title: A 12-month prospective cohort study of injury in international rowers Lumbar load in adolescent fast bowlers: A prospective injury study. Injury risk is different in team and individual youth sport. Injury risk in professional football players with special reference to the playing position and training periodization. How Much Rugby is Too Much? A Seven-Season Prospective Cohort Study of Match Exposure and Injury Risk in Professional Rugby Union Players Does direction of results of abstracts submitted to scientific conferences on drug addiction predict full publication? Fast bowling match workloads over 5-26 days and risk of injury in the following month. The prevalence, incidence and severity of low back pain among international-level rowers Volume of physical activity and injury occurrence in young basketball players. An assessment of training volume in professional rugby union and its impact on the incidence, severity, and nature of match and training injuries The 5- or 10-km Marikenloop Run: A Prospective Study of the Etiology of Running-Related Injuries in Women. Injury history as a risk factor for incident injury in youth soccer Previous injury as a risk factor for injury in elite football: a prospective study over two consecutive seasons Injury Patterns, Physiological Profile, and Performance in University Rugby Union. The feasibility of creating a checklist for the assessment of the methodological quality both of randomised and non-randomised studies of health care interventions. Increase in ACL and PCL injuries after implementation of a new professional football league Reductions in pre-season training loads reduce training injury rates in rugby league players High chronic training loads and exposure to bouts of maximal velocity running reduce injury risk in elite Gaelic football. Injury patterns in Swedish elite athletics: annual incidence, injury types and risk factors A step towards understanding the mechanisms of running-related injuries. The NLstart2run study: Training-related factors associated with running-related injuries in novice runners. Incidence of soccer injuries and their relation to training and team success Relationship between training load and injury in professional rugby league players. Association of Injury History and Incident Injury in Cadet Basic Military Training. Risk Factors for Injury in Subelite Rugby League Players Incidence and characteristics of injuries in elite Australian junior rugby league players. Importance of Various Training-Load Measures in Injury Incidence of Professional Rugby League Athletes. Multivariate modelling of subjective and objective monitoring data improve the detection of non-contact injury risk in elite Australian footballers. Identifying high risk loading conditions for in-season injury in elite Australian football players.
abstract: Objective In this study , the injury incidence and association with type and volume of training in international rowers were described . Design A prospect i ve cohort design was used over a 12-month period . Patients 20 international rowers who were competing as part of the Irish Amateur Rowing Union squad system . Methods The rowers were interviewed monthly , and data were collected regarding their training and competition exposure as well as their injury experience . Results A mean injury rate of 3.67 per 1000 exposure hours was reported with a total of 44 injuries reported in a 12-month period . The mean number of injuries sustained per athlete was 2.2 ( 1.24 ) over the 12-month period . The area where the greatest number of injuries were reported was the lumbar spine ( 31.82 % of total injuries , 95 % CI 20 to 50 ) ( fig 2 ) followed by the knee ( 15.91 % of total injuries , 95 % CI 10 to 30 ) and the cervical spine ( 11.36 % of total injuries , 95 % CI 5 to 24 ) . Half of the injuries ( 22 injuries , 50 % of total reported injuries ) were to the spine ( χ2 = 30.8 , df = 9 , p = 0.0003 ) . Ergometer training load was the most significantly associated with injury risk ( r = 0.68 , p = 0.01 ) . Conclusion International rowers are at higher risk of injury than most non-contact sports and some contact sports . The high risk of lumbar spine injury and the significant association of high volume of ergometer training merit further research to reduce time and competition lost to injury OBJECTIVES This study aim ed to identify modifiable mechanisms associated with low back injury in adolescent cricket fast bowlers . DESIGN A prospect i ve study design examined the association between intrinsic risk factors , workload , bowling kinematics , lumbar load and low back injury incidence . METHODS Twenty-five injury free fast bowlers , aged 14 - 19 years , were assessed prior to the start of a  cricket season and observed during the season for low back injuries . RESULTS The twelve bowlers who suffered a low back injury displayed ; decreased hip flexion at front foot contact ( 46±6 ° vs 51±6 ° ) , increased pelvis rotation ( 287±11 ° vs 277±11 ° ) increased thorax lateral flexion ( 50±6 ° vs 40±8 ° ) at ball release , and larger peak lumbar flexion ( 10.5±4.9Nmkg(-1)m(-1 ) vs 6.9±2.5Nmkg(-1)m(-1 ) ) and lateral flexion moments ( 12.5±2.6Nmkg(-1)m(-1 ) vs 10.6±1.9Nmkg(-1)m(-1 ) ) . They also exhibited reduced muscular endurance of the back extensors ( 103±33s vs 132±33s ) and increased knee valgus angle during a single leg decline squat on the dominant ( 9±3 ° vs 5±4 ° ) and non-dominant leg ( 9±4 ° vs 6±3 ° ) in comparison to uninjured bowlers . CONCLUSIONS Bowlers who experience greater lumbar loads during bowling , have reduced back extensor muscle endurance , and demonstrate impaired control of the lumbo-pelvic-hip complex , are at increased risk of low back injury . This combination of strength , control and biomechanical factors may be key mechanical elements of low back injury causation in adolescent fast bowlers OBJECTIVES This study compared sports injury incidence in young high-level athletes from various team and individual sports and investigated if sport participation patterns are linked to injuries . DESIGN Prospect i ve cohort follow-up . METHODS Pupils from a public sports school ( 12 - 19 years ) were recruited over two separate school years ( 2008 - 2009 : 42 weeks , n=199 athletes ; 2009 - 2010 : 40 weeks , n=89 athletes ) .  Training and competition volume and intensity were recorded via a personal sports diary .  