Vitamin D and Stress Fractures in Sport: Preventive and Therapeutic Measures-A Narrative Review

Association between prolactin and history of stress fracture in elite sprinters and jumpers

To investigate the risk factor for stress fractures and the characteristics of the laboratory data in eumenorrheic female track and field athletes competing at an elite level. Elite eumenorrheic sprinters and jumpers were recruited. Bone mineral density, bone metabolism markers, 25-OH Vitamin D, and hormones, including prolactin and free testosterone were measured. Total of 84 high school and collegiate athletes were enrolled in the study and among them, 33 athletes had a history of stress fractures during or after high school. Their personal background, bone mineral density, bone metabolism markers, 25-OH Vitamin D, and free testosterone were not different between the group with a history of stress fracture and without a history of stress fracture. Prolactin levels were higher in athletes with stress fractures compared to those without (15.70 ± 10.59 ng/mL vs. 11.59 ± 5.06 ng/mL, p = 0.081), although this difference was not statistically significant. Logistic regression analysis revealed that prolactin was a significant predictive factor for stress fractures (odds ratio: 1.10; 95% CI: 1.01-1.20; p = 0.023). Prolactin may be linked to stress fractures in eumenorrheic sprinters and jumpers, and further research is needed to confirm its role as a predictive factor.

Pictorial Review of Paediatric Limp

A limp is an abnormal, uneven or laboured gait typically resulting from pain, weakness, or structural deformity involving the hip, lower limb, spine or abdominopelvic abnormalities. Limps in children are common and have diverse causes that can be benign to life-threatening including trauma, congenital malformations, and neoplastic diseases. Diagnosis involves identifying gait abnormality thoroughly examining history and physical exam, assessing tenderness and range of motion, and completing targeted lab and radiographic studies. We present an imaging review of various usual and unusual causes of limp in different age groups such as in toddlers (1-3 years), children (4-10 years), and adolescents (11-16 years) with a comprehensive literature review.

Injury Profiling in Male Police Cadets During Initial Training Phase: A Retrospective Cohort Study

Musculoskeletal injuries during the "Initial Training Phase" (ITP) are a major medical problem faced by law enforcement agencies worldwide. Aiming to develop an injury prevention strategy, we examined the incidence, type, associated factors, and severity of injuries and secondarily tracked their evolution over time by batches in a police academy. A retrospective cohort study was conducted using prospectively collected injury data on 979 newly recruited male police cadets enrolled in eight batches between 2015 and 2023. Among the 376 injured participants (age: 18.1 ± 0.3 years, body-mass: 75.8 ± 12.5 kg, body-height: 173.7 ± 4.0 cm, body mass index [BMI]: 25.1 ± 4.1 kg·m-2, body-fat percentage: 18.1% ± 5.1%), 405 injuries were recorded during the ITP. Musculoskeletal injury data were analyzed according to type, associated-factors, severity, and evolution across batches. Almost half of the recruits (41.4%) sustained at least one musculoskeletal injury. Based on injury frequency (39-69 case) and exposure time (20,944.5-43,006.5 hours per participant) indices, and with an implication of scientific training tips, the long-term follow-up over-batches showed that the injury incidence was decreased 2.5-fold from Batch 1 to Batch 8 (p < .0001). Most injuries occurred between Weeks 2 and 5 (80% cumulative). The most common injury type was medial tibial stress syndrome (36.0%), followed by iliotibial band syndrome (12.6%), and ankle sprain (10.4%). This injury profile aligns with previous studies on law enforcement recruits, although comparisons should be made cautiously due to variations in training programs and recruit characteristics between agencies. The most frequently reported perceived potential contributors of injuries were vitamin and mineral deficiencies (20.7%), overweight/obesity (19.1%), and harsh physical activities (13.0%). During ITP, almost half of the recruits sustained at least one musculoskeletal injury, most of them in the fourth week. Some of the major associated factors of injury could be controlled resulting in a potential reduction of the injury incidence by up to 2.5 times. Implementing tailored fitness programs, incorporating subjective and objective training load assessments, and enhancing monitoring could significantly decrease injury rates, improve recruit readiness, and reduce resource and time waste on injury treatment.

