Female athlete triad and stress fractures

Distal Femoral Stress Fractures Has High Operation Rates in Adolescent and Young Adult Athletes

BACKGROUND

Although stress fractures of the distal femur are rare, symptoms can overlap with other peri-articular knee pathology, delaying diagnosis. Untreated stress fractures have the potential to progress into completed fractures with a higher likelihood for requiring surgery and longer recovery times in otherwise healthy adolescents and young adults. This case series represents the largest cohort of adolescent athletes with distal femoral stress fractures who presented with activity-related knee pain.

METHODS

Patients treated nonoperatively and operatively for metaphyseal distal femur stress fractures at a tertiary referral center over a four-year period were retrospectively identified from the medical record.

RESULTS

Eight patients (mean age 16.8 y; range 14 to 22 y; 87.5% male; mean body mass index [BMI] 20.9) with a total of 10 distal femur stress fractures were identified. All patients were involved in competitive sports or military training. There was an average of 3.8 encounters with a medical provider between presentation with activity-related knee pain and diagnosis with distal femur stress fracture. All except 1 patient (87.5%) were initially incorrectly diagnosed with another type of peri-articular knee pathology. Six stress fractures (60%) were treated conservatively with protected weight bearing, activity modification, and gradual return to activity. Four completed stress fractures (40%) required operative fixation-3 healed uneventfully, while 1 had an asymptomatic delayed union. Vitamin D insufficiency (<30 ng/mL) was identified in 7 of 8 patients (87.5%) and 3 patients (37.5%) had an underweight BMI (<18.5). The mean clinical follow-up was 13.1 weeks (range, 2.8 to 32.0 wk).

CONCLUSIONS

High clinical suspicion for distal femoral stress fractures is needed to avoid misdiagnosis or delayed diagnosis in young, active individuals with activity-related knee pain refractory to conservative management. In this patient population, activity-related knee pain recalcitrant to activity modification, rest, and physical therapy warrants further workup with magnetic resonance imaging and orthopaedic evaluation. Though rare, misdiagnosis can result in catastrophic fractures with prolonged rehabilitation needs. An open line of communication and streamlined access for referral between primary care providers and orthopaedic surgeons is critical in preventing misdiagnosis and delayed treatment. Furthermore, the treatment of concomitant metabolic disorders and nutritional deficiency should not be neglected when treating distal femoral stress fractures.

LEVEL OF EVIDENCE

Level-IV (case series).

Sacral stress fractures in athletes

PURPOSE

Fatigue stress fractures are a common overuse injury, frequently associated with high load-bearing endurance activities such as running, military training and aerobic exercise. While these fractures can arise at any site, sacral stress fractures are poorly studied with evidence consisting mainly of case reports and limited case series. This review aims to analyze and summarize all reports published to date describing cases of sacral stress fracture in athletes.

METHODS

PubMed, Embase, Web of Science and the Cochrane Database were systematically searched for studies reporting on Stress Fractures of the Sacrum. Insufficiency fractures of the elderly were excluded.

RESULTS

The literature review revealed 49 studies reporting on 124 cases of sacral stress fractures. Seventy-six patients (61%) were professional or collegiate level athletes, and 37 (30%) were military recruits or police officers in training. Seventeen female athletes were identified as suffering from low bone mineral density (25%), 9 of which reported menstrual irregularities. Thirteen female patients (19%) had a history of eating disorders.

CONCLUSION

While most sacral stress fractures occur in normal bones exposed to abnormal repetitive loads, the high percentage of lower bone mineral density can blur the lines between fatigue fractures and insufficiency fractures. The causes of these fractures are multifactorial. High endurance sports and the features of the female athlete triad were found in high percentage of the cases. Conservative treatment is the mainstay of treatment, consisting of ceasing of training and a period of rehabilitation and gradual return to training and competition.

