| Study (first author, year and location) | Sport/activity | Study design and duration | Participant population | Injury definition and method of measurement | Results: injuries per 1000 h (95% CI) |
| Andren-Sandberg, 1982, Lund, Sweden12 | Handball | Prospective cohort; 3-day annual tournament over 3 years | All competitors in Lundaspelen junior league tournament (n = 7320) | Definition: all injuries. Measurement: questionnaire completed by person responsible for team 2 weeks after tournament. Cases checked with tournament doctor and emergency department records | Boys: <11 years, 26 (6 to 131); 11–12 years, 30 (9 to 102); 13–14 years, 41 (15 to 114). Girls: <11 years, 31 (7 to 153); 11–12 years, 41 (13 to 137); 13–14 years, 26 (8 to 88) |
| Backous, 1988, Washington, USA13 | Soccer | Prospective cohort; 5 weeks | Participants aged 6–17 years in five 1-week soccer camps (681 boys, 458 girls) | Definition: any soccer-related medical problem causing the player to miss full participation in one or more sessions of competition or instruction. Measurement: all injuries observed and recorded by a single trainer certified by the National Athletic Trainers’ Association | Boys, 6.1 (5.0 to 7.6). Girls, 7.0 (5.5 to 9.0) |
| Davidson, 1987, Australia14 | Rugby union | Prospective; 18 years | All competitors participating in interschool rugby matches at one private school | Definition: all injuries presenting to a casualty station operating on-site during Saturday interschool matches. Measurement: a documentation system recorded details of all treated injuries | <13 years, 13.6 (11.4 to 16.3); 14–15 years, 18.4 (15.6 to 21.6) |
| de Loes, 1988, Skaraborg County, Sweden15 | Soccer | Prospective cohort; 1 year | All members of the municipal population (n = 31620) | Definition: any incident causing absence from further sporting participation. Measurement: an injury surveillance system registered all visits to medical clinics in the municipality. All injured persons were contacted for a telephone interview. Exposure data were collected via a questionnaire sent to 7% of the population, sports clubs data and information from school PE classes | Boys: 8–10 years, 0.04 (0.01 to 0.15); 11–12 years, 0.10 (0.03 to 0.29); 13–14 years, 0.19 (0.08 to 0.48). Girls: 8–10 years, 0.14 (0.03 to 0.77); 10–12 years, 0.47 (0.22 to 1.02); 13–14 years, 0.38 (0.25 to 0.97) |
| Durie, 2000, Christchurch, New Zealand16 | Rugby | Prospective cohort; one season | Competitors in schoolboy rugby (n = 442) | Definition: all players injured during game; minor, player played again within 7 days; moderate, unable to play 1–3 weeks; severe, unable to play >3 weeks. Measurement: team managers recorded all injuries; injured players were assessed by an investigator; insurance claims were also cross-checked | All injuries: under 13, 20.0 (11.3 to 35.5); under 14, 20.8 (15.0 to 28.8); under 15, 25.0 (17.6 to 35.5); under 16, 26.9 (19.0 to 38.2). Moderate and severe injuries: under 13, 3.6 (1.1 to 13.1); under 14, 4.2 (2.1 to 8.6); under15, 7.6 (4.0 to 14.2); under 16, 7.8 (4.0 to 15.3) |
| Elias, 2001, USA17 | Soccer | Prospective cohort; 10 years | Participants aged 9–19 years in the USA cup, an annual youth soccer tournament | Definition: all incidents treated by the USA cup medical facility. Measurement: information on all patients presenting to the tournament medical facility was collected using a paper encounter form | Boys: <12 years, 11.22 (10.58 to 13.20); <14 years, 11.81 (10.89 to 12.79); <16 years, 16.05 (14.99 to 17.19). Girls: <12 years, 12.64 (11.03 to 14.48); <14 years, 16.92 (15.48 to 18.49); <16 years, 17.68 (16.25 to 19.24) |
| Emery, 2006, Calgary, Canada18 | Soccer (indoor and outdoor) | Prospective cohort; one season | Participants competing in indoor (n = 142) and outdoor (n = 317) soccer teams | Definition: any soccer injury that resulted in the inability to complete a full session, or miss a subsequent sport session, and/or required medical attention. Measurement: each injured player or a team designate completed an injury report form; email or telephone contact was maintained fortnightly to capture missing data | Indoor soccer: 4.45, (3.10 to 6.19). Outdoor soccer: 5.59 (4.42 to 6.97) |