Assessment of Sex-Specific Associations between Athletic Identity and Nutrition Habits in Competitive Youth Athletes

Given the psychological aspects of sports nutrition, understanding one's athletic identity (AI) may improve targeted nutrition education. Therefore, the purpose of this study was to examine nutrition habits and AI among uninjured youth athletes. Athletic Identity Measurement Scale (AIMS) and custom Sports Nutrition Assessment for Consultation (SNAC) scores collected prospectively at local sporting events were retrospectively assessed via Mann-Whitney, Kruskal-Wallis, logistic regression, and ANCOVA tests (95% CI). Among 583 athletes (14.5 ± 2.1 years; 59.9% female), the total AIMS scores did not differ by sex (males 39.9 ± 7.2; females 39.3 ± 7.5; maximum 70). The Social Identity (p = 0.009) and Exclusivity (p = 0.001) subscores were higher in males, while the Negative Affectivity subscores were lower (p = 0.019). Females reported frequent associations between SNAC and AIMS, particularly Negative Affectivity, which was positively associated with stress fracture history (p = 0.001), meal-skipping (p = 0.026), and desiring nutrition knowledge (p = 0.017). Males receiving weight recommendations reported higher Negative Affectivity subscores (p = 0.003), and higher total AIMS scores were observed in males with fatigue history (p = 0.004) and a desire for nutrition knowledge (p = 0.012). Fatigue and stress fracture history predominated in high-AI males and females, respectively, suggesting that poor sports nutrition may present differently by sex. As suboptimal nutrition was frequently related to high Negative Affectivity subscores, these habits may increase following poor sports performance.

Clinical Features and Therapeutic Process of Sacral Fatigue Fractures in Adolescents

BACKGROUND

Sacral fatigue fractures are a rare injury but should be considered as a differential diagnosis for low back and buttock pain in young adults. Collective reports are limited, most of which have focused on long-distance runners.

PURPOSE

To investigate the characteristics of sacral fatigue fractures in adolescents.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

We analyzed patient background characteristics, physical examination and imaging findings, and treatment courses of those diagnosed with sacral fatigue fractures using magnetic resonance imaging.

RESULTS

Among 34 patients with sacral fatigue fractures, 15 and 19 were male and female patients, respectively, with an age range of 11 to 19 years (mean age, 15.0 years). Almost all patients were athletes, and 29 patients performed their sport ≥5 times a week. Long-distance runners were the most commonly affected, comprising 7 patients, and participants in other common sports such as baseball (6 patients), basketball (4 patients), and soccer (3 patients) were also affected. Physical examination revealed tension sign (Lasègue test) on the affected side in 6 patients and tight hamstrings in 24 patients. Imaging findings included 18 patients with right-side involvement, 12 with left-side involvement, and 4 with involvement on both sides. In 11 patients, spina bifida occulta was observed at S1 and 8 patients had a history of lumbar spondylolysis with 4 patients having concurrent sacral fatigue fractures. Physical therapy was performed concurrently with the cessation of exercise, and return to exercise was permitted if the pain had been relieved after 1 month. All patients returned to sports at a median of 48 days (range, 20-226 days) after symptom onset. However, 2 patients experienced recurrence (1 patient on the ipsilateral side and 1 patient on the contralateral side).

CONCLUSION

Sacral stress fractures are not limited to long-distance runners in this population and can manifest as lower back pain or buttock pain in athletes participating in a variety of sports. Although the course of treatment was generally good, the possibility of recurrence must always be considered.

Vitamin D Deficiency in Professional Football Players during Competitive Season of Italian First Division (Serie A)

BACKGROUND

Data in the literature have demonstrated the crucial role that vitamin D plays in the human organism, and recent studies also emphasize this essential role of vitamin D in athletes. Indeed, vitamin D acts on the skeletal muscles and plays a fundamental role in numerous physiological processes involved in immune function. Many factors such as sun exposure, skin tone, body mass index and chronic illness affect vitamin D levels. The aim of the study is to evaluate vitamin D levels in professional football players in Italy and investigate the variations in vitamin D values in footballers who train at different latitudes.

METHODS

The study performed is a retrospective observational study analyzing 25-OH vitamin D values in professional football players of the Italian First Division (Serie A). Two teams during the competitive season were selected: team A (latitude of 41° N in southern Italy) and team B (latitude of 45° N in northern Italy). Three time periods were identified and were classified as follows: the first quarter (May, June, July, and August), the second quarter (September, October, November, and December) and the third quarter (January, February, March, and April). The purpose of this was to study the average values of vitamin D during the year corresponding to different levels of sunlight exposure. Each athlete was subjected to at least one sampling during the three quarters of the competitive season.

