Polygenic Risk Score, Cardiorespiratory Fitness, and Cardiometabolic Risk Factors: WASEDA'S Health Study.

PURPOSE: This study estimated an individual's genetic liability to cardiometabolic risk factors by polygenic risk score (PRS) construction and examined whether high cardiorespiratory fitness (CRF) modifies the association between PRS and cardiometabolic risk factors. METHODS: This cross-sectional study enrolled 1,296 Japanese adults aged ≥40 years. The PRS for each cardiometabolic trait (blood lipids, glucose, hypertension, and obesity) was calculated using the LDpred2 and clumping and thresholding methods. Participants were divided into low-, intermediate-, and high-PRS groups according to PRS tertiles for each trait. CRF was quantified as peak oxygen uptake (VO 2 peak) per kg body weight. Participants were divided into low-, intermediate-, and high-CRF groups according to the tertile VO 2 peak value. RESULTS: Linear regression analysis revealed a significant interaction between PRS for triglyceride (PRS TG ) and CRF groups on serum TG levels regardless of the PRS calculation method, and attenuated the association between PRS TG and TG levels in the high-CRF group. Logistic regression analysis revealed a significant sub-additive interaction between LDpred2 PRS TG and CRF on the prevalence of high TG, indicating that high CRF attenuated the genetic predisposition to high TG. Furthermore, a significant sub-additive interaction between PRS for body mass index and CRF on obesity was detected regardless of the PRS calculation method. These significant interaction effects on high TG and obesity were diminished in the sensitivity analysis using VO 2 peak per kg fat-free mass as the CRF index. Effects of PRSs for other cardiometabolic traits were not significantly attenuated in the high-CRF group regardless of PRS calculation methods. CONCLUSIONS: The findings of the present study suggest that individuals with high CRF overcome the genetic predisposition to high TG levels and obesity.

Muscle injuries in athletics during the 2020 Tokyo Olympic Games: differences between heats and finals.

BACKGROUND: The aim of this study was to analyze muscle injuries and their related risk factors during the Athletics events of the 2020 Tokyo Olympic Games including the differences in muscle injury rates between heats and finals. METHODS: We included and analyzed in this study muscle injuries diagnosed by either magnetic resonance imaging, ultrasound, or physical examinations by at least two physicians, from Athletics athletes participating at the 2020 Tokyo Olympic Games. Data from electronic medical records, including sex, nationality, event, and the round (heat vs. final) during which the muscle injury occurred and the air temperature in the stadium, measured every five minutes during the competition were extracted. RESULTS: Among the 1631 athletes who competed, a total of 36 athletes (20 males and 16 females) were diagnosed with a muscle injury during the 2020 Tokyo Olympic Games. Among them, 24 occurred during heats (1.47 per 100 athletes) and 12 during finals (2.20 per 100 athletes) (P=0.25). Logistic regression analysis revealed that the geographic region of athletes' origin was a factor associated with muscle injury, with the highest muscle injury rate being in athletes from Africa (odds ratio [OR]=4.74, 95% confidence interval [CI]) = 1.75 to 12.82) and North America (OR=3.02, 95%CI=1.27 to 7.20). For male athletes, competing in finals was a risk factor to sustain a muscle injury (OR=2.55, 95%CI=1.01 to 6.45). CONCLUSIONS: During the 2020 Olympic Games, muscle injury rate was higher in finals than in heats, reaching statistical significance in male athletes.

Characteristics of non-exercise activity thermogenesis in male collegiate athletes under real-life conditions.