Sports injuries ( time-loss definition ) were registered by medical staff members using a st and ardized question naire . RESULTS Injury incidence was significantly higher in team compared with individual sports ( 6.16 versus 2.88 injuries/1000h , respectively ) , as a result of a higher incidence of both traumatic ( RR=2.17 ; CI95%=1.75 - 2.70 ; p<0.001 ) , and overuse injuries ( RR=2.06 ; CI95%=1.46 - 2.91 ; p<0.001 ) . A Cox proportional hazards regression revealed that team sports participation had a hazard ratio of 2.00 ( CI95%=1.49 - 2.68 ; p<0.001 ) compared to individual sports , with additionally previous injury being a risk and age a protective factor . The number of competitions per 100 days was significantly higher in team sports , whereas the number of intense training sessions per 100 days was significantly lower . In team sports , the number of competitions per 100 days was positively associated with injuries ( HR=1.072 ; CI95 % [ 1.033 ; 1.113 ] ; p<0.001 ) , while in individual sports the number of competitions per 100 days had a protective effect ( HR=0.940 ; CI95 % [ 0.893 ; 0.989 ] ; p=0.017 ) . CONCLUSIONS Team sports participation entailed a higher injury risk , whatever the injury category . Further research should eluci date the role of characteristics related to sport participation in injury causation AIM The aim of this study was to examine injury incidence in professional football players according to the playing positions and with a special reference to training periodization . METHODS A Spanish professional team was followed prospect ively for the 2007 - 08 and 2008 - 09 seasons and exposure times and time-loss injuries were individually recorded during all training sessions and matches .  Heart rate  was monitored in all training sessions . RESULTS total of 114 injuries were registered during the study period ( mean injury incidence : 6.6 injuries per 1000 hours ) . The frequency of injuries was not uniformly distributed by playing positions ( P<0.001 ) , as forwards and central defenders sustained the greatest number of injury episodes and the highest match absence . Ligament sprains and muscle strains accounted for 50 % of all injuries and 62 % of all match absences . The highest incidence of sprains was achieved during pre-season and the beginning of the competition period . The risk to sustain a muscular strain peaked at the beginning and in the final weeks of the competition period and was related ( r=0.72 ; P<0.05 ) to mean heart rate during the training stage . CONCLUSION The results suggest that there exists a difference of injury risk according to the period of the season and therefore , injury prevention strategies should be introduced from pre-season . Moreover , training workloads should be controlled to avoid increasing the risk of muscle strains Introduction Numerous studies have documented the incidence and nature of injuries in professional rugby union , but few have identified specific risk factors for injury in this population using appropriate statistical methods . In particular , little is known about the role of previous short-term or longer-term match exposures in current injury risk in this setting . Objectives Our objective was to investigate the influence that match exposure has upon injury risk in rugby union . Method We conducted a seven-season ( 2006/7–2012/13 ) prospect i ve cohort study of time-loss injuries in 1253 English premiership professional players . Players ’ 12-month match exposure ( number of matches a player was involved in for ≥20 min in the preceding 12 months ) and 1-month match exposure ( number of full-game equivalent [ FGE ] matches in preceding 30 days ) were assessed as risk factors for injury using a nested frailty model and magnitude-based inferences . Results The 12-month match exposure was associated with injury risk in a non-linear fashion ; players who had been involved in fewer than ≈15 or more than ≈35 matches over the preceding 12-month period were more susceptible to injury . Monthly match exposure was linearly associated with injury risk ( hazard ratio [ HR ] : 1.14 per 2 st and ard deviation [ 3.2 FGE ] increase , 90 % confidence interval [ CI ] 1.08–1.20 ; likely harmful ) , although this effect was substantially attenuated for players in the upper quartile for 12-month match exposures ( > 28 matches ) . Conclusion A player ’s accumulated ( 12-month ) and recent ( 1-month ) match exposure substantially influences their current injury risk . Careful attention should be paid to planning the workloads and monitoring the responses of players involved in : ( 1 ) a high ( > ≈35 ) number of matches in the previous year , ( 2 ) a low ( < ≈15 ) number of matches in the previous year , and ( 3 ) a low-moderate number of matches in previous year but who have played intensively in the recent past . These findings make a major contribution to evidence -based policy decisions regarding match workload limits in professional rugby union Background Data from scientific literature show that about 63 % of abstract s presented at biomedical conferences will be published in full . Some studies have indicated that full publication is associated with the direction of results ( publication bias ) . No study has looked into the occurrence of publication bias in the field of addiction . Objectives To investigate whether the significance or direction of results of abstract s presented at the major international scientific conference on addiction is associated with full publication Methods The conference proceedings of the US Annual Meeting of the College on Problems of Drug Dependence ( CPDD ) , were h and search ed for abstract s of r and omized controlled trials and controlled clinical trials that evaluated interventions for prevention , rehabilitation and treatment of drug addiction in humans ( years search ed 1993–2002 ) . Data regarding the study design s and outcomes reported were extracted . Subsequent publication in peer review ed journals was search ed in MEDLINE and EMBASE data bases , as of March 2006 . Results Out of 5919 abstract s presented , 581 met the inclusion criteria ; 359 ( 62 % ) conference abstract s had been published in a broad variety of peer review ed journals ( average time of publication 2.6 years , SD + /- 1.78 ) . The proportion of published studies was almost the same for r and omized controlled trials ( 62.4 % ) and controlled clinical trials ( 59.5 % ) while studies that reported positive results were significantly more likely to be published ( 74.5 % ) than those that did not report statistical results ( 60.9 % . ) , negative or null results ( 47.1 % ) and no results ( 38.6 % ) , Abstract s reporting positive results had a significantly higher probability of being published in full , while abstract s reporting null or negative results were half as likely to be published compared with positive ones ( HR = 0.48 ; 95%CI 0.30–0.74 ) Conclusion Clinical trials were the minority of abstract s presented at the CPDD ; we found evidence of possible publication bias in the field of addiction , with negative or null results having half the likelihood of being published than positive ones OBJECTIVES This study examined whether high match fast bowling workloads in the short to medium term were associated with increased  bowling injury rates . DESIGN Prospect i ve cohort study . METHODS Over a 