Adolescent Physical Activity-Related Injuries in Sports Club, School Sports and Other Leisure Time Physical Activitie

R äisänen e al., C ogen Medicine (2016), 3: 1260786 h p://dx.doi.o g/10.1080/2331205X.2016.1260786 Page 1 o 11 Recei ed: 18 Augus 2016 Accep ed: 09 No embe 2016 Fi s Published: 17 No embe 2016 *Co esponding au ho : Anu M. Räisänen, Tampe e Resea ch Cen e o Spo s Medicine, UKK Ins i u e o H eal h P o mo i on R esea c h, P.O. Box 3 0 , 33501 Tampe e, Finland E- mail: [email p o ec ed]i Re iewing edi o : Albe Lee, The Chinese Uni e si y o Hong Kong, Hong Kong Addi ional in o ma ion is a ailable a he end o he a icle SPORTS & EXERCISE | RESEARCH ARTICLE Adolescen physical ac i i y- ela ed inju ies in spo s club, school spo s and o he leisu e ime physical ac i i ies Anu M. Räisänen1*, Ja i Pa kka i1, Lo a Ka hola2and A ja Rimpelä3,4 Abs ac :Backg ound: The objec i e was o s udy physical ac i i y (PA)- ela ed inju ies in spo s club, school spo s, and o he leisu e ime PA, and he associa- ions be ween inju ies and PA pa icipa ion equency and in ensi y. Me hods : A na ionally ep esen a i e sample was ob ained and a s uc u ed ques ionnai e was sen . A o al o 9,462 Finns (12–18 yea s) comple ed he su ey. P e alence o PA- ela ed inju ies was ga he ed by sepa a e ques ions abou spo s club inju ies, school spo s inju ies and o he leisu e ime PA inju ies. Resul s : Inju y p e alence was highe in spo s club ac i i ies han in o he leisu e ime PA o school spo s o boys ( p < 0.001) and gi ls ( p < 0.001). The p e alence o o he leisu e ime inju ies was highe han he p e alence o inju ies in school spo s o boys ( p < 0.001) and gi ls ( p < 0.001). Inju ies we e associa ed wi h highe equency (OR 10.4, 95% CI 6.7–16.3) and in ensi y (OR 4.1, 95% CI 2.9–5.8) o PA. Conclusions : Ou o he h ee se ings, inju y p e alence was highes in spo s club ac i i ies. Highe PA pa icipa- ion equency and in ensi y inc eased he isk o inju y. The e seems o be a need o u he p e en a i e measu es o educe he isks o PA- ela ed inju ies, espe- cially in he spo s club se ing. Subjec s: Physical Educa ion; You h Spo ; Heal h P omo ion; Spo s Inju y; Quan i a i e Me hods in Spo ; Child en and You h Keywo ds: adolescen ; a hle ic inju ies; exe cise; inju ies; physical ac i i y © 2016 The Au ho (s). This open access a icle is dis ibu ed unde a C ea i e Commons A ibu ion (CC-BY) 4.0 license. ABOUT THE AUTHORS This s udy is pa o he Adolescen Heal h and Li es yle Su ey (AHLS). The AHLS is a na ionwide su ey sys em moni o ing he heal h and heal h- ela ed li es yle o young people in Finland. The su ey has been conduc ed e e y second yea since 1977. P o esso A ja Rimpelä has been he p incipal in es iga o o AHLS nea ly 30 yea s. Physical ac i i y has been pa o he subjec s since e y beginning while inju ies ela ed o physical ac i i y is a new subjec , led by adjunc p o esso Ja i Pa kka i. The p incipal au ho Anu Räisänen p epa es he doc o al hesis on physical ac i i y ela ed inju ies and hei p e en ion among adolescen s. PUBLIC INTEREST ST ATEMENT Pa icipa ion in physical ac i i y (PA) p o ides posi i e e ec s on heal h and wellbeing. The downside o PA is he isk o inju y. Adolescen s a e ac i e in di e en se ing: in spo s clubs, schools, and in uno ganised ac i i ies du ing leisu e ime. In spo s clubs he p opo ion o adolescen s who ge inju ed is highe han in o he se ings. Bu on he o he hand, o he leisu e ime PA is mo e widely p ac iced. This leads o a high numbe o inju ies e en hough he p opo ion o inju ed adolescen s is lowe han in spo s clubs. Highe equency and highe in ensi y o PA is associa ed wi h a highe isk o inju ies. The e is an u gen need o in oduce p o en inju y p e en ion measu es, such as neu omuscula aining, sa e equipmen and en i onmen in di e en PA se ings. R äisänen e al., C ogen Medicine (2016), 3: 1260786 h p://dx.doi.o g/10.1080/2331205X.2016.1260786 Page 2 o 11 1. In oduc ion Physical ac i i y (PA) in adolescence is associa ed wi h a ious posi i e ou comes on heal h, wellbe- ing, and socio-economic ac o s. Adolescen PA p o ides heal h bene i s such as imp o ed bone heal h (Hallal, Vic o a, Aze