Anterior cruciate ligament (ACL) injuries are among the most common and debilitating knee injuries in professional athletes with an incidence in females up to eight-times higher than their male counterparts. ACL injuries can be career-threatening and are associated with increased risk of developing knee osteoarthritis in future life. The increased risk of ACL injury in females has been attributed to various anatomical, developmental, neuromuscular, and hormonal factors. Anatomical and hormonal factors have been identified and investigated as significant contributors including osseous anatomy, ligament laxity, and hamstring muscular recruitment. Postural stability and impact absorption are associated with the stabilizing effort and stress on the ACL during sport activity, increasing the risk of noncontact pivot injury. Female patients have smaller diameter hamstring autografts than males, which may predispose to increased risk of re-rupture following ACL reconstruction and to an increased risk of chondral and meniscal injuries. The addition of an extra-articular tenodesis can reduce the risk of failure; therefore, it should routinely be considered in young elite athletes. Prevention programs target key aspects of training including plyometrics, strengthening, balance, endurance and stability, and neuromuscular training, reducing the risk of ACL injuries in female athletes by up to 90%. Sex disparities in access to training facilities may also play an important role in the risk of ACL injuries between males and females. Similarly, football boots, pitches quality, and football size and weight should be considered and tailored around females’ characteristics. Finally, high levels of personal and sport-related stress have been shown to increase the risk of ACL injury which may be related to alterations in attention and coordination, together with increased muscular tension, and compromise the return to sport after ACL injury. Further investigations are still necessary to better understand and address the risk factors involved in ACL injuries in female athletes. Cite this article: Bone Jt Open 2024;5(2):94–100

The anterior cruciate ligament (ACL) is frequently injured in elite athletes, with females up to eight times more likely to suffer an ACL tear than males. Biomechanical and hormonal factors have been thoroughly investigated; however, there remain unknown factors that need investigation. The mechanism of injury differs between males and females, and anatomical differences contribute significantly to the increased risk in females. Hormonal factors, both endogenous and exogenous, play a role in ACL laxity and may modify the risk of injury. However, data are still limited, and research involving oral contraceptives is potentially associated with methodological and ethical problems. Such characteristics can also influence the outcome after ACL reconstruction, with higher failure rates in females linked to a smaller diameter of the graft, especially in athletes aged < 21 years. The addition of a lateral extra-articular tenodesis can improve the outcomes after ACL reconstruction and reduce the risk of failure, and it should be routinely considered in young elite athletes. Sex-specific environmental differences can also contribute to the increased risk of injury, with more limited access to and availablility of advanced training facilities for female athletes. In addition, football kits are designed for male players, and increased attention should be focused on improving the quality of pitches, as female leagues usually play the day after male leagues. The kit, including boots, the length of studs, and the footballs themselves, should be tailored to the needs and body shapes of female athletes. Specific physiotherapy programmes and training protocols have yielded remarkable results in reducing the risk of injury, and these should be extended to school-age athletes. Finally, psychological factors should not be overlooked, with females’ greater fear of re-injury and lack of confidence in their knee compromising their return to sport after ACL injury. Both intrinsic and extrinsic factors should be recognized and addressed to optimize the training programmes which are designed to prevent injury, and improve our understanding of these injuries. Cite this article: Bone Joint J 2023;105-B(10):1033–1037

There is a disparity in sport-related injuries between sexes, with females sustaining non-contact musculoskeletal injuries at a higher rate. Anterior cruciate ligament ruptures are between two and eight times more common than in males, and females also have a higher incidence of ankle sprains, patellofemoral pain, and bone stress injuries. The sequelae of such injuries can be devastating to an athlete, resulting in time out of sport, surgery, and the early onset of osteoarthritis. It is important to identify the causes of this disparity and introduce prevention programmes to reduce the incidence of these injuries. A natural difference reflects the effect of reproductive hormones in females, which have receptors in certain musculoskeletal tissues. Relaxin increases ligamentous laxity. Oestrogen decreases the synthesis of collagen and progesterone does the opposite. Insufficient diet and intensive training can lead to menstrual irregularities, which are common in female athletes and result in injury, whereas oral contraception may have a protective effect against certain injuries. It is important for coaches, physiotherapists, nutritionists, doctors, and athletes to be aware of these issues and to implement preventive measures. This annotation explores the relationship between the menstrual cycle and orthopaedic sports injuries in pre-menopausal females, and proposes recommendations to mitigate the risk of sustaining these injuries. Cite this article: Bone Joint J 2023;105-B(7):723–728

