Prevention Of Stress Fractures Research Articles

Can hydrogen prevent stress fractures in athletes?

As a result of the ability of hydrogen rich water to delay muscle fatigue, and considering that tired striated muscles do not sufficiently protect the bone from mechanical stress, the hypothetical mechanism according to which the consumption of the respective drink by athletes could reduce the incidence of stress fractures is discussed. The application of patches with transdermal release of molecular hydrogen in the areas where stress fractures occur frequently could strengthen this preventive action, due to the local anti-inflammatory and regenerative action established experimentally on the senescent bone, to which could be added the stimulation of osteogenesis, the inhibition of bone resorption and the prevention of fractures due to the antioxidant action. The hypothesis can be tested experimentally using the rabbit tibia as a model, or statistical studies can be done on the incidence of stress fractures in athletes who consume hydrogen rich water. Even baths in water saturated with molecular hydrogen can prevent stress fractures, because they reduce the perception of muscle fever, and the plasters could also prevent the complications of this type of fractures.

Stress Fractures of the Lower Limb in Military Personnel (Literature Review)

Summary. Stress fractures are a common pathology among military personnel, occurring with a frequency of 1.5% to 31%, depending on the studied contingents. Fractures of the lower limbs occur more often, leading to impaired function and a long-term decrease in working capacity, which determines the medical, social, and economic significance of the problem. The issues of timely diagnosis and optimal treatment of stress fractures of the lower extremities in order to minimize the time of return to military service remain undefined. Objective: an analysis of the literature devoted to stress fractures of the lower limb in military personnel. Material and Methods. A search in PubMed databases from 1952 to 2023 using the search strategy “stress fractures in militaries” was conducted. Results. 671 publications were found and a significant increase in their number (249) over the past 7 years was noted; meta-analyses were 4 and randomized controlled studies were 28. Other publications belong to III and IV levels of evidence. Among all publications, only 401 were related to stress fractures of the lower extremities in military personnel. Conclusions. Stress fractures occur when increased and repeated load is applied to normal bone, which leads to microdamages and fractures. The etiology of stress fractures is multifactorial. The main complaints are localized pain with or without swelling and tenderness on palpation, aggravated by physical exertion. Early diagnosis is critical and is based on a careful history, orthopedic examination, and evaluation of appropriate imaging modalities. Classification of stress fractures based on type, location, and risk is important for determining treatment strategy. The analysis of the literature indicates a lack of protocols for the treatment and prevention of stress fractures of the lower extremities in military personnel. However, modern literature in this area is mostly of low quality and consists of studies of a small sample. This necessitates further research, especially in terms of prevention and surgical treatment.

Amenorrhea and Stress Fractures in Female New Jersey Division III Collegiate Runners: An Opportunity for Increased Health Education

BACKGROUND: In the National Collegiate Athletic Association (NCAA), 9.1% of the injuries reported by women’s cross-country athletes between 2014-2019 were fractures. Both history of amenorrhea and prior stress fractures have been found to predict incidence of subsequent bone stress injuries among female athletes. Although excessive exercise is a major contributor to the development of amenorrhea, there are currently no studies on the association between amenorrhea and stress fractures in New Jersey (NJ) National NCAA Division III Women’s cross country or track athletes. This study aims to determine if there is an association between incidence of amenorrhea and subsequent occurrence of stress fractures among this population, and to identify a possible area for increased reproductive health education. METHODS: This is a survey-based study. Participants were female athletes over the age of 18 who currently participate in collegiate cross country or track running at a NJ Division III school. Coaches of the Division III cross country and track teams in NJ distributed a survey to their female athletes to gain participants for this study. Survey data included information on participant menstrual history, stress fracture history, and athletic involvement. Participants also indicated if their school’s staff had ever educated them on the importance of menstrual regularity and athletics. Descriptive statistics and comparison between groups were analyzed. RESULTS: In total, 68 survey responses were collected. Survey respondents included female NJ cross country and track athletes ages 18-23, from a total of eight institutions. During training or competition, 58.8% of the study participants missed at least one menstrual cycle and 45.6% experienced a stress fracture. There is a significant association between having missed at least one menstrual cycle during training or competition and the number of stress fractures experienced by the athlete (p = 0.044). Only 30.9% of respondents indicated that someone from their school’s staff spoke to them about the importance of maintaining regular menstruation during training. CONCLUSION: This study confirms that both amenorrhea and stress fractures are commonly seen among NJ NCAA Division III female cross country and track athletes. Our data also highlights a need for increased education of NJ Division III female athletes regarding the importance of maintaining regular menstruation as a means of stress fracture prevention. Further investigation of the role of amenorrhea on the incidence of stress fractures may shine light on an important area for prevention and increased health education.

