Table 1 Overview of characteristics of leagues and results of studies included
League (country) Duration of break (restart of group training) | General conditions (pre vs. post) | Study | N | Variables (definition) |
|---|---|---|---|---|
Bundesliga (Germany) 9 weeks (after 3 weeks) | Substitutions: 3 vs. 5 Spectators: yes vs. no Matches/week: 1.0 vs. 1.5 | Krutsch et al. [23] | 26 match days (pre1 = first 8 match days of season 19/20, pre2 = 9 match days before break, post = 9 match days after break) | Injury incidence (fractures, joint, ligament, muscle, and tendon injuries, contusions, injuries of nervous system; injuries per 1000 football hours of training, matches, and overall exposure) [number/1000 h] |
Radziminski et al. [17] | 34 match days (pre = 25 match days before break, post = 9 match days after break) | Total distance (sum of running distance of all players of a team) [m] Very high-intensity running (team distance at 21–24 km/h) [m] Sprinting (team distance > 24 km/h) [m] | ||
Santana et al. [18] | 34 match days (pre = 25 match days before break, post = 9 match days after break) | Total distance (sum of running distance of all players of a team) [km] Sprints (team number of sprints with min. 1 s ≥ 22.68 km/h) [number] | ||
Seshadri et al. [24] | 34 match days (pre = 25 match days before break, post = 9 match days after break) | Injury rate (any trauma or musculoskeletal injury that caused loss of game time) [team number/match] | ||
Thron et al. [3] | 34 match days (pre = 25 match days before break, post = 9 match days after break) | Total distance (sum of running distance of all players of a team) [km] Average peak velocity (mean of maximum velocities in a team) [km/h] High-intensity distance (team distances at 17–23.99 km/h) [km] Sprinting distance (team distances ≥ 24 km/h) [km] Injury occurrence ((neuro-)muscular injuries, brain injuries, injuries to tendons, ligaments, or bones) [average injuries/team/match] | ||
Ekstraklasa (Poland) 12 weeks (after 8 weeks) | Substitutions: 3 vs. 5 Spectators: yes vs. no Matches/week: 0.9 vs. 1.5 | Radziminski et al. [17] | 37 match days (pre = 26 match days pre, post = 11 match days after break) | Total distance (sum of running distance of all players of a team) [m] High-intensity running (team distance at 19.8–25.2 km/h) [m/min] Sprinting (team distance > 25.2 km/h) [m/min] High-intensity actions (team number of high-intensity runs and sprints) [number] |
Hrvatski Telekom PRVA Liga (Croatia) 12 weeks (after 6 weeks) | Substitutions: 3 vs. 5 Spectators: yes vs. no Matches/week: 0.9 vs. 1.4 | Sekulic et al. [20] | 17 match days (pre = 7 match days after winter break and before Covid-19 break, post = 10 match days after break; 21 players from same team) | Position classification (central defenders, fullbacks, midfielders, forwards) Total distance (average of running distance of all players for the same position in a team) [m] Low-intensity running (mean player distance ≤ 14.3 km/h) [m] Running (mean player distance at 14.4–19.7 km/h) [m] High-intensity running (mean player distance ≥ 19.8 km/h) [m] Total accelerations (> 0.5 m/s2) [number] Total decelerations (< − 0.5 m/s2) [number] |
La Liga (Spain) 13 weeks (after 8 weeks) | Substitutions: 3 vs. 5 Spectators: yes vs. no Matches/week: 1.0 vs. 1.9 | Garcia-Aliaga et al. [19] | 22 match days (pre = first 11 match days of season 19/20, post = 11 match days after break) | Distance (average per team per match) [km] Distance (distance covered per minute per team and per match) [m/min] Medium-speed running distance (team distance at 14.1–21 km/h) [m and m/min] High-speed running distance (team distance at 21.1–24 km/h) [m/min] Sprinting-speed running distance (team distance > 24 km/h) [m and m/min and number] Accelerations (team number > 3 m/s2) [number and number/min] Decelerations (team number ≤ 3 m/s2) [number and number/min] Maximum speed (maximum team speed) [km/h] Average speed (mean team speed) [km/h] |
Raya-González et al. [21] | 38 match days (pre = 27 match days before break, post = 11 match days after break) | Team grouping into worsened ranking after break [WRS] and improved ranking after break [IMP] Total running distance (distance covered per team and minute) [m/min] High-intensity running distance (team distance at 21–24 km/h per minute) [m/min] Very high-intensity distance (team distance > 24 km/h per minute) [m/min] Accelerations (team number > 3 m/s2) [number] Decelerations (team number ≤ 3 m/s2) [number] | ||
De Souza et al. [22] | 12 match days (pre = last match day before break, post = 11 match days after break) | Total running distance (sum of running distance of all players of a team) [km] Running distance < 14.0 km/h (team distance) [km] Running distance at 14.0–20.9 km/h (team distance) [km] Running distance at 21.0–23.9 km/h (team distance) [km] Running distance > 24.0 km/h (team distance) [km] Running actions > 24.0 km/h (sum of team) [number] | ||
Serie A (Italy) 15 weeks (after 8 weeks) | Substitutions: 3 vs. 5 Spectators: yes vs. no Matches/week: 0.9 vs. 2.0 | Rampinini et al. [7] | 38 match days (pre1 = 12 match days until winter break; pre2 = 13 match days from winter break until lockdown; post = 13 match days after lockdown) | Total distance (mean of total match distances) [m/min] Very high-speed distance (mean match distances > 20 km/h) [m/min] Sprinting (mean match distances > 25 km/h) [m/min] High-acceleration distance (mean match distances > 3 m/s2) [m/min] High-deceleration distance (mean match distances < -3 m/s2) [m/min] |
Marotta et al. [25] | 38 match days (pre = 26 match days before break, post = 12 match days after break) | Incidence rate (any injuries) [number of injuries × 1000) / (athletes in-game (at risk) × n° games × 1.5 (match hour)] |