Introduction. Perception of ACL injury prevention programs amongst professional netball players and coaches has not been studied. We investigated (1) level of awareness and experience of ACL injury prevention programs; (2) use of ACL injury prevention programs; and (3) barriers to implementing ACL injury prevention program in netball. Methodology. Female netball players representing Welsh senior and under-21 teams and elite and amateur coaches were invited electronically to this web-based study between 1st May–31st July 2021. Information on ACL injury susceptibility and seriousness, knowledge, experience, and implementation of ACL injury prevention programs were ascertained. Results. Twenty-eight players (77.8%) and 29 coaches (13.2%) completed the questionnaire. Seventeen (60.7%) players and 15 (51.7%) coaches reported female athletes were at greater risk for sustaining ACL injuries. Over 90% of respondents identified netball as high-risk, whilst 89% of players and 76% of coaches reported these injuries to be preventable. Two (7.1%) players and 6 (20.7%) coaches utilised ACL injury prevention programs with lack of time and engagement from coaches and players identified. Majority of respondents indicated that their club has neither promoted, advocated nor demonstrated exercises for ACL injury prevention. Over 90% of respondents would utilise such programs if it minimised players risk with appropriate training and information. Conclusion. Study highlights limited knowledge of female athletes’ increased susceptibility of ACL injuries with lack of communication and education of ACL injury prevention programs between sporting associations, coaches and players. Results demonstrate willingness of players and coaches to implement ACL injury prevention programs in Welsh netball

Abstract. Introduction. Perception of ACL injury prevention programs amongst professional netball players and coaches has not been studied. We investigated (1) level of awareness and experience of ACL injury prevention programs; (2) use of ACL injury prevention programs; and (3) barriers to implementing ACL injury prevention program in netball. Methodology. Female netball players representing Welsh senior and under-21 teams and elite and amateur coaches were invited electronically to this web-based study between 1st May–31st July 2021. Information on ACL injury susceptibility and seriousness, knowledge, experience, and implementation of ACL injury prevention programs were ascertained. Results. Twenty-eight players (77.8%) and 29 coaches (13.2%) completed the questionnaire. Seventeen (60.7%) players and 15 (51.7%) coaches reported female athletes were at greater risk for sustaining ACL injuries. Over 90% of respondents identified netball as high-risk, whilst 89% of players and 76% of coaches reported these injuries to be preventable. Two (7.1%) players and 6 (20.7%) coaches utilised ACL injury prevention programs with lack of time and engagement from coaches and players identified. Majority of respondents indicated that their club has neither promoted, advocated nor demonstrated exercises for ACL injury prevention. Over 90% of respondents would utilise such programs if it minimised players risk with appropriate training and information. Conclusion. Study highlights limited knowledge of female athletes’ increased susceptibility of ACL injuries with lack of communication and education of ACL injury prevention programs between sporting associations, coaches and players. Results demonstrate willingness of players and coaches to implement ACL injury prevention programs in Welsh netball

