Physiological Parameters of Bone Health in Elite Ballet Dancers

Analysis of the effects of eating and emotions on reproductive axis function in patients with functional hypothalamic amenorrhea

Objective: To investigate the effects of eating and emotions on reproductive axis function in patients with functional hypothalamic amenorrhea (FHA).

Methods: A retrospective cohort study was conducted to summarize the clinical and endocrine characteristics of 58 patients with FHA at initial diagnosis and to follow up the recovery of ovulation and spontaneous menstruation in the patients to investigate these biochemical indicators and their effects on recovery outcomes.

Results: Among patients with FHA, 13.8% (8/58) and 15.5% (9/58) had above moderately severe depressive and severe anxiety symptoms respectively, and 25.9% (15/58) were at high risk for eating disorders. 34.5% (20/58) were included assessed as having recovered. The non-recovered group had higher scores on the Patient Health Questionnaire (PHQ-9) (p = .022) and higher scores on the Eating Attitude Test-26 (EAT-26) (p = .03) as well as bulimia and food preoccupation (p = .041). Follicle diameter >5 mm at initial diagnosis was an independent factor influencing recovery of reproductive axis function (odds ratio = 7.532; 95% confidence interval, 1.321-42.930; p = .023).

Conculsions: Mood disorders and a certain risk of eating disorders were present in FHA.These, together with weight loss, endocrine and follicle size, could influence the outcome.

Evaluation of the Physiological and Psychological Impact of Ballet Performances Across Age Cohorts: An Observational Uncontrolled Case Study

Background: Ballet, epitomized by iconic seasonal performances such as "The Nutcracker," combines artistic expression with considerable physical demands. This study investigated the physiological and psychological responses of ballet dancers to the demands of intensive training and performance, with a specific focus on "The Nutcracker." Methods: Thirty- eight dancers volunteered for the study, including 6 youths (10.5 + 1.8 years, n = 6 female), 7 adolescents (15.4 + 1.1 years, n = 5 female), and 25 adults (21.1 + 2.1 years, n = 20 female). Employing an uncontrolled observational design, this pilot study tracked key biomarkers such as CK-MM for muscle damage and B-ALP for bone health, alongside psychological measures via PANAS-C/PANAS and DASS-21. Results: Significant findings included a post-performance reduction in cortisol and depression levels. Conclusion: These insights advocate for tailored strategies that address the multifaceted needs of dancers, acknowledging the intricate balance required to maintain peak performance and overall health within the demanding realm of professional ballet.

A novel non-invasive method for predicting bone mineral density and fracture risk using demographic and anthropometric measures

Fractures are costly to treat and can significantly increase morbidity. Although dual-energy x-ray absorptiometry (DEXA) is used to screen at risk people with low bone mineral density (BMD), not all areas have access to one. We sought to create a readily accessible, inexpensive, high-throughput prediction tool for BMD that may identify people at risk of fracture for further evaluation. Anthropometric and demographic data were collected from 492 volunteers (♂275, ♀217; [44 ​± ​20] years; Body Mass Index (BMI) = [27.6 ​± ​6.0] kg/m2) in addition to total body bone mineral content (BMC, kg) and BMD measurements of the spine, pelvis, arms, legs and total body. Multiple-linear-regression with step-wise removal was used to develop a two-step prediction model for BMC followed by BMC. Model selection was determined by the highest adjusted R2, lowest error of estimate, and lowest level of variance inflation (α ​= ​0.05). Height (HTcm), age (years), sexm=1, f=0, %body fat (%fat), fat free mass (FFMkg), fat mass (FMkg), leg length (LLcm), shoulder width (SHWDTHcm), trunk length (TRNKLcm), and pelvis width (PWDTHcm) were observed to be significant predictors in the following two-step model (p ​< ​0.05). Step1: BMC (kg) = (0.006 3 × HT) ​+ ​(-0.002 4 × AGE) ​+ ​(0.171 2 × SEXm=1, f=0) ​+ ​(0.031 4 × FFM) ​+ ​(0.001 × FM) ​+ ​(0.008 9 × SHWDTH) ​+ ​(-0.014 5 × TRNKL) ​+ ​(-0.027 8 × PWDTH) - 0.507 3; R2 ​= ​0.819, SE ​± ​0.301. Step2: Total body BMD (g/cm2) = (-0.002 8 × HT) ​+ ​(-0.043 7 × SEXm=1, f=0) ​+ ​(0.000 8 × %FAT) ​+ ​(0.297 0 × BMC) ​+ ​(-0.002 3 × LL) ​+ ​(0.002 3 × SHWDTH) ​+ ​(-0.002 5 × TRNKL) ​+ ​(-0.011 3 × PWDTH) ​+ ​1.379; R2 ​= ​0.89, SE ​± ​0.054. Similar models were also developed to predict leg, arm, spine, and pelvis BMD (R2 ​= ​0.796-0.864, p ​< ​0.05). The equations developed here represent promising tools for identifying individuals with low BMD at risk of fracture who would benefit from further evaluation, especially in the resource or time restricted setting.

