title: Use of simple measures of physical activity to predict stress fractures in young men undergoing a rigorous physical training program. Risk factors of acute and overuse musculoskeletal injuries among young conscripts: a population-based cohort study Increase in injury risk with low body mass and aerobic-running fitness in elite Australian football. Step test performance and risk of stress fractures among female army trainees. Risk Factors for Injuries in Football Epidemiology of stress fracture and lower-extremity overuse injury in female recruits. Effect on injuries of assigning shoes based on foot shape in air force basic training. Intrinsic risk factors for exercise-related injuries among male and female army trainees Changes in running mechanics and spring-mass behaviour induced by a 5-hour hilly running bout 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. Risk Factors for Lower Extremity Injuries in Elite Female Soccer Players Predictors of Lower Extremity Injury Among Recreationally Active Adults Injury Reduction Effectiveness of Selecting Running Shoes Based on Plantar Shape Overuse injuries in female infantry recruits during low-intensity basic training. Prevention of common overuse injuries by the use of shock absorbing insoles Epidemiological patterns of musculoskeletal injuries and physical training. Biomechanical and lifestyle risk factors for medial tibia stress syndrome in army recruits: a prospective study. Risk Factors for Injury in Subelite Rugby League Players Effect of pre-accession physical fitness on training injuries among US Army recruits. 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. Health and economic burden of running-related injuries in runners training for an event: A prospective cohort study. A randomized trial of preexercise stretching for prevention of lower-limb injury. 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 Calcium and vitamin d supplementation decreases incidence of stress fractures in female navy recruits.
abstract: Among a population of r and omly selected US Marine Corps recruits at Marine Corps Recruit Depot , San Diego , California , the authors developed a screening tool to identify individuals at high risk for lower extremity stress fracture when beginning a rigorous physical training program .  The screening tool was developed among 1,286 recruits , then tested and refined among 1,078 additional recruits . The refined algorithm , consisting of five physical activity questions and a 1.5-mi ( 2.4-km ) run time , revealed that 21.6 % of " high risk " subjects suffered more than three times as many stress fractures as " low risk " subjects . These data suggest that risk of stress fracture during rigorous physical training is increased by poor physical fitness and low levels of physical activity prior to their entry into the program 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 PURPOSE To assess the relationships between player characteristics ( including age , playing experience , ethnicity , and physical fitness ) and in-season injury in elite Australian football . DESIGN Single-cohort , prospect i ve , longitudinal study . METHODS Player characteristics ( height , body mass , age , experience , ethnicity , playing position ) , preseason fitness ( 6-min run , 40-m sprint , 6 × 40-m sprint , vertical jump ) , and in-season injury data were collected over 4 seasons from 1 professional Australian football club . Data were analyzed for 69 players , for a total of 3879 player rounds and 174 seasons . Injury risk ( odds ratio [ OR ] ) and injury severity ( matches missed ; rate ratio [ RR ] ) were assessed using a series of multilevel univariate and multivariate hierarchical linear models . RESULTS A total of 177 injuries were recorded with 494 matches missed ( 2.8±3.3 matches/injury ) . The majority ( 87 % ) of injuries affected the lower body , with hamstring ( 20 % ) and groin/hip ( 14 % ) most prevalent . Nineteen players ( 28 % ) suffered recurrent injuries . Injury incidence was increased in players with low body mass ( OR=0.887 , P=.005 ) , with poor 6-min-run performance ( OR=0.994 , P=.051 ) , and playing as forwards ( OR=2.216 , P=.036 ) . Injury severity was increased in players with low body mass ( RR=0.892 , P=.008 ) , tall stature ( RR=1.131 , P=.002 ) , poor 6-min-run ( RR=0.990 , P=.006 ) , and slow 40-m-sprint ( RR=3.963 , P=.082 ) performance . CONCLUSIONS The potential to modify intrinsic risk factors is greatest in the preseason period , and improvements in aerobic-running