Introduction. Anterior Cruciate Ligament (ACL) injury prevention programs can reduce injury risk in various sports. The perception of ACL injury prevention programs amongst professional netball players and coaches has not been studied. The purpose of the study was to determine (1) level of awareness and experience of ACL injury prevention programs; (2) use of ACL injury prevention programs; and (3) barriers and potential facilitators to implementing a sustainable ACL injury prevention program in netball. Methods. This cross-sectional observational study was undertaken using the CHERRIES checklist. Female netball players representing Welsh senior and under-21 teams and elite and amateur coaches were invited electronically to participate in this web-based study between 1st May – 31st July 2021. Information on ACL injury susceptibility and seriousness, knowledge, experience, and implementation of ACL injury prevention programs were ascertained. Results. Twenty-eight players (77.8%) and 29 coaches (13.2%) completed the questionnaire. Seventeen (60.7%) players and 15 (51.7%) coaches reported female athletes were at greater risk for sustaining ACL injuries. Over 90% of respondents identified netball as high-risk, whilst 89% of players and 76% of coaches reported these injuries to be preventable. Only two (7.1%) players and 6 (20.7%) coaches utilised an ACL injury prevention program with lack of time and engagement from coaches and players identified. Majority of respondents indicated that their club has neither promoted, advocated the use nor demonstrated exercises for ACL injury prevention. Over 90% of respondents would utilise an ACL injury prevention program if it minimised players risk with appropriate information and demonstration of exercises. Conclusion. This study highlights limited knowledge of female athletes' increased susceptibility of ACL injuries amongst players and coaches with lack of communication and education of ACL injury prevention programs between sporting associations, coaches, and players. However, the results demonstrate willingness amongst both players and coaches to implement an ACL injury prevention program in netball

Purpose. Stress fractures (SFs) are highly prevalent in female athletes, especially runners (1337%), and result in pain and lost training time. There are numerous risk factors for SFs in athletes; however, the role of bone quality in the etiology of SFs is currently unknown. Therefore, our primary objective was to examine whether there are characteristic differences in bone quality and bone strength in female athletes with lower limb SFs using high-resolution peripheral quantitative computed tomography (HR-pQCT). A secondary objective was to compare muscle strength between SF subjects and controls. Method. Female athletes with (n=19) and without (n=19) lower limb SFs were recruited from the local community. All SFs were medically confirmed by a physician and subjects were assessed within 1–47 weeks (12.7 13.7) of diagnosis. Controls were age-, training volume- and sport-matched to SF athletes. Bone density and microarchitectural bone parameters such as cortical thickness and porosity, as well as trabecular thickness, separation and number of all subjects were assessed using HR-pQCT at two distal tibia scanning sites (distal, ultra-distal). Finite element (FE) analysis was employed to estimate bone strength and load sharing of cortical and trabecular bone from the HR-pQCT scans. Regional analysis was applied to the HR-pQCT scans to investigate site-specific bone differences between groups. Muscle torque was measured by a Biodex dynamometer as a surrogate of muscle strength. Independent sample t-tests and Mann-Whitney U-tests were used for statistical analyses (p < 0.05). Results. Significant differences and trends indicated compromised trabecular bone and slightly thicker cortices with fewer pores in SF subjects compared with controls. This was most pronounced in the posterior region of the distal tibia, which is the site of highest tensile stresses during running and a common SF site. FE analysis indicated significantly higher cortical loads (median 4.2% higher; p=0.03) in the distal tibia site (but not ultra-distal site) of SF subjects compared to controls. The SF group exhibited significantly reduced knee extension strength (median 18.3% lower; p=0.03) and a trend towards reduced plantarflexion (median 17.3% lower; p=0.24) and eversion strength (median 9.6% lower; p=0.49) compared to controls. Conclusion. This is the first study to compare bone microarchitectural quality and lower-limb muscle strength between female athletes with SFs and health controls. A reduced trabecular bone quality in SF subjects may result in an insufficient ability to absorb and distribute tibial loads. This, in turn, may lead to higher stresses in the cortex and a higher risk for SFs. Low muscle strength may increase SF risk by providing insufficient muscular support to counteract shear stresses associated with reaction forces during running. Further study is needed to determine whether a resistance-training program can improve bone quality and in turn, reduce SF risk