15 year period ,  workload patterns for 235 individual fast bowlers during time periods from 5 to 26 days were examined to consider whether there was an increased injury rate during the month ( 28 days ) subsequent to the workload . RESULTS Fast bowlers who bowled more than 50 match overs in a 5 day period had a significant increase in injury over the next month compared to bowlers who bowled 50 overs or less RR 1.54 ( 95 % CI 1.04 - 2.29 ) . For periods ranging from 12 to 26 days , there was no statistically-significant increase in injury over the next month from exceeding thresholds of certain amounts of overs , although bowlers who bowled more than 100 overs in 17 days had a non-significant increase in injury over the next month RR 1.78 ( 95 % CI 0.90 - 3.50 ) . CONCLUSION There were no statistically-significant increases in subsequent injury risk for high workloads for periods of 12 - 26 days , although exceeding 100 overs in 17 days ( or less ) was associated with higher injury rates . Compression of cricket fixtures is likely to have only a minimal contribution to increased fast bowling injury rates being seen in the T20 era ( along with sudden workload increases due to transferring between forms of the game , which has been previously established as a major contributor ) Background / aims There is a paucity of prospect i ve cohort studies investigating the incidence of  low back pain ( LBP ) in rowing . We investigated ( 1 ) the prevalence and incidence of LBP among international-level rowers in New Zeal and , ( 2 ) the relationship between training volume and LBP and ( 3 ) the effect of LBP on rowers ’ ability to train and compete . Methods This was a prospect i ve cohort study of 76 New Zeal and representative rowers , including 46 men ( mean age 22 , SD=4 ) and 30 women ( mean age 21 , SD=4 ) . Data were collected using an online question naire repeated monthly for 12 months . Results The prevalence of LBP ranged from 6 % to 25 % throughout the year . The incidence of episodes of LBP was 1.67 per 1000 exposure-hours . A total of 72 episodes of LBP were reported by 40 rowers ( 53 % ) during 12 months . Of these , 45 % had an incidental effect on training . 29 % minor , 18 % moderate and 9 % had a major effect as determined by the length of time the training was interrupted . There was a high correlation between new LBP and total training hours per month ( r=0.83 , p<0.01 ) . A previous history of LBP was a risk factor in developing new LBP ( OR 2.06 , 95 % CI 1.22 to 3.48 , p=0.01 ) . Age was also a risk factor , with the likelihood of developing LBP increasing for every year ( OR 1.08 , 95 % CI 1.01 to 1.15 , p=0.02 ) . Conclusions LBP is common among New Zeal and representative rowers . There is a high correlation between training load and the development of LBP Participation in organised , competitive physical activity by young athletes is increasing rapidly . This is concurrent with an increase in sporting injuries in the young population . This pilot study aim ed to compare the weekly volume and types of physical activity in young basketball players injured and not injured during the season . Detailed physical activity and injury data were prospect ively collected in 46 school-level basketball players aged 14 to 18 years . Participants completed physical activity logs which documented the type of physical activity undertaken , what the activity consisted of ( i.e. training , competition ) and the level at which it was played on a daily basis . Allied health staff completed a weekly injury form . Results showed that injured and uninjured athletes participated in a similar volume of total weekly physical activity over the season . However , injured athletes ( p = 0.04 ) and athletes who specifically sustained overuse injuries ( p = 0.01 ) participated in a greater amount of basketball refereeing than uninjured athletes . Based on these findings it was concluded that greater participation in running-type physical activity such as refereeing , as an addition to training and competition , may predispose the young basketball player to increased injury risk . Future research using larger sample sizes are required to further investigate the role of participation volume and type on injury occurrence in adolescent athletes . Key pointsBasketball players participating in larger amounts of running-type physical activity , in addition to regular training and competition , may be predisposed to overuse injuryFuture studies using larger sample sizes are required to investigate the precise volumes of physical activity that increase injury riskThis would assist in the development of participation guidelines to decrease the current injury rates observed in the young athletic population Abstract A prospect i ve cohort study was used to assess the influence of training volume on injuries sustained by 502 professional rugby union players in Engl and . Training volumes ( excluding warm-ups , cool-downs , and recovery sessions ) , player injuries , and player match exposure times were reported weekly . Higher training volumes ( > 9.1 hours per week ) did not increase the incidence of match or training injuries . However , higher training volumes did increase the severity of match injuries , particularly during the second half , and consequently result ed in a significant increase in the number of days ' absence due to match injuries . Although lower-limb injuries were the most common match and training injuries , shoulder dislocations/instabilities result ed in more days ' absence during weeks of higher training volumes , but the differences were not significant . The least number of days lost due to injuries occurred during weeks of intermediate training volumes ( 6.2–9.1 h per week ) . Training volume was not correlated with final league position . Fitness testing , defence , and rucking and mauling components were identified as being very high- or high-risk training activities . Our results provide evidence of the benefits of modifying the volume and content of rugby union training to reduce the risk associated with injuries to professional players Study Design Prospect i ve cohort . Background The popularity of running events is still growing , particularly among women ; however , little is known about the risk factors for running-related injuries in female runners . Objectives The aims of this study were to determine the incidence and characteristics ( site and recurrence ) of running-related injuries and to identify specific risk factors for running-related injuries among female runners training for a 5- or 10-km race . Methods Four hundred thirty-five women registered for the Marikenloop run of 5 or 10 km were recruited . Follow-up data were collected over 12 weeks using question naires , starting 8 weeks before the event and ending 4 weeks after the event . Two orthopaedic tests ( navicular drop test