title: Risk factors of acute and overuse musculoskeletal injuries among young conscripts: a population-based cohort study The Association of Hip Strength and Flexibility with the Incidence of Adductor Muscle Strains in Professional Ice Hockey Players * Effect on injuries of assigning shoes based on foot shape in air force basic training. A prospective cohort study of hamstring injuries in competitive sprinters: preseason muscle imbalance as a possible risk factor Intrinsic risk factors for exercise-related injuries among male and female army trainees Injury rates and injury risk factors among federal bureau of investigation new agent trainees Ability of Preseason Body Composition and Physical Fitness to Predict the Risk of Injury in Male Collegiate Hockey Players Cigarette smoking, physical fitness, and injuries in infantry soldiers. Contralateral risk factors associated with exertional medial tibial pain in women. Injury Reduction Effectiveness of Selecting Running Shoes Based on Plantar Shape Core stability measures as risk factors for lower extremity injury in athletes. Overuse injuries in female infantry recruits during low-intensity basic training. What Risk Factors Are Associated With Musculoskeletal Injury in US Army Rangers? A Prospective Prognostic Study Risk factors for bone stress injuries: a follow-up study of 102,515 person-years. Intrinsic risk factors for inversion ankle sprains in females--a prospective study. Intrinsic Risk Factors of Noncontact Ankle Sprains in Soccer Emergency Department Visits Among Pediatric Patients for Sports-related Injury: Basic Epidemiology and Impact of Race/Ethnicity and Insurance Status Identifying risk factors for contact injury in professional rugby league players--application of a frailty model for recurrent injury. Injuries and injury risk factors among British army infantry soldiers during predeployment training
abstract: Background Military service in Finl and is compulsory for all male citizens and annually about 80 % of 19-year-old men enter into the service . The elevated risk for many chronic diseases and loss of function among those who are inactive and unfit can be often detected already in youth . On the other h and , activity-induced injuries among young are true public health issue . The purpose of the present prospect i ve cohort follow-up study was to evaluate predictive associations between acute or overuse injuries and their various intrinsic risk factors . Methods Four successive cohorts of conscripts who formed a representative sample of Finnish young men were followed for 6 months . At the beginning of the service , the risk factors of injuries were measured and recorded and then the acute and overuse injuries treated at the garrison clinic were identified . Predictive associations between injuries and their risk factors were examined by multivariate Cox ’s proportional hazard models . Results Of the 1411 participants , 27 % sustained an acute injury and 51 % suffered from overuse injury . Concerning acute injuries , highest risk for severe injuries were detected among conscripts with low fitness level in both the st and ing long-jump and push-up tests ( hazard rate , HR=5.9 ; 95 % CI : 1.6‒21.3 ) . A history of good degree in school sports was not a protective factor against acute injuries . High waist circumference and , on the other h and , being underweight according to BMI increased the HR for overuse injuries . Brisk leisure time physical activity before military entry was a protective factor against overuse injuries . Poor result in Cooper ’s test was a warning signal of elevated risk of overuse injuries . Conclusion We confirmed previous findings that low level of physical fitness is predictor for musculoskeletal injuries during intensive physical training . The U-shaped relationship between body composition and overuse injuries was noticed indicating that both obesity and underweight are risk factors for overuse injuries . Persons with excellent sports skills according to their earlier degrees in school sports had similar HR for acute injuries than those with poorer degrees . This indicates that school-age sports skills and fitness do not carry far and therefore preventive programmes are needed to prevent activity-induced injuries This prospect i ve study was conducted to determine whether hip muscle strength and flexibility play a role in the incidence of adductor and hip flexor strains in National Hockey League ice hockey team players .  