match or training, resulting in time loss (unable to take full part in future soccer activities) or medical attention (> 1 day but still able to take full part in future soccer activities) Traumatic injuries resulted from a specific, identifiable event. Overuse injuries resulted from repeated microtrauma without a single identifiable event | Rate of perceived exertion; global intensity of each training session rated on Borg 15-point scale Psychosocial stress and recovery; Recovery Stress Questionnaire for athletes (RESTQ-Sport) | Physical stress (min); duration of training sessions and matches Training load; product of the session-RPE and the physical stress Monotony; daily mean training load divided by the SD of the daily mean training load over a 1-week period Strain; product of weekly training load and monotony |
Delecroix et al. [29] 2019 France | 4 (U19) and 5 (U21) seasons | U19: n = 52; mean age 16.8 ± 0.9 yrs U21: n = 70; mean age 20.1 ± 0.3 yrs | Any physical complaint sustained by a player that resulted from a football match or training, that made the player unable to participate in a future football training or match | Rate of perceived exertion; global intensity of each training session and match rated on a 0–10-point scale | Workload (au); product of the session-RPE and duration of training session and matches A:C ratio (au); 1-week workload divided by the average workload of the last 28/21/14 days Week-to-week load changes; 1-week load divided by accumulated load of previous 7 days |
Raya- González et al. [30] 2019 Spain | 1 season | N = 22 Mean age 18.6 ± 0.6 yrs | A non-contact injury that occurred during a scheduled training session or match that caused absence from the next training session or match | Rate of perceived exertion; global intensity of each training session and match rated on a 0–10-point scale | Workload (au); the sum of load (RPE*duration) for all training sessions and matches for each week A:C ratio; sum of the current week’s load (acute load) divided by the average weekly training load over the previous four weeks (chronic load) |