Table 3 Preseason conditioning: study characteristics.

Author, year, study type (setting)	Participants and recruitment	Groups/intervention (compliance)	Outcomes (follow‐up period)	Comments
Hewett 1999 Prospective intervention study (USA)	1263 high school students from 43 sports teams (basketball, volleyball, soccer). Volunteer team allocation into 3 groups: 2 female and 1 male	(A) Preseason conditioning: 366 female athletes (185 volleyball, 97 soccer, 84 basketball; 15 different teams); 6 week preseason neuromuscular training programme (flexibility, plyometrics, weight training and landing mechanics); 60–90 min sessions; 3 times a week. (B) Control groups: 463 female athletes (81 volleyball, 193 soccer, 189 basketball). (C) Male controls: 434 male athletes (209 soccer, 225 basketball) (Compliance: self‐reported).	Injury definition: knee ligament sprain or rupture causing player to seek care of athletic trainer and leading to at least 5 days of lost time from practice and games). Severity classification: classified by type, mechanism and treatment. (1 sporting season) Authors' conclusion: positive: neuromuscular training reduced serious knee injuries in females.	Data collection methods: injury documented by athletic trainers: (1) weekly reporting forms to monitor numbers of injuries along with game and practice injury risk exposures; (2) individual injury reporting forms to monitor injury type, mechanism + treatment. Injury verification: athletic trainer diagnosed serious injury with physician referral. ACL ruptures diagnosed with arthroscopy.
Heidt 2000 RCT (USA)	300 female soccer players (aged 14–18)	(A) Preseason conditioning: n = 42; 7 week programme consisting of sport‐specific cardiovascular training, plyometric work, strength training and flexibility; 20 sessions in total (2 treadmill and 1 plyometric session a week). (B) Control: n = 258; no intervention. (Compliance: not described).	Injury definition: any injury causing the athlete to miss a game or practice. Severity classification: (1) missed 1 game/practice; (2) missed 2–3 games/practices; (3) missed 4–7 games/practices; (4) missed 2–4 weeks; (5) missed 1–2 months; (6) season‐ending injury. (1 year: August–November and March–August). Authors' conclusion: positive: preseason conditioning prevents injury in female soccer players.	Data collection methods: injury information collected by school's athletic trainer (blinded). Injury verification: data recorded on injury incident report form (type, mechanism, severity, event in which occurred, type of shoe worn).

ACL, anterior cruciate ligament; RCT, randomised controlled trial.