fitness and increased body mass may protect against in-season injury in elite Australian football BACKGROUND Stress fractures and other musculoskeletal injuries are major sources of morbidity among female military trainees . Several risk factors have been postulated , particularly pre-existing fitness , usually assessed with post-entry run time for ≥ 1.0 mile . PURPOSE Physical fitness is not formally evaluated prior to Army entry . If a valid and simple test that identified women at increased risk of stress fracture were available and could be applied prior to entry , it would facilitate cost-benefit studies of deferral or interventions . These analyses were undertaken to determine if a 5-minute step test conducted before entry identified women at increased risk . METHODS A prospect i ve study was conducted of weight-qualified women entering the Army in 2005 - 2006 , with analyses completed in 2011 . At the pre-entry examination , information was collected on age , BMI , smoking , race , and activity level . Everyone took the step test . All outpatient medical encounters were captured , and stress fractures and other musculoskeletal injuries identified . Women with stress fractures and those with other musculoskeletal injuries were evaluated separately . RESULTS 1568 women were included in the study ; 109 developed stress fractures and 803 other musculoskeletal injury . Women who failed the step test had a 76 % higher stress fracture incidence and a 35 % higher incidence of other musculoskeletal injuries . There was effect modification between age and test failure for stress fracture . CONCLUSIONS A step test that can be administered before military entry identifies women with increased incidence of stress fracture and other musculoskeletal injury . This test could be used pre-entry to defer or target high-risk recruits for tailored fitness training before or after military entrance Background The injury risk in football is high , but little is known about causes of injury . Purpose To identify risk factors for football injuries using a multivariate model . Study Design Prospect i ve cohort study . Methods Participants were 306 male football players from the two highest divisions in Icel and . Before the 1999 football season started , the following factors were examined : height , weight , body composition , flexibility , leg extension power , jump height , peak O2 uptake , joint stability , and history of previous injury . Injuries and player exposure were recorded throughout the competitive season . Results Older players were at higher risk of injury in general ( odds ratio [ OR ] = 1.1 per year , P = 0.05 ) . For hamstring strains , the significant risk factors were age ( OR = 1.4 [ 1 year ] , P < 0.001 ) and previous hamstring strains ( OR = 11.6 , P < 0.001 ) . For groin strains , the predictor risk factors were previous groin strains ( OR = 7.3 , P = 0.001 ) and decreased range of motion in hip abduction ( OR = 0.9 [ 1 ° ] , P = 0.05 ) . Previous injury was also identified as a risk factor for knee ( OR = 4.6 ) and ankle sprains ( OR = 5.3 ) . Conclusions Age and previous injury were identified as the main risk factors for injury among elite football players from Icel and PURPOSE The purpose of this prospect i ve study was to examine rates and risk factors for overuse injuries among 824 women during Marine Corps Recruit Depot basic training at Parris Isl and , SC , in 1999 . METHODS Data collected included training day exposures ( TDE ) , baseline performance on a st and ardized 1.5-mile timed run , and a pretraining question naire highlighting exercise and health habits . The women were followed during training for occurrence of stress fracture and other lower-extremity overuse injury . RESULTS There were 868 lower-extremity overuse injuries for an overall injury rate of 12.6/1000 TDE . Rates for initial and subsequent injury were 8.7/1000 and 20.7/1000 TDE , respectively . There were 66 confirmed lower-extremity stress fractures among 56 ( 6.8 % ) women ( 1.0/1000 TDE ) . Logistic regression modeling indicated that low aerobic fitness ( a slower time on the timed run ( > 14.4 min ) ) , no menses in six or more consecutive months during the past year , and less than 7 months of lower-extremity weight training were significantly associated with stress fracture incidence . Self-rated fair-poor fitness at baseline was the only variable significantly associated with other non-stress fracture overuse injury during basic training . CONCLUSIONS Among this sample of women , the risk of lower-extremity overuse injury was high , with a twofold risk of subsequent injury . The results suggest that stress fracture injury might be decreased if women entered training with high aerobic fitness and participated frequently in lower-extremity strength training . Furthermore , women reporting a history of menstrual irregularity at their initial medical exam may require closer observation during basic training 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 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 Abstract The aim of this study was to investigate changes in running mechanics and spring-mass behaviour with fatigue induced by 5-hour hilly running ( 5HHR ) . Running mechanics were measured pre- and post-5HHR at 10 , 12 and 14 km · h-1 on an instrumented treadmill in eight ultramarathon runners , and sample d at 1000 Hz for 10 consecutive steps . Contact ( tc ) and aerial ( ta ) times were determined from ground reaction force ( GRF ) signals and used to compute step frequency ( f ) . Maximal GRF , loading rate , downward displacement of the centre of mass ( Δz ) , and leg length change ( ΔL ) during the support phase were determined and used to compute both vertical ( Kvert ) and leg ( Kleg ) stiffness . A significant decrease in tc was observed at 12 and 14 km · h-1 result ing in an increase of f at all speeds . Duty factor and Fmax significantly decreased at 10 km · h-1 . A significant increase in Kvert and Kleg was observed at all running speeds with significant decreases in Δz and ΔL . Despite the shorter duration , the changes in running mechanics appeared to be in the same direction ( increased f and Kvert , decrease in Δz and Fmax ) but of lower amplitude compared with those obtained after an ultra-trail or an ultramarathon 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 Background : The incidence of lower extremity injuries in female soccer players is high , but the risk factors for injuries are unknown . Purpose : To investigate risk factors for lower extremity injuries in elite female soccer players . Study Design : Cohort study ; Level of evidence , 3 . Methods : Players in the Norwegian elite female soccer league ( N = 12 teams ) participated in baseline screening tests before the 2009 competitive soccer season . The screening included tests assessing maximal lower extremity strength , dynamic balance , knee valgus angles in a drop-jump l and ing , knee joint laxity , generalized joint laxity , and foot pronation . Also included was a question naire to collect information on demographic data , elite-level experience , and injury history . Time-loss injuries and exposure in training and matches were recorded prospect ively in the subsequent soccer season using weekly text messaging . Players reporting an injury were contacted to collect data regarding injury circumstances . Univariate and multivariate regression analyses were used to calculate odds ratios ( ORs ) and 95 % confidence intervals ( CIs ) for ±1 st and ard deviation of change . Results : In total , 173 players underwent complete screening tests and registration of injuries and exposure throughout the season . A total of 171 injuries in 107 players ( 62 % ) were recorded ;  ligament and muscle injuries were the most frequent . Multivariate analyses showed that a greater body mass index ( BMI ) ( OR , 1.51 ; 95 % CI , 1.21 - 1.90 ; P = .001 ) was the only factor significantly associated with new lower extremity injuries . A greater BMI was associated with new thigh injuries ( OR , 1.51 ; 95 % CI , 1.08 - 2.11 ; P = .01 ) , a lower knee valgus angle in a drop-jump l and ing was associated with new ankle injuries ( OR , 0.64 ; 95 % CI , 0.41 - 1.00 ; P = .04 ) , and a previous knee injury was associated with new lower leg and foot injuries ( OR , 3.57 ; 95 % CI , 1.27 - 9.99 ; P = .02 ) , whereas none of the factors investigated influenced the risk of new knee injuries . Conclusion : A greater BMI was associated with lower extremity injuries in elite female soccer players . Clinical Relevance : Increased knowledge on risk factors for lower extremity injuries enables more targeted prevention strategies with the aim of reducing injury rates in female soccer players Objective To identify gender-specific predictors of lower extremity injury among a sample of adults engaging in running , walking , or jogging ( RWJ ) for exercise .  