ОЦЕНКА ОБЕСПЕЧЕННОСТИ ВИТАМИНОМ D ЮНЫХ СПОРТСМЕНОВ

Optimal vitamin D supplementation is necessary for the normal course of growth and develop-ment processes, bone formation, prevention of stress fractures, improvement of recovery after injuries and physical exertion in young athletes. There is a high prevalence of vitamin D deficien-cy in children and adolescents in Russia currently. The number of studies on the prevalence of vitamin D metabolic disorders in young athletes is insufficient. The purpose of this research was to assess the vitamin D availability in young athletes. Methods used: cross-sectional, single-center study included young athletes from 24 kinds of sports who underwent medical examination in March to July, 2022. Serum 25-hydroxycalciferol (25(OH)D3) was measured in all athletes using the chemiluminescence analysis. Results: 527 young athletes (254 (48.2%) boys/273 (51.8%) girls) aged 10 to 17 years and 11 months old (average 15.2 [14.2; 16.5] y/o) were examined. Vit-amin D deficiency (25(OH)D3 <20 ng/ml) was detected in 226 (42.9%) athletes, of which severe deficiency (25(OH)D3 <10 ng/ml) was in 5 (2%). Vitamin D insufficiency was diagnosed in 219 (41.6%), and the optimal level of 25(OH)D3 (>30 ng/ml) was detected only in 82 (15.5%). There were no statistically significant gender differences in the frequency of occurrence of vitamin D insufficiency (p=0.561) and deficiency (p=0.673). Conclusion: extremely low vitamin D availa-bility in young athletes was revealed. Conducting further research on the prevalence of vitamin D deficiency and ways to correct it in young athletes is necessary to start working on recommended optimizing and preventive and therapeutic approaches to correcting of the vitamin D levels in high-performance youth sports.

Unraveling the physiologic paradoxes that underlie exercise prescription for stress fracture prevention.

The effects of exercise on stress fracture risk are paradoxical. Exercise can promote both bone formation and resorption, which in turn, can reduce and increase risk of stress fractures, respectively. We review classic and current literature that suggests that the processes that underlie these responses to exercise are distinct. Bone remodeling involves osteoclastic resorption of fatigue-damaged bone, coupled with subsequent bone deposition to replace the damaged tissue. Bone modeling involves the independent action of osteoblasts and osteoclasts forming or resorbing bone, respectively, on a surface. In the formation mode, modeling results in increased bone stiffness, strength, and resistance to fatigue. Both the remodeling and modeling responses to exercise require significant time for newly deposited bone to fully mineralize. We propose that recognizing these two distinct physiologic pathways and their related time courses reveals the theoretical basis to guide exercise prescription to promote bone health during periods of heightened stress fracture risk. Such guidance may include minimizing rapid increases in the duration of repetitive exercises that may cause fatigue damage accrual, such as long-distance running and marching. Rather, limiting initial exercise characteristics to those known to stimulate bone formation, such as short-duration, moderate-to-high impact, dynamic, and multidirectional activities with rest insertion, may increase the fatigue resistance of bone and consequently minimize stress fracture risk.

Promoting adaptive bone formation to prevent stress fractures in military personnel

ABSTRACT Mechanical loading leads to adaptive bone formation – the formation of new bone on existing skeletal surfaces – which increases bone strength and fatigue resistance. The same mechanical loading can also cause microdamage to bone and development of a stress fracture through targeted remodelling. Stress fractures are common in military recruits and cause significant morbidity, lost training time, and discharge from military service. This narrative review proposes strategies to promote adaptive bone formation as a novel approach to mitigate the risk of stress fracture injuries during arduous military training. Exercise that is unaccustomed, dynamic, high-impact, multidirectional, intermittent, and includes extended rest periods to restore bone mechanosensitivity, is most osteogenic. New bone formation can take up to one year to mineralize, and so new exercise training programmes should be initiated well in advance of military activities with high risk of stress fracture. Bone mechanosensitivity is highest in adolescence, before puberty, and so increasing physical activity in youth is likely to protect skeletal health in later life, including for those in the military. Recent data show that adaptive bone formation takes place during initial military training. Adaptive bone formation can also be supported with adequate sleep, vitamin D, calcium, and energy availability. Further evidence on how strategies to promote adaptive bone formation affect stress fracture risk are required. Adaptive bone formation can be optimized with a range of training and nutritional strategies to help create a resilient skeleton, which may protect against stress fracture throughout military service.