edo, & Wells, 2006), lowe blood p essu e (Janssen & LeBlanc, 2010), posi i e changes on he ma ke s o me abolic synd ome (Janssen & LeBlanc, 2010), and lowe odds o o e weigh and obesi y (Janssen, Ka zma zyk, Boyce, King, & Picke , 2004). Adolescen PA also p omo es sel -es eem (Biddle & Asa e, 2011; Hallal e al., 2006) and men al heal h (Biddle & Asa e, 2011). In addi ion o he posi i e heal h e ec s, PA pa icipa ion in adolescence p edic s highe edu- ca ional le el, highe socio-economic s a us and highe ea nings in adul hood (Ka i e al., 2016; Koi usil a, Nupponen, & Rimpelä, 2011). O he impo an bene i s o PA pa icipa ion a e elaxa ion ( an Mechelen e al., 1996), un, enjoymen , social suppo , social in e ac ion (Allende , Cowbu n, & Fos e , 2006) i p o ides. E en hough spo s and ec ea ional ac i i ies a e gene ally sa e and p omo e good heal h, i has been ecognized ha PA- ela ed inju ies ha e a signi ican impac on public heal h (Finch, Wong Shee, & Clappe on, 2014; Schwebel & B ezausek, 2014). The incidence o PA- ela ed inju ies is high- e among adolescen s han adul s (Schmikli, Backx, Kemle , & an Mechelen, 2009), and in he pas decades, inju y occu ence among young people has inc eased (Tii ikainen, Lounamaa, Paa ola, Kumpula, & Pa kka i, 2008). Pa icipa ion in spo s and ec ea ional ac i i ies has been iden i ied as a majo cause o adolescen inju ies (Picke e al., 2005). In Finland, adolescen spo s club pa ici- pa ion is he s onges isk ac o o inju y hospi aliza ion h oughou adolescence and ea ly adul - hood (Ma ila, Pa kka i, Koi usil a, Kannus, & Rimpelä, 2009). PA- ela ed inju ies also ha e long e m consequences since hey can lead o sub-op imal heal h in la e li e (D awe & Fulle , 2001; Kujala, Kap io, & Sa no, 1994). Inju ies ha e been epo ed o be he leading cause why people s op pa icipa ing in PA (Na ional Cen e o Disease Con ol & P e en ion, 2002). I has been es ima ed ha annually 8% o adoles- cen s d op ou o ec ea ional spo ing ac i i ies because o inju ies o he ea o ge ing inju ed (G imme , Jones, & Williams, 2000). Reducing he isk o inju y inc eases he likelihood o he con in- ued heal h bene i (MacKay e al., 2004). The i s s ep in he sequence o p e en ion o PA- ela ed inju ies is es ablishing he ex en o he inju y p oblem ( an Mechelen, Hlobil, & Kempe , 1992). S udies on adolescen PA- ela ed inju ies o en ocus on he indi iduals who pa icipa e in spo s in he eli e le el, while ela i ely li le is known abou he inju ies ha occu in o he PA se ings. Some p io s udies ha e in es iga ed PA- ela ed inju ies in di e en se ings among 6–12-yea -old child en (Bloeme s e al., 2012; Jespe sen e al.,2015; Ve hagen, Colla d, Paw, & an Mechelen, 2009), bu we a e no awa e o p e ious s udies on spo s club, school spo s and leisu e ime PA- ela ed inju ies on adolescen popula ions. In spo s club he ac i i ies a e usually s uc u ed and o en he ocus is on imp o ing he pe o - mance in a single spo . In his s udy school spo s co e bo h he manda o y and sel -selec ed physical educa ion classes ( hese a e manda o y in Finland) and possible s uden spo ac i i ies o ganised by he school, o example ball games o ganised du ing he ecess o a e school. O he leisu e ime PA consis s o uno ganised physical ac i i ies, which in Finland can a y by he season, since win e o e s e y di e en oppo uni ies o PA summe . The main objec i e o his s udy was o compa e he inju y a es o 12–18-yea -olds in h ee se - ings: spo s club, school spo s and leisu e ime physical ac i i ies. The second aim was o s udy he associa ion be ween age and inju y p e alence in di e en se ings. Thi dly his s udy se ou o in- es iga e he associa ion be ween PA- ela ed inju ies and PA-pa icipa ion equency and exe cise in ensi y. Based on p e ious s udies on younge popula ions, we hypo hesized ha he e would be mo e inju ies in spo s clubs han in o he PA se ings. R äisänen e al., C ogen Medicine (2016), 3: 1260786 h p://dx.doi.o g/10.1080/2331205X.2016.1260786 Page 3 o 11 2. Ma e ials and me hods 2.1. Da a collec ion This s udy is pa o he Adolescen Heal h and Li es yle Su ey (AHLS). The AHLS is a na ionwide su ey sys em moni o ing he heal h and