RESULTS

Both vitamin D insufficiency (10.1%) and overt deficiency (1.93%) were found in Italian Serie A players. Insufficient vitamin D values are between 20 ng/mL and 29 ng/mL and overt deficiency values <20 ng/mL. At the same time, the data demonstrated a significant variation in vitamin D values depending on the period of the competitive season and the latitude of the cities of the two teams. In detail, there was no significant difference in the first quarter, while there was a significant increase in vitamin D values in team B in the second and third quarter, at p < 0.01 and p < 0.05, respectively.

CONCLUSIONS

Latitude and seasons have a significant impact on vitamin D levels. Therefore, it is essential to measure vitamin D in professional football players, especially during the spring and winter months, so as to monitor changes in levels in relation to the season and latitude and evaluate any supplements. Further studies should be performed to evaluate the relationship between vitamin D deficiency and football players' athletic performance.

Medial Tibial Stress Syndrome (Shin Splint): Prevalence, Causes, Prevention, and Management in Saudi Arabia

Background/aims Medial tibial stress syndrome (MTSS), also known as "shin splint", is most often described as exertional leg pain along the shinbone (tibia), which occurs due to the inflammation of the muscles, tendons, and bone tissue in this area. This study aims to assess the prevalence, risk factors, and their association with the development of MTSS, as well as the effective treatments that reduce pain and improve functions among the Saudi general population. Materials and method The present cross-sectional study was conducted on the general population of Saudi Arabia through an electronic survey over a period of three months. The study sample of 443 patients was deemed and considered. The study included participants from the general population in Saudi Arabia above the age of 18. A structured self-response questionnaire was given to the participants after institutional research ethical approval was obtained for the study. Results Among the 443 participants, the majority were male (n = 228, 51.5%), aged 18-29 (n = 227, 51.2%), and residing in the central region of Saudi Arabia (n = 398, 89.8%). Most participants reported engaging in sporting activities (n = 211, 47.6%), with high-intensity training being the most common (n = 93, 44.1%). Only a small proportion (n = 8, 1.8%) reported a previous diagnosis of MTSS. Analysis revealed associations between MTSS prevalence and certain demographic factors, including walking surface preferences and engagement in specific sports. Treatment strategies for MTSS included rest, ice application, physiotherapy, and pain-relieving medication, with varying degrees of satisfaction and recurrence rates among participants. Conclusion The study provides valuable insights into the prevalence, risk factors, management, and preventive measures related to MTSS among the Saudi general population. While certain demographic factors and exercise practices were associated with MTSS prevalence, effective treatment options such as rest, physiotherapy, and appropriate footwear were reported. Moreover, adherence to preventive measures such as stretching, proper footwear selection, and gradual training progression may help mitigate the risk of MTSS development.

Vitamin D levels in Portuguese military personnel

INTRODUCTION

In Portugal, most adults have inadequate levels of vitamin D. Active duty military personnel need to be always ready for duty, perform tasks in specific contexts and overcome high physical and mental demands, which raises the relevance of knowing their vitamin D levels. This study aims to characterise vitamin D levels of Portuguese active duty military personnel and evaluate the effect of military status on the prevalence of vitamin D sufficiency, adjusted for season of the year, age and gender.

METHODS

A retrospective cross-sectional study, based on vitamin D measurements carried out at the Armed Forces Hospital between 2014 and 2020, was fulfilled including the variables age, gender, vitamin D level and dosing date for military personnel and civilians. Comparison of proportions test and the generalised linear regression model were used for data analysis with a significance level of 5%.

RESULTS

Out of 2782 subjects, 62.7% were military personnel. Mean±SD level of vitamin D was 24.5±10.6 ng/mL and 23.7±11.5 ng/mL in military personnel and civilians, respectively. In the military personnel, the prevalence of vitamin D sufficiency, insufficiency and deficiency was, respectively, 25.2%, 40.1% and 34.6%. Prevalence of vitamin D sufficiency was similar in the civilians cohort and, also, between Armed Forces branches. Military status had no effect on the prevalence of vitamin D sufficiency, especially after adjustments.

CONCLUSIONS

We present data on vitamin D levels of Portuguese active duty military personnel. Our results found that military personnel are no more at risk of vitamin D inadequacy than civilians, but only a quarter of active duty military personnel had vitamin D sufficiency. Therefore, they can benefit from vitamin D levels assessment towards vitamin D levels optimisation. Further studies are still needed, especially among military personnel with higher risk of vitamin D deficiency.