Design Prospect i ve cohort study . Setting Cooper Clinic Preventive Medicine Center , Dallas , Texas . Participants Participants were 2,481 men and 609 women who underwent a physical examination between 1970 and 1981 and returned a follow-up survey in 1986 . Predictor variables measured at baseline included height , weight , and cardiorespiratory fitness . At follow-up , participants recalled information about musculoskeletal injuries , physical activity levels , and other predictors for lower extremity injury over two time periods , 5 years and 12 months . Main Outcome Measures An injury was defined as any self-reported lower extremity injury that required a consultation with a physician . Cox proportional hazards regression ( HR ) was used to predict the probability of lower extremity injury for the 5-year recall period , and unconditional logistic regression was used for the 12-month recall period . Results Among men , previous lower extremity injury was the strongest predictor of lower extremity injury ( HR = 1.93–2.09 ) , regardless of recall period . Among women , RWJ mileage > 20 miles/wk was the strongest predictor for the 5-year period ( HR = 2.08 ) , and previous lower extremity injury was the strongest predictor for the 12-month period ( HR = 2.81 ) . Conclusions For healthy adults , walking at a brisk pace for 10–20 miles per week accumulates adequate moderate-intensity physical activity to meet national recommendations while minimizing the risk for musculoskeletal lower extremity injury . Clinicians may use this information to provide appropriate injury prevention counseling to their active patients 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 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 Sedentary individuals , particularly new military recruits , who start a physical training program have a substantial risk of developing an overuse injury of the lower limb . In this study we investigated the effect of neoprene insoles on the incidence of overuse injuries during 9 weeks of basic military training . The experimental group consisted of 237 r and omly selected new recruits , while 1151 recruits were the control group . Insoles were given to the experimental group and compliance was monitored . A panel of doctors documented and classi fied all injuries occurring during the 9 week period . A total of 54 ( 22.8 % ) and 237 ( 31.9 % ) injuries were reported in the experimental and control groups , re spectively . In both groups , the majority of injuries were overuse ( experimental group , 90.7 % ; control group , 86.4 % ) . The mean weekly incidence of total overuse injuries and tibial stress syndrome was significantly lower ( P < 0.05 ) in the experimental group . The mean incidence of stress fractures was lower in the experimental group but not significantly so ( 0.05 < P < 0.1 ) . This study shows that the incidence of total overuse injuries and tibial stress syndrome during 9 weeks of basic military training can be reduced by wearing insoles PURPOSE The purpose of this study was to identify rates of diagnosis-specific musculoskeletal injuries in U.S. Marine Corps recruits and to examine the association between patterns of physical training and these injuries . METHODS Subjects were 1,296 r and omly selected male Marine recruits , ages 17 to 28 yr , who reported to Marine Corps Recruit Depot San Diego for boot camp training between January 12 and September 14 , 1993 . Recruits were followed prospect ively through 12 wk of training for injury outcomes . Injury patterns were examined in relation to weekly volumes and types of vigorous physical training . RESULTS The overall injury rate was 39.6 % ( number of recruits injured/ population at risk ) , with 82 % of injuries occurring in the lower extremities . Overuse injuries accounted for 78 % of the diagnoses . The most frequent site of injury was the ankle/foot region ( 34.3 % of injuries ) , followed by the knee ( 28.1 % ) . Ankle sprains ( 6.2 % , N = 1,143 ) , iliotibial b and syndrome ( 5.3 % , N = 1,143 ) , and stress fractures ( 4.0 % , N = 1,296 ) were the most common diagnoses . Injury rates were highest during the weeks with high total volumes of vigorous physical training and the most hours of running and marching . Weekly injury rates were significantly correlated with hours of vigorous physical training ( overuse injuries r = 0.667 , P = 0.018 ; acute injuries r = 0.633 , P = 0.027 ) . CONCLUSIONS The results of this controlled epidemiological investigation indicate that volume of vigorous physical training may be an etiologic factor for exercise-related injuries . The findings also suggest that type of training , particularly running , and abrupt increases in training volume may further contribute to injury risk Medial tibial stress syndrome ( MTSS ) is a common injury in active population s and has been suggested to be a result of both biomechanical and lifestyle factors . The main aim of this study was to determine prospect ively whether gait biomechanics and lifestyle factors can be used as a predictor of MTSS development . British infantry male recruits ( n=468 ) were selected for the study .  