Biomechanical Basis of Predicting and Preventing Lower Limb Stress Fractures During Arduous Training.

Stress fractures at weight-bearing sites, particularly the tibia, are common in military recruits and athletes. This review presents recent findings from human imaging and biomechanics studies aimed at predicting and preventing stress fractures. Peripheral quantitative computed tomography (pQCT) provides evidence that cortical bone geometry (tibial width and area) is associated with tibial stress fracture risk during weight-bearing exercise. The contribution of bone trabecular microarchitecture, cortical porosity, and bone material properties in the pathophysiology of stress fractures is less clear, but high-resolution pQCT and new techniques such as impact microindentation may improve our understanding of the role of microarchitecture and material properties in stress fracture prediction. Military studies demonstrate osteogenic outcomes from high impact, repetitive tibial loading during training. Kinetic and kinematic characteristics may influence stress fracture risk, but there is no evidence that interventions to modify biomechanics can reduce the incidence of stress fracture. Strategies to promote adaptive bone formation, in combination with improved techniques to assess bone strength, present exciting opportunities for future research to prevent stress fractures.

INCIDENCE OF STRESS FRACTURE IN MILITARY RECRUITS: DOES MODIFICATION OF TRAINING PROGRAMME REDUCE THE INCIDENCE?

Introduction: Stress fracture though easily preventable is often neglected . Objectives 1. To assess whether modification of the training programme reduces the incidence of stress fracture among recruits . Results The average incidence of stress fracture from 01 Jul 2000 to 30 Jun 2004 was 36.10 per 1000, while after modification of the training programme it was 24.96 per 1000. This reduction in incidence of stress fracture was found to be statistically significant. Chi square value is 17.87, (p<0.001) Discussion Several studies on prevention of stress fractures in basic military training have been conducted. Incidence of stress fracture may be reduced by modification of training schedules. Limitations Due to various constraints, the modified training programme could be implemented only for one year. What we already know? 1. The incidence of stress fracture and various modalities of reduction in incidence of stress fracture in military recruits are known in military recruits What this article adds? 1. This article add a novel method of reduction in incidence of stress fracture in military recruits.

Relationship between tartrate-resistant acid phosphatase 5b and stress fractures in female athletes.

Approximately 10% of female athletes have a history of stress fractures, which most commonly occur between the ages of 16 and 17 years old. We investigated whether tartrate-resistant acid phosphatase 5b (TRACP-5b), which is a bone resorption marker, can serve as a valid predictor of stress fractures in female athletes in their teens and 20s. Three hundred and sixteen elite female athletes were recruited between 2013 and 2015. Serum TRACP-5b and various hormones were examined in blood samples. The serum TRACP-5b level was compared between athletes with and without stress fractures within 3 months after the initial collection of their blood samples. The 316 athletes were divided into two age groups: 13-19 years old and 20-29 years old. Thirty-six athletes (11.4%) experienced new stress fractures within 3 months after the initial collection of their blood samples. The median serum TRACP-5b level was significantly higher in teenage athletes with new stress fractures than in teenage athletes without new stress fractures. In univariate logistic regression analysis, the Z-score of serum TRACP-5b was a significant predictive factor of stress fractures in teenage athletes only (odds ratio: 1.87; 95% CI: 1.31-2.66; P < 0.0012). For teenage female athletes, TRACP-5b is a predictor of the risk of stress fractures, and measuring TRACP-5b levels may be useful to prevent stress fractures.

Vitamin D for Improved Bone Health and Prevention of Stress Fractures: A Review of the Literature.

Vitamin D is a vital nutrient and hormone needed for many essential functions in overall health. There is growing literature examining the role of vitamin D not only in the general population but also in athletes. The most predominantly studied area of vitamin D pertains to bone health. Recently, there has been increased investigation into the relationship of vitamin D and stress fractures, including genetic polymorphisms, levels of 25-hydroxyvitamin D, and bioavailable vitamin D. This review will address the most recent developments of vitamin D research and its important role in bone health in athletes.

