Michelle Barrack - Academia.edu (original) (raw)

Papers by Michelle Barrack

BMJ Open Sport & Exercise Medicine

ObjectivesWe evaluated the effect of a nutrition education intervention on bone stress injury (BS... more ObjectivesWe evaluated the effect of a nutrition education intervention on bone stress injury (BSI) incidence among female distance runners at two NCAA Division I institutions.MethodsHistorical BSI rates were measured retrospectively (2010–2013); runners were then followed prospectively in pilot (2013–2016) and intervention (2016–2020) phases. The primary aim was to compare BSI rates in the historical and intervention phases. Pilot phase data are included only for descriptive purposes. The intervention comprised team nutrition presentations focused on optimising energy availability plus individualised nutrition sessions for runners with elevated Female Athlete Triad risk. Annual BSI rates were calculated using a generalised estimating equation Poisson regression model adjusted for age and institution. Post hoc analyses were stratified by institution and BSI type (trabecular-rich or cortical-rich).ResultsThe historical phase included 56 runners and 90.2 person-years; the intervention...

Clinical Journal of Sport Medicine, 2021

: The Male Athlete Triad is a syndrome of 3 interrelated conditions most common in adolescent and... more : The Male Athlete Triad is a syndrome of 3 interrelated conditions most common in adolescent and young adult male endurance and weight-class athletes and includes the clinically relevant outcomes of (1) energy deficiency/low energy availability (EA) with or without disordered eating/eating disorders, (2) functional hypothalamic hypogonadism, and (3) osteoporosis or low bone mineral density with or without bone stress injury (BSI). The causal role of low EA in the modulation of reproductive function and skeletal health in the male athlete reinforces the notion that skeletal health and reproductive outcomes are the primary clinical concerns. At present, the specific intermediate subclinical outcomes are less clearly defined in male athletes than those in female athletes and are represented as subtle alterations in the hypothalamic–pituitary–gonadal axis and increased risk for BSI. The degree of energy deficiency/low EA associated with such alterations remains unclear. However, available data suggest a more severe energy deficiency/low EA state is needed to affect reproductive and skeletal health in the Male Athlete Triad than in the Female Athlete Triad. Additional research is needed to further clarify and quantify this association. The Female and Male Athlete Triad Coalition Consensus Statements include evidence statements developed after a roundtable of experts held in conjunction with the American College of Sports Medicine 64th Annual Meeting in Denver, Colorado, in 2017 and are in 2 parts—Part I: Definition and Scientific Basis and Part 2: The Male Athlete Triad: Diagnosis, Treatment, and Return-to-Play. In this first article, we discuss the scientific evidence to support the Male Athlete Triad model.

Nutrients

Background: Nutrition fuels optimal performance for athletes. With increased research development... more Background: Nutrition fuels optimal performance for athletes. With increased research developments, numerous diets available, and publicity from professional athletes, a review of dietary patterns impact on athletic performance is warranted. Results: The Mediterranean diet is a low inflammatory diet linked to improved power and muscle endurance and body composition. Ketogenic diets are restrictive of carbohydrates and proteins. Though both show no decrements in weight loss, ketogenic diets, which is a more restrictive form of low-carbohydrate diets, can be more difficult to follow. High-protein and protein-paced versions of low-carbohydrate diets have also shown to benefit athletic performance. Plant-based diets have many variations. Vegans are at risk of micronutrient deficiencies and decreased leucine content, and therefore, decreased muscle protein synthesis. However, the literature has not shown decreases in performance compared to omnivores. Intermittent fasting has many differ...