Athletes experience high total energy expenditure; therefore, it is important to understand the characteristics of the components contributing to this expenditure. To date, few studies have examined particularly the volume and activity intensity of non-exercise activity thermogenesis (NEAT) in athletes compared to non-athletes under real-life conditions. This study aimed to determine the volume and intensity of NEAT in collegiate athletes. Highly trained Japanese male collegiate athletes (n = 21) and healthy sedentary male students (n = 12) participated in this study. All measurements were obtained during the athletes' regular training season under real-life conditions. NEAT was calculated using metabolic equivalent (MET) data using an accelerometer. The participants were asked to wear a validated triaxial accelerometer for 7 consecutive days. Physical activity intensity in NEAT was classified into sedentary (1.0-1.5 METs), light (1.6-2.9 METs), moderate (3.0-5.9 METs), and vigorous (≥6 METs) intensity. NEAT was significantly higher in athletes than in non-athletes (821 ± 185 kcal/day vs. 643 ± 164 kcal/day, p = 0.009). Although there was no significant difference in NEAT values relative to body weight (BW) between the groups (athletes: 10.5 ± 1.7 kcal/kg BW/day, non-athletes: 10.4 ± 2.2 kcal/kg BW/day, p = 0.939), NEAT to BW per hour was significantly higher in athletes than in non-athletes (0.81 ± 0.16 kcal/kg BW/h vs. 0.66 ± 0.12 kcal/kg BW/h, p = 0.013). Athletes spent less time in sedentary and light-intensity activities and more time in vigorous-intensity activities than non-athletes (p < 0.001, p = 0.019, and p = 0.030, respectively). Athletes expended more energy on vigorous- and moderate-intensity activities than non-athletes (p = 0.009 and p = 0.011, respectively). This study suggests that athletes' NEAT relative to BW per day is similar to that of non-athletes, but athletes spend less time on NEAT, which makes them more active in their daily lives when not exercising and sleeping.

Differences in Lumbopelvic Alignment in Adolescent Male Soccer Players With Bilateral and Unilateral Lumbar Bone Stress Injuries: An MRI Evaluation.

Background: Differences in the physical characteristics of bilateral and unilateral lumbar bone stress injuries (BSIs) are unknown. Purpose: To compare bilateral and unilateral lumbar BSIs in adolescent male soccer players, with a focus on lumbopelvic alignment. Study Design: Cross-sectional study; Level of evidence, 3. Methods: A total of 78 players (age range, 12-15 years) from a local soccer club who had magnetic resonance imaging (MRI) evaluations were included in the study. Lumbopelvic alignment and lumbar BSI were evaluated using short-tau inversion recovery and 3-dimensional LAVA on 3-T MRI; lumbar BSI was defined as the presence of bone marrow edema and/or the complete and incomplete fracture in the pars region on the MRI. Pelvic tilt (PT) and pelvic outflare angles were assessed on the kicking and pivoting sides, and asymmetry for each parameter was calculated by subtracting the kicking side from the pivoting side. In addition, the lumbar lordosis (LL), sacral slope (SS), and SS relative to LL (calculated by subtracting LL from the SS) were assessed. One-way analysis of variance was performed to compare lumbopelvic alignment in players with bilateral BSI, unilateral BSI, or no abnormal findings (controls). Results: No significant differences were found regarding lumbopelvic alignment between the players with bilateral versus unilateral lumbar BSI. PT asymmetry was significantly greater in both players with bilateral lumbar BSI and unilateral lumbar BSI compared with controls (P = .018 and P = .016, respectively). In addition, SS relative to LL was significantly greater in players with bilateral lumbar BSI compared with controls (P < .001). Conclusion: Although there were no significant lumbopelvic alignment differences between bilateral and unilateral BSI, players with bilateral BSI exhibited increased sacral anterior tilt relative to the LL, and the pelvis was more posterior on the pivoting side than on the kicking side in both players with bilateral BSI and unilateral BSI. Our results suggest that lumbopelvic alignment assessment may contribute to the management strategy for players with lumbar BSI and to the identification of players at high risk of lumbar BSI.

Being underweight, academic performance and cognitive control in undergraduate women.

The prevalence of underweight among young women is a serious international health issue. However, the evidence on how being underweight negatively affects brain health and cognition is still unclear. This study investigated the association between underweight status, academic performance, and neurocognitive control in young Japanese women using a cross-sectional design. We analyzed the academic performance of female undergraduates, comparing underweight and healthy-weight groups (n = 43; age 18-23 years, M = 21.1, SD = 1.3) based on their grade point average (GPA). We also analyzed their error-related negativity (ERN), an electrophysiological measure that potentially reflects academic performance, during an arrowhead version of the flanker task to assess cognitive control of action monitoring. Participants with a low body mass index were found to have lower GPAs. Furthermore, the underweight students exhibited smaller ERN amplitudes, which indicates decreased cognitive control in action monitoring. These findings suggest that a healthy weight status is essential for effective cognitive functioning and academic success in young adult women, among whom being underweight is a serious health problem.