Background. Non-contact anterior cruciate ligament (ACL) injuries occurs with a higher incidence in female athletes compared with males after the onset of puberty. One anatomical factor with clinically observable differences between males and females is lower extremity alignment. The knee joint valgus in the coronal plane, which is associated with ACL injury risk, is composed of rotation of the tibia around the stationary femur and hip rotation combined with knee flexion. The purpose of this study was to prove the difference of hip rotation between female and male handball players with or without history of ACL injury. Methods. Elite collegiate athletes on the varsity handball team (17 females and 24 males) were recruited. Whereas 8 females and 1 male had a history of ACL injury, there were 9 females and 23 males with no history of ACL injury. The 6 measures of hip joint motion [flexion, extension, abduction, adduction, external rotation (ER), and internal rotation (IR)] and the 2 measures of knee joint motion (flexion and extension) were measured with the standard procedure using a goniometer. Results. The range of ER in ACL-injured females (37±7.5) was smaller than in uninjured females (49±8.2). The range of IR in ACL-injured female players (55±9.6) was greater than in uninjured females (41±13). There was no difference in ER+IR between ACL-injured and uninjured females. In the ACL-injured male handball player, ER was dominant to IR. Compared with the uninjured males, the ACL-injured female players showed smaller range of ER, greater ranges of IR and greater ER+IR. Conclusions. ACL-injured female handball players had greater hip IR with smaller hip ER, compared with uninjured counterpart. Hip rotation may be a crucial risk factor for ACL injury in female athletes. Level of evidence. 2b

A quick, portable and reliable tool for predicting ACL injury could be an invaluable instrument for athletes, coaches, and clinicians. The gold standard, Vicon motion analysis, despite having a high sensitivity and risk specificity, is not practical for coaches or clinicians to use on a routine basis for assessing athletes. The present study validated the Kinect device to the currently used method of chart review in predicting athletes at high risk. A total of 114 participants were recruited from both the men and women McGill Varsity Sports Program. 69 males and 45 female athletes were evaluated to assess the specificity and sensitivity of the Kinect device in predicting athletes at high risk of injury. Each athlete performed three-drop vertical jumps off of a 31cm box and the data was recorded and risk score was generated. Generation of this data is done by our uniquely programmed software that measures landing angles at different time frames and compares live results to previously known data of injured athletes. A chart review was then performed by a clinician, blinded to these risk scores, to risk stratify the same athletes as high or low risk of ACL injury based on their medical charts. Data reviewed incorporated pre-season physical exams along with documented known risk factors for ACL injury, including previous knee injuries, family history of ACL injury, gender, sport, and BMI. Positive risk factors were assigned one point while negative risk factors assigned zero points. The Kinect device, powered by our software, identified 40 athletes as having a high-risk score (> 55%), and subsequently, five (4.39%) sustained an ACL injury by the end of their respective sport seasons. Two male and two female basketball players along with one male soccer player sustained non-contact ACL injuries. Given that all five of the injured athletes were in the cohort of 40 identified as high risk by the Kinect, this yielded a sensitivity of 100% for the device. As for the specificity, the Kinect computed 35 false positives, yielding a specificity of 68% for the duration of the study. The medical chart review identified 36 athletes as high risk and 60 as being low risk of ACL injury. Four of the athletes that sustained an ACL injury were in the group of 36 identified as high risk by the clinician. However, one of the five participants who sustained an ACL injury was not captured by the medical chart assessment, yielding a sensitivity of 80% and a specificity of 65% for the clinician. When it comes to injury prediction, it is preferred to have a high sensitivity even if the specificity is slightly lower as this ensures that all athletes who are at risk will be captured. Our data demonstrated that the chart analysis provided one false negative and led to missing one high-risk athlete who ended up sustaining an ACL injury. Based on the comparison of sensitivity and specificity, the Kinect system provides a slightly better predictive analysis for predicting ACL injury compared to chart review