Arthrodiastasis in the Management of Perthes’ Disease: A Systematic Review

Abstract Background This systematic review explores the relevant literature to assess the efficacy of the use of arthrodiastasis in the management of Perthes disease. Until this moment, arthrodiastasis is not well established for its use in Perthes disease as opposed to other containment procedures. Furthermore, there are no clear indications for its use in this disease. Methodology 12 articles were matched to the inclusion criteria and all articles were reviewed and radiological and clinical data was collected and compiled. Results a significant increase in postoperative range of motion compared to the preoperative ones was found. Final Stullberg classification was ascertained showing majority of patients ending with stages two and three. Complications were also assessed with majority of them being superficial pin tract infections. Conclusion the use of arthrodiastasis is a valid treatment option for Perthes disease however more articles need to be produced showing comparative data of arthrodiastasis versus other containment procedures. Index Terms- Arthrodiastasis, Perthes’ Disease, LCPD, Hinged Distraction the preservation of an intact and congruent femoral head. It is proposed that by applying distraction early in the disease, before any significant collapse of the femoral head had occurred, further fragmentation would be halted.[3]Articulated hip distraction maintains the proper head position by containment in abduction, extension, and neutral rotation. It also decreases joint pressure and thus decreases the deforming force and provides a good environment for cartilage repair. The femoral head deformity that develops in Perthes’ disease is believed to occur during this fragmentation phase of the disease. The possibility for joint motion allows for articular cartilage nutrition and the molding effect of the acetabulum. The aim of the articulated distraction method is to neutralize muscle and weight-bearing forces, to prevent stress fractures of subchondral immature bone, and to encourage synovial circulation and promote creeping substitution by breaking the ‘vicious circle’ of necrosis.[4]

Vitamin D3 Supplementation and Stress Fractures in High-Risk Collegiate Athletes - A Pilot Study.

IntroductionVitamin D is paramount to bone health and little is known about vitamin D’s role in the prevention of stress fractures in high-risk athletes. This study consists of a prospective, cross-sectional analysis accompanied by a retrospective review for control comparison of vitamin D3 supplementation in high-risk athletes. Our hypothesis is that supplemental vitamin D3 treatment will decrease the occurrence of stress fractures in high-risk collegiate athletes.Materials and MethodsA total of 118 NCAA Division I athletes were recruited from 6 high-risk collegiate teams. Blood draws in August and February established baseline 25(OH)D levels. Subjects with serum 25(OH)D <30 ng/mL were supplemented with 50,000 IU of vitamin D3/week for 8 weeks. Treated subjects were re-tested to ensure serum 25(OH)D levels rose to sufficient status. All enrolled subjects were monitored for the development of stress fractures. A 5-year retrospective chart review of athletes from the same sports teams was conducted to determine the incidence of any reported stress fractures in the past.ResultsProspective: 112 of the 118 enrolled subjects were tested in August. Sixty-one demonstrated vitamin D sufficiency (40.2 ng/mL ±8.28) and 51 were either insufficient or deficient (22.7 ng/mL ±4.89). Of the 118 enrolled subjects, 104 were tested in February. Fifty-six demonstrated vitamin D sufficiency (40.7 ng/mL ±9.47) and 48 were insufficient or deficient (21.6 ng/mL ±5.87). Two stress fractures were diagnosed amongst our cohort of 118 student athletes (1.69%). Retrospective: 34 stress fractures were diagnosed in 453 subjects from 01/2010-05/2015 (7.51%). Amongst our athletic teams, the cross-country team specifically demonstrated a statistically significant decrease in stress fracture incidence (p<0.05). We also found a statistically significant reduction in stress fracture incidence amongst the current overall cohort compared to our retrospective cohort (p<0.05).ConclusionIn our population, almost half of the tested athletes proved to be vitamin D deficient. Hypovitaminosis D was prevalent throughout the winter months compared with the summer. With vitamin D3 supplementation, the stress fracture rate in our overall cohort demonstrated a statistically significant decrease from 7.51% to 1.65% (p=0.009).