and extension of the first metatarsophalangeal joint ) were performed in the 8 weeks before the event . Running-related injuries , defined as running-related pain of the lower back and /or the lower extremity that restricted running for at least 1 day , were assessed at 1- , 2- , and 3-month follow-ups . Results Of 417 female runners with follow-up data ( 96 % ) , 93 runners ( 22.3 % ) reported 109 running-related injuries , mainly of the hip/groin , knee , and lower leg . Multivariable Cox regression analysis showed that a weekly training distance of more than 30 km ( hazard ratio = 3.28 ; 95 % confidence interval [ CI ] : 1.23 , 8.75 ) and a previous running injury longer than 12 months prior ( hazard ratio = 1.88 ; 95 % CI : 1.03 , 3.45 ) were associated with the occurrence of running-related injuries . Conclusion Hip/groin , knee , and lower-leg injuries were common among female runners . Only weekly training distance ( greater than 30 km ) and previous running injury ( greater than 12 months prior ) were associated with running-related injuries in female runners training for a 5- or 10-km event . Level of Evidence Etiology , 2b . J Orthop Sports Phys Ther 2016;46(6):462 - 470 . Epub 26 Apr 2016 . doi:10.2519/jospt.2016.6402 Objectives : To determine if athletes with a self reported history of previous injury have a higher incident injury rate than athletes without a self reported injury history . Methods : A prospect i ve cohort study of Classic League soccer players playing at the level under 12 through under 18 .  Injury history forms were mailed to all registering Classic League soccer players in the North Carolina Youth Soccer Association during 1997–2000 ( n = 7000 ) ; 1483 ( 19 % ) returned the baseline question naire and were followed up for injuries . Results : There were 5139 player-seasons of follow up and an estimated 171 957 athlete-exposures . More than half self reported an injury history ( 59.7 % ) . Overall , the unadjusted incidence rate was 4.6 ( 95 % confidence interval ( CI ) 4.3 to 4.9 ) incident injuries per 1000 athlete-exposures . Multivariate generalised Poisson regression modelling indicated that players with one previous injury had a twofold greater risk of incident injury ( IRR = 2.6 ; 95 % CI 2.0 to 3.3 ) , and those with two or more previous injuries had a threefold greater risk of incident injury ( IRR = 3.0 ; 95 % CI 2.3 to 3.8 ) compared with athletes with no previous injuries . Conclusions : Injury history was associated with an increased injury rate . This suggests that , even in these youth soccer players , those with an injury history may be at higher risk Background : Previous injury is often proposed to be a risk factor for football injury , but most studies rely on players reporting their own medical history and are thus potentially subject to recall bias . Little is known about the natural variation in injury pattern between seasons . Objectives : To study whether prospect ively recorded injuries during one season are associated with injuries sustained during the following season , and to compare injury risk and injury pattern between consecutive seasons . Methods : The medical staffs of 12 elite Swedish male football teams prospect ively recorded  individual exposure and time loss injuries over two full consecutive seasons ( 2001 and 2002 ) . A multivariate model was used to determine the relation between previous injury , anthropometric data , and the risk of injury . Results : The training and match injury incidences were similar between seasons ( 5.1 v 5.3 injuries/1000 training hours and 25.9 v 22.7/1000 match hours ) , but analysis of injury severity and injury patterns showed variations between seasons . Players who were injured in the 2001 season were at greater risk of any injury in the following season compared with non-injured players ( hazard ratio 2.7 ; 95 % confidence interval 1.7 to 4.3 , p<0.0001 ) . Players with a previous hamstring injury , groin injury , and knee joint trauma were two to three times more likely to suffer an identical injury in the following season , whereas no such relation was found for ankle sprain . Age was not associated with an increased injury risk . Conclusions : This study confirmed previous results showing that previous injury is an important risk factor for football injury . Overall injury incidences were similar between consecutive seasons , indicating that an injury surveillance study covering one full season can provide a reasonable overview of the injury problem among elite football players in a specific environment . However , a prolonged study period is recommended for analyses of specific injury patterns CONTEXT Rugby union is a physically dem and ing collision sport with high injury rates . There is a common perception that higher training loads result in greater injury risk in field-based sports . OBJECTIVES To determine injury , anthropometric , and physical-performance characteristics in junior rugby union players and investigate the interaction between training load and injury across a competitive season . DESIGN Prospect i ve cohort study . METHODS Fifty-one players ( age 19.2 ± 0.7 y ) from an under-20 university rugby union team ( forwards , n = 27 ; backs , n = 24 ) participated in a study conducted over a competition season . Training load , injury characteristics , anthropometry , physiological performance , and match time-loss injury incidence were observed . RESULTS Backs had significantly lower body mass ( ES [ 95 % CI ] = 1.6 [ 0.9 , 2.2 ] ) , skinfold thickness ( ES = 1.1 [ 0.5 , 1.7 ] ) , strength ( squat ES = 0.6 [ 0.0 , 1.2 ] , deadlift ES = 0.6 [ 0.0 , 1.1 ] , bench press ES = 0.9 [ 0.4 , 1.5 ] ) , lower-body power ( ES = 0.4 [ -0.2 , 1.0 ] ) , and higher maximal aerobic capacity ( ES = -0.3 [ -0.8 , 0.3 ] ) than forwards . Match injury incidence was 107.3 injuries/1000 player hours ( forwards 91.4/1000 , backs 125.5/1000 ) during preseason and 110.7 injuries/1000 player hours ( forwards 124.1/1000 , backs 95.2/1000 ) during in-season . Forwards showed higher incidence of joint and ligament ( P = .049 ) and upper-limb ( P = .011 ) injuries than backs . No significant relationship between overall training load and match injury incidence was found . However , lower match injury incidence was associated with higher weekly training volume in backs ( P = .007 ) . CONCLUSIONS Positional differences in body composition , performance , injury characteristics , and match injury patterns were identified in junior university rugby union players , indicating the need for position-specific training programs to reduce risk of injury OBJECTIVE : To test the feasibility of creating a valid and reliable checklist with the following features : appropriate for assessing both r and omised and non-r and omised studies ; provision of both an overall score for study quality and a profile of scores not only