Effects of an Individualized vs. Standardized Vitamin D Supplementation on the 25(OH)D Level in Athletes

Vitamin D is crucial to the health and performance of athletes. Although the exact vitamin D requirements for athletes have not been established, maintaining a 25(OH)D level of at least 40 ng/mL is considered beneficial. This randomized controlled intervention study aimed to determine whether an individual loading dose formula for vitamin D supplementation is more effective than standardized supplementation and suitable enough for athletes to meet a target value of 40 ng/mL. In a 10-week supplementation study conducted during the winter months in Germany, 90 athletes with insufficient vitamin D levels (25(OH)D < 30 ng/mL) were randomly assigned to receive either a universal dose of 2000 IU/day of vitamin D or a loading dose of 4000 IU/day, followed by a maintenance dose of 1000 IU/day. The total 25(OH)D concentration was measured from dried blood spots at three time points: at baseline, at the computed date of 40 ng/mL, and after the 10-week period. Additionally, a vitamin-D-specific questionnaire was issued. On the day when 25(OH)D blood concentrations of 40 ng/mL were calculated to prevail, the individualized group had a significantly higher 25(OH)D level than the standardized group (41.1 ± 10.9 ng/mL vs. 32.5 ± 6.4 ng/mL, p < 0.001). This study demonstrated that the examined formula is suitable enough for athletes to achieve a 25(OH)D concentration of 40 ng/mL. This indicates that a personalized approach is more effective than a one-size-fits-all approach in restoring adequate vitamin D levels in athletes.

Bioglass and Vitamin D3 Coatings for Titanium Implants: Osseointegration and Corrosion Protection

The use of MAPLE synthesized thin films based on BG and VD3 for improving the osseointegration and corrosion protection of Ti-like implant surfaces is reported. The distribution of chemical elements and functional groups was shown by FTIR spectrometry; the stoichiometry and chemical functional integrity of thin films after MAPLE deposition was preserved, optimal results being revealed especially for the BG+VD3_025 samples. The morphology and topography were examined by SEM and AFM, and revealed surfaces with many irregularities, favoring a good adhesion of cells. The thin films' cytotoxicity and biocompatibility were evaluated in vitro at the morphological, biochemical, and molecular level. Following incubation with HDF cells, BG57+VD3_ 025 thin films showed the best degree of biocompatibility, as illustrated by the viability assay values. According to the LDH investigation, all tested samples had higher values compared to the unstimulated cells. The evaluation of cell morphology was performed by fluorescence microscopy following cultivation of HDF cells on the obtained thin films. The cultivation of HDF's on the thin films did not induce major cellular changes. Cells cultured on the BG57+VD3_025 sample had similar morphology to that of unstimulated control cells. The inflammatory profile of human cells cultured on thin films obtained by MAPLE was analyzed by the ELISA technique. It was observed that the thin films did not change the pro- and anti-inflammatory profile of the HDF cells, the IL-6 and IL-10 levels being similar to those of the control sample. The wettability of the MAPLE thin films was investigated by the sessile drop method. A contact angle of 54.65° was measured for the sample coated with BG57+VD3_025. Electrochemical impedance spectroscopy gave a valuable insight into the electrochemical reactions occurring on the surface.

Changes in Serum Bone Metabolism Markers after Living Donor Liver Transplantation (LDLT) and Their Association with Fracture Occurrences

Living donor liver transplantation (LDLT) is lifesaving, but can lead to osteoporosis and fractures. In our 3-year study of 25 LDLT recipients, we observed significant reductions in lumbar spine and femoral neck T scores, along with bone resorption marker reductions and liver regeneration marker increases. Serum calcium levels increased, while osteoprotegerin (OPG) decreased and Dickkopf-related protein 1 (DKK-1) increased. Patients who suffered fractures within 3 years of LDLT had higher serum OPG, lower serum nuclear factor kappa B ligand (RANKL), a higher OPG/RANKL ratio and higher serum DKK-1 levels. OPG, RANKL, OPG/RANKL ratio and DKK-1 levels before LDLT predicted hip or spine fractures within three years after LDLT. Further research is necessary to determine the optimal level of osteoclastic activity for preventing fracture onset.