PROPHYLACTIC OF STRESS FRACTURES OF VERTEBRAE ADJACENT TO TRANSPEDICULAR SCREW FIXATION FOR OSTEOPOROSIS

ABSTRACT Objective: To assess the efficacy and use of vertebroplasty as a prophylactic measure to prevent stress fractures of vertebrae adjacent to transpedicular screw fixation with augmentation for osteoporosis. Methods: An experimental cadaveric study was performed to assess the overall strength of 10 cadaveric blocks of T10-L4 vertebral segments with simulation of L1 fracture and T12-L2 transpedicular 4-screw system with augmentation. T11 and L2 vertebroplasty cranial and caudal to the transpedicular system was performed in 5 blocks in the main group. Stress testing of the blocks was performed by placing them under a vertically directed load until destruction. Results: Vertically directed load on the blocks in the main group (0.84 ± 0.39831 kN) resulted in T11 vertebrae fractures. Vertebrae with augmentation were resistant to the load in the main group. T10 vertebrae fractures in the blocks of the main group occurred at a load of 1.91 ± 0.40566 kN. Conclusion: 1. The adjacent T11 vertebra is the weakest vertebra in the anatomical blocks of T10-L4 vertebral segments with simulation of L1 fracture (type A according to the AO/Magerl classification) and the T12-L2 4-screw transpedicular system with augmentation. 2. Bone cement injection into the T11 cranial vertebra adjacent to the level of fixation increases the overall strength of the blocks 3. Vertebroplasty of the overlying vertebra is an effective way to prevent its fracture and in case of osteoporosis. 4. Prophylactic vertebroplasty of the vertebra caudal to the level of fixation is unnecessary due to the insignificant risk of a fracture. Level of Evidence III; Experimental – Quasi experiments

Risk factors of stress fractures due to the female athlete triad: Differences in teens and twenties.

The female athlete triad (Triad), defined by the American College of Sports Medicine as low energy availability (LEA) with or without disordered eating, menstrual dysfunction, and low bone mineral density (BMD), is associated with stress fractures and athletes aged 16-17years are most susceptible. To examine whether the Triad increases the risk of stress fractures, athletes were assigned to a "teenage" group and a "20s" group. This prospective study enrolled 390 elite female athletes and was conducted from 2012 to 2016 at Japan Institute of Sports Sciences. Blood concentrations of various hormones were examined, and BMD was measured at the lumbar spine and throughout the whole body using dual-energy X-ray absorptiometry. LEA was defined as body weight ≤85% of the ideal body weight for teenage athletes, or BMI ≤17.5 for athletes in their 20s. Low BMD was defined as a BMD Z-score of <-1.0 in the lumbar spine and the whole body. Among 390 athletes enrolled, 36 developed new stress fractures within 3months of registration. The risk for stress fractures due to the Triad in teenage athletes was higher than for athletes in their 20s. In teenage female athletes, secondary amenorrhea, low BMD for the whole body, and a low ratio of actual body weight to ideal body weight increased the risk for stress fractures by 12.9 times, 4.5 times, and 1.1 times, respectively. To prevent stress fractures in female athletes with the Triad, age of athletes should be taken into consideration.

Geometric and "True" Densitometric Characteristics of Bones in Athletes with Stress Fracture and Menstrual Disturbances: A Systematic Review.

Stress fractures can lead to short- and long-term consequences, impacting participation in sport and general health. Recognizing which skeletal characteristics render bones susceptible to stress fracture may aid stress-fracture prevention. Menstrual disturbances among exercising women are a known risk factor for stress fracture; therefore, assessing skeletal commonalities between women with stress fractures and women with menstrual disturbances may increase our understanding of why menstrual disturbances put athletes at greater risk for stress fracture. Three-dimensional (3D) bone imaging tools provide detailed information about volumetric bone mineral density (vBMD) and bone structure that cannot be obtained using traditional two-dimensional (2D) techniques. This systematic review serves to: (1) evaluate the current literature available on vBMD, bone geometry, and bone structure in exercising women with menstrual disturbances and exercising women with stress fractures, and (2) assess the common skeletal characteristics between both conditions. Our aim is to reveal bone properties beyond 2D areal BMD that may indicate increased susceptibility to stress fracture among exercising women with menstrual disturbances. A search of the PubMed/Medline database was completed in May 2018. Eligible articles included those that reported vBMD, bone geometry, or bone structure obtained from 3D imaging techniques or estimated from 2D imaging techniques. Only studies conducted in premenopausal exercising women and girls who had a stress fracture, a menstrual disturbance, or both were included. Twenty-four articles met the inclusion criteria. Bone area and cortical thickness at the tibia were identified as altered both in women with menstrual disturbances and in women with stress fractures; however, there was inconsistency in the results observed for all bone parameters. The majority of skeletal parameters of the lower extremities were not significantly different between exercising women with and without stress fractures and between those with and without menstrual disturbances. Most studies were moderate or low quality based on study design, and only one article combined both conditions to explore vBMD and bone geometry in athletes with menstrual disturbances and a history of stress fracture. These findings highlight the need for more skeletal research on the intersection of these health conditions in exercising women. The lack of observed differences in skeletal parameters suggests that risk factors other than bone geometry and structure may be the primary causes of stress fracture in these women.