for the quality of reporting , internal validity ( bias and confounding ) and power , but also for external validity . DESIGN : A pilot version was first developed , based on epidemiological principles , review s , and existing checklists for r and omised studies . Face and content validity were assessed by three experienced review ers and reliability was determined using two raters assessing 10 r and omised and 10 non-r and omised studies . Using different raters , the checklist was revised and tested for internal consistency ( Kuder-Richardson 20 ) , test-retest and inter-rater reliability ( Spearman correlation coefficient and sign rank test ; kappa statistics ) , criterion validity , and respondent burden . MAIN RESULTS : The performance of the checklist improved considerably after revision of a pilot version . The Quality Index had high internal consistency ( KR-20 : 0.89 ) as did the subscales apart from external validity ( KR-20 : 0.54 ) . Test-retest ( r 0.88 ) and inter-rater ( r 0.75 ) reliability of the Quality Index were good . Reliability of the subscales varied from good ( bias ) to poor ( external validity ) . The Quality Index correlated highly with an existing , established instrument for assessing r and omised studies ( r 0.90 ) . There was little difference between its performance with non-r and omised and with r and omised studies . Raters took about 20 minutes to assess each paper ( range 10 to 45 minutes ) . CONCLUSIONS : This study has shown that it is feasible to develop a checklist that can be used to assess the method ological quality not only of r and omised controlled trials but also non-r and omised studies . It has also shown that it is possible to produce a checklist that provides a profile of the paper , alerting review ers to its particular method ological strengths and weaknesses . Further work is required to improve the checklist and the training of raters in the assessment of external validity Abstract Purpose In the season 2008–2009 , a third professional football league was established in Germany . This study analysed the influence of increased training and playing intensity on severe knee injuries in football players . Methods In a prospect i ve controlled one-season trial , injury incidence and injury patterns of players of the newly established professional football league were analysed , particularly with regard to ruptures of the anterior ( ACL ) and posterior ( PCL ) cruciate ligaments . Players of the highest amateur level served as a control group . Results Four hundred and eight players of 24 teams were allocated to two groups . The overall training exposure was significantly ( p < 0.001 ) higher in the new professional league ( 335.3 h per player ) than at the amateur level ( 286.6 h per player ) . Players at both levels showed similar overall injury rates and injury patterns . However , players in the professional league had a significantly higher ( p = 0.04 ) incidence of ACL and PCL injuries , than players at the amateur level . More than 90 % of all ACL and PCL ruptures in both groups were sustained by players , who had played at least one level lower in the previous season . In addition , injuries of players who had sustained repeat injuries over the season were more severe . Conclusion The introduction of a new professional football league increased the training and playing intensity of players as well as the number of ACL and PCL ruptures . A specific injury prevention concept , particularly for players facing rapidly increasing training and playing intensity , seems to be m and atory . Level of evidence Prospect i ve controlled cohort study , Level II Objectives : To investigate if reductions in pre-season training loads reduced the incidence of training injuries in rugby league players , and to determine if the reductions in training loads compromised the improvements in physical fitness obtained during the pre-season preparation period . Methods : A total of 220 sub-elite rugby league players participated in this 3 year prospect i ve study . Players underwent measurements of speed , muscular power , and maximal aerobic power before and after three 4 month ( December to March ) pre-season preparation periods ( 2001–2003 ) . A periodised skills and conditioning program was implemented , with training loads progressively increased in the general preparatory phase of the season ( December to February ) and reduced slightly in March in preparation for the competitive phase of the season . Training loads were calculated by multiplying the training session intensity by the duration of the training session . Following the initial season ( 2001 ) , training loads were reduced through reductions in training duration ( 2002 ) and training intensity ( 2003 ) . The incidence of injury was prospect ively recorded over the three pre-season periods . Results : The training loads for the 2002 and 2003 pre-season periods were significantly lower ( p<0.001 ) than those in 2001 . The incidence of injury was significantly higher in the 2001 pre-season than the 2002 and 2003 pre-season periods . The increases in maximal aerobic power progressively improved across the three seasons with a 62–88 % probability that the 2002 and 2003 pre-season improvements in maximal aerobic power were of greater physiological significance than the 2001 pre-season improvements in maximal aerobic power . Conclusions : These findings demonstrate that reductions in pre-season training loads reduce training injury rates in rugby league players and result in greater improvements in maximal aerobic power OBJECTIVES To examine the relationship between chronic training loads , number of exposures to maximal velocity , the distance covered at maximal velocity , percentage of maximal velocity in training and match-play and subsequent injury risk in elite Gaelic footballers . DESIGN Prospect i ve cohort design . METHODS Thirty-seven elite Gaelic footballers from one elite squad were involved in a one-season study . Training and game loads ( session-RPE multiplied by duration in min ) were recorded in conjunction with external match and training loads ( using global positioning system technology ) to measure the distance covered at maximal velocity , relative maximal velocity and the number of player exposures to maximal velocity across weekly periods during the season . Lower limb injuries were also recorded . Training load and GPS data were modelled against injury data using logistic regression . Odds ratios ( OR ) were calculated based on chronic training load status , relative maximal velocity and number of exposures to maximal velocity with these reported against the lowest reference group for these variables . RESULTS Players who produced over 95 % maximal velocity on at least one occasion within training environments had lower risk of injury compared to the reference group of 85 % maximal