The American Journal of Clinical Nutrition, 2010

Background: Female adolescent runners have an elevated prevalence of low bone mass for age-an out... more Background: Female adolescent runners have an elevated prevalence of low bone mass for age-an outcome that may be partially due to inadequate energy intake. Objective: The objective was to evaluate diet, menstrual history, serum hormone concentrations, and bone mass in female adolescent runners with normal or abnormal bone turnover. Design: Thirty-nine crosscountry runners (age: 15.7 6 0.2 y) participated in the study, which included a 7-d dietary assessment with the use of a food record and daily 24-h dietary recalls; serum measures of insulin-like growth factor I, estradiol, leptin, parathyroid hormone, progesterone, triiodothyronine, 25-hydroxycholecalciferol, bone-specific alkaline phosphatase (BAP), and cross-linked Ctelopeptides of type I collagen (CTX); an evaluation of height, weight, bone mass, and body composition with the use of dualenergy X-ray absorptiometry; and a questionnaire to assess menses and sports participation. Age-and sex-specific BAP and CTX concentrations of at least the 97th percentile and no greater than the third percentile, respectively, were considered abnormal. Results: All abnormal BAP and CTX concentrations fell within the elevated (!97%) range. Runners with an elevated bone turnover (EBT) (n = 13) had a lower body mass, fewer menstrual cycles in the past year, lower estradiol and 25-hydroxycholecalciferol concentrations, and a higher prevalence of body mass index ,10% for age, vitamin D insufficiency, amenorrhea, and low bone mass. Girls with EBT consumed less than the recommended amounts of energy and had a higher prevalence of consuming ,1300 mg Ca than did those with normal bone turnover. Conclusions: Runners with EBT had a profile consistent with energy deficiency. Nutritional support to increase energy, calcium intake, and 25-hydroxycholecalciferol concentrations may improve bone mineral accrual in young runners with EBT. This trial was registered at clinicaltrials.gov as NCT01059968.

Current Reviews in Musculoskeletal Medicine, 2013

Updated prevalence estimates of all 3 components of the Female Athlete Triad, a syndrome characte... more Updated prevalence estimates of all 3 components of the Female Athlete Triad, a syndrome characterized by low energy availability, functional hypothalamic amenorrhea, and osteoporosis, is low (0 %-16 %), however, estimates of 1 or 2 concurrent components approach 50 %-60 % among certain athlete groups. Recent research identifies components of the Triad among female adolescent athletes, particularly those participating in leanness sports, such as endurance running. This is alarming, as adolescents require adequate nutrition and normal hormone function to optimize bone mineral gains during this critical developmental period. Current literature highlights new assessments, such as measurements of bone microarchitecture and hormone levels to better evaluate bone strength and the hormonal and metabolic profile of athletes with and at risk for the Triad. Recent data also provides support for additional potential consequences of the Triad, such as endothelial dysfunction and related cardiovascular effects, stress fractures, and musculoskeletal injuries. Additional prospective research is needed to evaluate long-term indicators and consequences of the Triad and identify effective behavioral treatment strategies.

Medicine & Science in Sports & Exercise, 2017

Medicine & Science in Sports & Exercise, 2011

Endurance runners with low bone mass during adolescence may risk attaining a low peak bone minera... more Endurance runners with low bone mass during adolescence may risk attaining a low peak bone mineral density (BMD) in adulthood. Alternatively, they may mature late and undergo delayed bone mineral accumulation. The purpose of this study was to evaluate 40 adolescent runners (aged 15.9 ± 0.2 yr) at two time points, approximately 3 yr apart, to assess bone mass status and identify variables associated with bone mass change. Follow-up measures included a questionnaire to assess menstrual status, training, and sports participation history, height and weight, and a dual-energy x-ray absorptiometry scan to assess total body, total hip, and lumbar spine BMD, bone mineral content (BMC), BMD z-score, and body composition. We used -1 and -2 BMD z-score cutoffs to categorize runners with low bone mass. Eighty-seven percent of girls with low BMD at baseline had low BMD at the follow-up. Girls with low compared with normal baseline BMD had lower follow-up adjusted total body (2220.4 ± 65.8 vs 2793.1 ± 68.2 g, P < 0.001), total hip (27.0 ± 1 vs 33.9 ± 1.0 g, P < 0.05), and lumbar spine (47.8 ± 2.0 vs 66.3 ± 2.2 g, P < 0.001) BMC values. Variables related to 3-yr training volume, menstrual function, age, developmental stage, and change in body mass explained 29%-54% of the variability in BMC change. The majority of adolescent runners with low BMD at baseline had low BMD after a 3-yr follow-up. Our observations suggest that "catch-up" accrual may be difficult and, thus, emphasize the importance of gaining adequate bone mineral during the early adolescent years.