Humeral Fracture in a Young CrossFit Practitioner

CrossFit (CrossFit Inc, Washington, DC) is a recent, high-intensity strength and conditioning sport that is growing in popularity worldwide. Potential risks and injuries have been described in previous reports. Distal humeral fractures without direct trauma were related to sports like baseball or wrestling. However, they have never been reported in a CrossFit athlete. We present the first case of distal humeral fracture associated with a CrossFit workout, during a gymnastic movement. Our patient had no relevant medical history but the investigation revealed reduced vitamin D levels and low bone density. The patient was surgically treated and he completed the rehabilitation program. He returned to sports practice 12 weeks after the surgery.

Difference in Levels of Vitamin D between Indoor and Outdoor Athletes: A Systematic Review and Meta-Analysis

Vitamin D, its importance in different processes taking place in the human body, the effects of abnormal levels of this hormone, either too low or too high, and the need for supplementation have been extensively researched thus far. Variances in exposure to sunlight can cause vitamin D levels to fluctuate. Indoor activity can be a factor for these fluctuations and can lead to a decrease in vitamin D levels. We conducted a systematic review and meta-analysis aiming to identify whether indoor compared to outdoor training has a significant influence on vitamin D levels; we also performed subgroup analyses and multivariate meta-regression. The type of training has an impact on vitamin D levels that is influenced by multiple cofounders. In a subgroup analysis not considering cofounders, the mean serum vitamin D was 3.73 ng/mL higher in outdoor athletes, a difference which barely fails to achieve significance (p = 0.052, a total sample size of 5150). The indoor-outdoor difference is only significant (clinically and statistically) when considering studies performed exclusively on Asian athletes (a mean difference of 9.85 ng/mL, p < 0.01, and a total sample size of 303). When performing the analyses within each season, no significant differences are observed between indoor and outdoor athletes. To control for multiple cofounders (the season, latitude, and Asian/Caucasian race) simultaneously, we constructed a multivariate meta-regression model, which estimated a serum vitamin D concentration lower by 4.446 ng/mL in indoor athletes. While a multivariate model suggests that outdoor training is associated with slightly higher vitamin D concentrations when controlling for the season, latitude, and Asian/Caucasian race, the type of training has a numerically and clinically small impact. This suggests that vitamin D levels and the need for supplementation should not be decided based on training type alone.

VITAMIN D AND INJURIES IN DANCERS: A SYSTEMATIC REVIEW

Vitamin D is involved in many different functions in the human body. Despite the well-known benefits of vitamin D and increasing trends of testing and supplementation, there is still a high prevalence of vitamin D deficiency worldwide, present in the general but also in the highly-active population such as athletes and dancers. Dancers are at a higher risk of vitamin D deficiency due to their long working hours spent indoors, without exposure to sunlight. The high level of workload and physical demands also put dancers at a high risk of injuries. The aim of this review was to systematically analyze the existing evidence on the association of vitamin D (serum level and supplementation) and injuries in dancers. Medline, Scopus, SportDiscus and Web of Science were searched to identify the available peer-reviewed articles. Five articles met the inclusion criteria (two interventional and three observational studies), three of which additionally investigated the relationship between vitamin D and muscle function. The reported results on positive influence of vitamin D serum level or vitamin D supplementation effect on reduced injury occurrence and enhanced muscular function in adolescent and elite professional ballet dancers are promising but the evidence is limited due to a low number of studies, small samples, and methodological limitations.

Vitamin D Fortification and Its Effect on Athletes' Physical Improvement: A Mini Review

Poor vitamin D status is a widespread problem regardless of age and sex, emphasizing the necessity of new food sources to improve vitamin D levels. Currently, approximately 60% of dietary vitamin D consumption occurs via fortified foods. Vitamin D insufficiency (50-90%) is widespread according to age and region, despite different levels of sunlight exposure. The food industry must identify more effective strategies to increase normal dietary vitamin D intake and improve overall health. Strategies for vitamin D fortification include bioaddition, wherein a vitamin D-rich food source is added to staple foods during processes. These bioadditive strategies expand the range of vitamin D-containing foods and appeal to different preferences, cultures, and economic statuses. In several countries, vitamin D deficiency places athletes at a high risk of disease susceptibility. Due to low sun exposure, athletes in countries with higher and lower levels of sunlight have similar risks of vitamin D deficiency. In this review, we summarize recent technical advances to promote vitamin D utilization by humans during sports activities and in relation to the normal practices of athletes.