| Emery, 2006, Calgary, Canada19 | Ice hockey | Prospective cohort, one season | Participants aged 9–16 years registered with the Calgary Minor Hockey Association (n = 986) | Definition: any injury that required medical attention, resulted in cessation from participation in either session that injury occurred or subsequent session. Measurement: injury surveillance system organised to monitor all injuries; included 5 data collection instruments: weekly participant exposure sheet, individual injury report form, therapist injury assessment form, physician diagnosis/treatment plan form and preseason medical form | 9–10 years, 1.12 (0.61 to 1.87); 11–12 years, 3.32 (2.49 to 4.34); 13–14 years, 4.16 (3.26 to 5.23) |
| Garraway, 1995, Scotland20 | Rugby union | Prospective cohort; one season | Members of 26 Scottish Rugby Union affiliated clubs in the South of Scotland (n = 204 aged <16 years) | Definition: any injury that prevented the player from training or playing rugby for the remainder of the game in which the injury was sustained. Measurement: one ‘linkman’ from each club recorded all injury events; weekly visits ensured all details were completed; players were also contacted mid-season and at the end of the season to ensure completeness of registered injuries | <16 years, 3.41 (2.28 to 5.11) |
| Hoff, 1986, Kansas city, USA21 | Soccer (indoor and outdoor) | Prospective cohort; one season | Participants aged under 16 years in Western Missouri Soccer League and Miracle Sports Complex (outdoor, n = 455, indoor, n = 366) | Definition: any medical problem that occurred in practice or play that caused player to miss all or part of game or practice or which limited player ability. Measurement: self-addressed prepaid envelopes and questionnaires were sent to all parents seeking information on all injuries; coaches were also surveyed about injuries on their teams and information about practice and warm-up | Outdoor soccer: <8 years, 4.4 (1.8 to 1.12); 8–9 years, 4.5 (2.1 to 9.8); 10–11 years, 2.6 (1.1 to 6.6); 12–13 years, 9.1 (5.6 to 14.7); 14–15 years, 6.0 (2.2 to 15.8). Indoor soccer: <8 years, 11.1 (2.7 to 59.7); 8–9 years, 13.0 (4.7 to 37.3); 10–11 years, 46.8 (29.9 to 72.7); 12–13 years, 37.8 (23.5 to 60.6); 14–15 years, 75.8 (54.3 to 103.7) |
| Inklaar, 1996, Netherlands22 | Soccer | Prospective cohort; half season | Male competitors participating in two non-professionals sporting clubs | Definition: any injury that resulted in a reduction in the amount of soccer activity, the need for advice or treatment or adverse social or economic effects. Measurement: players reported injuries each week to a contact person (usually coach or team leader) delegated to the team; additional information was sought from therapists if necessary | 13–14 years, 12.8 (6.7 to 25.4) |
| Kakavelikas, 2003, Greece23 | Soccer | Prospective cohort; one year | Competitors aged 12–15 years in 24 Greek soccer clubs (n = 287) | Definition: any condition that limits athletic participation for at least the day after the day of onset. Measurement: injured players were examined by a specialist, and a standardised rating form recorded all relevant injury data; team coaches registered all injuries with the study; telephone contact with specialists occurred if more details were required. | Total, 4.0 (3.5 to 4.6); games, 5.6 (4.6 to 6.8); practice, 3.3 (2.7 to 4.0) |
| Le Gall, 2006, France24 | Soccer | Prospective cohort; 10 seasons | Competitors aged 13–15 years in the French National Institute of Football | Definition: any injuries received during game or practice that prevented the player from participating in game or practice for at least 48 h, not including the day of injury. Measurement: all injuries were recorded by a single physician based at the football centre for the study duration | <14 years, 4.9 (4.5 to 5.4); <15 years, 4.6 (4.2 to 5.1); <16 years, 5.2 (4.7 to 5.8); total, 4.8 (4.5 to 5.1); games, 11.2 (10.1 to 12.4); practice, 3.9 (3.6 to 4.2) |
| Lindenfeld, 1994, USA25 | Indoor soccer | Prospective observation; 7 weeks | Competitors of all ages at an indoor soccer arena | Definition: incident causing player to leave field, play to be stopped by referee or request for medical attention. Measurement: study representative observed each game and examined each injury. A questionnaire was completed with each injured player | Boys: <12 years, 28 (6.6 to 141.6); 12–15 years, 44 (20.9 to 93.5). Girls: <12 years, 56 (20.2 to 151.2); 12–15 years, 63 (25.9 to 152.4) |