International study of physicians' opinion on physician-patient sex concordance when treating athletes.

BACKGROUND: The effect of physician-patient sex concordance in medicine has been reported in many studies. Whether physicians believe that the sex concordance between physician and athlete influences treatment has not been investigated. OBJECTIVE: To determine whether physicians believe that the sex concordance between physician and athlete influences treatment. DESIGN: Cross-sectional study. SETTING: Online survey. PARTICIPANTS: One thousand one hundred ninety-three sports medicine physicians in 51 countries. Participants were sports medicine physicians trained in orthopedics (n = 443 [37.1%]) and nonorthopedics (n = 750 [62.9%]). INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Participants were asked to decide whether sex of the physician made them better suited to care for athletes of concordant or different sexes along with their personal background. RESULTS: Orthopedic sports medicine physicians agreed less than nonorthopedic sports medicine physicians regarding the statement "MALE sports medicine physicians are better suited than their female counterparts to care for MALE athletes" (odds ratio [OR] 0.56, 95% confidence interval [CI] 0.35-0.91, p = .02), and compared to sports medicine physicians based in Europe, those based in Asia agreed more to this statement (OR 7.91, 95% CI 4.60-13.60, p < .01). In addition, regarding the statement "FEMALE sports medicine physicians are better suited than their male counterparts to care for FEMALE athletes," compared to sports medicine physicians based in Europe, those based in Asia (OR 9.12, 95% CI 5.63-14.79, p < .01) and North America (OR 2.18, 95% CI 1.46-3.25, p < .01) agreed more and orthopedic sports medicine physicians agreed less than nonorthopedic sports medicine physicians (OR 0.61, 95% CI 0.39-0.93, p = .02) to this statement. CONCLUSIONS: Sports medicine physicians trained in orthopedics felt sex concordance was less important than physicians trained in other specialties. Asian sports medicine physicians believed sex concordance was more important compared to physicians in other regions.

Associations between cardiorespiratory fitness and lifestyle-related factors with DNA methylation-based ageing clocks in older men: WASEDA'S Health Study.

DNA methylation-based age estimators (DNAm ageing clocks) are currently one of the most promising biomarkers for predicting biological age. However, the relationships between cardiorespiratory fitness (CRF), measured directly by expiratory gas analysis, and DNAm ageing clocks are largely unknown. We investigated the relationships between CRF and the age-adjusted value from the residuals of the regression of DNAm ageing clock to chronological age (DNAmAgeAcceleration: DNAmAgeAccel) and attempted to determine the relative contribution of CRF to DNAmAgeAccel in the presence of other lifestyle factors. DNA samples from 144 Japanese men aged 65-72 years were used to appraise first- (i.e., DNAmHorvath and DNAmHannum) and second- (i.e., DNAmPhenoAge, DNAmGrimAge, and DNAmFitAge) generation DNAm ageing clocks. Various surveys and measurements were conducted, including physical fitness, body composition, blood biochemical parameters, nutrient intake, smoking, alcohol consumption, disease status, sleep status, and chronotype. Both oxygen uptake at ventilatory threshold (VO2 /kg at VT) and peak oxygen uptake (VO2 /kg at Peak) showed a significant negative correlation with GrimAgeAccel, even after adjustments for chronological age and smoking and drinking status. Notably, VO2 /kg at VT and VO2 /kg at Peak above the reference value were also associated with delayed GrimAgeAccel. Multiple regression analysis showed that calf circumference, serum triglyceride, carbohydrate intake, and smoking status, rather than CRF, contributed more to GrimAgeAccel and FitAgeAccel. In conclusion, although the contribution of CRF to GrimAgeAccel and FitAgeAccel is relatively low compared to lifestyle-related factors such as smoking, the results suggest that the maintenance of CRF is associated with delayed biological ageing in older men.

Longitudinal changes in youth baseball batting based on body rotation and separation.