Limb symmetry on a battery of functional tests is becoming more common as a clinical rehabilitation tool serving as a proxy assessment for readiness to return to sport following anterior cruciate ligament reconstruction (ACLR). The predictive capability of each included test for determining the likelihood of a second ACL injury is not well known. This study combines 14 established functional tests into a comprehensive return-to-sport assessment (RTSA). Study purpose: to determine if any of the functional tests were independently related to a second ACL injury occurring after the patient was cleared for return to sport. The RTSA was administered to 226 individuals after primary, unilateral ACLR who were followed for at least 24 months (51% female; mean ± SD age, 18.9 ± 4.0 years at RTSA, 9.4 ± 2.4 months post-surgery). The RTSA included 14 tests that involved calculation of Limb Symmetry Indices (LSI): leg press [LP], eccentric hamstring strength [HS], hip adductor strength [HA], Y Balance Test (anterior [YANT], posteromedial [YPM], posterolateral [YPL]), single hop [SH], triple hop [TH], crossover hop [CH], 6 meter timed hop [TiH], lateral hop [LH], medial hop [MH], vertical jump [VJ], single leg squat [SLS]. LSI averaged values of three trials for each leg for LP, HS, HA, SH, TH, CH, TiH, LH, MH, VJ, and SLS. The lowest bilateral difference across three trials was used for YANT, YPM, and YPL. Logistic regression using backward elimination was used to predict the odds of a second non-contact ACL injury using the RTSA, sex, age, and months post-surgery at RTSA as the independent variables. Twenty-five (11%) patients returned to have a subsequent ACL surgery. Twenty of the 25 experienced a second non-contact ACL injury (70% female; 10 ipsilateral, 10 contralateral). Of the 14 female athletes, there were eight contralateral and six ipsilateral tears. In males, there were two contralateral and four ipsilateral tears. The mean time from surgery to injury was 20.5 ± 9.8 months. Age (OR; 95%CI: 0.75; 0.58, 0.92), LP (0.97; 0.93, 0.99), YANT (1.21; 1.02, 1.43), and TiH (1.10; 1.01, 1.20) were found to be significantly associated with the odds of re-injury. Age, YANT, and the LSI of LP and TiH have a statistically significant impact on the odds of a second ACL injury after ACL reconstruction. YANT has an OR of 1.21, indicating that a 1cm increase in asymmetry will increase the likelihood of re-injury by 21%, holding all else constant. A 1% increase in the TiH LSI results in a 10% increase in the odds of re-injury. The risk of re-injury decreases as age increases. The OR for LP symmetry was near 1.0 and therefore may not have a clinically relevant effect on re-injury risk. Although LSI is a straightforward, quantitative measure, clinicians should not solely rely on it as a proxy for recovery of knee function. Many tests are available for clinical assessments, but this study found only a few of the tests to have significant associations with a subsequent ACL injury following return to play after ACL reconstruction

A 21-year-old female athlete presented with bilateral lumps in her calves which became painful on exercise. Exploration revealed entrapment of the superficial peroneal nerves. Her symptoms were relieved by fasciectomy