Plantar pressure variables , lifestyle factors comprising smoking habit and aerobic fitness as measured by a 1.5 mile timed-run were collected on the first day of training .  Injury data were collected during the 26 week training period and incidence rate was 7.9 % ( n=37 ) . A logistic regression model for membership of the MTSS and non-MTSS groups was developed . An imbalance in foot pressure with greater pressure on the medial side than on the lateral side was the primary risk factor . Low aerobic fitness , as deduced from a 1.5 mile timed-run and smoking habit were also important , but were additive risk factors for MTSS . In conclusion , " poor " biomechanics were the strongest predictors of MTSS development but lifestyle factors were also important . The logistic regression model combining all three risk factors was capable of predicting 96.9 % of the non-injured group and 67.5 % of the MTSS group with an overall accuracy of 87.7 % . While the model has yet to be vali date d against an external sample and limitations exist with regards to the quality of the data collected , it is nonetheless suggested that the combined analysis of biomechanical and lifestyle factors has the potential to improve the prediction of MTSS 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 OBJECTIVE To evaluate the association of pre-accession physical fitness , as measured by a five-minute step test , with incidence of overuse injuries and outpatient healthcare utilization among male United States ( US ) Army recruits . PARTICIPANTS US Army male trainees who met weight st and ards and took a pre-accession fitness test .  METHODS In this prospect i ve cohort study , incidence and outpatient healthcare visits for overuse injuries during the first 90 days of military service were compared between recruits who failed the pre-accession step test with those who passed . RESULTS The hazard rate ratio for injury among recruits who failed the fitness test compared to those who passed the test was 1.31 ( 95 % C.I = 1.20 - 1.44 ) . Among the subset of recruits with at least one medical encounter for an overuse injury , the utilization rate ratio for subjects who failed the fitness test versus those who passed was 1.15 ( 95 % C.I = 1.09 - 1.22 ) . Other factors associated with increased risk of injury or healthcare utilization include age , body mass index , and smoking history . CONCLUSIONS Risk of injury and utilization were associated with fitness test results . These findings may have implication s for military accession and training policy as well as for other physically dem and ing training programs such as police , fire fighters and athletes 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 Prospect i ve running-related injury ( RRI ) data from runners training for an event are scarce , especially with regard to RRI-associated costs . Therefore , the aim of this study was to investigate the prevalence and economic burden of RRIs in runners participating in an organized training program preparing them for an event . This was a prospect i ve cohort study with 18 weeks of follow-up . Individuals aged 18 or older and registered to participate in an organized running program were eligible .  Follow-up surveys were sent every 2 weeks to collect data about running exposure , RRIs , and costs .  Of the 161 potential participants , 53 ( 32.9 % ) were included in this study . A total of 32 participants reported 41 RRIs . The mean prevalence during follow-up was 30.8 % [ 95 % confidence interval ( CI ) 25.6 - 36.0 % ] . Overuse was the main mechanism of RRI ( 85.4 % , n = 35 ) . An RRI was estimated to have an economic burden of € 57.97 ( 95 % CI € 26.17 - 94.00 ) due to healthcare utilization ( direct costs ) and € 115.75 ( 95 % CI € 10.37 - 253.73 ) due to absenteeism from paid work ( indirect costs ) . These results indicate that the health and economic burden of RRIs may be considered significant for public health . Therefore , prevention programs are needed for runners participating in organized training programs