BACKGROUND: Identifying the characteristics of batting mechanics, such as the proper angle and position of each body segment in youth baseball players, is important for proper instructions. This study aimed to identify the age-related changes in batting kinematics including rotational and separational movements of the head, upper trunk, pelvis, and arms, in youth baseball players. METHODS: Over the three seasons, we measured the batting motion of baseball players aged 6- to 12 years using three high-speed cameras. Participants were divided into six age categories according to the little league eligibility rules (players were classified according to their age as of July 31 of a given year). Toss batting was performed using an automatic tossing machine set obliquely in front of the batter. Additionally, we analyzed the rotation angles of the head, upper trunk, pelvis, and arm direction, and the separation angles-calculated using the difference of each rotational angle and the head movement distance and step width-at five points in batting phase: stance, load, foot contact, pre-swing, and ball contact. Finally, 17 players from under 8 (U8, i.e., approximately 7-8 years) to U10 and 13 from U11 to U13 were analyzed. A one-way repeated measures analysis of variance was performed to analyze age-related changes in batting kinematics. RESULTS: Several age-related changes in batting kinematics at various batting point were observed. The head-to-upper trunk separation angle increased with age from U8 to U10 during the foot contact (effect sizes [ES] = 0.658) and from U11 to U13 during the pre-swing (ES = 0.630). Additionally, the U13 showed a significantly increase in the upper and pelvis separation angles during load, foot contact, and pre-swing compared with U11 and U12 (ES = 0.131, 0.793, and 0.480). CONCLUSION: Various changes in batting kinematics occurred among each age group. Notably, U12 and U13 had the greater upper trunk-to-pelvis separation angle at foot contact and pre-swing compared to U11. Therefore, it would be important for the instruction of younger baseball players to understand the underdevelopment of trunk separation when batting and encourage the acquisition of such separation movements.

The combined effect of rowing exercise and the intake of functional foods containing inulin on muscle mass and bone mineral density in older Japanese women.

AIM: Aging decreases muscle mass and bone mineral density (BMD), especially in older women. It has been reported that rowing and inulin intake positively affect muscle and bone, respectively. We examined the synergistic effect of rowing and functional food intake, including inulin, on lean body mass, BMD, and physical function parameters in older Japanese women. METHODS: Fifty women aged 65-79 years were divided into four groups with or without inulin intake and rowing. The interventions were carried out for 12 weeks in each group. We assessed lean body mass and BMD using dual-energy X-ray absorptiometry at baseline and after the intervention and examined the changes in the values in each group. RESULTS: Lean body mass in all groups decreased, and the change in lean body mass in the group with rowing and inulin intake was significantly smaller than that in the group without them (-0.05 ± 0.61; -0.83 ± 0.59 kg; P = 0.030). The BMD in the three intervention groups increased after the 12-week intervention. The change in BMD in each of the three intervention groups showed significant differences compared with the control group (Rowing + Inulin: P = 0.03; Rowing + No inulin: P = 0.01; No rowing + Inulin: P < 0.01). CONCLUSIONS: Rowing and the intake of functional foods, including inulin, synergistically prevented a decrease in lean body mass. These factors, individually and additively, might increase BMD in older Japanese women. Geriatr Gerontol Int 2023; 23: 779-787.

Changes of bone turnover markers and testosterone in Japanese male endurance runners: a pilot study.

INTRODUCTION: The bone metabolism of male endurance runners during a competitive season has been little studied. Furthermore, Japanese runners have a special competitive season. This study aimed to investigate the change of bone turnover markers (BTMs) and other hormones in Japanese male endurance runners. MATERIALS AND METHODS: We investigated biochemical markers, bone formation and resorption markers and sex hormones, body composition using dual-energy X-ray absorptiometry (DXA), and training volume during a competitive season. 11 (age: 24.0 ± 4.3 years) Japanese male endurance runners were analyzed in this study. They participated in all measurements three times a year: the baseline (BL), the post-track period (PT), and the road race period (RR). RESULTS: Fat mass (FM) and percentage of body fat (% body fat) at RR (p = 0.009, p = 0.009) were lower than at BL. Specific bone alkaline phosphatase (BAP) decreased at PT (p = 0.004) and RR (p = 0.004) compared with BL. However, the bone resorption marker did not change. Free testosterone at PT (p = 0.032) was lower than BL. There was no correlation with blood variables and body composition or training volume. CONCLUSION: BAP and testosterone in Japanese male endurance runners decreased during the competitive season. However, there was no correlation between blood variables and training volume.