heal h- ela ed li es yle o young people in Finland. The su ey has been conduc ed e e y second yea since 1977. The su ey co e s se e al opics ela ed o adolescen heal h. Some o he opics al e na e and he ques ions abou PA- ela ed inju ies we e included in he su ey in 2009 and 2013. This s udy epo s he combined da a om hose wo yea s. In each s udy yea , a na ionally ep esen a i e sample o 12, 14, 16, and 18-yea -old Finns bo n on ce ain days in June, July, and Augus was ob ained om he Popula ion Regis e Cen e. The da es o bi h used in he sampling we e selec ed o ensu e he sample included di e en subjec s o each s udy yea . A 12 page s uc u ed ques ionnai e was mailed in Feb ua y o bo h s udy yea s. Enclosed wi h he ques ionnai e he subjec s ecei ed pe sonal use names and passwo ds, and in- o ma ion abou he op ion o comple ing he ques ionnai e online. Up o h ee ollow-up enqui ies we e sen o non- esponden s. The ques ionnai e was sen o a o al o 19,318 subjec s: 9,920 sub- jec s in 2009 and 9,398 subjec s in 2013. 2.2. S udy pa icipan s In 2009 he numbe o esponden s was 5,516, ou o which 2,288 we e boys and 3,228 we e gi ls. In 2013, 4,158 esponded (1,687 boys and 2,471 gi ls). Fo he combined da a o 2009 and 2013, he e- sponse a e was 50%. A o al o 212 subjec s we e excluded om he analysis due o inconsis encies be ween hei inju y in o ma ion and hei PA pa icipa ion in o ma ion o in o ma ion abou hei s u- den s a us. In hese cases he subjec epo ed no PA pa icipa ion o being a s uden bu epo ed an inju y in ha se ing, o ice e sa. Ou o he 9,462 subjec s included in he s udy, 59% we e gi ls and 41% we e boys. The dis ibu ions o age g oups o boys and gi ls a e p esen ed in Table 1. Pa icipa ion a es in spo s club ac i i ies, school spo s, and o he leisu e ime PA a e p esen ed in Table 2. 2.3. Measu emen s 2.3.1. PA- ela ed inju ies The inju y p e alence e e s o he p opo ion o subjec s who had been inju ed in physical ac i i ies du ing he pas wel e mon hs. The inju y p e alence’s in h ee se ings we e based on h ee ques- ions: “Du ing he pas yea , ha e you su e ed an inju y while pa icipa ing in spo s club ac i i ies?”, “Du ing he pas yea ha e you su e ed an inju y while pa icipa ing in a physical educa ion class o ins uc ed s uden spo ?”, and “Du ing he pas yea ha e you su e ed an inju y while pa icipa ing in o he leisu e ime physical ac i i ies (no in a spo s club)?” In 2009, h ee op ions we e p o ided: “No”, “Once”, and “Twice o mo e”. In 2013, he e we e ou op ions: “No”, “Once”, “Twice”, and “Th ee imes o mo e”. Due o he di e en answe op ions in 2009 and 2013, he inju y da a we e combined o c ea e a dicho omous a iable consis ing o classes “No inju ed” and “Inju ed a leas once”. In o ma ion abou s uden s a us was inqui ed wi h he ques ion “A he momen , a e you a s uden ?” Th ee op ions we e p o ided: “No, I’m no a s uden ”, “Yes, I am a ull ime s uden ”, and “Yes, I’m a s uden alongside going o wo k”. In he Finnish educa ion sys em, physical educa ion is manda o y in comp ehensi e schools, gene al uppe seconda y schools, and oca ional schools. Table 1. P opo ions o subjec s in age g oups by gende Age (yea s) Boy s ( n = 3,881) Gi ls ( n = 5,581) % 95% CI % 95% CI 12 16.5 15.3–17.7 12.4 9.9–14.9 14 30.7 29.2–32.2 29.8 28.6–31.0 16 30.2 28.8–31.6 29.2 28.0–30.4 18 22.6 21.3–23.9 28.6 27.4–29.8 No e: CI = con idence in e al. Page 4 o 11 R äisänen e al., C ogen Medicine (2016), 3: 1260786 h p://dx.doi.o g/10.1080/2331205X.2016.1260786 Table 2. P opo ions o subjec s pa icipa ing in spo s club ac i i ies, school spo s and o he leisu e ime physical ac i i ies by gende Physical ac i i y se ing Boy s ( n = 3,881) Gi ls ( n = 5,581) % 95% CI % 95% CI Spo s club ac i i ies 52.5 50.8–54.2 47.7 46.3–49.1 School spo s 97.2 96.7–97.7 97.4 97.0–97.8 Leisu e ime PA 95.6 94.9–96.3 97.1 96.6–97.6 No e: CI = con idence in e al. Based on his, i was assumed ha all he subjec s, who epo ed being s uden s, pa icipa e in school spo s (physical educa ion classes and s uden spo s). The inju y p e alence in spo s club ac i i ies was calcula ed as a pe cen age o subjec s epo ing a leas one spo s club inju y ou