Medicine & Science in Sports & Exercise, 2011

International Journal of Sport Nutrition and Exercise Metabolism, Apr 1, 2012

Functional hypothalamic amenorrhea is common among female athletes and may be difficult to treat.... more Functional hypothalamic amenorrhea is common among female athletes and may be difficult to treat. Restoration of menses (ROM) is crucial to prevent deleterious effects to skeletal and reproductive health. To determine the natural history of menstrual disturbances in female college athletes managed with nonpharmacologic therapies including increased dietary intake and/or decreased exercise expenditure and to identify factors associated with ROM. A 5-yr retrospective study of college athletes at a major Division I university. 373 female athletes' charts were reviewed. For athletes with menstrual disturbances, morphometric variables were noted. Months to ROM were recorded for each athlete. Fifty-one female athletes (19.7%) had menstrual disturbances (14.7% oligomenorrheic, 5.0% amenorrheic). In all, 17.6% of oligo-/amenorrheic athletes experienced ROM with nonpharmacologic therapy. Mean time to ROM among all athletes with menstrual disturbances was 15.6 ± 2.6 mo. Total absolute (5.3 ± 1.1 kg vs. 1.3 ± 1.1 kg, p < .05) and percentage (9.3% ± 1.9% vs. 2.3% ± 1.9%, p < .05) weight gain and increase in body-mass index (BMI; 1.9 ± 0.4 kg/m2 vs. 0.5 ± 0.4 kg/m2, p < .05) emerged as the primary differentiating characteristics between athletes with ROM and those without ROM. Percent weight gain was identified as a significant positive predictor of ROM, OR (95% CI) = 1.25 (1.01, 1.56), p < .05. Nonpharmacologic intervention in college athletes with menstrual disturbances can restore regular menstrual cycles, although ROM may take more than 1 yr. Weight gain or an increase in BMI may be important predictors of ROM.

Bone, Jan 9, 2007

During adolescence, skeletal integrity of girls is largely dependent on menstrual function and im... more During adolescence, skeletal integrity of girls is largely dependent on menstrual function and impact exercise, yet currently there is limited research regarding the interaction between menstrual status and type of mechanical loading associated with various high school sports. Our purpose was to examine associations of menstrual status, type of mechanical loading, and bone mineral density (BMD) in female high school athletes participating in high/odd impact or repetitive/non-impact sport. Participants were 161 female high school athletes (15.7 ± 1.3 years; 165.3 ± 6.9 cm; 59.4 ± 8.7 kg) representing high/odd impact (n = 93, including soccer, softball, volleyball, tennis, lacrosse, and track sprinters and jumpers), or repetitive/non-impact sports (n = 68, including swimmers, cross-country and track distance runners who participated in events ≥ 800 m). Areal BMD was measured by DXA at the spine (L1-L4), proximal femur, and total body. Menstrual status was determined by selfreport. Athletes with primary, secondary or oligomenorrhea were combined into a single group (oligo/amenorrheic) and compared to eumenorrheic athletes. Analysis of covariance (ANCOVA) with Bonferroni post hoc comparisons adjusted for age, BMI, and gynecological age were used to compare BMD of athletes in combined mechanical loading and menstrual status groups. We found significantly greater total hip (p = 0.04) and trochanter (p = 0.02) BMD (g cm − 2 ) among eumenorrheic high/odd impact compared to eumenorrheic repetitive/non-impact athletes, and greater spine (p = 0.01) and trochanter (p = 0.04) BMD among high/odd impact eumenorrheic athletes compared to repetitive/nonimpact oligo/amenorrheic athletes. Chi-squared analysis of BMD Z-scores adjusted for gynecological age showed a significantly greater percentage of repetitive/non-impact athletes (33.9%) compared to high/odd impact athletes (11.8%) with low spine BMD for their age (BMD Z-score ≤ −1 SD) (p = 0.001), indicating that a high percentage of female high school athletes participating in repetitive loading sports, and especially those with oligo/amenorrhea, may not be accruing bone at the expected rate. Female adolescent athletes should be evaluated periodically and advised of the possible negative effects of oligo/amenorrhea on bone health.