Characteristics of upper limb mass, muscle CSA and stiffness in adolescent baseball players with and without elbow injury.

Since elbow injuries are common in adolescent baseball players, this study aimed to determine the relationship between musculoskeletal status and elbow injuries in 47 baseball players aged 12-14 years. Participants answered a questionnaire and had their general body measurements taken. Magnetic resonance imaging was used to evaluate muscle cross sectional areas (CSA) of the upper arm flexor and extensor muscles, and x-ray absorptiometry was used to determine the mass of the upper arm and the total mass of the forearm and hand. Shear wave elastography was used to determine muscle stiffness of the biceps brachii, brachialis, pronator teres, and brachioradialis. An orthopedic surgeon performed a clinical assessment and elbow ultrasonography for each participant to diagnose elbow injuries. The measured values were compared between the elbow injury and control groups using two-sample t-tests. The elbow injury group had significantly higher muscle stiffness in the brachialis (p < 0.001) and brachioradialis (p = 0.004) muscles and greater elbow flexor CSA of the distal upper arm (p = 0.004) than the control group. The total mass of the forearm and hand and the mass ratio of the forearm and hand to the upper arm were significantly greater in the elbow injury group than in the control group (p = 0.002 and p < 0.001). Thus, it may be necessary to increase flexibility of the brachialis and brachioradialis flexible by stretching and massaging in addition to evaluating the mass distal to the elbow and the elbow flexor muscle size of the distal upper arm to manage elbow injury in youth baseball players. Characteristics of Upper Limb Mass, Muscle Cross-Sectional Area and Stiffness in Adolescent Baseball Players with and without Elbow Injury.

Growth pattern of lumbar maturity stage at L1 to L5 during adolescent growth spurt.

PURPOSE: This study aimed to clarify the order of the lumbar maturity stage, each at L1 to L5, and the relationships between age at peak height velocity (APHV) and the lumbar maturity stage. METHODS: A total of 120 male first-grade junior high school soccer players were enrolled and followed for two years, and measurements were performed five times (T1 to T5). The lumbar maturity stage was assessed according to the degree of lesion of the epiphyseal from L1 to L5 using magnetic resonance imaging and classified into three stages: cartilaginous stage, apophyseal stage, and epiphyseal stage. The relationships between T1 and T5 temporal changes and developmental stages divided by 0.5 year increments based on APHV and the lumbar maturity stage at L1 to L5 were examined. For the apophyseal stage, developmental age calculated based on the difference between APHV and chronological age between each lumbar vertebra was compared. RESULTS: We found that part of the cartilaginous stages decreased as time progressed, while that of the apophyseal and epiphyseal stages increased at L1 to L5 (chi-square test, p < 0.01). L5 matured earlier with the apophyseal stage than L1 to L4 (p < 0.05). The lumbar maturity stage was attained toward L1 from L5, comparing different lumbar levels. CONCLUSION: The lumbar maturity stage progresses from L5 toward L1, and the apophyseal and epiphyseal stages would replace the cartilaginous stage at approximately 14 years of age or after APHV.

Awareness and Knowledge of Medical Issues Related to Female Athletes Among Track and Field Coaches.

Introduction: Little is known regarding medical knowledge pertaining to female athletes among track and field coaches and their interactions with female athletes regarding medical problems. Methods: Participants were track and field coaches (369 males and 43 females) with Japan Sport Association certification and they completed an anonymous survey on their knowledge of medical problems pertinent to female athletes including whether the coaches knew about the female athlete triad and relative energy deficiency in sports; their feelings about female athletes' use of contraceptive pills; whether they speak about menses with the female athletes; and whether they have a gynecologist for consultation regarding their medical problems. Results: Females coaches were significantly more likely to be aware of the triad (odds ratio (OR), 3.44; p = 0.003); to have access to a physician able to address the gynecological problems of female athletes (OR, 9.22; p < 0.001); and to talk to their female athletes about menses (OR, 2.30; p = 0.015) than their male counterparts. Coaches with more experience tended to be aware of the triad and relative energy deficiency in sports compared with those with ≤5 years of experience. Conclusion: Females coaches are aware of the triad, talk about menses with their female athletes, and have access to a physician who can address gynecological problems with compared to male counterparts. Educating all coaches on these problems is essential to provide adequate support to female athletes.