Management of Stress Fractures in Ballet

Stress fractures are highly prevalent in ballet dancers and lead to notable time loss from dancing. Nutritional status, body composition, bone mineral density, and rate of increase in activity are among the components that influence risk for stress fractures. Proper evaluation and management of stress fractures is essential including a review of the causative factors involved in each stress injury. The purpose of this article was to summarize current evidence for risk factors involved in dancers' stress fractures to optimize prevention and treatment. Identified associated factors include low energy availability, low bone mineral density, low fat body composition, abnormal lower extremity biomechanics, genetic factors, and high training loads.

Anthropometric Factors Associated With Bone Stress Injuries in Collegiate Distance Runners: New Risk Metrics and Screening Tools?

BACKGROUND

Lower limb bone stress injury (BSI) of the pelvis, femur, and tibia is prevalent in collegiate track and field distance runners. Bone mineral density (BMD), body composition (BComp), and anthropometric parameters before initial collegiate injury have not been compared between runners with BSI and their noninjured counterparts.

PURPOSE

To characterize bone health in relation to BComp and anthropometric measurements from total-body dual x-ray absorptiometry (DXA) scans in collegiate male and female distance runners before BSI and develop BMD prediction models.

STUDY DESIGN

Case-control study; Level of evidence, 3.

METHODS

Distance runners (N = 79) from a single university track and field team were retrospectively enrolled into this study. The runners completed a DXA scan during the fall season (August-November) and participated in sport activities before the scan. Three months after scanning, electronic medical records were reviewed for the occurrence of BSI. An independent-sample t test was used to compare BMD (total and regional [spine, pelvis, and legs]), BComp (% body fat, fat mass, and lean mass), and anthropometric measurements (shoulder width and leg, arm, and trunk length) between runners with versus without BSI (included subgroup analysis by sex). Multiple linear regression with stepwise removal was used to determine variables most predictive of BMD.

RESULTS

Of the 79 enrolled participants (42 male, 37 female), 18 runners (22.8%; 11 female, 7 male) sustained a lower limb BSI. Compared with the noninjured group, injured runners had lower total and regional BMD (P < .001 for all) and shorter leg and arm lengths (P < .05 for both), whereas injured male runners had lower fat mass and injured female runners had lower lean mass in the legs (P < .05 for both). Injured runners' age-matched total BMD Z score (-0.1 ± 0.6) was considered clinically normal. BComp and anthropometric measures were predictive of total and regional BMD (P < .05; R 2 = 0.64-0.80; percentage error = 3.8%-4.8%).

CONCLUSION

The DXA scans of injured runners prior to incidence indicated lower BMD compared with noninjured runners. Shorter limb lengths, lower fat mass (male), and lower leg lean mass (female) may also be indicative of risk. Certain BComp and anthropometric measures were predictive of BMD.

Pelvic region bone density, soft tissue mass, and injury frequency in female professional ballet dancers and soccer athletes

We recently observed a high prevalence of low pelvic bone mineral density (BMD) in female professional ballet performers. Because this population is susceptible to musculoskeletal overuse injuries, we aimed to determine which regions of the pelvis may be at greatest risk compared to general population females (GENPOP) as well as professional female soccer players (SOCCER, a comparison to other elite athletes regularly subjected to high degrees of loading). Three groups of age-matched females [(GENPOP; n = 38, 27±1yrs), (BALLET; single company, n = 36, 26±3yrs), (SOCCER; single NWSL® club, n = 34, 25±1yrs)] consented to have their BMD and body composition assessed (DEXA, GE®). In addition to soft tissue and total and regional BMD analyses, a segmental analysis of the pelvis was performed to determine site-specific BMD for the iliac fossa, iliac fossa/iliac crest/ilium combined, pubic bone, ischium, and sacrum. A mixed-model ANOVA followed by a Tukey's post-hoc test was used to compare the groups (Type-I error; α = 0.05). The BALLET group had lower pelvic BMD for all measures (Avg.%Diff. = 15%-27%, p<0.001) compared to the SOCCER group and for the ischium (Avg.%Diff.= 8%; p=0.007) and sacrum (Avg.%Diff. ​= ​7%; p = 0.028) compared to the GENPOP group. The BALLET group had lower lean mass for all measures compared to the other groups (Avg.%Diff. = 12%-18%; p < 0.01). Professional ballet performers exhibit reduced pelvic region soft tissue and site-specific BMD not previously detected using standard DEXA analyses. These findings highlight which pelvic regions may benefit from preventative strength training and/or nutritional interventions.