Sports medicine (Auckland, N.Z.), Jan 26, 2015

Participation in sports offers many health benefits to athletes of both sexes. However, subsets o... more Participation in sports offers many health benefits to athletes of both sexes. However, subsets of both female and male athletes are at increased risk of impaired bone health and bone stress injuries. The Female Athlete Triad (Triad) is defined as the interrelationship of low energy availability (with or without disordered eating), menstrual dysfunction, and low bone mineral density. The Triad may result in health consequences, including bone stress injuries. Our review presents evidence that an analogous process may occur in male athletes. Our review of the available literature indicates that a subset of male athletes may experience adverse health issues that parallel those associated with the Triad, including low energy availability (with or without disordered eating), hypogonadotropic hypogonadism, and low bone mineral density. Consequently, male athletes may be predisposed to developing bone stress injuries, and these injuries can be the first presenting feature of associated Tr...

International journal of sports physical therapy, 2014

During the 2013-14 school year, over 763,000 female athletes participated in interscholastic runn... more During the 2013-14 school year, over 763,000 female athletes participated in interscholastic running sports in the United States. Recent studies have indicated associations between the female athlete triad (Triad) and stress fracture or other musculoskeletal injuries in elite or collegiate female running populations. Little is known about these relationships in an adolescent interscholastic running population. The purpose of this study was to determine the associations between Triad and risk of lower extremity musculoskeletal injury among adolescent runners. Eighty-nine female athletes competing in interscholastic cross-country and track in southern California were followed, prospectively. The runners were monitored throughout their respective sport season for lower extremity musculoskeletal injuries. Data collected included daily injury reports, Eating Disorder Examination Questionnaire (EDE-Q) that assessed disordered eating attitudes/behaviors, a questionnaire on menstrual histor...

Biological Trace Element Research, 2005

Serum iron levels have been shown to decline both with fever and with strenuous exercise, leading... more Serum iron levels have been shown to decline both with fever and with strenuous exercise, leading to the supposition that the decrease might be the result of a rise in core body temperature. To evaluate this hypothesis, the serum iron response to an exercise-induced 1.5 degrees C rise in core body temperature was measured. To increase core temperature, five females and two males exercised in an environmental chamber heated to 41 degrees C with a relative humidity of 40%. Blood samples were taken before exercise and immediately after body temperature increased approximately 1.5 degrees C. Blood was also collected 1 h, 6 h, and 24 h postexercise. Results showed that the core body temperature significantly increased (p<0.001) from a mean baseline value of 36.5 +/- 0.1 degrees C to 38.1 +/- 0.1 degrees C following exercise. A one-way repeated measures analysis of variance was used to examine the effect of increased core body temperature on serum iron levels over the five time periods: preexercise, immediate postexercise, and 1 h, 6 h, and 24 h post exercise. The results indicated that there were no significant differences in serum iron levels among time periods. This suggests that the previously reported depression of serum iron levels that occurs with fever and after prolonged exercise is not the result of hyperthermia. Rather, the change in serum iron occurs in response to biological or physiological stressors, such as bacterial infection, muscle damage, or unusual trauma. Further studies are needed to explicate the mechanisms responsible for these changes.

Current Sports Medicine Reports, 2014

The female athlete triad is a medical condition often observed in physically active girls and wom... more The female athlete triad is a medical condition often observed in physically active girls and women and involves three components: (1) low energy availability with or without disordered eating, (2) menstrual dysfunction, and (3) low bone mineral density. Female athletes often present with one or more of the three triad components, and early intervention is essential to prevent its progression to serious end points that include clinical eating disorders, amenorrhea, and osteoporosis. This consensus statement presents a set of recommendations developed following the first (San Francisco, CA) and second (Indianapolis, IN) International Symposia on the Female Athlete Triad. This consensus statement was intended to provide clinical guidelines for physicians, athletic trainers, and other health care providers for the screening, diagnosis, and treatment of the female athlete triad and to provide clear recommendations for return to play. The expert panel has proposed a risk stratification point system that takes into account magnitude of risk to assist the physician in decision making regarding sport participation, clearance, and return to play. Guidelines are offered for clearance categories, management by a multidisciplinary team, and implementation of treatment contracts.