Developmental stage and lower quadriceps flexibilities and decreased gastrocnemius flexibilities are predictive risk factors for developing Osgood-Schlatter disease in adolescent male soccer players.

PURPOSE: This study aimed to elucidate the influential predictive risk factors of Osgood-Schlatter disease (OSD) on the support (non-kicking) leg among adolescent soccer players considering peak height velocity (PHV) age and investigate the cut-off values of the predictive variables. METHODS: A cohort of 302 Japanese adolescent male soccer players aged 12-13 years were followed over 6 months. All players underwent physical examination, tibial tubercle ultrasonography, anthropometric and whole-body composition measurements, and muscle flexibility test of the support leg at the baseline. The developmental stage was evaluated from the PHV age. The OSD of the support leg was diagnosed 6 months later; players were divided into the OSD and control (CON) groups. The predictive risk factors were analyzed by multivariate logistic regression analysis. RESULTS: There were 42 players who had developed OSD at baseline and they were excluded from the study. Among the 209 players, 43 and 166 belonged to the OSD and CON groups, respectively. The predictive risk factors of OSD development were PHV age ± 6 months at baseline (p = 0.046), apophyseal stage of tibial tuberosity maturity at baseline (p < 0.001), quadriceps flexibility ≥ 35° at baseline (p = 0.017), and decrease in gastrocnemius flexibility in 6 months (p = 0.009). CONCLUSION: PHV age ± 6 months at baseline, apophyseal stage of the tibial tuberosity at baseline, quadriceps flexibility ≥ 35° at baseline, and decrease in gastrocnemius flexibility in 6 months are predictive risk factors of OSD development in the support leg among adolescent male soccer players. It is crucial to know the PHV age of each player, and not only the flexibility of quadriceps muscle but also the gastrocnemius should be monitored to predict OSD. LEVEL OF EVIDENCE: II.

Controlling Behavior, Sex Bias and Coaching Success in Japanese Track and Field.

Coaching athletes is a complex and lengthy process. Recently, attention has been given to coaches over-controlling behavior toward the athletes' personal lives and possible sex bias, but the impact of these behaviors on coaching success is unclear. An anonymous survey was answered by 412 track and field coaches (male: 369; female: 43), comprising questions regarding controlling behaviors, sex bias, and personal background. A Chi-square test and logistic regression were performed to determine the factors related to the coach's characteristics and their success in coaching athletes (to national vs. non-national level). The results showed that controlling behaviors and sex-bias-related beliefs were present. The coaches who coached national-level athletes were more likely to be older, more experienced, and were national level athletes themselves. More national-level coaches reported controlling behaviors but fewer held sex bias beliefs than the non-national level coaches. However, the strength of these beliefs (scores for controlling behavior and sex bias) was not related to the coaching success.

Risk Factors for Symptomatic Bilateral Lumbar Bone Stress Injury in Adolescent Soccer Players: A Prospective Cohort Study.

BACKGROUND: Lumbar bone stress injury (BSI) is a high-risk long time-loss injury for adolescent soccer players. However, the risk factors for lumbar BSI are unclear. PURPOSE: To identify the risk factors for bilateral lumbar BSI for adolescent soccer players. STUDY DESIGN: Case-control study; Level of evidence, 3. METHODS: Adolescent soccer players underwent orthopaedic examination, whole-body dual energy x-ray scan, lumbar magnetic resonance imaging (MRI), and muscle tightness testing at baseline. Lumbar lordosis (LL), sacral slope, maturity stage of lumbar vertebral body, and bone marrow edema (BME) at the L5 were examined via MRI. In addition, bone mineral density and content; trunk lean body mass via dual energy x-ray scan; and bilateral muscle tightness including the iliopsoas, hamstrings, and quadriceps were measured. Lumbar BSI was diagnosed as positive bilateral BME and extension-based lumbar pain. All participants were examined twice, one at 6 months and one at 1 year, after the baseline examination. Multivariate logistic regression analysis was performed to identify the risk factors for bilateral lumbar BSI. RESULTS: A total of 69 (26.3%) players were diagnosed with bilateral lumbar BSI. Asymptomatic BME (odds ratio [OR], 4.260; 95% CI, 2.153-8.431), apophyseal stage of the lumbar vertebral body (OR, 3.438; 95% CI, 1.698-6.959), sacral slope relative to LL ≥5° (OR, 4.067; 95% CI, 2.021-8.181), and hamstring tightness ≥50° (OR, 3.221; 95% CI, 1.385-7.489) were significantly associated with bilateral lumbar BSI. CONCLUSION: The incidence of bilateral lumbar BSI was common at 26.2%. Asymptomatic BME, sacral anterior tilt relative to LL, immature lumbar epiphyses, and hamstring tightness were found to be risk factors for bilateral lumbar BSI. The results of this study suggest that regular MRI examination could facilitate the early detection of BME, and improvement in hamstring flexibility and lumbosacral alignment may prevent bilateral lumbar BSI in young athletes.