o subjec s epo ing pa icipa ion in spo s club ac i i ies. The in- ju y p e alence in school spo s ac i i ies was calcula ed as a pe cen age o subjec s epo ing a leas one school spo s inju y ou o subjec s epo ing being s uden s. The inju y p e alence in o he leisu e ime PA was calcula ed as a pe cen age o subjec s epo ing a leas one leisu e ime PA inju y ou o subjec s epo ing pa icipa ion in o he leisu e ime PA. 2.3.2. PA pa icipa ion and exe cise in ensi y PA pa icipa ion le els we e de i ed om wo ques ions: “How o en do you pa icipa e in spo s in you leisu e ime h ough spo s club aining, compe i ions o games?” and “How o en do you pa - icipa e in PA in o he ways in you leisu e ime?” Se en al e na i es we e p o ided: “no a all”, “less o en han once a mon h”, “1–2 imes a mon h”, “app oxima ely once a week”, “2–3 imes a week”, “4–5 imes a week”, and “app oxima ely e e y day”. Exe cise in ensi y was de e mined om he ques ion “When I do spo s o PA, usually I expe ience: no swea ing o ge ing ou o b ea h/some swea ing o ge ing ou o b ea h/mode a e swea ing o ge ing ou o b ea h/ex ensi e swea ing o ge ing ou o b ea h/I do no exe cise in my leisu e ime”. To de e mine whe he exe cise in ensi y was ela ed o inju ies, he inju ies in spo s club, school spo s, and o he leisu e ime PA we e combined in o a new dicho omous a iable: “Su e ed a leas one PA- ela ed inju y”. The inju y p e alence was calcula ed as he p opo ion o subjec s epo ing a leas one inju y ou o all he subjec s. 2.4. E hics The s udy ollows he e hical p inciples o he Decla a ion o Helsinki. Subjec s we e in o med o he aims, me hods, olun a y pa icipa ion, p i acy and con iden iali y o he collec ed in o ma ion. The s udy p o ocol has been app o ed by he E hics Commi ee o Tampe e Region ( e e ence Lausun o 2/2010) and he E hics Commi ee o he Pi kanmaa Hospi al Dis ic ( e e ence ETLR06226). W i en in o med consen was no equi ed. 2.5. S a is ical me hods S a is ical analyses we e pe o med using he SPSS so wa e (IBM SPSS S a is ics Ve sion 23 o Windows). Since some subjec s had been inju ed in mo e han one PA se ing, he g oups we e no conside ed o be independen when compa ing he inju y p e alence be ween he spo s club ac i i- ies, school spo ac i i ies, and o he leisu e ime PA. The e o e McNema ’s es o wo ela ed samples was used o es he di e ences in inju y p e alence be ween PA se ings. Pea son’s χ2 es was used o es di e ences in he inju y p e alence be ween age g oups. Odds a ios (ORs) we e used o es o di e ences in he inju y p e alence by spo club pa icipa ion equency, o he lei- su e ime PA pa icipa ion equency and exe cise in ensi y. ORs we e ob ained om mul i a ia e logis ic eg ession analysis. Age and gende whe e en e ed in o each mul i a ia e model o adjus o hei po en ial con ounding e ec . A p- alue o <0.05 was conside ed s a is ically signi ican . Page 5 o 11 R äisänen e al., C ogen Medicine (2016), 3: 1260786 h p://dx.doi.o g/10.1080/2331205X.2016.1260786 3. Resul s 3.1. Inju y p e alence in di e en se ings Ou o he subjec s who epo ed pa icipa ing in PA in any o he h ee se ings, 32.0% (95% CI, 31.0–33.0) had su e ed a leas one PA- ela ed inju y in he pas 12 mon hs. The inju y p e alence in spo s club ac i i ies was 27.5% (95% CI, 25.4–29.6) o boys and 23.8% (95% CI, 22.0–25.6) o gi ls. In school spo s ac i i ies, he inju y p e alence was 9.8% (95% CI, 8.8–10.8) o boys and 10.0% (95% CI, 9.2–10.8) o gi ls. In o he leisu e ime PA, he inju y p e alence was 17.6% (95% CI, 16.3–18.9) o boys and 13.3% (95% CI, 12.3–14.3) o gi ls. Acco ding o he McNema ’s es o wo ela ed samples, he inju y p e alence in spo s club ac- i i ies was signi ican ly highe han he inju y p e alence in school spo s and in o he leisu e ime PA o boys ( p < 0.001) and gi ls ( p < 0.001). The p e alence o o he leisu e ime PA inju ies was highe han he p e alence o school spo inju ies o boys ( p < 0.001) and gi ls ( p < 0.001). Pea son’s χ2 es was used o es o di e ences be ween age g oups. The inju y p e alence in spo s club, school spo s and o he leisu e ime PA by age g oups a e shown in Figu e 1. The inju y p e alence a ied signi ican ly be ween he age