Exploring Health Demographics of Female Collegiate Rowers

CONTEXT

Limited information exists about health patterns among female rowers at the collegiate level. Furthermore, the element of weight class (lightweights classified as <130 lb [59 kg]) as a factor in the physical and mental health of female collegiate athletes has not been investigated, despite weight requirements in sport being a risk factor for the female athlete triad.

OBJECTIVE

To test the hypotheses that (1) components of the female athlete triad were more prevalent in lightweight than in openweight rowers; (2) perceived stress levels were greater in lightweight than in openweight rowers; and (3) rowers who were unable to row due to injury had greater perceived stress levels than uninjured athletes.

DESIGN

Cross-sectional study.

SETTING

Twelve collegiate women's rowing programs consisting of 6 National Collegiate Athletic Association Division I openweight and 6 Intercollegiate Rowing Association-level lightweight teams.

PATIENTS OR OTHER PARTICIPANTS

A total of 158 female collegiate rowers (78 lightweight, 80 openweight).

MAIN OUTCOME MEASURE(S)

An electronic survey addressing injury history, diet and eating habits and body image (according to the triad screening questionnaire), stress levels (Perceived Stress Scale), and athlete identity (Athlete Identity Measurement Scale) was administered.

RESULTS

Lightweight rowers reported limiting or carefully controlling foods more frequently than openweight rowers (41.9% to 29.9%, P = .013). A history of an eating disorder was more prevalent among lightweight than openweight rowers (25.7% to 13.0%, P = .048). Prevalences of stress fractures and menstrual irregularities did not differ between weight classes. Lightweight and openweight rowers' scores on the Perceived Stress Scale (16.0 ± 9.9 and 17.3 ± 6.4, respectively) were not different. Injured rowers scored higher on the Perceived Stress Scale (19.4 ± 7.2) than did uninjured rowers (16.6 ± 5.72).

CONCLUSIONS

Weight class did not contribute to differences in the prevalence of female athlete triad components or perceived stress, although lightweight rowers were more likely to have a history of eating disorder. Injury may be a risk factor for increased stress in this population.

Bone Scintigraphy: A Review of Technical Aspects and Applications in Orthopedic Surgery

Due to its high sensitivity, low cost, accessibility, and ease of use, bone scintigraphy is used in orthopedic surgery for the diagnosis and management of varied pathology. It is commonly used for insufficiency fractures, metastatic neoplasia, staging and surveillance of sarcoma, and nonaccidental trauma. It augments diagnoses, including stress or occult fractures, musculoskeletal neoplasia or infection, and chronic regional pain syndrome, in patients presenting with normal results on radiographs. Bone scan images are resistant to metal-based implant artifact, allowing effective evaluation of failed total joint prostheses. Bone scintigraphy remains an underused tool in the evaluation and management of orthopedic patients. [Orthopedics. 2019; 42(1):e14-e24.].

Biomarkers in Sports and Exercise: Tracking Health, Performance, and Recovery in Athletes

Lee, EC, Fragala, MS, Kavouras, SA, Queen, RM, Pryor, JL, and Casa, DJ. Biomarkers in sports and exercise: tracking health, performance, and recovery in athletes. J Strength Cond Res 31(10): 2920–2937, 2017—Biomarker discovery and validation is a critical aim of the medical and scientific community. Research into exercise and diet-related biomarkers aims to improve health, performance, and recovery in military personnel, athletes, and lay persons. Exercise physiology research has identified individual biomarkers for assessing health, performance, and recovery during exercise training. However, there are few recommendations for biomarker panels for tracking changes in individuals participating in physical activity and exercise training programs. Our approach was to review the current literature and recommend a collection of validated biomarkers in key categories of health, performance, and recovery that could be used for this purpose. We determined that a comprehensive performance set of biomarkers should include key markers of (a) nutrition and metabolic health, (b) hydration status, (c) muscle status, (d) endurance performance, (e) injury status and risk, and (f) inflammation. Our review will help coaches, clinical sport professionals, researchers, and athletes better understand how to comprehensively monitor physiologic changes, as they design training cycles that elicit maximal improvements in performance while minimizing overtraining and injury risk.