Hip flexion , abduction , and adduction strength were measured in 81 players before two consecutive seasons . Thirty-four players were cut , traded , or sent to the minor league before the beginning of the season . Injury and individual exposure data were recorded for the remaining 47 players . Eight players experienced 11 adductor muscle strains , and there were 4 hip flexor strains . Preseason hip adduction strength was 18 % lower in the players who subsequently sustained an adductor muscle strain compared with that of uninjured players . Adduction strength was 95 % of abduction strength in the uninjured players but only 78 % of abduction strength in the injured players . Preseason hip adductor flexibility was not different between players who sustained adductor muscle strains and those who did not . These results indicate that preseason hip strength testing of professional ice hockey players can identify players at risk of developing adductor muscle strains . A player was 17 times more likely to sustain an adductor muscle strain if his adductor strength was less than 80 % of his abductor strength BACKGROUND This study examined whether assigning running shoes based on the shape of the bottom of the foot ( plantar surface ) influenced injury risk in Air Force Basic Military Training ( BMT ) and examined risk factors for injury in BMT . METHODS Data were collected from  BMT recruits during 2007 ; analysis took place during 2008 . After foot examinations , recruits were r and omly consigned to either an  experimental group ( E , n=1042 men , 375 women ) or a control group ( C , n=913 men , 346 women ) . Experimental group recruits were assigned motion control , stability , or cushioned shoes for plantar shapes indicative of low , medium , or high arches , respectively . Control group recruits received a stability shoe regardless of plantar shape .  Injuries during BMT were determined from outpatient visits provided from the Defense Medical Surveillance System . Other injury risk factors ( fitness , smoking , physical activity , prior injury , menstrual history , and demographics ) were obtained from a question naire , existing data bases , or BMT units . RESULTS Multivariate Cox regression controlling for other risk factors showed little difference in injury risk between the groups among men ( hazard ratio [E/C]=1.11 , 95 % CI=0.89 - 1.38 ) or women ( hazard ratio [E/C]=1.20 , 95 % CI= 0.90 - 1.60 ) . Independent injury risk factors among both men and women included low aerobic fitness and cigarette smoking . CONCLUSIONS This prospect i ve study demonstrated that assigning running shoes based on the shape of the plantar surface had little influence on injury risk in BMT even after controlling for other injury risk factors Background : Hamstring injuries are common in sprinters . Identifying preseason risk factors is essential to target injury-prone athletes and develop injury preventive measures . Objective : To investigate the incidence of hamstring muscle injury in sprinters over an athletic season and to explore the preseason predictor of this injury . Design : Prospect i ve cohort study . Participants : 44 sprinters from the Hong Kong Sports Institute , the Hong Kong Amateur Athletic Association and intercollegiate athletic teams were recruited . Methods : Preseason assessment of hamstring flexibility , concentric and eccentric isokinetic peak torque and peak torque angle were obtained at the beginning of an athletic season . The athletes were followed over 12 months and were asked to report all injuries result ing from training and competition . Results : Eight athletes sustained hamstring injuries over the season . The injury rate was 0.87 per 1000 h of exposure . The incidence of injuries was higher at the beginning of the season , with 58.3 % injuries occurring in the first 100 h of exposure . Cox regression analysis revealed that athletes with a decrease in the hamstring : quadriceps peak torque ratio of less than 0.60 at an angular velocity of 180 ° /s have a 17-fold increased risk of hamstring injury . Conclusion : Performing preseason hamstring : quadriceps peak torque ratio assessment s may be useful to identify sprinters susceptible to hamstring injury Physical training-related injuries are common among army recruits and other vigorously active population s , but little is known about their causation . To identify intrinsic risk factors , we prospect ively measured 391 army trainees . For 8 weeks of basic training , 124 men and 186 women ( 79.3 % ) were studied . They answered question naires on past activities and sports participa tion , and were measured for height , weight , and body fat percentage ; 71 % of the subjects took an initial army physical training test . Women had a significantly higher incidence of time-loss injuries than men , 44.6 % com pared with 29.0 % . During training , more time-loss in juries occurred among the 50 % of the men who were slower on the mile run , 29.0 % versus 0.0 % . Slower women were likewise at greater risk than faster ones , 38.2 % versus 18.5 % . Men with histories of inactivity and with higher body mass index were at greater