Table 1

Operational definitions used in the study

Training sessionTeam training that involved physical activity under the supervision of the coaching staff
MatchCompetitive or friendly match against another team
InjuryInjury resulting from playing football and leading to a player being unable to fully participate in future training or match play (ie, time-loss injury)
RehabilitationA player was considered injured until the team medical staff allowed full participation in training and availability for match selection
Index injuryThe first reported injury of each player is assumed to be an index injury
ReinjuryInjury of the same type and at the same site as an index injury occurring not more than 2 months after a player's return to full participation from the index injury
Slight/minimal injuryInjury causing absence of 0–3 days from training and match play
Mild injuryInjury causing absence of 4–7 days from training and match play
Moderate injuryInjury causing absence of 8–28 days from training and match play
Severe injuryInjury causing absence of over 28 days from training and match play
Traumatic injuryInjury with sudden onset and known cause
Overuse injuryInjury with insidious onset and no known trauma
Injury rateNumber of injuries per 1000 player-hours ((Σ injuries/Σ exposure-hours)×1000)
Injury burdenNumber of days of absence per 1000 player-hours ((Σ days of absence/Σ exposure-hours)×1000)