g oups in spo s club inju ies o boys (p< 0.05) and gi ls (p< 0.05). The spo s club inju y p e alence was highes in he 16 and 18-yea -olds among boys Figu e 1. Inju y p e alence (%) in spo s club ac i i ies, school spo s and o he leisu e ime physical ac i i ies in he pas 12 mon hs by age g oup o boys and gi ls p esen ed wi h 95% con idence in e al (CI). No es: P opo ions we e calcula ed om hose epo ing pa icipa ion in spo s club ac i i ies/being s uden s/ pa icipa ion in o he leisu e ime PA. Pea son’s χ 2 es was used o es o di e ences be ween age g oups. Page 6 o 11 R äisänen e al., C ogen Medicine (2016), 3: 1260786 h p://dx.doi.o g/10.1080/2331205X.2016.1260786 Table 3. Age and gende -adjus ed ORs and 95% CIs o spo s club inju ies by equency o spo s club ac i i y F equency o spo s club ac i i y OR 95% CI p- alue Less han once a mon h 1 1–2 Times a mon h 1.8 1.0–3.1 0.041* App oxima ely once/week 1.5 0.9–2.3 0.103 2–3 Times/week 3.1 2.0–4.6 <0.001* 4–5 Times/week 6.9 4.5–10.5 <0.001* App oxima ely daily 10.4 6.7–16.3 <0.001* No e: ORs we e de i ed om mul i a ia e logis ic eg ession analysis. *S a is ical signi icance based on p< 0.05. and in he 14-yea -olds among gi ls. In school spo s and o he leisu e ime PA, he inju y p e alence was lowes in he olde age g oups among boys ( p < 0.001) and gi ls ( p < 0.001). 3.2. Associa ions be ween inju ies and PA pa icipa ion and in ensi y Mul i a ia e logis ic eg ession analysis was used o es o he associa ions be ween inju ies and PA pa icipa ion and in ensi y. Spo s club inju ies we e associa ed wi h he equency o spo s club ac i i ies. The odds a io was highes o hose who pa icipa ed in spo s club ac i i ies app oxi- ma ely e e y day (OR 10.4, 95% CI 6.7–16.3). Pa icipa ing in spo s club ac i i ies 2–3 imes pe week o mo e o en signi ican ly inc eased he isk o spo s club inju y. The ORs o spo s club inju- ies by pa icipa ion equency a e p esen ed in Table 3. The isk o o he leisu e ime PA inju ies inc eased when pa icipa ion equency was once a week o highe . The ORs o o he leisu e ime inju ies by pa icipa ion equency a e p esen ed in Table 4. Table 4. Age and gende -adjus ed ORs and 95% CIs o o he leisu e ime inju ies by equency o leisu e ime physical ac i i y (PA) F equency o o he leisu e ime PA OR 95% CI p- alue Less han once a mon h 1 1–2 Times a mon h 1.3 0.8–2.2 0.232 App oxima ely once/week 1.7 1.1–2.6 0.013* 2–3 Times/week 2.1 1.4–3.1 0.001* 4–5 Times/week 2.6 1.7–3.9 <0.001* App oxima ely daily 3.1 2.0–4.7 <0.001* No e: ORs we e de i ed om mul i a ia e logis ic eg ession analysis. *S a is ical signi icance based on p< 0.05. Table 5. Age and gende -adjus ed ORs and 95% CIs o all physical ac i i y- ela ed inju ies by in ensi y o physical ac i i y In ensi y (swea ing/ge ing ou o b ea h) OR 95% CI p- alue None 1 Some 1.6 1.1–2.3 0.009* Mode a e 2.2 1.6–3.2 <0.001* Ex ensi e 4.1 2.9–5.8 <0.001* No e: ORs we e de i ed om mul i a ia e logis ic eg ession analysis. *S a is ical signi icance based on p< 0.05. Page 7 o 11 R äisänen e al., C ogen Medicine (2016), 3: 1260786 h p://dx.doi.o g/10.1080/2331205X.2016.1260786 Exe cise in ensi y was associa ed wi h he isk o PA- ela ed inju y. Those epo ing mode a e o ex ensi e swea ing/ge ing ou o b ea h when exe cising had 4.1 imes highe isk o inju y com- pa ed o hose, who didn’ swea /ge ou o b ea h when exe cising. The ORs o all PA- ela ed inju- ies by in ensi y le el a e p esen ed in Table 5. 4. Discussion To ou knowledge, his is he i s s udy o compa e he inju y p e alence in spo s club ac i i ies, schools spo s and o he leisu e ime PA among adolescen s. The indings o his s udy demons a e ha he inju y p e alence was signi ican ly highe in spo s club ac i i ies han in school spo s ac- i i ies and o he leisu e ime PA. In addi ion, he p e alence o o he leisu e ime PA inju ies was highe han he p e alence o school spo inju ies. One possible explana ion o hese di e ences could be he in ensi y o PA, since ou esul s also show ha exe cise in ensi y was associa ed wi h he isk o inju y. The spo s club PA is s uc u ed and he goal is o imp o e spo s pe o mance, he e o e i is possibly mo e in ense han o he