Physical interventions for preventing stress fractures of the lower limbs

Physical interventions for preventing stress fractures of the lower limbs

Beyond Ground Reaction Forces: Towards a Wearable Device for Monitoring Bone Stress, Preventing Stress Fractures

Beyond Ground Reaction Forces: Towards a Wearable Device for Monitoring Bone Stress, Preventing Stress Fractures

Establishment of the simplified technique for estimating joint moments in foot during running

To prevent injuries such as stress fractures during long-distance running, it is important to clarify the joint loads on the foot. The purpose of this study was to establish a method of estimating joint moments on foot during stance phase in running. Loads on the ankle, tarsometatarsal, and metatarsophalangeal joints were estimated by a new simplified foot model with the three-dimensional force distribution on the bottom of shoe sole. Three-dimensional ground reaction force distributions were obtained from a running test with special shoes on which three-axis miniature force sensors had been mounted. Foot model consisted of three segments: toe, mid foot, and heel. Each segment was linked with metatarsophalangeal, tarsometatarsal, and ankle joints, respectively. By calculating inverse dynamics with this model, each joint moment component, which is the contribution of forces on each sensor to joint moments, could be estimated. Each joint moment was equivalent with the sum of moment components. Results showed that the tarsometatarsal and metatarsophalangeal joint moments are estimated during the whole stance phase. The moment component distributions of each joint could also be quantified. In comparison of the moment components corresponding to each metatarsal bone, the loads of the second- and third-ray metatarsal bones were higher than those of the others. Furthermore, the effect of sole thickness distribution on moment component distribution was also confirmed. Increase of sole thickness in the vicinity of the first and fifth metatarsal bone heads reduced the load of the second- and third-ray metatarsal bones. These results showed a possibility to prevent stress fractures on foot with the sole design.

Gender differential and implications in the epidemiology of stress fractures among cadets of Indian Armed Forces

BackgroundMost studies on stress fractures in India have been carried out among recruits as against officer trainees and limited to males. With the continuous induction of women in the Armed Forces, it was decided to carry out a study among officer trainees of the three services and compare the epidemiology among genders. MethodsA prospective study was carried out in 2011–2012 at Training Institutes of the three services where male and female cadets train together. Baseline data was collected for all trainees who joined the academy during the study period. All cadets were followed up for development of stress fractures for which details were taken. Additional information was taken from the Training Institute. ResultsA total of 3220 cadets (2612 male and 608 female cadets) were included in the study. Overall 276 cadets were observed to have stress fractures during training – making an incidence of 6.9% for male cadets and 15.8% for female cadets. Females were found to have a significantly higher incidence of stress fractures. Further the distribution and onset of stress fractures in females was observed to be distinct from males. ConclusionThe significant gender differential observed in the study indicates differential role of intrinsic and extrinsic risk factors in the causation of stress fractures among male and female. Special consideration needs to be given to these while planning and implementing measures for prevention. Further studies may be carried out on subject and on the effect of interventions in stress fracture prevention.

Is vitamin D effective in preventing stress fractures?

EVIDENCE-BASED ANSWER Vitamin D supplementation with calcium likely reduces the risk of stress fractures by 20% in female military recruits (SOR: B, single RCT). There is a weak association with high vitamin D intake and reduced risk of stress fractures in adolescents (SOR: B, based on a single prospective cohort). Low serum 25-(OH) vitamin D levels are associated with an increased risk of stress fractures (no SOR given).