velocity on at least one occasion ( OR : 0.12 , p=0.001 ) . Higher chronic training loads ( ≥4750AU ) allowed players to tolerate increased distances ( between 90 to 120 m ) and exposures to maximal velocity ( between 10 to 15 exposures ) , with these exposures having a protective effect compared to lower exposures ( OR : 0.22 p=0.026 ) and distance ( OR=0.23 , p=0.055 ) . CONCLUSIONS Players who had higher chronic training loads ( ≥4750AU ) tolerated increased distances and exposures to maximal velocity when compared to players exposed to low chronic training loads ( ≤4750AU ) . Under- and over-exposure of players to maximal velocity events ( represented by a U-shaped curve ) increased the risk of injury Objective To estimate the incidence , type and severity of musculoskeletal injuries in youth and adult elite athletics athletes and to explore risk factors for sustaining injuries . Design Prospect i ve cohort study conducted during a 52-week period . Setting Male and female youth and adult athletics athletes ranked in the top 10 in Sweden ( n=292 ) . Results 199 ( 68 % ) athletes reported an injury during the study season . Ninety-six per cent of the reported injuries were non-traumatic ( associated with overuse ) . Most injuries ( 51 % ) were severe , causing a period of absence from normal training exceeding 3 weeks . Log-rank tests revealed risk differences with regard to athlete category ( p=0.046 ) , recent previous injury ( > 3 weeks time-loss ; p=0.039 ) and training load rank index ( TLRI ; p=0.019 ) . Cox proportional hazards regression analyses showed that athletes in the third ( HR 1.79 ; 95 % CI 1.54 to 2.78 ) and fourth TLRI quartiles ( HR 1.79 ; 95 % CI 1.16 to 2.74 ) had almost a twofold increased risk of injury compared with their peers in the first quartile and interaction effects between athlete category and previous injury ; youth male athletes with a previous serious injury had more than a fourfold increased risk of injury ( HR=4.39 ; 95 % CI 2.20 to 8.77 ) compared with youth females with no previous injury . Conclusions The injury incidence among both youth and adult elite athletics athletes is high . A training load index combing hours and intensity and a history of severe injury the previous year were predictors for injury . Further studies on measures to quantify training content and protocol s for safe return to athletics are warranted OBJECTIVES To investigate the association between training-related characteristics and running-related injury using a new conceptual model for running-related injury generation , focusing on the synergy between training load and previous injuries , short-term running experience or body mass index ( > or < 25 kg m(-2 ) ) . DESIGN Prospect i ve cohort study with a 9-month follow-up . METHODS The data of two previous studies using the same methodology were revisited . Recreational runners ( n = 517 ) reported information about running training characteristics ( weekly distance , frequency , speed ) , other sport participation and injuries on a dedicated internet platform  . Weekly volume ( dichotomized into < 2h and ≥ 2 h ) and session frequency ( dichotomized into < 2 and ≥ 2 ) were the main exposures because they were considered necessary causes for running-related injury . Non-training-related characteristics were included in Cox regression analyses as effect-measure modifiers . Hazard ratio was the measure of association . The size of effect-measure modification was calculated as the relative excess risk due to interaction . RESULTS One hundred sixty-seven runners reported a running-related injury . Crude analyses revealed that weekly volume < 2h ( hazard ratio = 3.29 ; 95 % confidence intervals = 2.27 ; 4.79 ) and weekly session frequency < 2 ( hazard ratio = 2.41 ; 95 % confidence intervals = 1.71 ; 3.42 ) were associated with increased injury rate . Previous injury was identified as an effect-measure modifier on weekly volume ( relative excess risk due to interaction = 4.69 ; 95 % confidence intervals = 1.42 ; 7.95 ; p = 0.005 ) and session frequency ( relative excess risk due to interaction = 2.44 ; 95 % confidence intervals = 0.48 ; 4.39 ; p = 0.015 ) . A negative synergy was found between body mass index and weekly volume ( relative excess risk due to interaction = -2.88 ; 95 % confidence intervals = -5.10 ; -0.66 ; p = 0.018 ) . CONCLUSIONS The effect of a runner 's training load on running-related injury is influenced by body mass index and previous injury . These results show the importance to distinguish between confounding and effect-measure modification in running-related injury research OBJECTIVES The incidence of running-related injuries is high . Some risk factors for injury were identified in novice runners , however , not much is known about the effect of training factors on injury risk . Therefore , the purpose of this study was to examine the associations between training factors and running-related injuries in novice runners , taking the time varying nature of these training-related factors into account . DESIGN Prospect i ve cohort study . METHODS 1696 participants completed weekly diaries on running exposure and injuries during a 6-week running program for novice runners .  Total running volume ( min ) , frequency and mean intensity ( Rate of Perceived Exertion )  were calculated for the seven days prior to each training session . The association of these time-varying variables with injury was determined in an extended Cox regression analysis . RESULTS The results of the multivariable analysis showed that running with a higher intensity in the previous week was associated with a higher injury risk . Running frequency was not significantly associated with injury , however a trend towards running three times per week being more hazardous than two times could be observed . Finally , lower running volume was associated with a higher risk of sustaining an injury . CONCLUSIONS These results suggest that running more than 60min at a lower intensity is least injurious . This finding is contrary to our expectations and is presumably the result of other factors . Therefore , the findings should not be used plainly as a guideline for novices . More research is needed to establish the person-specific training patterns that are associated with injury One hundred-eighty players in a male soccer senior division of 12 teams were observed prospect ively for 1 year to study the risk of soccer injuries in relation to exposure and to establish the connection between training , injuries , and team success . Totally , more than 100 hours of practice were analyzed . All injuries were examined by the same orthopaedic surgeon . On the average , each team played 36 games and had 95 practice sessions with 66 % attendance of selected players . A direct correlation was noted be tween team success and the amount of training . Teams with more than average