Taking a holistic approach to managing difficult stress fractures

Stress fractures and other bony stress injuries occur along a spectrum of severity which can impact treatment and prognosis. When treating these injuries, it should be borne in mind that no two stress fractures behave exactly alike. Given that they are not a consistent injury, standardized treatment protocols can be challenging to develop. Treatment should be individualized to the patient or athlete, the causative activity, the anatomical site, and the severity of the injury. A holistic approach to the treatment of the most difficult stress fractures should be taken by orthopedists and sports medicine specialists. This approach is necessary to obtain optimal outcomes, minimize loss of fitness and time away from sports participation, and decrease the risk of recurrence.

A curious case of stress fracture in a transsexual athlete

Femoral neck stress fractures in young healthy individuals are rare and occur in those who take part in physical training with repetitive loading and those with osteoporosis. Bone density is related to sex hormone status, which is artificially manipulated during gender reassignment. Conflicting evidence currently exists on the effect of cross sex hormone treatment on bone density, with no literature suggesting a link between hormone treatment in gender reassignment and stress fractures. Our aim is to highlight the potential risk of stress fractures amongst transsexual patients receiving cross sex hormones as part of gender reassignment. The patient presented with groin pain after competing in a running event. Despite a number of risk factors, there was a delay in diagnosis, which could have led to complications compromising outcome. Femoral neck stress fractures should be considered in the differential diagnosis of transsexual patients receiving hormone treatment with non-specific groin/thigh pain following exercise.

Medical expenditures in division I collegiate athletics: an analysis by sport and gender

OBJECTIVE

Medical expenses for collegiate athletics include providing a training room with its supplies, equipment, personnel costs, and insurance coverage. Additional expenses beyond the training room include imaging, diagnostic testing, specialty consultations, and surgeries. We hypothesized that there would be no difference in average expenses or number of claims between male and female athletes over a 5-year period.

DESIGN

Prospective patient cohort.

SETTING

A sports medicine center serving athletes in Big 10 Conference intercollegiate sports.

ASSESSMENT OF RISK FACTORS

All medical claims and charges for 36 varsity teams were analyzed from 2005 to 2010. The teams were categorized into 3 groups: female-only teams, male-only teams, and coed teams. Analysis of sports with corresponding male and female teams was also performed.

MAIN OUTCOME MEASUREMENTS

Claims and charges for medical care for 36 intercollegiate athletic teams over 5 years.

RESULTS

Individual team claims and charges were stable over the study period. In 11 of the 14 sex-matched sports, the female teams had higher average annual charges. After normalizing for roster size in the sex-matched sports, females had 0.97 more average annual claims (P < 0.01) and $1459 higher annual charges (P = 0.001) than their male counterparts. The charges per claim were similar between the sexes. The 5 teams with the highest average annual charges were football, wrestling, softball, women's crew, and men's lacrosse. When normalized for roster size, the 5 sports with the highest average annual charges per athlete were softball, women's diving, men's basketball, wrestling, and men's gymnastics.

CONCLUSION

Charges per claim were similar between the sex-matched sports, but the female sports had a higher number of annual claims per athlete and thus higher total charges per athlete/year. Football had the highest average annual total charges as a team, but when normalized for roster size football charges per athlete/year were similar to those of other sports.

Femoral neck stress fracture in a female athlete: a case report

OBJECTIVE

The purpose of this case report is to describe chiropractic rehabilitation of a master's-level athlete with proximal femoral stress fracture and provide a brief discussion of stress fracture pathology.

CLINICAL FEATURES

A 41-year-old female master's-level endurance athlete presented with chronic groin pain later diagnosed and confirmed by magnetic resonance imaging as a stress fracture of the femoral neck. After diagnosis, the patient was referred to a doctor of chiropractic at week 1 of the non-weight-bearing physical rehabilitation process. At that time, the patient presented with sharp and constant groin pain rated 6/10 on a numeric rating scale.