leisu e ime PA. In school spo s he goal is mainly educa ional and he in ensi y is likely o be lowe han in he o he PA se ings. P e ious s udies on inju ies in spo s clubs, school spo s and o he leisu e ime inju ies ha e been done on school child en, aged 12 yea s and unde . Jespe sen e al. (2015) s udied musculoskele al inju ies among 6–12-yea -old Danish school child en. They epo ed he highes a e o auma ic inju ies in spo s (1.57 inju ies/1,000 PA uni s), ollowed by leisu e ime PA (0.57 inju ies/1,000 PA uni s) and PE lessons (0.14 inju ies/1,000 PA uni s). In he iPlay s udy Ve hagen e al. (2009) s udied inju ies among 10–12 yea s old Du ch child en. The inju y incidence densi y was highes in spo s (0.66), ollowed by PE (0.50) and leisu e ime PA (0.39). The di e ences be ween se ings we e no signi ican . Besides hese s udies ocusing on child en, di ec compa isons a e di icul o make due o di e ences in inju y de ini ions and da a collec ion me hods. The common end in he esul s o his s udy and he wo k o Jespe sen e al. (2015) and Ve hagen e al. (2009) is ha in all he h ee s udies, he p e alence o inju ies is highes among spo s club ac i i ies. The e o e i can be sug- ges ed ha p e en a i e measu es should be in oduces mo e ex ensi ely o spo s club ac i i ies, especially o he spo s popula among adolescen s. Among boys he p e alence o spo s club inju ies inc eased wi h age. I has been p e iously e- po ed ha in adolescen spo s he in ensi y and aining load inc ease p og essi ely wi h age (Malisoux, F isch, U hausen, Seil, & Theisen, 2013b). In ensi y being associa ed wi h he isk o inju y, he inc ease in in ensi y could explain he inc ease in boys’ inju y p e alence. P e ious s udies sug- ges ha he ela ion be ween inju ies and age is spo -speci ic. In a socce inju y s udy he 16- and 18-yea -old boys had lowe inju y incidence han he 14-yea -olds (Eme y, Meeuwisse, & Ha mann, 2005). In a hockey inju y s udy he inju y incidence inc eased signi ican ly wi h age (Eme y & Meeuwisse, 2006). In he cu en s udy he p e alence o spo s club inju ies among gi ls was high- es in he 14-yea -olds. This is in line wi h he esul s o Eme y e al. ( 2005) epo ing a highe inci- dence o socce inju ies among he 14-yea -olds han he 16 and 18-yea -olds. Spo is one possible ac o con ibu ing o he di e ences in inju y p e alence be ween age g oups in his s udy. In his s udy, isk o PA- ela ed inju ies inc eased when he equency o PA inc eased. The inc ease o isk was highes in spo s club inju ies, whe e hose pa icipa ing app oxima ely daily had 10.4 imes highe isk o inju y han hose pa icipa ing less han once a mon h. This high inc ease in he isk is somewha su p ising, since he e is e idence ha aining has a p o ec i e e ec agains inju y (Gabbe , 2016). In spo s, bo h o e aining and unde - aining could be linked wi h a high incidence o inju ies (Gabbe , 2016). Unde - aining is possibly associa ed wi h inju ies in o he PA se ings also. In he iPlay-s udy, Bloeme s e al. ( 2012) s udied inju ies in leisu e ime PA, spo s and physical educa ion classes in 10–12-yea -old child en. They demons a ed ha he leas ac i e child en had he highes isk o inju y and iden i i he cu -o le el o be 5 h o PA pe week. The esul s o he cu en s udy do no suppo he heo y ha low le els o pa icipa ion o unde - aining inc ease he isk o inju y. I is impo an o bea in mind ha in his s udy he equency o spo s club ac i i ies and o he leisu e ime PA we e analysed sepa a ely and his could yield di e en esul s han using weekly o al exposu e. Page 8 o 11 R äisänen e al., C ogen Medicine (2016), 3: 1260786 h p://dx.doi.o g/10.1080/2331205X.2016.1260786 In his s udy in ensi y was de ined as he le el o swea ing/ge ing ou o b ea h du ing exe cise. Swea ing and ge ing ou o b ea h a e ecommended o adolescen s since hey need bo h mode - a e and igo ous exe cise (Wo ld Heal h O ganiza ion, 2010). Pa icipa ing in in ense exe cise should no be limi ed by he ea o inju y. One possible app oach o lowe ing he isk o inju y in in ense exe cise is de eloping be e mo emen skills. Neu omuscula aining p og ams aimed o imp o e mo emen skills ha e p oduced lowe inju y a es in