British journal of sports medicine, 2014

Medicine & Science in Sports & Exercise, 2006

Medicine & Science in Sports & Exercise, 2006

Medicine & Science in Sports & Exercise, 2008

Identify the prevalence of and traits that may increase the risk of low bone mineral density (BMD... more Identify the prevalence of and traits that may increase the risk of low bone mineral density (BMD) among 93 female adolescent competitive endurance runners. Participants were 93 high school runners, ages 13-18 yr, from southern California. Eating attitudes and behaviors were assessed using the Eating Disorder Examination Questionnaire (EDE-Q). Menstrual and sports participation history were evaluated using an interviewer-assisted, self-report questionnaire. Bone mineral density (BMD) of the spine (L1-L4), total hip, and total body were measured by dual-energy x-ray absorptiometry. The -2 and -1 BMD age-matched, gender-specific z-score cutoffs were used to categorize girls as having low bone mass for age. Among the female runners, 11.8% and 28% met the -2 and -1 BMD z-score cutoffs, respectively, whereas 25.8% reported menstrual irregularity (MI). Total hip BMD, lumbar spine BMD, and lumbar spine BMD z-score were significantly lower in runners with MI after adjusting for body mass index (BMI) and lean tissue mass. Runners that participated in five or more compared with three seasons of endurance running exhibited a significantly lower total body and lumbar spine BMD z-score after adjusting for BMI, lean tissue mass, and number of menstrual cycles in the past year. Multiple regression analysis indicated that MI, participation in five or more seasons of endurance running, BMI, and lean tissue mass were independent predictors of low BMD. Female adolescent endurance runners may represent a population with an increased risk of low bone mass. Future studies are necessary to further understand the factors contributing to low bone mass in young runners and to identify behavioral strategies that will promote optimal bone mineral accumulation during the adolescent years.

Medicine & Science in Sports & Exercise, 2004

Medicine & Science in Sports & Exercise, 2010

BMJ Open Sport & Exercise Medicine

ObjectivesWe evaluated the effect of a nutrition education intervention on bone stress injury (BS... more ObjectivesWe evaluated the effect of a nutrition education intervention on bone stress injury (BSI) incidence among female distance runners at two NCAA Division I institutions.MethodsHistorical BSI rates were measured retrospectively (2010–2013); runners were then followed prospectively in pilot (2013–2016) and intervention (2016–2020) phases. The primary aim was to compare BSI rates in the historical and intervention phases. Pilot phase data are included only for descriptive purposes. The intervention comprised team nutrition presentations focused on optimising energy availability plus individualised nutrition sessions for runners with elevated Female Athlete Triad risk. Annual BSI rates were calculated using a generalised estimating equation Poisson regression model adjusted for age and institution. Post hoc analyses were stratified by institution and BSI type (trabecular-rich or cortical-rich).ResultsThe historical phase included 56 runners and 90.2 person-years; the intervention...