injury risk than other men , as were the shortest women . We conclude that female gender and low aerobic fitness measured by run times are risk factors for training injuries in army trainees , and that other factors such as prior activity levels and stature may affect men and women differently Background A one-year prospect i ve examination of injury rates and injury risk factors was conducted in Federal Bureau of Investigation ( FBI ) new agent training . Methods Injury incidents were obtained from medical records and injury compensation forms . Potential injury risk factors were acquired from a lifestyle question naire and existing data at the FBI Academy . Results A total of 426 men and 105 women participated in the project . Thirty-five percent of men and 42 % of women experienced one or more injuries during training . The injury incidence rate was 2.5 and 3.2 injuries/1,000 person-days for men and women , respectively ( risk ratio ( women/men ) = 1.3 , 95 % confidence interval = 0.9 - 1.7 ) . The activities most commonly associated with injuries ( % of total ) were defensive tactics training ( 58 % ) , physical fitness training ( 20 % ) , physical fitness testing ( 5 % ) , and firearms training ( 3 % ) . Among the men , higher injury risk was associated with older age , slower 300-meter sprint time , slower 1.5-mile run time , lower total points on the physical fitness test ( PFT ) , lower self-rated physical activity , lower frequency of aerobic exercise , a prior upper or lower limb injury , and prior foot or knee pain that limited activity . Among the women higher injury risk was associated with slower 300-meter sprint time , slower 1.5-mile run time , lower total points on the PFT , and prior back pain that limited activity . Conclusion The results of this investigation supported those of a previous retrospective investigation emphasizing that lower fitness and self-reported pain limiting activity were associated with higher injury risk among FBI new agents Background : Injuries in collegiate ice hockey can result in significant time lost from play . The identification of modifiable risk factors relating to a player ’s physical fitness allows the development of focused training and injury prevention programs targeted at reducing these risks . Purpose : To determine the ability of preseason fitness outcomes to predict in-season on-ice injury in male collegiate ice hockey players . Study Design : Prognostic cohort study . Level of Evidence : Level 3 . Methods : Athlete demographics , percentage body fat , aerobic capacity ( 300-m shuttle run ; 1- , 1.5- , 5-mile run ) , and strength assessment ( sit-ups , push-ups , grip strength , bench press , Olympic cleans , squats ) data were collected at the beginning of 8 successive seasons for 1 male collegiate ice hockey team . Hockey-related injury data and player-level practice /game athlete exposure ( AE ) data were also prospect ively collected . Seventy-nine players participated ( 203 player-years ) . Injury was defined as any event that result ed in the athlete being unable to participate in 1 or more practice s or games following the event . Multivariable logistic regression was performed to determine the ability of the independent variables to predict the occurrence of on-ice injury . Results : There were 132 injuries ( mean , 16.5 per year ) in 55 athletes . The overall injury rate was 4.4 injuries per 1000 AEs . Forwards suffered 68 % of the injuries . Seventy percent of injuries occurred during games with equal distribution between the 3 periods . The mean number of days lost due to injury was 7.8 ± 13.8 ( range , 1 - 127 days ) . The most common mechanism of injury was contact with another player ( 54 % ) . The odds of injury in a forward was 1.9 times ( 95 % CI , 1.1 - 3.4 ) that of a defenseman and 3 times ( 95 % CI , 1.2 - 7.7 ) that of a goal ie . The odds of injury if the player ’s body mass index ( BMI ) was ≥25 kg/m2 was 2.1 times ( 95 % CI , 1.1 - 3.8 ) that of a player with a BMI < 25 kg/m2 . The odds ratios for bench press , maximum sit-ups , and Olympic cleans were statistically significant but close to 1.0 , and therefore the clinical relevance is unknown . Conclusion : Forwards have higher odds of injury relative to other player positions . BMI was predictive of on-ice injury . Aerobic fitness and maximum strength outcomes were not strongly predictive of on-ice injury Reliable data on the impact of physical training on light infantry units in terms of injuries and time loss are sparse . This study evaluated a light infantry unit ( n = 181 ) prospect ively and followed it throughout one year of infantry training and operations . Fifty-five percent of the soldiers ( n = 101 ) experienced one or more injuries . Eighty-eight percent of the injuries were training-related conditions , which result ed in 1,103 days of limited duty . Lower extremity overuse injuries were the most common type of injury documented . Fractures accounted for the greatest number of days of limited duty . Risk factors for training-related injuries identified by this study were cigarette smoking , high percentage of body fat , extremely high or low body mass index , low endurance levels , and low muscular endurance levels ( sit-ups ) . Logistic regression showed that cigarette smoking and low endurance levels were independent risk factors for training injuries . These data indicate that the incidence of training-related injuries in infantry units is high . A number of modifiable injury risk factors were identified , suggesting that many of these injuries may be preventable PURPOSE This study aim ed to prospect ively analyze the role of factors on the contralateral side of the kinetic chain in the development of exertional medial tibial pain ( EMTP ) . METHODS Eighty-one female physical education students were tested at the beginning of their first academic year . Within the testing protocol , contralateral isokinetic hip muscle strength and full-body kinematic parameters during a single-leg drop jump were evaluated . Online question naires were administered weekly , and personal interviews were conducted every 3 months to assess injury follow-up . EMTP was diagnosed by an experienced medical doctor . Cox regression analysis was used to identify the potential risk factors for the development of EMTP . RESULTS After exclusion of subjects with diagnosed bilateral EMTP , 11 subjects were included in the EMTP group . Fifty-three subjects did not develop any lower extremity overuse injury and were included in the control group . The leg not at risk within subjects who developed EMTP was compared with an uninjured leg of those in the control group . Increased transverse plane motion for the contralateral lower leg segment during l and ing phase was found to be a significant predictor ( P = 0.012 ) for EMTP . Analysis of the isokinetic data did not reveal altered hip muscle strength parameters for the leg not at risk within the EMTP group . CONCLUSIONS Impaired dynamic joint stability or accessory movements were found in the transverse plane of the contralateral lower leg segment of EMTP subjects . This contralateral instability might have contributed to altered movement patterns within the kinetic chain function of EMTP subjects . No contralateral hip muscle strength parameters were found to predict EMTP in this study Knapik , JJ , Swedler , DI , Grier , TL , Hauret , KG , Bullock , SH , Williams , KW , Darakjy , SS , Lester , ME , Tobler , SK , and Jones , BH . Injury reduction effectiveness of selecting running shoes based on plantar shape . J Strength Cond Res 23(3 ) : 685 - 697 , 2009-Popular running magazines and running shoe companies suggest that imprints of the bottom of the feet ( plantar shape ) can be used as an indication of the height of the medial longitudinal foot arch and that this can be used to select individually appropriate types of running shoes . This study examined whether or not this selection technique influenced injury risk during United States Army Basic Combat Training ( BCT ) . After foot examinations ,  BCT recruits in an experimental group ( E : n = 1,079 men and 451 women ) selected motion control , stability , or cushioned shoes for plantar shapes judged to represent low , medium , or high foot arches , respectively . A control group ( C : n = 1,068 men and 464 women ) received a stability shoe regardless of plantar shape . Injuries during BCT were determined from outpatient medical records . Other previously known injury risk factors ( e.g. , age , fitness , and smoking ) were obtained from a question naire and existing data bases . Multivariate Cox regression controlling for other injury risk factors showed little difference in injury risk between the E and C groups among men ( risk ratio ( E/C ) = 1.01 ; 95 % confidence interval = 0.88 - 1.16 ; p = 0.87 ) or women ( risk ratio ( E/C ) = 1.07 ; 95 % confidence interval = 0.91 - 1.25 ; p = 0.44 ) . In practical application , this prospect i ve study demonstrated that selecting shoes based on plantar shape had little influence on injury risk in BCT . Thus , if the goal is injury prevention , this selection technique is not necessary in BCT INTRODUCTION / PURPOSE Decreased lumbo-pelvic ( or core ) stability has been suggested to contribute to the etiology of lower extremity injuries , particularly in females . This prospect i ve study compares  core stability measures  between genders and between athletes who reported an injury during their season versus those who did not . Finally , we looked for one or a combination of these strength measures that could be used to identify athletes at risk for lower extremity injury . METHODS Before their season , 80 female ( mean age = 19.1 + /- 1.37 yr , mean weight 65.1 + /- 10.0 kg ) and 60 male ( mean age = 19.0 + /- 0.90 yr , mean weight 78.8 + /- 13.3 kg ) intercollegiate basketball and track athletes were studied .  