Background The minimum size required for a successful quadrupled hamstring autograft ACL reconstruction remains controversial. The risks of ACL re-tear in younger patients who tend to participate in a higher level of sports activity, and female athletes who have numerous predisposing factors, are poorly defined. Purpose To identify risk factors for graft re-tears within 2 years of ACL surgery. The hypotheses are that female sex, a smaller size graft, and younger patients will increase the odds of failure. Study Design Cohort Study. Level of evidence, 3. A cohort of 503 athletes undergoing primary, autograft hamstring ACL reconstruction, performed by a single surgeon using the same surgical technique and rehabilitation protocol, between September-December 2012, was followed for a total duration of 2 years. Return to play was allowed between 6 and 12 months post-surgery upon completion of functional testing. Exclusion criteria included infections, revisions, double bundle techniques, multi-ligament injuries, non-compliance, BTB/allografts/hybrid grafts. Primary outcome consisted of binary data (ACL graft re-tear or no tear) as measured on physical exam (Lachman and pivot shift) and MRI. Multivariate logistic regression statistical analysis with model fitting was used to investigate the predictive value of sex, age, and graft size on ACL re-tear. Secondary sensitivity analyses were performed on the adolescent subgroup, age and graft size as categorical variables, and testing for interactions among variables. Sample size was calculated based on the rule of 10 events per independent variable for logistic regression. The mean age of the 503 athletes was 27.5 (SD 10.6; range = 12–61). There were 235 females (47%) and 268 males (53%) with a 6 % rate of re-tears (28 patients; 17 females). Mean graft size was 7.9 (SD 0.6; range = 6–10). Univariate analyses of graft size, sex, and age only in the model showed that younger age (odds ratio [OR] = 0.86; 95% confidence interval [CI] = 0.80–0.93; P = .001] and smaller graft size (OR = 0.36; 95% CI = 0.18–0.70; P = .003) were significantly predictive of re-tear. Female sex was correlated with re-tear but was not significant (OR = 1.8; 95% CI = 0.84–3.97; P = .13). Multivariate analysis with all 3 variables in the model showed similar significant results. Graft size < 8 mm (OR = 2.95; 95% CI = 1.33–6.53; P = .008) and age < 25 (OR = 7.01; 95% CI = 2.40–20.53; P = .001) were significantly predictive of re-tear. Entire model was statistically significant (Omnibus test P = .001; Hosmer-Lemeshow statistic P = .68; Receiver Operating Curve [ROC] = 0.8). Surgeons should counsel their patients who are female, younger than 25 and with a graft size less than 8 mm accordingly and consider modifying their surgical or rehabilitation techniques to mitigate these re-tear risks

Aims

The Single Assessment Numerical Evalution (SANE) score is a pragmatic alternative to longer patient-reported outcome measures (PROMs). The purpose of this study was to investigate the concurrent validity of the SANE and hip-specific PROMs in a generalized population of patients with hip pain at a single timepoint upon initial visit with an orthopaedic surgeon who is a hip preservation specialist. We hypothesized that SANE would have a strong correlation with the 12-question International Hip Outcome Tool (iHOT)-12, the Hip Outcome Score (HOS), and the Hip disability and Osteoarthritis Outcome Score (HOOS), providing evidence for concurrent validity of the SANE and hip-specific outcome measures in patients with hip pain.

Background: The relation between Adolescent Idiopathic Scoliosis (AIS) and exercising is rather ambiguous. The latter has often been considered both as a therapeutic means as well as a causative factor of the former. Aim of this cross-sectional case-control study was the assessment of the incidence of AIS among athletes and non-athletes in order to determine whether athletic activities play a potential role (positive or not) in the development of AIS. Methods: A group of 2387 adolescents (1177 boys and 1210 girls) was evaluated. Their mean age was 13.4 years (range:12–15 years). All patients completed a detailed questionnaire concerning personal, somatometric and secondary sex characteristics, type, duration and character of daily performed physical activities and existing cases of AIS among their relatives. The patients were classified into 2 groups according to their answers; ‘athletes’ and ‘non-athletes’. The 2 groups were statistically comparable as far as age, height, weight, onset of menstruation and prevalent extremity were concerned. All children underwent physical examination by 3 orthopaedic surgeons that were unaware of their level of athletic activities. Children considered, by all examiners, to be suspicious of suffering from scoliosis underwent further radiographic evaluation. Results: One hundred and seventy seven children (66 boys and 111 girls) were considered as suspicious; in 99 cases (athletes: 48, non-athletes:51) AIS was radiographically confirmed. No statistically significant difference was found between athletes and non-athletes adolescents (p=0.927), athletes and non-athletes boys (p=0.888) and athletes and non-athletes girls (p=0.804), as far as the prevalence of AIS was concerned. There was also no statistically significant difference between male athletes and non-athletes (p=0.899) and female athletes and non-athletes (p=0.311) as far as the mean value of the Cobb angle of the main scoliotic curve was concerned. Conclusions: This study’s results show that systematic exercising is not positively or negatively associated with a higher or lower incidence of AIS. Furthermore, actively participating in sports activities doesn’t seem to correlate with the degree of the main scoliotic curve either