training showed a diminishing number of injuries . A high practice -to- game ratio seems to be advantageous . One injury every third game and every ninth practice session was documented . For the individual player the incidence of injury was 7.6/1000 practice hours and 16.9/1000 game hours . The incidence of injury was higher at training camps . Correlation was noted between the design of the train ing and the incidence of injuries . The duration of warming up seemed adequate , but its content did not appear to be satisfactory from a clinical point of view . Re design of the warm-up with more emphasis on flexibility and the addition of a cool-down is suggested to reduce injuries OBJECTIVES To investigate the relationship between training load and injury in professional rugby league players ; DESIGN Prospect i ve cohort study ; METHODS Seventy-nine professional rugby league players ( mean±SD age , 23.3±3.8 years ) participated in this four-year study . A periodized field , strength , and power training program was implemented , with training loads progressively increased in the general preparatory phase of the season and reduced during the competitive phase of the season . Training loads and injuries were recorded for each training session . RESULTS Training load was significantly related ( P<0.05 ) to overall injury ( r=0.82 ) , non-contact field injury ( r=0.82 ) , and contact field injury ( r=0.80 ) rates . Significant relationships were also observed between the field training load and overall field injury ( r=0.68 ) , non-contact field injury ( r=0.65 ) , and contact field injury ( r=0.63 ) rates . Strength and power training loads were significantly related to the incidence of strength and power injuries ( r=0.63 ) . There was no significant relationship between field training loads and the incidence of strength and power injuries . However , strength and power training loads were significantly ( P<0.01 ) associated with the incidence of contact ( r=0.75 ) and non-contact ( r=0.82 ) field training injuries . CONCLUSIONS These findings suggest that the harder rugby league players train , the more injuries they will sustain , and that high strength and power training loads may contribute indirectly to field injuries . Monitoring of training loads and careful scheduling of field and gymnasium sessions to avoid residual fatigue is warranted to minimize the effect of training-related injuries on professional rugby league players PURPOSE This study aim ed to determine the association between injury history at enrollment and incident lower extremity ( LE ) injury during cadet basic training among first-year military cadets . METHODS Medically treated LE injuries during cadet basic training documented in the Defense Medical Surveillance System were ascertained in a prospect i ve cohort study of three large US military academies from 2005 to 2008 . Both acute injuries ( International Classification of Disease , Ninth Revision , codes in the 800 - 900s , including fracture , dislocations , and sprains/strains ) and injury-related musculoskeletal injuries ( International Classification of Disease , Ninth Revision , codes in the 700s , including inflammation and pain , joint derangement , stress fracture , sprain/strain/rupture , and dislocation ) were included . Risk ratio ( RR ) and 95 % confidence interval ( CI ) were computed using multivariate log-binomial models stratified by gender . RESULTS During basic training , there were 1438 medically treated acute and 1719 musculoskeletal-related LE injuries in the 9811 cadets . The most frequent LE injuries were sprains/strains ( 73.6 % of acute injuries ) and inflammation and pain ( 89.6 % of musculoskeletal-related injuries ) . The overall risk of incident LE injury was 23.2 % ( 95 % CI = 22.3%-24.0 % ) . Cadets with a history of LE injury were at increased risk for incident LE injury . This association was identical in males ( RR = 1.74 , 95 % CI = 1.55 - 1.94 ) and females ( RR = 1.74 , 95 % CI = 1.52 - 1.99 ) . In site-specific analyses , strong associations between injury history and incident injury were observed for hip , knee ligament , stress fracture , and ankle sprain . Injury risk was greater ( P < 0.01 ) for females ( 39.1 % ) compared with males ( 18.0 % ) . The elevated injury risk in females ( RR = 2.19 , 95 % CI = 2.04 - 2.36 ) was independent of injury history ( adjusted RR = 2.09 , 95 % CI = 1.95 - 2.24 ) . CONCLUSION Injury history upon entry to the military is associated with the incidence of LE injuries sustained during cadet basic training . Prevention programs targeted at modifiable factors in cadets with a history of LE injury should be considered Background Although player fatigue and playing intensity have been suggested to contribute to injuries in rugby league players , no study has confirmed if the level of physical fitness is a risk factor for injury in rugby league players . The aim of this study was to identify risk factors for injury in subelite rugby league players . Hypothesis Low physical fitness levels are risk factors for injury in subelite rugby league players . Study Design Cohort study ; Level of evidence , 2 . Methods One hundred fifty-three players from a subelite rugby league club underwent preseason measurements of muscular power ( vertical jump ) , speed ( 10- and 40-m sprint ) , and maximal aerobic power ( multistage fitness test ) over 4 competitive seasons . All injuries sustained by players were prospect ively recorded over the 4 competitive seasons . Results The risk of injury was greater in players with low 10- and 40-m speed . Players with a low maximal aerobic power had a greater risk of sustaining a contact injury . In addition , players who completed less than 18 weeks of training before sustaining their initial injuries were at greater risk of sustaining a subsequent injury . Conclusions Subelite rugby league players with low speed and maximal aerobic power are at an increased risk of injury . In addition , players who complete less than 18 weeks of training before sustaining an initial injury are at greater risk of sustaining a subsequent injury . These findings highlight the importance of speed and endurance training to reduce the incidence of injury in subelite rugby league players OBJECTIVES Rugby league ( RL ) is a physically dem and ing collision sport , yet few studies describe injuries at the junior level despite their potential impact on career pathways and long-term health . With the absence of an injury surveillance paradigm in junior competition , this study aim ed to investigate injury incidence in an Australian setting . DESIGN Prospect i ve cohort study . METHODS A set of injury surveillance forms were developed and used to record injury characteristics , mechanism , severity and follow-up throughout one season . RESULTS Junior RL players ( n=368 , age : 15.8±1.0 years ) from 15 clubs