Hip abduction and external rotation strength , abdominal muscle function , and back extensor and quadratus lumborum endurance  was tested for each athlete . RESULTS Males produced greater hip abduction ( males = 32.6 + /- 7.3%BW , females = 29.2 + /- 6.1%BW ) , hip external rotation ( males = 21.6 + /- 4.3%BW , females = 18.4 + /- 4.1%BW ) , and quadratus lumborum measures ( males = 84.3 + /- 32.5 s , females = 58.9 + /- 26.0 s ) . Athletes who did not sustain an injury were significantly stronger in hip abduction ( males = 31.6 + /- 7.1%BW , females = 28.6 + /- 5.5%BW ) and external rotation ( males = 20.6 + /- 4.2%BW , females = 17.9 + /- 4.4%BW ) . Logistic regression analysis revealed that hip external rotation strength was the only useful predictor of injury status ( OR = 0.86 , 95 % CI = 0.77 , 0.097 ) . CONCLUSION Core stability has an important role in injury prevention . Future study may reveal that differences in postural stability partially explain the gender bias among female athletes PURPOSE The purpose of this prospect i ve study was to investigate the epidemiology of overuse injuries and to identify common risk factors for stress fractures among female and male recruits in a new light infantry basic training design ed to minimize the incidence of overuse injuries . METHODS Study subjects were male and female recruits in the 16-wk light infantry basic training . A control group of noncombat female medics whose military service did not include dem and ing physical activities was recruited to assess the female recruits ' preinduction physical preparedness . Pretraining survey of all participants ' medical and sports participation histories was conducted . Anthropometric measurements were performed . Subjects were followed every 3 wk for overuse injuries . Stress fractures were diagnosed by radiography or scintigraphy . RESULTS Ninety-nine female recruits , 36 male recruits , and 55 controls participated . Although 31 % of the controls reported regular preinduction sports participation , less than 25 % of both male and female recruits did . Stress fractures incidence was 0 % among males and controls but 12 % among female recruits ( P = 0.03 ) . The mean body mass index of female recruits with stress fractures was 19.2 + /- 2.6 versus 22.5 + /- 3.3 kg x m of female recruits without stress fractures ( P = 0.02 , odds ratio = 1.397 , 95 % confidence interval = 1.065 - 1.833 ) . No statistically significant difference was found between female and male military trainees in the incidence of other overuse injuries , but there was a statistical trend ( P = 0.07 ) for more back pain among females . CONCLUSIONS Lower body mass index was the only variable identified as a risk factor for stress fractures among female recruits in the present study . It does not explain the markedly different response of female and male recruits ' bones to the low dem and training . There may be an intrinsic difference between male and female bone resistance to fatigue Background Musculoskeletal injury is the most common reason that soldiers are medically not ready to deploy . Underst and ing intrinsic risk factors that may place an elite soldier at risk of musculoskeletal injury may be beneficial in preventing musculoskeletal injury and maintaining operational military readiness . Findings from this population may also be useful as hypothesis-generating work for particular civilian setting s such as law enforcement officers ( SWAT teams ) , firefighters ( smoke jumpers ) , or others in physically dem and ing professions . Questions / purpose sThe purpose s of this study were ( 1 ) to examine whether using baseline measures of self-report and physical performance can identify musculoskeletal injury risk ; and ( 2 ) to determine whether a combination of predictors would enhance the accuracy for determining future musculoskeletal injury risk in US Army Rangers . Methods Our study was a planned secondary analysis from a prospect i ve cohort examining how baseline factors predict musculoskeletal injury . Baseline predictors associated with musculoskeletal injury were collected using surveys and physical performance measures . Survey data included demographic variables , injury history , and biopsychosocial questions . Physical performance measures included  ankle dorsiflexion , Functional Movement Screen , lower and upper quarter Y-balance test , hop testing , pain provocation , and the Army Physical Fitness Test ( consisting of a 2-mile run and 2 minutes of sit-ups and push-ups ) . A total