Aim: To quantify the effect of overhead sports on static scapular position. Method: Three cohorts of young adults were evaluated: Swimmers (n=35), Tennis players (n=32) and Controls (n=33). Scapular position was determined using the method described by DiVita. Details of overhead activities, hand dominance and history of shoulder injuries were obtained by questionnaire. All measurements were performed by a single observer. Results: DiVita’s normalised ratios in dominant shoulders were 1.57±0.09 for swimmers, 1.61±0.11 for tennis players and 1.57±0.12 for controls. For non-dominant shoulders, the ratios were 1.58±0.1.5, 1.59±0.13 and 1.63±0.13 respectively. There were no significant differences between groups. Within male subjects, there were no differences in scapular size between athletes and controls on either dominant or non-dominant sides. However, scapular distance was significantly greater in swimmers in both shoulders (dominant p=0.009, non-dominant p=0.028) and in the dominant shoulder in tennis players (p=0.037) when compared with controls. Female athletes showed no differences in scapular size when compared with controls but female swimmers had greater scapular sizes on their non-dominant sides when compared with controls (p=0.016). Conclusions: There were measurable anthropometric differences between athletes and controls that supported our hypothesis of greater scapular distances in both shoulders in swimmers and in the dominant shoulder in tennis players when compared with controls. However, these were not borne out using a normalised ratio. DiVita’s method of assessing static scapula position is readily applicable to clinical and sporting settings and proved reproducible with minimal equipment. It may be worthy of further investigation

Aims

This study aims to report the outcomes in the treatment of unstable proximal third scaphoid nonunions with arthroscopic curettage, non-vascularized bone grafting, and percutaneous fixation.

Purpose. Alpine skiing is associated with large skeletal loads with distinct patterns of loading rate and direction, and alpine skiers were previously found to have a robust bone structure compared to normally active controls. However, it is not known whether the mechanical stimuli experienced by skiers are also associated with enhanced bone microarchitecture and strength. Thus, the purpose of this study was to use high-resolution peripheral quantitative computed tomography (HR-pQCT) to compare bone macro- and microarchitecture and bone strength between elite alpine skiers and normally active controls. Method. Participants included 7 female and 12 male members of the Canadian Alpine Ski Team, and 10 female and 16 male normally active control subjects. A whole body dual energy X-ray absorptiometry (DXA) scan was performed to measure lean mass and percent body fat. HR-pQCT (XtremeCT, Scanco) was used to assess bone macro- and microarchitecture including total, cortical and trabecular bone area, total and cortical bone mineral density (BMD), and bone volume ratio (BV/TV) of the dominant distal tibia and radius. Finite element analysis was applied to the HR-pQCT scans to estimate bone strength (failure load, N). Analysis of covariance (ANCOVA) was used to compare outcomes between groups adjusting for body weight (tibia) and height (tibia and radius). Results. Bone area of the distal radius was significantly greater in female (30%, p<.001) and male (21%, p=.003) skiers compared with controls. Similarly, distal radius failure load was greater in female (37%, p=.001) and male (42%, p<.001) skiers. Higher BV/TV was apparent in the distal tibia of the male (18%, p=.005) and female skiers (19%, p=.012) and at the radius for the male skiers (19%, p=.02) compared with controls. High BV/TV is associated with a higher trabecular area at the distal tibia for the female athletes (14%, p=.06) and the distal radius for male athletes (32%, p=.002). Distal tibia failure load was higher in male (18%, p<.001) and female skiers (22%, p=.012) compared with controls. Distal tibia failure load remained significantly higher for the male athletes even after adjusting for lean mass. Conclusion. Compared to controls, skiers have larger bone areas at the radius in men and women, and at the tibia in women. Trabecular bone volume is augmented in skiers compared with controls, even after adjusting for height and weight. After adjusting for lean mass, group differences in bone strength were still apparent at the distal tibia in men, suggesting that direct mechanical input associated with alpine skiing affects bone microarchitecture. In conclusion a larger bone size and greater trabecular bone volume may represent skeletal adaptations to the extreme mechanical environment experienced during competitive skiing, and likely contribute to the greater bone strength observed in skiers compared with controls at both skeletal sites