| Maehlum, 1986, Norway26 | Soccer | Prospective cohort; one soccer tournament | Competitors aged under 18 years in the Norway Cup Soccer Tournament (1016 boy’s teams,322 girl’s teams) | Definition: all incidents and hyperventilations treated in field hospitals or on field. Measurement: all injuries requiring treatment were recorded on specific forms by assigned staff members | Boys: <12 years, 9.3 (6.9 to 12.7); 12–13 years, 9.1 (7.2 to 11.6). Girls: 12–13 years, 13.0 (8.9 to 19.2) |
| McMahon, 1993, Melbourne, Australia27 | Australian rules Football and Vickick (a modified version for players aged under 10 years) | Prospective cohort; one season | Competitors in a random sample of 18 under 15 teams, 18 under 10 teams and 18 Vickick clinics | Definition: any trauma that caused some disability or pain; injuries classified into those requiring health service use and those causing functional impairment. Measurement: a volunteer coordinator for each club or clinic maintained exposure data and completed injury report forms for each injured player | All injuries: Vickick, 3.49 (2.0–5.0); <10 years, 8.29 (6.5–10.1); <15 years, 9.79 (8.2–11.4). Functional impairment: Vickick, 1.49 (0.7–2.8); <10 years, 4.89 (3.5–6.3); <15 years, 7.32 (6.0–8.7). Health service use: Vickick, 0.33 (0.1–0.8); <10 years, 0.64 (0.2–1.4); <15 years, 3.93 (2.9–4.9) |
| Nilsson, 1978, Oslo, Norway28 | Soccer | Prospective cohort; one soccer tournament | Competitors participating in the Norway Cup | Definition: any injury occurring during participation in the soccer tournament which resulted in first aid treatment being sought at a first-aid tent; reported injuries excluded blisters and minor skin abrasions. Measurement: all relevant injury details were recorded at the first aid stations | Boys*: 11–12 years, 12; 13–14 years, 15 |
| Pasternack, 1996, Rochester, NY, USA29 | Baseball | Prospective cohort; one season | Competitors aged 7–18 years participating in two Little League Baseball organisations | Definition: all ball-related injuries in players aged 7–8 years and ball-related facial injuries in players aged 9–12 years that resulted in a missed game, evaluation by a physician or dentist, or inability to play a certain position. Measurement: the manager of each team completed an survey form for each injury | 7–8 years, 0.13 (0.05 to 0.39); 9–12 years, 0.12 (0.06 to 0.24) |
| Pringle, 1998, Auckland, New Zealand30 | Rugby union, rugby league, netball | Observational cross-section; 4-week period (258 games) | Competitors aged 6–15 years in organised competition at 15 venues (1932 rugby union, 1730 rugby league, 1512 netball) | Definition: minor, discomfort after game but able to play following week; moderate, prevented participation in following weeks. Measurement: trained observers completed incidence sheet plus an interview with player after game; a telephone interview followed within 3 days after incident; follow-up occurred 1 week later to determine if player could compete in game | All injuries: rugby union, 15.5 (10.5 to 23.0); rugby league, 24.5 (17.8 to 33.7); netball, 13.0 (7.9 to 21.3). Moderate injuries: rugby union, 0.6 (0.2 to 3.6); rugby league, 9.5 (5.7 to 15.9); netball, 6.1 (3.0 to 12.5) |
| Roberts, 1999, Minnesota, USA31 | Ice hockey | Prospective cohort | Competitors aged 11–19 years in five community-sponsored ice hockey tournaments (695 boys, 112 girls) | Definition: any disability evaluated by the tournament trainer or on-site doctor; significant, causing cessation of participation the day after injury, any dental injury requiring professional attention, any injury to the head or face, or any injury requiring substantive professional attention. Measurement: all injuries were recorded by a certified athletic trainer at the time of evaluation | All injuries: boys: 12–13 years, 127.3 (72.5 to 212.7); 14–15 years, 85.5 (44.2 to 159.2); girls: 12–15 years, 50.5 (20.6 to 123.1). Significant injuries: boys: 12–13 years, 57.9 (25.7 to 129.0); 14–15 years, 42.7 (17.3 to 104.3) |