of 320 Rangers were invited to enroll and 211 participated ( 66 % ) . Occurrence of musculoskeletal injury was tracked for 1 year using monthly injury surveillance surveys , medical record review s , and a query of the Department of Defense healthcare utilization data base . Injury surveillance data were available on 100 % of the subjects . Receiver operator characteristic curves and accuracy statistics were calculated to identify predictors of interest . A logistic regression equation was then calculated to find the most pertinent set of predictors . Of the 188 Rangers ( age , 23.3 ± 3.7 years ; body mass index , 26.0 ± 2.4 kg/m2 ) remaining in the cohort , 85 ( 45.2 % ) sustained a musculoskeletal injury of interest .  Results Smoking , prior surgery , recurrent prior musculoskeletal injury , limited-duty days in the prior year for musculoskeletal injury , asymmetrical ankle dorsiflexion , pain with Functional Movement Screen clearing tests , and decreased performance on the 2-mile run and 2-minute sit-up test were associated with increased injury risk . Presenting with one or fewer predictors result ed in a sensitivity of 0.90 ( 95 % confidence interval [ CI ] , 0.83–0.95 ) , and having three or more predictors result ed in a specificity of 0.98 ( 95 % CI , 0.93–0.99 ) . The combined factors that contribute to the final multivariable logistic regression equation yielded an odds ratio of 4.3 ( 95 % CI , 2.0–9.2 ) , relative risk of 1.9 ( 95 % CI , 1.4–2.6 ) , and an area under the curve of 0.64 . Conclusions Multiple factors ( musculoskeletal injury history , smoking , pain provocation , movement tests , and lower scores on physical performance measures ) were associated with individuals at risk for musculoskeletal injury . The summation of the number of risk factors produced a highly sensitive ( one or less factor ) and specific ( three or more factors ) model that could potentially be used to effectively identify and intervene in those persons with elevated risk for musculoskeletal injury . Future research should establish if screening and intervening can improve musculoskeletal health and if our findings among US Army Rangers translate to other occupations or athletes . Level of Evidence Level II , prognostic study PURPOSE The aim of the present study was to assess the risk factors for magnetic resonance imaging (MRI)-detected bone stress injuries in the pelvis , hip , thigh , and knee in a large cohort of Finnish conscripts during a follow-up of 102,515 person-years . METHODS An epidemiologic prospect i ve cohort study of 152,095 conscripts , including 2345 ( 1.5 % ) females , was conducted . Localized pain in the pelvis , hip , thigh , or knee result ed in an orthopedic surgeon 's consultation and subsequent MRI examination at the Central Military Hospital , Helsinki , Finl and . Risk factors were systematic ally collected from 1998 to 2004 , including data on conscripts ' physical fitness and body composition measured at the beginning of their military service . RESULTS Altogether , 319 MRI-detected bone stress injuries of the pelvis , hip , thigh , or knee were identified in our cohort ; thus , the incidence was 311 ( 95 % CI : 277 - 345 ) per 100,000 person-years . The female : male ratio varied substantially , depending on the anatomic location of the injury ; it was highest for sacral injuries ( female : male ratio = 51.1 ) and lowest for injuries of the femoral condyle ( female : male ratio = 0.8 ) . In univariate Cox regression analysis , poor muscle strength and a poor result in a 12-min run were significantly associated with bone stress injuries . In multivariable analysis , the strongest risk factors for bone stress injuries were female gender ( hazard ratio 8.2 ; 95 % CI : 4.8 - 14.2 ) and higher age ( hazard ratio 2.1 ; 95 % CI : 1.4 - 3.1 ) . CONCLUSIONS Female military trainees have a highly increased risk of bone stress injuries of the pelvis and hip compared with male conscripts . Sacral stress fractures are typical bone stress injuries in female military recruits . Physicians should remember the possibility of bone stress injury , especially when examining stress-related pain symptoms of the pelvic area in physically active young adult females Ankle sprains are extremely common . However , very little is known about the variables that predispose individuals to these injuries . The purpose of this study was to examine prospect ively intrinsic risk factors for inversion sprains in a young physically active female population . One hundred and fifty-nine female physical education students were evaluated for several possible intrinsic risk factors for  inversion sprains  at the beginning of their academic study . The evaluated intrinsic risk factors included anthropometrical and physical characteristics , ankle joint position