PURPOSE This study investigated the effect of muscle stretching during warm-up on the risk of exercise-related injury . METHODS 1538 male army recruits were r and omly allocated to stretch or control groups . During the ensuing 12 wk of training , both groups performed active warm-up exercises before physical training sessions . In addition , the stretch group performed one 20-s static stretch under supervision for each of six major leg muscle groups during every warm-up . The control group did not stretch . RESULTS 333 lower-limb injuries  were recorded during the training period , including 214 soft-tissue injuries . There were 158 injuries in the stretch group and 175 in the control group . There was no significant effect of preexercise stretching on all-injuries risk ( hazard ratio [ HR ] = 0.95 , 95 % CI 0.77 - 1.18 ) , soft-tissue injury risk ( HR = 0.83 , 95 % CI 0.63 - 1.09 ) , or bone injury risk ( HR = 1.22 , 95 % CI 0.86 - 1.76 ) . Fitness ( 20-m progressive shuttle run test score ) , age , and enlistment date all significantly predicted injury risk ( P < 0.01 for each ) , but height , weight , and body mass index did not . CONCLUSION A typical muscle stretching protocol performed during preexercise warm-ups does not produce clinical ly meaningful reductions in risk of exercise-related injury  in army recruits . Fitness may be an important , modifiable risk factor 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 INTRODUCTION Stress fractures ( SFx ) are one of the most common and debilitating overuse injuries seen in military recruits , and they are also problematic for nonmilitary athletic population s. The goal of this r and omized double-blind , placebo-controlled study was to determine whether a calcium and vitamin D intervention could reduce the incidence of SFx in female recruits during basic training . MATERIAL S AND METHODS We recruited 5201 female Navy recruit volunteers and r and omized them to 2000 mg calcium and 800 IU vitamin D/d or placebo .  SFx were ascertained when recruits reported to the Great Lakes clinic with symptoms . All SFx were confirmed with radiography or technetium scan according to the usual Navy protocol . RESULTS A total of 309 subjects were diagnosed with a SFx result ing in an incidence of 5.9 % per 8 wk . Using intention-to-treat analysis by including all enrolled subjects , we found that the calcium and vitamin D group had a 20 % lower incidence of SFx than the control group ( 5.3 % versus 6.6 % , respectively , p = 0.0026 for Fisher 's exact test ) . The per protocol analysis , including only the 3700 recruits who completed the study , found a 21 % lower incidence of fractures in the supplemented versus the control group ( 6.8 % versus 8.6 % , respectively , p = 0.02 for Fisher 's exact test ) . CONCLUSIONS Generalizing the findings to the population of 14,416 women who entered basic training at the Great Lakes during the 24 mo of recruitment , calcium and vitamin D supplementation for the entire cohort would have prevented approximately 187 persons from fracturing . Such a decrease in SFx would be associated with a significant decrease in morbidity and financial costs
target: Primary findings indicate that there is ( a ) strong evidence that poor performance on a set distance run for time is a predictor for MSK-I risk in both genders ; ( b ) strong evidence that poor performance on timed shuttle runs is a predictor for MSK-I risk in males ; ( c ) moderate evidence in males and limited evidence in females that poor performance on a timed step test is a predictor of MSK-I risk ; and ( d ) limited or insufficient evidence that poor performance on the Cooper run test , maximal and submaximal aerobic grade d exercise tests , and the Conconi test are predictors of MSK-I risk in males or females or both .
  Several measures of CRE are risk factors for training-related MSK-I in military and civilian athletic population s , indicating that CRE may be an important measure for MSK-I risk stratification
background: A systematic review of the association between physical fitness and musculoskeletal injury risk : part 1—cardiorespiratory endurance .
  J Strength Cond Res 31(6 ) : 1744–1757 , 2017—Musculoskeletal injuries ( MSK-Is ) are a significant health problem for both military and athletic population s. Research indicates that MSK-I is associated with physical fitness ; however , the association between specific components of physical fitness and MSK-I in military and athletic population s has not been systematic ally examined .