high in ensi y spo s among adolescen popula- ions (Hägglund, A oshi, Wagne , & Waldén, 2013; Rössle e al., 2014; Soliga d e al., 2008; Wedde kopp, Kal o , Lundgaa d, Rosendahl, & F obe g, 1999). School-based inju y p e en ion p o- g am consis ing o neu omuscula aining has also been used success ully o educe he inju y isk and a he same ime o imp o e heal h ac o s like adiposi y and i ness (Richmond, Kang, Doyle-Bake , Ne el-Agui e, & Eme y, 2016). In o ganized se ings, such as spo s clubs, ano he me hod o lowe he inju y incidence is implemen ing an inju y su eillance sys em. Implemen ing a su eillance sys em can imp o e awa eness o he p oblem and u he mo i a e coaching s a o implemen p e en a i e measu es (Malisoux, F isch, U hausen, Seil, & Theisen, 2013a). In he Finnish educa ion sys em, physical educa ion classes a e manda o y in comp ehensi e schools, gene al uppe seconda y schools, and oca ional schools. In his s udy, he inju y p e a- lence was lowe in school spo s ac i i ies han in o he PA se ings. Howe e , i could be a gued ha when pa icipa ion is manda o y and he goal is educa ional, he isk o inju y should be as low as possible. This esul could indica e ha u he p e en a i e measu es should be implemen ed o lowe he inju y isk in school spo s ac i i ies. The coaches in he spo club ac i i ies and he eache s in school spo s possess an impo an ole in inju y p e en ion. The coaches, suppo s a and eache s mus en o ce ules and he use o sa e y equipmen , such as helme s and p o ec i e eye wea when applicable. They mus also assess he en i onmen al ac o s, like wea he condi ions, and e alua e o he condi ions in which equipmen a e used, such as he appa a us in gymnas ics. In addi ion o hese ac o s load needs o be consid- e ed. In spo s club coaches should moni o he load indi idually and make adjus men s o aining and compe i ion loads i necessa y (Soliga d e al., 2016). In school spo s he eache s should con- side ha he s uden s mos ac i e in physical educa ion lessons a e usually ac i e also in spo s clubs, o he leisu e ime PA (T i ono Rexen e al., 2014). Child en wi h low habi ual le els o PA a e a an inc eased isk o inju y (Nau a, Ma in-Diene , Ma in, an Mechelen, & Ve hagen, 2015). Manda o y physical educa ion classes can be he only o m o PA o hese child en. The eache has a esponsi- bili y o keep he lessons sa e o all child en and insu e ha he load is manageable o e e yone. The la ge, andomly d awn sample can be conside ed a s eng h o his s udy. The esponse a e o his s udy was 50%. I has been epo ed ha in su ey s udies he non- esponden s ha e poo e heal h beha iou , heal h and socio-economic backg ound (Pie ilä, Ran akallio, & Lää ä, 1995). The aim o his s udy was o compa e inju y a es in di e en PA se ings in gi ls and boys o di e en age g oups. Physically ac i e adolescen s we e expec ed o espond a a highe a e, and hus, he o al esponse a e was no conside ed o ha e a majo impac on he epo ed compa isons. This s udy has some limi a ions. Re ospec i e, sel - epo ed inju y his o y has he po en ial o ecall bias. Howe e , Gabbe, Finch, Bennell, and Wajswelne ( 2003) epo ed ha pa icipan s we e able o co ec ly indica e whe he hey had been inju ed o uninju ed in he pas 12 mon hs. To minimize he impac o ecall bias on he esul s, we only asked o he inju y s a us and did no eques mo e de ails, such as he numbe o inju ies, he inju ed body egion, he inju y ype, he se e i y o he diagnosis. In he su ey he wo d “inju y” was no de ined. I was up o he subjec how hey pe cei ed he wo d. Since he pu pose o his s udy was o compa e he inju y a es in di e en se ings, we belie e he lack o de ailed inju y de ini ion was no necessa y, since he subjec p obably de ined inju ies simila ly in he di e en se ings. I is possible ha some mino inju ies and o e use inju ies ha e no been epo ed, and hus, he epo ed inju y a es migh sligh ly unde es ima e he si ua ion. This is a possible limi a ion o he s udy. Page 9 o 11 R äisänen e al., C ogen Medicine (2016), 3: 1260786 h p://dx.doi.o g/10.1080/2331205X.2016.1260786 Since physical educa ion is manda o y, we in e p e ed ha all subjec s epo ing o be s uden s pa icipa