sense , isokinetic ankle muscle strength , lower leg alignment characteristics , postural control and muscle reaction time during a sudden inversion perturbation . All sports injuries were registered during 1 - 3 years and exposure to sport was recorded ( mean : 15.33+/-4.33 h a week ) . Thirty-two ( 20 % ) of the 159 females sprained their ankle . The number of ankle sprains per 1000 h of sports exposure was 0.75 . The Cox regression analysis revealed that females with less accurate passive joint inversion position sense [ hazard ratio ( HR ) : 1.08 , 95 % confidence interval ( CI ) : 1.02 - 1.14 for absolute error at 15 degrees inversion ] , a higher extension range of motion at the first metatarsophalangeal joint ( HR : 1.03 , 95 % CI : 1.00 - 1.06 ) and less coordination of postural control ( HR : 0.96 , 95 % CI : 0.93 - 1.00 for endpoint excursion ; HR : 0.94 , 95 % CI : 0.89 - 0.99 for maximal endpoint excursion ) are at greater risk of an ankle sprain . The findings of this study suggest that effective prevention and conservative rehabilitation of ankle inversion sprains should include attention to these variables Background : Ankle sprain is an extremely common injury in soccer players . Despite extensive research , the intrinsic cause of this injury under noncontact conditions remains unclear . Purpose : To identify intrinsic risk factors for noncontact ankle sprains in professional soccer players . Study Design : Cohort study ; Level of evidence , 2 Methods : One hundred professional soccer players were assessed in the preseason for potential risk factors of noncontact ankle sprains . The assessment included ( A ) ankle joint asymmetries ( right-left ) in isokinetic muscle strength , flexibility , proprioception , and stability ; ( B ) somatometric asymmetries ; ( C ) previous injuries ; and ( D ) lateral dominance traits .  Noncontact ankle sprains were prospect ively recorded and diagnosed for a full competition period ( 10 months ) . Results : Seventeen of the players sustained at least 1 noncontact ankle sprain . Logistic regression revealed that players with ( A ) eccentric isokinetic ankle flexion strength asymmetries ( odds ratio [ OR ] = 8.88 ; 95 % confidence interval [ CI ] , 1.95 - 40.36 , P = .005 ) , ( B ) increased body mass index ( OR = 8.16 ; 95 % CI , 1.42 - 46.63 , P = .018 ) , and ( C ) increased body weight ( OR = 5.72 ; 95 % CI , 1.37 - 23.95 , P = .017 ) each had a significantly higher risk of a noncontact ankle sprain . A trend for younger players ( OR = 0.28 ; 95 % CI , 0.061 - 1.24 , P = .092 ) and for players with ankle laxity asymmetries ( OR = 3.38 ; 95 % CI , 0.82 - 14.00 , P = .093 ) to be at greater risk for ankle sprain was also apparent to the limit of statistical significance ( .05 < P < .10 ) . Conclusion : Functional strength asymmetries of the ankle flexors and increased body mass index and body weight raise the propensity for ankle sprains in professional soccer players . Age and asymmetries in ankle laxity are potential factors worth revisiting , as there was an indication for younger players and players with ankle instability to be at higher risk for ankle injury . Proper preseason evaluation may improve prevention strategies for this type of injury in soccer Objectives : ( 1 ) To characterize the demographics and external causes of pediatric sports injury-related visits ( SIRVs ) to emergency departments ( EDs ) . ( 2 ) To analyze the effect of race/ethnicity and insurance on SIRVs to EDs . Methods : A stratified r and om- sample cross-sectional survey of EDs in the National Hospital Ambulatory Medical Care Survey was conducted from 1997 - 2001 ; for patients younger than 19 years , we used all visits [ n = 33,654 ; injury-related visits ( IRVs ) = 13,496 , SIRVs = 2990 ] . We examined both the external cause codes and the actual verbatim text of all IRVs . National estimates of pediatric IRVs were obtained using the assigned patient visit weights in the National Hospital Ambulatory Medical Care Survey data bases and SUDAAN 9.1 software ( SAS Institute , Inc. , Cary , NC ) . Results : Sports injuries result ed in 2.5 million visits annually , or 23 % of ED IRVs . Male sex , older age ( 6 - 18 years ) , and white race/ethnicity are associated with higher rates of SIRVs . Cycling , basketball , playground injuries , and football result ed in the largest numbers of ED SIRVs . Leading diagnoses for SIRVs included fractures and dislocations , sprains and strains , open wounds , and contusions .  