Clinical Journal of Sport Medicine, 2021

: The Male Athlete Triad is a syndrome of 3 interrelated conditions most common in adolescent and... more : The Male Athlete Triad is a syndrome of 3 interrelated conditions most common in adolescent and young adult male endurance and weight-class athletes and includes the clinically relevant outcomes of (1) energy deficiency/low energy availability (EA) with or without disordered eating/eating disorders, (2) functional hypothalamic hypogonadism, and (3) osteoporosis or low bone mineral density with or without bone stress injury (BSI). The causal role of low EA in the modulation of reproductive function and skeletal health in the male athlete reinforces the notion that skeletal health and reproductive outcomes are the primary clinical concerns. At present, the specific intermediate subclinical outcomes are less clearly defined in male athletes than those in female athletes and are represented as subtle alterations in the hypothalamic–pituitary–gonadal axis and increased risk for BSI. The degree of energy deficiency/low EA associated with such alterations remains unclear. However, available data suggest a more severe energy deficiency/low EA state is needed to affect reproductive and skeletal health in the Male Athlete Triad than in the Female Athlete Triad. Additional research is needed to further clarify and quantify this association. The Female and Male Athlete Triad Coalition Consensus Statements include evidence statements developed after a roundtable of experts held in conjunction with the American College of Sports Medicine 64th Annual Meeting in Denver, Colorado, in 2017 and are in 2 parts—Part I: Definition and Scientific Basis and Part 2: The Male Athlete Triad: Diagnosis, Treatment, and Return-to-Play. In this first article, we discuss the scientific evidence to support the Male Athlete Triad model.

Nutrients

Background: Nutrition fuels optimal performance for athletes. With increased research development... more Background: Nutrition fuels optimal performance for athletes. With increased research developments, numerous diets available, and publicity from professional athletes, a review of dietary patterns impact on athletic performance is warranted. Results: The Mediterranean diet is a low inflammatory diet linked to improved power and muscle endurance and body composition. Ketogenic diets are restrictive of carbohydrates and proteins. Though both show no decrements in weight loss, ketogenic diets, which is a more restrictive form of low-carbohydrate diets, can be more difficult to follow. High-protein and protein-paced versions of low-carbohydrate diets have also shown to benefit athletic performance. Plant-based diets have many variations. Vegans are at risk of micronutrient deficiencies and decreased leucine content, and therefore, decreased muscle protein synthesis. However, the literature has not shown decreases in performance compared to omnivores. Intermittent fasting has many differ...

The American Journal of Clinical Nutrition, 2010

Background: Female adolescent runners have an elevated prevalence of low bone mass for age-an out... more Background: Female adolescent runners have an elevated prevalence of low bone mass for age-an outcome that may be partially due to inadequate energy intake. Objective: The objective was to evaluate diet, menstrual history, serum hormone concentrations, and bone mass in female adolescent runners with normal or abnormal bone turnover. Design: Thirty-nine crosscountry runners (age: 15.7 6 0.2 y) participated in the study, which included a 7-d dietary assessment with the use of a food record and daily 24-h dietary recalls; serum measures of insulin-like growth factor I, estradiol, leptin, parathyroid hormone, progesterone, triiodothyronine, 25-hydroxycholecalciferol, bone-specific alkaline phosphatase (BAP), and cross-linked Ctelopeptides of type I collagen (CTX); an evaluation of height, weight, bone mass, and body composition with the use of dualenergy X-ray absorptiometry; and a questionnaire to assess menses and sports participation. Age-and sex-specific BAP and CTX concentrations of at least the 97th percentile and no greater than the third percentile, respectively, were considered abnormal. Results: All abnormal BAP and CTX concentrations fell within the elevated (!97%) range. Runners with an elevated bone turnover (EBT) (n = 13) had a lower body mass, fewer menstrual cycles in the past year, lower estradiol and 25-hydroxycholecalciferol concentrations, and a higher prevalence of body mass index ,10% for age, vitamin D insufficiency, amenorrhea, and low bone mass. Girls with EBT consumed less than the recommended amounts of energy and had a higher prevalence of consuming ,1300 mg Ca than did those with normal bone turnover. Conclusions: Runners with EBT had a profile consistent with energy deficiency. Nutritional support to increase energy, calcium intake, and 25-hydroxycholecalciferol concentrations may improve bone mineral accrual in young runners with EBT. This trial was registered at clinicaltrials.gov as NCT01059968.