ed in schools spo s. Since he s uden s’ in gene al uppe seconda y schools and oca ional schools ha e some eedom o choose when hey pa icipa e in physical educa ion classes, i is pos- sible ha all he 18-yea -old s uden s had no pa icipa ed in PE du ing he pas 12 mon hs. Hence he a e o school spo inju ies migh be sligh ly unde es ima ed. This can be seen as a limi a ion o he s udy. Acco ding o he “sequence o p e en ion” he nex should be es ablishing ae iology and mecha- nisms o inju ies ( an Mechelen e al., 1992). The e o e in he u u e i would be bene icial o s udy in which spo s and physical ac i i ies he inju ies occu . This would p o ide u he in o ma ion o hose wo king on implemen ing inju y p e en ion me hods. To e alua e he e ec i eness o imple- men a ion measu es and p og ammes, we ecommend egula moni o ing o inju y p e alence among adolescen popula ion. 5. Conclusions This s udy sugges s ha he a e o PA- ela ed inju ies is highe in spo s club ac i i ies han in o he se ings o PA among adolescen s. Since inju y in adolescence can ha e implica ions o u u e pa - icipa ion in PA and also o u u e heal h, i is impo an o in oduce p e en a i e measu es mo e ex ensi ely, mos u gen ly o he spo s club se ing. Some cau ion should be used when in e p e ing hese esul s since his s udy is based on sel - epo ed inju ies. This s udy also sugges s ha inju y a es a e associa ed wi h PA pa icipa ion equency and in- ensi y. I is ecommended o heal h bene i s ha adolescen s pa icipa e in PA daily. Howe e ou esul s indica e ha pa icipa ing in PA as li le as 2–3 imes a week inc eases he isk o PA- ela ed inju y. Since PA pa icipa ion gene a es se e al bene i s o heal h and wellbeing, adolescen PA pa icipa ion should no be limi ed due o ea o inju y. Ins ead, he esul s o his esea ch suppo he idea ha u he p e en a i e measu es a e needed o lowe he isk o inju y in di e en se - ings. To e alua e he e ec o p e en a i e measu es, i is impo an o moni o adolescen PA- ela ed inju y p e alence and inju y se ings in egula basis. In he u u e, i is impo an o ollow PA- ela ed inju ies egula ly so ha a po en ial inc ease in inju ies can be e ealed and p e en i e measu es can be s a ed. Acknowledgemen s We hank M Lasse Pe e o he School o Heal h Sciences, Uni e si y o Tampe e, o compiling he da a, and we a e g a e ul o he s a is ical ad ice o M Ka i Tokola om he UKK Ins i u e o Heal h P omo ion Resea ch. Funding This s udy was inancially suppo ed by he Finnish Minis y o Social A ai s and Heal h (law on heal h p omo ion app op ia ion); The Finnish Minis y o Educa ion and Cul u e; The Compe i i e S a e Resea ch Funding o he Expe Responsibili y A ea o Tampe e Uni e si y Hospi al [g an numbe 9P041]; The Founda ion o Spo s Ins i u e. Compe ing In e es s The au ho s decla e no compe ing in e es s. Au ho de ails Anu M. Räisänen1 E-mail:anu. aisanen@u a. i Ja i Pa kka i 1 E-mail: ja i.pa kka i@u a. i ORCID ID: h p://o cid.o g/0000-0001-5211-9845 Lo a Ka hola 2 E-mail: ka hola.lo a.m@s uden .u a. i A ja Rimpelä 3,4 E- mail: a ja. impela@u a. i 1 Tampe e Resea ch Cen e o Spo s Medicine, UKK Ins i u e o Heal h P omo ion Resea ch, P.O. Box 30, 33501 Tampe e, Finland. 2School o Medicine, Uni e si y o Tampe e, Tampe e, Finland. 3 School o Heal h Sciences and PERLA–Tampe e Cen e o Childhood, You h and Family Resea ch, Uni e si y o Tampe e, Tampe e, Finland. 4 Depa men o Adolescen Psychia y, Tampe e Uni e si y Hospi al, Tampe e, Finland. Ci a ion in o ma ion Ci e his a icle as: Adolescen physical ac i i y- ela ed inju ies in spo s club, school spo s and o he leisu e ime physical ac i i ies, Anu M. Räisänen, Ja i Pa kka i, Lo a Ka hola & A ja Rimpelä,Cogen Medicine(2016), 3: 1260786. Au ho s’ con ibu ions A ja Rimpelä and Ja i Pa kka i ini ia ed he s udy. Anu M. Räisänen, Ja i Pa kka i, Lo a Ka hola, and A ja Rimpelä con ibu ed o he s udy concep ion and design. Anu M. Räisänen ca ied ou he li e a u e sea ch. A ja Rimpelä conduc ed he da a collec ion and pe o med he p elimina y da a p epa a ions. Anu M. Räisänen and Lo a Ka hola conduc ed he da a analyses, and all he au ho s con ibu ed o he in e p e a ion o da a. Anu M. Räisänen,