provided baseline information . Of these , approximately six clubs ( n=122 ) provided longitudinal injury data . A total of 109 injuries ( 90 % match-related ) were recorded , with the tackle accounting for 61 % . Injury incidence ( 37.1 injuries per 1000 match hours ) was consistent with previous literature . Most injuries did not result in missed matches . The ankle and head/face were most frequently injured ( both 13 % ) , with ankle injuries leading to the highest losses of match-play . Contusions were common ( 38 % ) , although ligament injuries caused the greatest match-play losses . Injury site significantly differed between forwards and backs ( p=0.003 ) , with forwards sustaining more head/face and sternum injuries , and backs more ankle injuries . Injury type ( p=0.25 ) and severity ( p=0.09 ) were similar between positions . CONCLUSIONS Given the ongoing biological maturation in adolescent players and the injury risks related to RL , playing intensity , training regimes and injury incidence warrant rigorous documentation and monitoring . This study argues for functional but low-burden injury surveillance systems ( e.g. electronic platforms ) to be developed and implemented in junior RL PURPOSE To investigate the ability of various internal and external training-load ( TL ) monitoring measures to predict injury incidence among positional groups in professional rugby league athletes . METHODS TL and injury data were collected across 3 seasons ( 2013 - 2015 ) from 25 players competing in National Rugby League competition . Daily TL data were included in the analysis , including  session rating of perceived exertion ( sRPE-TL ) , total distance ( TD ) , high-speed-running distance ( > 5 m/s ) , and high-metabolic-power distance ( HPD ; > 20 W/kg ) . Rolling sums were calculated , nontraining days were removed , and athletes ' corresponding injury status was marked as " available " or " unavailable . " Linear ( generalized estimating equations ) and nonlinear ( r and om forest ; RF ) statistical methods were adopted . RESULTS Injury risk factors varied according to positional group . For adjustables , the TL variables associated most highly with injury were 7-d TD and 7-d HPD , whereas for hit-up forwards they were sRPE-TL ratio and 14-d TD . For outside backs , 21- and 28-d sRPE-TL were identified , and for wide-running forwards , sRPE-TL ratio . The individual RF models showed that the importance of the TL variables in injury incidence varied between athletes . CONCLUSIONS Differences in risk factors were recognized between positional groups and individual athletes , likely due to varied physiological capacities and physical dem and s. Furthermore , these results suggest that robust machine-learning techniques can appropriately monitor injury risk in professional team-sport athletes OBJECTIVES To assess the association between workload , subjective wellness , musculoskeletal screening measures  and non-contact injury risk in elite Australian footballers . DESIGN Prospect i ve cohort study . METHODS Across 4 seasons in 70 players from one club , cumulative weekly workloads ( acute ; 1 week , chronic ; 2- , 3- , 4-week ) and acute : chronic workload ratio 's ( ACWR : 1-week load/average 4-weekly load ) for session-Rating of Perceived Exertion ( sRPE ) and GPS-derived distance and sprint distance were calculated . Wellness , screening and non-contact injury data were also documented . Univariate and multivariate regression models determined injury incidence rate ratios ( IRR ) while accounting for interaction/moderating effects . Receiver operating characteristics determined model predictive accuracy ( area under curve : AUC ) . RESULTS Very low cumulative chronic ( 2- , 3- , 4- week ) workloads were associated with the greatest injury risk ( univariate IRR=1.71 - 2.16 , 95 % CI=1.10 - 4.52 ) in the subsequent week . In multivariate analysis , the interaction between a low chronic load and a very high distance ( adj-IRR=2.60 , 95 % CI=1.07 - 6.34 ) or low sRPE ACWR ( adj-IRR=2.52 , 95 % CI=1.01 - 6.29 ) was associated with increased injury risk . Subjectively reporting " yes " ( vs. " no " ) for old lower limb pain and heavy non-football activity in the previous 7 days ( multivariate adj-IRR=2.01 - 2.25 , 95 % CI=1.02 - 4.95 ) and playing experience ( > 9 years ) ( multivariate adj-IRR=2.05 , 95 % CI=1.03 - 4.06 ) was also associated with increased injury risk , but screening data were not . Predictive capacity of multivariate models was significantly better than univariate ( AUCmultivariate=0.70 , 95 % CI 0.64 - 0.75 ; AUCunivariate range=0.51 - 0.60 ) . CONCLUSIONS Chronic load is an important moderating factor in the workload-injury relationship . Low chronic loads coupled with low or very high ACWR are associated with increased injury risk OBJECTIVES To examine different timeframes for calculating acute to chronic workload ratio ( ACWR ) and whether this variable is associated with intrinsic injury risk in elite Australian football players . DESIGN Prospect i ve cohort study . METHODS Internal ( session rating of perceived exertion : sRPE ) and external ( GPS distance and sprint distance ) workload and injury data were collected from 70 players from one AFL club over 4 seasons . Various acute ( 1 - 2 weeks ) and chronic ( 3 - 8 weeks ) timeframes were used to calculate ACWRs : these and chronic load categories were then analysed to determine the injury risk in the subsequent month . Poisson regression with robust errors within a generalised estimating equation were utilised to determine incidence rate ratios ( IRR ) . RESULTS Altering acute and /or chronic timeframes did not improve the ability to detect high injury risk conditions above the commonly used 1:4 week ACWR . Twenty-seven ACWR/chronic load combinations were found to be " high risk conditions " ( IRR>1 , p<0.05 ) for injury within 7 days . Most ( 93 % ) of these conditions occurred when chronic load was low or very low and ACWR was either low ( < 0.6 ) or high ( > 1.5 ) . Once a high injury risk condition was entered , the elevated risk persisted for up to 28 days . CONCLUSIONS Injury risk was greatest when chronic load was low and ACWR was either low or high . This heightened risk remained for up to 4 weeks . There was no improvement in the ability to identify high injury risk situations by altering acute or chronic time periods from 1:4 weeks
target: Conclusions Our results demonstrate that the existence of a relationship between training load and injury continues to be well supported in the literature and is strongest for subjective internal training load .
  The directionality of this relationship appears to depend on the type and timeframe of load measured
background: Background The relationship between training load and musculoskeletal injury is a rapidly advancing area of research in need of an up date d systematic review .