Vitamin D Supplementation and Its Impact on Different Types of Bone Fractures

Vitamin D helps to balance the levels of calcium and phosphorus to maintain proper bone structure. It is also involved in essential biological roles and displays a wide spectrum of potential benefits in the human body. Since there are many types of fractures that occur at specific ages and due to different circumstances, the influence of vitamin D on the frequency of a particular fracture may differ. Thus, the authors investigated the possible preventive effect of vitamin D on the risks of vertebral fractures, hip fractures, stress fractures and pediatric fractures. Additional aspects of vitamin D, especially on recuperation after injures and its impact on the severity of particular fractures, were also discussed. It was suggested that vitamin D supplementation may contribute to a reduction in hip fracture risk due to reduced bone turnover, decreased frequency of falls and improved muscle function. Furthermore, vitamin D appears to lower the risk of stress fractures in athletes and military recruits. Due to a nonunified protocol design, presented investigations show inconsistencies between vitamin D supplementation and a decreased risk of vertebral fractures. However, a vitamin D preventive effect on pediatric fractures seems to be implausible.

Intramedullary Nailing of Concurrent Bilateral Tibial Stress Fractures Followed by Unilateral Tension Plating for a Nonunion in a Vitamin D-Deficient Elite Football Player

Stress fractures consist of a type of bone fracture that occurs due to repetitive mechanical stress instead of acute forceful injuries that cause common fractures. They are quite common among athletes at all competition levels and in army recruits who are expected to undergo extremely demanding exercises. While stress fractures can occur in any long bone, they are usually associated with the most common weight-bearing sites of lower extremities such as phalanges, metatarsals, tarsal bones, the tibia, and fibula. In this study, we report the surgical management of a 23-year-old African football player who sustained concurrent bilateral anterior cortex tibial midshaft fractures. His initial symptom was persistent subacute pain in both tibias. The initial conservative treatment was not successful and the patient was surgically treated with bilateral tibial intramedullary nails. However, the right tibia subsequently developed nonunion. Both intramedullary nails were removed and a tension plate was applied with an autologous iliac crest graft on the right tibia. Further blood test analysis revealed a significant vitamin D deficiency. The purpose of this article is to report different outcomes of the same primary surgical treatment for concurrent bilateral tibia stress fracture syndrome in an elite athlete due to vitamin D deficiency. To our knowledge, this is the first study that highlights the necessity of revising one of the intramedullary nailed concurrent tibia stress fractures with a tension plate and autologous graft to treat the established nonunion in an elite football player.

Vitamin D deficiency in athletes: Laboratory, clinical and field integration

Vitamin D deficiency is highly prevalent in athletes. Increased utilisation and storage depletion may be key contributing factor. We found a higher prevalence of vitamin D inadequacy (deficiency/ insufficiency) in power than endurance sport athletes, which may be related to vitamin D utilisation and reserve in skeletal muscles.

Metabolic Bone Diseases and New Drug Developments

Metabolic bone diseases are serious health issues worldwide, since several million individuals over the age of 50 are at risk of bone damage and should be worried about their bone health. One in every two women and one in every four men will break a bone during their lifetime due to a metabolic bone disease. Early detection, raising bone health awareness, and maintaining a balanced healthy diet may reduce the risk of skeletal fractures caused by metabolic bone diseases. This review compiles information on the most common metabolic bone diseases (osteoporosis, primary hyperparathyroidism, osteomalacia, and fluorosis disease) seen in the global population, including their symptoms, mechanisms, and causes, as well as discussing their prevention and the development of new drugs for treatment. A large amount of research literature suggests that balanced nutrition and balanced periodic supplementation of calcium, phosphate, and vitamin D can improve re-absorption and the regrowth of bones, and inhibit the formation of skeletal fractures, except in the case of hereditary bone diseases. Meanwhile, new and improved drug formulations, such as raloxifene, teriparatide, sclerostin, denosumab, and abaloparatide, have been successfully developed and administered as treatments for metabolic bone diseases, while others (romososumab and odanacatib) are in various stages of clinical trials.

Femoral Neck Stress Fractures in Athletes and the Military

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Femoral neck stress fractures (FNSFs) are an infrequent condition in athletic and military populations.

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A high index of suspicion with liberal use of magnetic resonance imaging (MRI) is vital for early recognition and treatment initiation.

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An associated hip effusion on MRI is a risk factor for an evolving stress injury and requires close assessment and consideration for repeat MRI.