Amateur ballet practicing, body image and eating behaviors: a comparative study of classical ballet dancers, gym users and sedentary women

BACKGROUND

Ballet dancers are a risk group for body image (BI) distortion, dissatisfaction and eating disorders (ED), but few studies have investigated these aspects in amateur adult practitioners. This study aimed to evaluate if amateur female adult classical ballet dancers presented different BI and behaviors for ED than gym users and sedentary women.

METHODS

This is a cross-sectional study where classical ballet dancers (n = 19) were compared to gym users (n = 19) and sedentary women (n = 19). Body mass index (BMI) was assessed, and a figure rating scale was applied to assess BI distortion/dissatisfaction. The body shape questionnaire (BSQ) was used to measure BI concern. The eating attitudes test (EAT-26) and the bulimic investigatory test, Edinburgh (BITE) were used for behaviors toward anorexia and bulimia.

RESULTS

BMI was significantly lower in ballet dancers than gym users and sedentary women (F, p = .04). BI distortion did not differ among the studied groups. BI dissatisfaction was lower (X², p = .041) in ballet dancers (75.0%) and gym users (70.6%) compared to sedentary women (100%). Correspondence analysis showed ballet dancers were mostly not concerned with BI, which was not observed among the other groups. The EAT-26 did not differ between the studied groups. The BITE score was lower (Tukey's post hoc test, p = .005) in the ballet dancers [mean 5.3 (5.6)] compared to the sedentary women [mean 10.9 (4.8)].

CONCLUSIONS

Data suggest that amateur classical ballet practicing is associated to better BI and fewer behaviors for ED in the studied population. The lower BMI in ballet dancers might explain these findings, and further studies should explore these associations.

The Role of Fatigue in Return to Sport Testing Following Anterior Cruciate Ligament Reconstruction

BACKGROUND

Fatigue may play a role in anterior cruciate ligament (ACL) injury, but has not been incorporated into objective test batteries for return to sport decisions following ACL reconstruction (ACLR) surgery. The effect of fatigue on muscle function and performance following surgery and rehabilitation has been poorly studied.

PURPOSE/HYPOTHESIS

The purpose of this study was to assess the effect of fatigue on performance of various hop tests used in clinical rehabilitation settings by examining LSI scores. The authors hypothesized that participants will have worse limb symmetry index scores following the fatigue protocol and that the operative limb (ACLR) will have a greater decline in function than the non-operative limb (CON).

STUDY DESIGN

Cross-Sectional Study.

METHODS

Participants (n=21 [Male = 15, Female = 6]; AGE = 24.6 ± 9.3) were at least six months post ACLR and in rehabilitation. Testing was performed over two separate sessions in either a non-fatigued (NFS) or fatigued state (FS). In the FS, individuals performed a series of exercises to exhaust muscular endurance, strength, and power systems, after which they performed as battery of seven hop tests (single hop for distance, triple hop for distance, crossover hop for distance, 6-meter timed hop, lateral rotation hop for distance, medial rotation hop for distance, and vertical jump for height). A 2(limb) x 2(time) ANOVA was used to compare limbs between each state.

RESULTS

Differences between limbs (CON vs ACLR) were observed for all hop tests in the NFS whereby the ACLR limb was observed to have reduced performance (↓5.4-9.1%, p <0.05). When tested in the FS, significant differences in performance between limbs remained for only the crossover (↓4.9%), medial rotation (↓7.1%), lateral rotation (↓5.5%), and vertical hop (↓10.0%)(p<0.05). When comparing the NFS and FS states, only the CON limb was observed to have significant decreases in performance of the Triple Hop (↓7.4%), Crossover (↓8.7%), and Lateral Rotation (↓5.2%)(p<0.05).

CONCLUSIONS

Following ACL reconstruction, there appears to be a greater loss in jump performance in the CON limb in the FS. These findings suggest it may be crucial to consider and assess the endurance of both limbs rather than just the ACLR limb when determining readiness for return to play.

LEVEL OF EVIDENCE

Level 3.