INTERVENTION AND OUTCOME

This patient avoided weight-bearing activity for 8 weeks while cross-training and was able to return to her sport after this period. The patient was progressed through a series of non-weight-bearing strengthening exercises for the lower extremity. Myofascial release therapy was performed on the gluteal, hip flexor, and groin muscle groups to improve range of motion. Motion palpation testing the lumbar and sacroiliac joints was performed during each session, and manipulative therapy was performed when necessary. The patient was seen once a week for 8 weeks. Reevaluation was performed at week 8; at that time, the patient reported no groin pain (0/10). The patient was discharged from care and referred back to the supervising physician for clearance to return to sporting activities. One month after discharge, she reported that she was pain free and had fully returned to sport activities.

CONCLUSION

This case report demonstrates the importance of a through clinical history, physical examination, and magnetic resonance imaging in the accurate diagnosis of a patient with chronic groin pain and that chiropractic care can contribute to rehabilitation programs for these injuries.

Update on stress fractures in female athletes: epidemiology, treatment, and prevention

Stress fractures are a common type of overuse injury in athletes. Females have unique risk factors such as the female athlete triad that contribute to stress fracture injuries. We review the current literature on risk factors for stress fractures, including the role of sports participation and nutrition factors. Discussion of the management of stress fractures is focused on radiographic criteria and anatomic location and how these contribute to return to play guidelines. We outline the current recommendations for evaluating and treatment of female athlete triad. Technologies that may aid in recovery from a stress fracture including use of anti-gravity treadmills are discussed. Prevention strategies may include early screening of female athlete triad, promoting early participation in activities that improve bone health, nutritional strategies, gait modification, and orthotics.

Stress fractures of the pelvis and legs in athletes: a review

CONTEXT

Stress fractures are common injuries in athletes, often difficult to diagnose. A stress fracture is a fatigue-induced fracture of bone caused by repeated applications of stress over time.

EVIDENCE ACQUISITION

PubMed articles published from 1974 to January 2012.

RESULTS

Intrinsic and extrinsic factors may predict the risk of stress fractures in athletes, including bone health, training, nutrition, and biomechanical factors. Based on their location, stress fractures may be categorized as low- or high-risk, depending on the likelihood of the injury developing into a complete fracture. Treatment for these injuries varies substantially and must account for the risk level of the fractured bone, the stage of fracture development, and the needs of the patient. High-risk fractures include the anterior tibia, lateral femoral neck, patella, medial malleolus, and femoral head. Low-risk fractures include the posteromedial tibia, fibula, medial femoral shaft, and pelvis. Magnetic resonance is the imaging test of choice for diagnosis.

CONCLUSIONS

These injuries can lead to substantial lost time from participation. Treatment will vary by fracture location, but most stress fractures will heal with rest and modified weightbearing. Some may require more aggressive intervention, such as prolonged nonweightbearing movement or surgery. Contributing factors should also be addressed prior to return to sports.

A prospective investigation of injury incidence and injury risk factors among Army recruits in military police training

BACKGROUND

United States Army military police (MP) training is a 19-week course designed to introduce new recruits to basic soldiering skills, Army values and lifestyle, and law enforcement skills and knowledge. The present investigation examined injury rates and injury risk factors in MP training.

METHODS

At the start of training, 1,838 male and 553 female MP recruits were administered a questionnaire containing items on date of birth, height, weight, tobacco use, prior physical activity, injury history, and menstrual history. Injuries during training were obtained from electronic medical records and the training units provided data on student graduation and attrition.

RESULTS

Successfully graduating from the course were 94.3% of the men and 83.7% of the women. Experiencing at least one injury during training were 34.2% of the men and 66.7% of the women (risk ratio (women/men) = 1.95, 95% confidence interval = 1.79-2.13). Recruits were at higher injury risk if they reported that they were older, had smoked in the past, or had performed less frequent exercise or sports prior to MP training. Men were at higher injury risk if they reported a prior injury and women were at higher risk if they reported missing at least six menstrual cycles in the last year or had previously been pregnant.