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Stress reactions and stable, incomplete FNSFs (<50% of femoral neck width) can be treated nonsurgically.

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Surgical intervention is accepted for high-risk, incomplete (≥50% of femoral neck width), and complete FNSFs.

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Overall, there is a paucity of high-quality literature on the rates of return to activity following FNSF.

Associations of Vitamin D Levels with Physical Fitness and Motor Performance; A Cross-Sectional Study in Youth Soccer Players from Southern Croatia

Simple Summary

Vitamin D is a fat-soluble prohormone crucial for bone mineralization, muscle contractility, and neurological conductivity. It is theorized that Vitamin D plays an important role in sport performances, especially in young athletes. In this study we examined the associations of levels of 25-hydroxyvitamin D (25(OH)D) with physical fitness and motor-performance achievements in youth soccer players from Southern Croatia. Participants were tested on physical fitness, motor performance and vitamin D at the end of the winter period, when levels of vitamin D are known to be lowest due to low exposure to sunlight. Results showed that deficiency of 25(OH)D was widespread among youth soccer players living in Southern Croatia. Low 25(OH)D levels were associated with lower results in fitness tests (i.e., tests of energetic capacities), but there was no correlation between 25(OH)D levels and the results in motor performance tests (i.e., skill tests). Our results support the theory of the association between vitamin D and energetic capacities of athletes, but there is no evidence on association between vitamin D and skill-based capacities.

Abstract

Vitamin D level is known to be a factor potentially influencing physical fitness, but few studies have examined this phenomenon among youth athletes. We aimed to evaluate the associations of vitamin D levels (as measured by 25-hydroxyvitamin D concentrations—25(OH)D) with various physical fitness and motor performance tests in youth football (soccer) players. This cross-sectional study included a total of 52 youth soccer players (15.98 ± 2.26 years old) from Southern Croatia. The participants were evaluated at the end of the winter period and data were collected of anthropometric measures (body mass and body height), vitamin D status (25(OH)D levels), physical fitness tests (sprints of 10 and 20 m, 20 yards test, the countermovement jump, the reactive strength index (RSI)) and motor performance tests (the soccer-specific CODS, the soccer-specific agility, and static balance). Among the studied players, 54% had 25(OH)D insufficiency/deficiency, showing a lack of 25(OH)D is widespread even in youth athletes living at a southern latitude. The 25(OH)D level was correlated with sprint 20 m, 20 yards tests, and RSI, showing a greater role of 25(OH)D in physical fitness tests where energetic capacity is essential than in sport-related motor performance tests where skills are crucial. Our results support the idea that vitamin D can play a determinant role in physical fitness tests with a clear physiological component, but is not crucial in motor performance tests related to specific sports where skills are a key component. Future studies should investigate the effects of vitamin D supplementation on the performance in physical fitness and motor performance tests among youth athletes.

Vitamin D in athletes: focus on physical performance and musculoskeletal injuries

PURPOSE

The aim of this review was to discuss the effects of vitamin D on physical performance and musculoskeletal injuries in athletes and provide information on the field applications of vitamin D.

METHODS

A systematic review was conducted to identify studies on vitamin D in athletes that assessed serum vitamin D levels, vitamin D and physical performance, vitamin D and musculoskeletal injuries, and practical guidelines for supplementation of vitamin D.

RESULTS

Several studies reported that a high proportion of athletes had vitamin D insufficiency or deficiency. Low serum levels of vitamin D in athletes were more pronounced in winter than in other seasons, and indoor athletes had lower serum vitamin D levels than outdoor athletes. Low vitamin D levels have been demonstrated to have negative effects on muscle strength, power, and endurance; increase stress fractures and other musculoskeletal injuries; and affect acute muscle injuries and inflammation following high-intensity exercises. Therefore, periodic assessment and monitoring of vitamin D levels are necessary in athletes; the recommended serum level of 25(OH)D is &gt; 32 ng/mL and the preferred level is &gt; 40 ng/mL (-1). In those with low levels of vitamin D, exposure to sunlight and an improved diet or supplements may be helpful. Particularly, 2000-6000 IU of supplemental vitamin D3 can be consumed daily.

CONCLUSION

Vitamin D is a potential nutritional factor that can significantly affect physical performance and musculoskeletal injuries in athletes. The importance and role of vitamin D in athletes should be emphasized, and the current levels of vitamin D should be assessed. Therefore, it is essential to periodically evaluate and monitor serum vitamin D levels in athletes.