| Schmidt-Olsen, 1985, Denmark32 | Soccer | Prospective cohort; 5-day tournament consisting of 945 matches (821.5 h) | Competitors aged 9–19 years competing in a soccer tournament (n = 6600) | Definition: any incident treated at tournament first aid stations; slight, minor first-aid, no advice to reduce activity; moderate, medical care but not hospitalisation, advice to reduce activity; severe, requires hospital treatment. Measurement: all treated injuries recorded by assigned staff | All injuries: boys: 9–11 years, 7.9 (3.7 to 17.1); 12–13 years, 9.9 (6.6 to 14.9); girls: 9–13 years, 0.92 (0.53 to 1.60). Moderate and severe injuries: boys: 9–11 years, 2.6 (0.94 to 7.6); 12–13 years, 4.0 (2.4 to 6.6); girls: 9–13 years, 0.52 (0.26 to 1.07) |
| Schmidt-Olsen, 1991, Denmark33 | Soccer | Prospective cohort; one year | Male competitors aged 12–18 years in 3 large soccer clubs (n = 496) | Definition: any injury that handicapped the player during game or required special treatment to continue play or prevented further participation. Measurement: all injuries were registered by team coaches or injured players | 12–13 years, 3.4 (2.0 to 7.2); 14–15 years, 3.8 (2.5 to 7.6) |
| Soderman, 2001, Umea, Sweden34 | Soccer | Prospective cohort; one season | Female competitors aged 14–20 years | Definition: a condition that made a player unable to participate fully in games or practice sessions. Measurement: all injuries were recorded and reported by the players in cooperation with the team coaches or trainers; regular contact was maintained by study personnel with players and team coaches | 14 years, 5.1*; 15 years, 7.6 |
| Stuart, 1995, USA35 | Ice hockey | Prospective cohort; one season | Competitors aged 9–14 years in youth hockey (n = 66) | Definition: any event that kept a player out of practice or competition for 24 h or necessitated the attention of a doctor. Measurement: all injuries identified and recorded; no information provided as to who identified injuries; coaches reported exposure time via attendance records | 9–10 years, 1.0 (0.1 to 8.9); 11–12 years, 1.8 (0.4 to 9.1); 13–14 years, 4.3 (2.3 to 11.2) |
| Sutherland, 1976, USA36 | Ice hockey | Prospective cohort | Competitors aged 5–14 years registered with the National Hockey League | Definition: no clear definition of injury given. Measurement: forms were completed by team coaches and trainers and submitted after each game; interviews with the injured player, coach or manager were necessary to obtain further data | 24.9 (19.3 to 32.0) |
| Timpka, 2002, Sweden37 | Bandy (similar to ice hockey) | Prospective cohort; one season | Competitors in Swedish South-eastern youth bandy league; rules allow 2 over-age players for each team per game | Definition: all events leading to a cessation of customary participation throughout the day after the injury, or that prevented participation in activities the following day or beyond, any brain concussion, any dental injury requiring professional attention, and any other injury that required professional treatment before return to play; severe, period of absence exceeding 8 days. Measurement: questionnaire eliciting injury information completed by head team coaches directly after each game and forwarded to the regional bandy association office; each team coach and injured player interviewed by a doctor at the end of the season | All injuries: youth 12, 1.5 (0.5 to 5.3); youth 13, 0.4 (0.1 to 2.4); youth 14, 3.2 (1.7 to 6.0); youth 15, 0.8 (0.2 to 2.9). Severe injuries: youth 12, 1.0 (0.2 to 4.1); youth 13, 0; youth 14, 1.8 (0.7 to 4.1); youth 15, 0.4 (0.1 to 2.2) |
| Willer, 2005, Ontario, Canada38 | Ice hockey | Prospective cohort; two seasons | Male competitors aged 4–18 years in a youth ice hockey program (n = 2632 (year 1) + n = 2639 (year 2)) | Definition: all injuries that results in doctor evaluation and required at least 24 h of restricted activity. Measurement: all injuries reported by team trainer using the Hockey Injury Canada Report form; each form contained a section completed by the treating doctor | Injuries during practice*: 4–7 years, 0.34; 7–8 years, 1.00; 9–10 years, 0.03; 11–12 years, 0.45; 12–13 years, 0.22; 14 years, 0. Injuries during games: 4–7 years, 0.13; 7–8 years, 0.83; 9–10 years, 1.51; 11–12 years, 1.42; 13–14 years, 1.97; 15 years, 1.46 |
*95% CI could not be calculated.