CONCLUSION

The present investigation was the first to identify injury rates and identify specific factors increasing injury risk during MP training.

The effects of delayed puberty on the growth plate

BACKGROUND

Many athletes are beginning intense training before puberty, a time of increased bone accrual when up to 25% of total bone mineral accrual occurs. Female athletes experiencing late or delayed pubertal onset may have open epiphyseal plates that are vulnerable to injury. This investigation's purpose was to determine whether a delay in puberty (primary amenorrhea) affects the growth plate immediately postpuberty and at maturity.

METHODS

Forty-eight female Sprague-Dawley rats (23 d old) were randomly assigned to 4 groups (n=12); short-term control (C-ST), long-term control (C-LT), short-term GnRH antagonist (G-ST), and long-term GnRH antagonist (G-LT). At 25 days of age, daily gonadotropin-releasing hormone antagonist (GnRH-a) injections were administered delaying pubertal onset. Left tibias were analyzed. Stained frontal slices of proximal tibia (5 µm thick) were analyzed in hypertrophic, proliferative, and reserve zones for total height, zone height, and cell/column counts. All procedures were approved by Institutional Animal Care and Use Committee at Brooklyn College.

RESULTS

Growth plate height was 19.7% wider in delayed puberty (G-ST) group and at maturity was 27.9% greater in G-LT group compared with control (C-LT) (P<0.05). No significant differences were found in short-term or long-term growth plate zone heights or cell/column counts between groups (P>0.05). Growth plate zone height normalized to total height resulted in 28.7% larger reserve zone in the short-term GnRH-a group but the proliferative zone was 8.5% larger in the long-term group compared with the control group (P<0.05). Normalized to growth plate height a significant decrease was found in column counts in proliferative zones of the short-term and long-term GnRH-a groups.

CONCLUSIONS

Current data illustrate that delayed puberty using GnRH-a injections results in significant growth plate height and decreases proliferative column counts and zone height, thus potentially contributing to decreases in bone mass at maturity.

CLINICAL RELEVANCE

Growth plate height increases indicate increased potential for growth and bone accrual. However, previous models report decreased bone volume following delayed puberty via GnRH-a injections that may have detrimental effects in the long term.

Taking the stress out of evaluating stress injuries in children

Pediatric stress injuries result from a mismatch between (a) the burden of activity on growing bone and cartilage and (b) their intrinsic biomechanical properties. Although the presentation of stress injuries varies with the specific physical activity and the site of injury, in children it varies primarily with the degree of skeletal maturation. During the past several years, there has been a substantial increase in the incidence of pediatric stress injuries. The differential diagnosis of a stress injury in a child or adolescent can be challenging because the injury sometimes can appear aggressive at imaging assessment. Awareness of the spectrum of imaging features of stress injuries can help the radiologist to reach the correct diagnosis and prevent unnecessary anxiety. This review depicts the range of stress injuries in children and adolescents in various anatomic locations, with emphasis on their appearances at magnetic resonance imaging.

Obstacles in the optimization of bone health outcomes in the female athlete triad

Maintaining low body weight for the sake of performance and aesthetic purposes is a common feature among young girls and women who exercise on a regular basis, including elite, college and high-school athletes, members of fitness centres, and recreational exercisers. High energy expenditure without adequate compensation in energy intake leads to an energy deficiency, which may ultimately affect reproductive function and bone health. The combination of low energy availability, menstrual disturbances and low bone mineral density is referred to as the 'female athlete triad'. Not all athletes seek medical assistance in response to the absence of menstruation for 3 or more months as some believe that long-term amenorrhoea is not harmful. Indeed, many women may not seek medical attention until they sustain a stress fracture. This review investigates current issues, controversies and strategies in the clinical management of bone health concerns related to the female athlete triad. Current recommendations focus on either increasing energy intake or decreasing energy expenditure, as this approach remains the most efficient strategy to prevent further bone health complications. However, convincing the athlete to increase energy availability can be extremely challenging. Oral contraceptive therapy seems to be a common strategy chosen by many physicians to address bone health issues in young women with amenorrhoea, although there is little evidence that this strategy improves bone mineral density in this population. Assessment of bone health itself is difficult due to the limitations of dual-energy X-ray absorptiometry (DXA) to estimate bone strength. Understanding how bone strength is affected by low energy availability, weight gain and resumption of menses requires further investigations using 3-dimensional bone imaging techniques in order to improve the clinical management of the female athlete triad.