Prediction and validation of total and regional skeletal muscle volume by using anthropometric measurements in prepubertal Japanese children.

It is difficult to easily estimate skeletal muscle (SM) volume in children. We aimed to develop regression-based prediction equations to estimate the total body and regional SM volume using calliper measurements of skinfold thickness and limb circumference and to investigate the validity of these equations. In total, 142 healthy, prepubertal, Japanese children, aged 6-12 years, were divided into two groups: the model development group (sixty boys, thirty-eight girls) and the validation group (twenty-six boys, eighteen girls). Contiguous magnetic resonance images were obtained from the first cervical vertebra to the ankle joints as reference data. SM volume was calculated from the summation of the digitised cross-sectional areas. Limb and waist circumferences were measured at mid-upper arm, mid-thigh, maximal calf and at the level of umbilicus. Each girth was corrected for subcutaneous adipose tissue thickness, as estimated by skinfold thickness measurements. Skinfold thickness was measured at the posterior upper arm, anterior thigh, medial calf and lateral to the umbilicus, using callipers. Significant correlations were observed between the site-matched SM volume, measured by MRI, and each corrected girth × standing height value in the model development group. When these SM volume prediction equations were applied to the validation group, the measured total body and regional SM volume were similar to the predicted values. These results suggest that the anthropometric prediction equations developed in this study provide reliable information about the total and regional SM volume in prepubertal Japanese children, with varying degrees of estimation accuracy for each region.

An international study on attitudes and opinions regarding female sports medicine physicians during pregnancy and the postpartum period.

OBJECTIVES: Supporting female sports medicine physicians to simultaneously be mothers and pursue professional careers is crucial to maintain gender diversity in sports medicine physicians. The purpose of this study is to understand the attitudes toward female sports medicine physicians during pregnancy and postpartum. METHODS: An anonymous online survey was distributed to sports medicine physicians practicing in 51 different countries. They were asked how comfortable they felt with female sports medicine physicians working on the sidelines of sporting events during pregnancy, if the female sports medicine physicians were as productive as their male counterparts after giving birth, and how satisfied they were with the percentage of female sports medicine physicians in their country. Data were analyzed using the chi-square test, and multivariate logistic regression analysis was performed to identify independent variables. RESULTS: In total, 1193 physicians (380 [31.9%] female) were included for analysis. Physicians in Asia were the least comfortable with pregnant sports medicine physicians working on the sidelines and those in North America were the most comfortable (odds ratio = 0.28 and 2.51, 95% confidence interval 0.18-0.44 and 1.55-4.06, respectively). More experienced sports medicine physicians (odds ratio = 1.01, 95% confidence interval 1.00-1.03; p < 0.05) and divorced physicians (odds ratio = 0.33, 95% confidence interval 0.12-0.91; p < 0.05) were less comfortable with pregnant female sports medicine physicians working on sidelines, and those trained in orthopedics were less likely to agree that female sports medicine physicians were equally as productive as male counterparts postpartum (odds ratio = 0.29, 95% confidence interval 0.10-0.88; p < 0.05). Female physicians were less satisfied with the percentage of female sports medicine physicians in their country (odds ratio = 0.41, 95% confidence interval 0.27-0.60; p < 0.01) than their male counterparts. CONCLUSIONS: Female sports medicine physicians may experience bias in their practice during pregnancy and postpartum.