Hispanic race/ethnicity was associated with lower rates of SIRVs across all insurance types . After controlling for demographic factors and insurance , Hispanic children were less likely to have an SIRV than white children ( odds ratio , 0.7 ; 95 % confidence interval , 0.6 - 0.9 ) . Conclusions : Sports and recreation are the leading causes of pediatric ED IRVs . Hispanic children , regardless of insurance status , had lower rates of SIRVs than white children , which helps explain the lower rate of nonfatal IRVs to EDs among Hispanic youth OBJECTIVES Well-developed physical qualities may protect against contact injuries . However , the potential contribution of physical qualities as risk or protective factors to contact injury risk is yet to be determined for rugby league . This study applied a frailty survival model that accounts for recurrent injury to identify risk factors for all physiotherapist-reported contact injury in professional rugby league players . DESIGN Prospect i ve cohort study . METHODS Sixty-six professional rugby league players participated in this three successive year prospect i ve study . At the start of each season , all players underwent measurements of st and ard anthropometry  ( height , body mass , and sum of seven skinfolds )  , speed ( 10 m and 40 m sprint ) , muscular strength ( 1 repetition maximum [ RM ] bench press , 1RM squat , 1RM weighted chin-ups ) , power ( vertical jump , bench throw , 1RM power clean , jump squat ) , and endurance ( maximum repetition bench press with 60 kg resistance ) , repeated-sprint ability ( 12 × 20 m sprints performed on a 20s cycle ) , prolonged high-intensity intermittent running ability ( 8 × 12 s maximal effort shuttles performed on a 48 s cycle ) , and maximal aerobic power ( multi-stage fitness test ) . Data was used to demonstrate the application of the frailty model extension of the Cox proportional regression model for recurrent events to identify factors associated with a high hazard ratio ( HR ) of injury . RESULTS Heavier ( body mass , HR=2.6 , 95 % CI=1.2 - 5.7 ) , and faster ( 40 m sprint , HR=2.1 , 95 % CI=1.0 - 4.2 ) players , and those with poorly developed prolonged high-intensity intermittent running ability ( HR=2.9 , 95 % CI=1.7 - 5.0 ) and upper-body strength ( chin-up , HR=2.2 , 95 % CI=1.3 - 3.7 ) had a higher incidence of contact injuries . CONCLUSIONS This study demonstrates application of a novel statistical approach for the analysis of injury data that is recurrent in nature . This approach identified that the greater impact forces generated from heavier players with faster speed may result in an increase in recurrent contact injury rates . However , the development of prolonged high-intensity intermittent running ability and upper-body strength and power may assist to reduce the risk of contact injury in professional rugby league players Purpose This prospect i ve cohort study examined injuries and injury risk factors in 660 British Army infantry soldiers during a predeployment training cycle . Methods Soldiers completed a question naire concerning physical characteristics , occupational factors , lifestyle characteristics ( including physical training time ) and previous injury . Direct measurements included height , body mass , sit-ups , push-ups and run time . Electronic medical records were screened for injuries over a 1-year period before operational deployment . Backward-stepping Cox regression calculated HR and 95 % CI to quantify independent injury risk factors . Results One or more injuries were experienced by 58.5 % of soldiers . The new injury diagnosis rate was 88 injuries/100 person-years . Most injuries involved the lower body ( 71 % ) , especially the lower back ( 14 % ) , knee ( 19 % ) and ankle ( 15 % ) . Activities associated with injury included sports ( 22 % ) , physical training ( 30 % ) and military training/work ( 26 % ) . Traumatic injuries accounted for 83 % of all injury diagnoses . Independent risk factors for any injury were younger age ( 17–19 years ( HR 1.0 ) , 20–24 years ( HR 0.71 , 95 % CI 0.55 to 0.93 ) , 25–29 years ( HR 0.89 , 95 % CI 0.66 to 1.19 ) and 30–43 years ( HR 0.41 , 95 % CI 0.27 to 0.63 ) , previous lower limb injury ( yes/no HR 1.49 , 95 % CI 1.19 to 1.87 ) and previous lower back injury ( yes/no HR 1.30 , 95 % CI 1.03 to 1.63 ) . Conclusion British infantry injury rates were lower than those reported for US infantry ( range 101–223 injuries/100 soldier-years ) , and younger age and previous injury were identified as independent risk factors . Future efforts should target reducing the incidence of traumatic injuries , especially those related to physical training and /or sports
target: Future studies should also consider measures of ME and MS as a function of upper body , lower body , and core strength , and their potential association with specific , rather than general ,
background: Abstract de la Motte , SJ , Gribbin , TC , Lisman , P , Murphy , K , and Deuster , PA .
  A systematic review of the association between physical fitness and musculoskeletal injury risk : part 2—muscular endurance and muscular strength .