The female athlete

Over time, women have become more extensively involved in athletic programs. The female athlete presents a unique challenge to sports medicine in general. Although specific types of injuries are the same as in the male athlete, the female athlete is at higher risk for some of these injuries. Injuries may be sport specific, but gender-related injuries are also related to morphologic and physiologic differences between the male and female athlete. This article reviews some of the differences between the male and female athlete and focuses on a few prominent injuries or risks related specifically to the woman athlete.

Surgical treatment of refractory tibial stress fractures in elite dancers: a case series

BACKGROUND

Treatment of tibial stress fractures in elite dancers is centered on rest and activity modification. Surgical intervention in refractory cases has important implications affecting the dancers' careers.

HYPOTHESIS

Refractory tibial stress fractures in dancers can be treated successfully with drilling and bone grafting or intramedullary nailing.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

Between 1992 and 2006, 1757 dancers were evaluated at a dance medicine clinic; 24 dancers (1.4%) had 31 tibial stress fractures. Of that subset, 7 (29.2%) elite dancers with 8 tibial stress fractures were treated operatively with either intramedullary nailing or drilling and bone grafting. Six of the patients were followed up closely until they were able to return to dance. One patient was available only for follow-up phone interview. Data concerning their preoperative treatment regimens, operative procedures, clinical union, radiographic union, and time until return to dance were recorded and analyzed.

RESULTS

The mean age of the surgical patients at the time of stress fracture was 22.6 years. The mean duration of preoperative symptoms before surgical intervention was 25.8 months. Four of the dancers were male and 3 were female. All had failed nonoperative treatment regimens. Five patients (5 tibias) underwent drilling and bone grafting of the lesion, and 2 patients (3 tibias) with completed fractures or multiple refractory stress fractures underwent intramedullary nailing. Clinical union was achieved at a mean of 6 weeks and radiographic union at 5.1 months. Return to full dance activity was at an average of 6.5 months postoperatively.

CONCLUSION

Surgical intervention for tibial stress fractures in dancers who have not responded to nonoperative management allowed for resolution of symptoms and return to dancing with minimal morbidity.

Delayed pubertal development by hypothalamic suppression causes an increase in periosteal modeling but a reduction in bone strength in growing female rats

The timing of the pubertal growth is a critical event in skeletal development. A delay in the onset of puberty has been correlated with increased stress fracture incidence in young women and as a result, suboptimal skeletal development may affect long-term bone strength. Gonadotropin releasing hormone antagonist (GnRH-a) injections were used to delay the onset of puberty in growing female rats. 23-day-old female rats were injected with a GnRH-antagonist at 2 dosage levels (n=15/group). The Low Dose group (1.25 mg/kg/dose) received daily injections for 27 days (sacrifice 49 days). The High Dose group received (5.0 mg/kg/dose) only 5 days per week over a 26 day period (sacrifice 48 days). Calcein injections measured bone formation activity on the periosteal and endocortical surfaces. Standard histomorphometric and biomechanical analyses were performed on the femora and ash content was measured on the tibiae of all animals. Serum estradiol and insulin-like growth factor (IGF)-1 levels were assayed. Significant delays in pubertal development occurred in the two GnRH-a groups as evidenced by delayed vaginal openings, decreased uterine and ovarian weights and suppressed estradiol levels compared to control. Femoral lengths were significantly shorter in the experimental groups and serum IGF-1 levels were higher than control. Bone strength and stiffness were significantly lower in the GnRH-a groups. Cortical bone area was decreased and total area was not different between groups. There was a significant decrease in % Ct.Ar/T.Ar. The decreased bone strength may have resulted from a decrease in the amount and distribution of bone, however, stress and Young's modulus were also decreased. There was a different response between endocortical formation indices and periosteal formation indices to the GnRH-a protocol. Endocortical bone formation rates decreased and there was an increase in periosteal labeled surface. A dose response between bone strength and GnRH-a dosage was found. The data suggest that hypothalamic suppression during pubertal development resulted in decreased bone strength which may result in fracture development.

Eating disorders in adolescence: what is the role of hormone replacement therapy?

PURPOSE OF REVIEW

To review the diagnostic criteria and clinical presentation of eating disorders in adolescence, to outline an approach to treatment, and examine evidence for prescribing hormone replacement therapy to increase bone mineral density in anorexia nervosa.

RECENT FINDINGS

Eating disorders are prevalent in adolescents and can present with amenorrhea and menstrual disturbances. Reduced bone mineral density leading to osteoporosis and increased fracture risk is a frequent, severe, and potentially irreversible complication of anorexia nervosa. The degree of bone mineral density reduction depends on the duration of amenorrhea and degree of malnutrition. Limited evidence supports the use of hormone replacement therapy to increase bone mineral density in adolescents with anorexia nervosa.

SUMMARY

In adolescents with amenorrhea or menstrual disturbances, the gynecologist should consider the possibility of an eating disorder. The diagnosis can be made on history and physical examination. If an eating disorder is suspected, the patient should be referred for evaluation and treatment. Support for the use of hormone replacement therapy to increase bone mineral density in adolescents with anorexia nervosa is limited, and its routine use should be discouraged. Weight restoration, calcium and vitamin D supplementation and the resumption of spontaneous menses is the mainstay of treatment.

Overuse injuries in female athletes

The last three decades have witnessed a tremendous increase in female sports participation at all levels. However, increased sports participation of female athletes has also increased the incidence of sport-related injuries, which can be either acute trauma or overuse injuries. Overuse injuries may be defined as an imbalance caused by overly intensive training and inadequate recovery, which subsequently leads to a breakdown in tissue reparative mechanisms. This article will review the most frequent overuse injuries in female athletes in the context of anatomical, physiological, and psychological differences between genders.

Voluntary run training but not estradiol deficiency alters the tibial bone-soleus muscle functional relationship in mice

The study's objective was to investigate how estrogen deficiency and run training affect the tibial bone-soleus muscle functional relationship in mice. Female mice were assigned into one of two surgical conditions, ovariectomy (OVX) or sham ovariectomy (sham), and one of two activity conditions, voluntary wheel running (Run) or sedentary (Sed). To determine whether differences observed between OVX and sham conditions could be attributed to estradiol (E2), additional OVX mice were supplemented with E2. Tibial bones were analyzed for their functional capacities, ultimate load, and stiffness. Soleus muscles were analyzed for their functional capacities, maximal isometric tetanic force (Po), and peak eccentric force. The ratios of bone functional capacities to those of muscle were calculated. The bone functional capacities were affected by both surgical condition and activity but more strongly by surgical condition. Ultimate load and stiffness for the sham group were 7–12% greater than those for OVX animals ( P = 0.002), whereas only stiffness was greater for Run than for Sed animals (9%; P = 0.015). The muscle functional capacities were affected by both surgical condition and activity; however, in contrast to the bone, the muscle was more affected by activity. Po and peak eccentric force were 10–21% greater for Run than for Sed animals ( P ≤ 0.016), whereas only Po was greater in sham than in OVX animals (9%; P = 0.011). The bone-to-muscle ratios of functional capacities were affected by activity but not by surgical condition or E2 supplementation. Thus a mismatch of bone-muscle function occurred in mice that voluntarily ran on wheels, irrespective of estrogen status.