Current Reviews in Musculoskeletal Medicine, 2013

Updated prevalence estimates of all 3 components of the Female Athlete Triad, a syndrome characte... more Updated prevalence estimates of all 3 components of the Female Athlete Triad, a syndrome characterized by low energy availability, functional hypothalamic amenorrhea, and osteoporosis, is low (0 %-16 %), however, estimates of 1 or 2 concurrent components approach 50 %-60 % among certain athlete groups. Recent research identifies components of the Triad among female adolescent athletes, particularly those participating in leanness sports, such as endurance running. This is alarming, as adolescents require adequate nutrition and normal hormone function to optimize bone mineral gains during this critical developmental period. Current literature highlights new assessments, such as measurements of bone microarchitecture and hormone levels to better evaluate bone strength and the hormonal and metabolic profile of athletes with and at risk for the Triad. Recent data also provides support for additional potential consequences of the Triad, such as endothelial dysfunction and related cardiovascular effects, stress fractures, and musculoskeletal injuries. Additional prospective research is needed to evaluate long-term indicators and consequences of the Triad and identify effective behavioral treatment strategies.

Medicine & Science in Sports & Exercise, 2017

Medicine & Science in Sports & Exercise, 2011

Endurance runners with low bone mass during adolescence may risk attaining a low peak bone minera... more Endurance runners with low bone mass during adolescence may risk attaining a low peak bone mineral density (BMD) in adulthood. Alternatively, they may mature late and undergo delayed bone mineral accumulation. The purpose of this study was to evaluate 40 adolescent runners (aged 15.9 ± 0.2 yr) at two time points, approximately 3 yr apart, to assess bone mass status and identify variables associated with bone mass change. Follow-up measures included a questionnaire to assess menstrual status, training, and sports participation history, height and weight, and a dual-energy x-ray absorptiometry scan to assess total body, total hip, and lumbar spine BMD, bone mineral content (BMC), BMD z-score, and body composition. We used -1 and -2 BMD z-score cutoffs to categorize runners with low bone mass. Eighty-seven percent of girls with low BMD at baseline had low BMD at the follow-up. Girls with low compared with normal baseline BMD had lower follow-up adjusted total body (2220.4 ± 65.8 vs 2793.1 ± 68.2 g, P < 0.001), total hip (27.0 ± 1 vs 33.9 ± 1.0 g, P < 0.05), and lumbar spine (47.8 ± 2.0 vs 66.3 ± 2.2 g, P < 0.001) BMC values. Variables related to 3-yr training volume, menstrual function, age, developmental stage, and change in body mass explained 29%-54% of the variability in BMC change. The majority of adolescent runners with low BMD at baseline had low BMD after a 3-yr follow-up. Our observations suggest that "catch-up" accrual may be difficult and, thus, emphasize the importance of gaining adequate bone mineral during the early adolescent years.

Medicine & Science in Sports & Exercise, 2011

International Journal of Sport Nutrition and Exercise Metabolism, Apr 1, 2012

Functional hypothalamic amenorrhea is common among female athletes and may be difficult to treat.... more Functional hypothalamic amenorrhea is common among female athletes and may be difficult to treat. Restoration of menses (ROM) is crucial to prevent deleterious effects to skeletal and reproductive health. To determine the natural history of menstrual disturbances in female college athletes managed with nonpharmacologic therapies including increased dietary intake and/or decreased exercise expenditure and to identify factors associated with ROM. A 5-yr retrospective study of college athletes at a major Division I university. 373 female athletes' charts were reviewed. For athletes with menstrual disturbances, morphometric variables were noted. Months to ROM were recorded for each athlete. Fifty-one female athletes (19.7%) had menstrual disturbances (14.7% oligomenorrheic, 5.0% amenorrheic). In all, 17.6% of oligo-/amenorrheic athletes experienced ROM with nonpharmacologic therapy. Mean time to ROM among all athletes with menstrual disturbances was 15.6 ± 2.6 mo. Total absolute (5.3 ± 1.1 kg vs. 1.3 ± 1.1 kg, p < .05) and percentage (9.3% ± 1.9% vs. 2.3% ± 1.9%, p < .05) weight gain and increase in body-mass index (BMI; 1.9 ± 0.4 kg/m2 vs. 0.5 ± 0.4 kg/m2, p < .05) emerged as the primary differentiating characteristics between athletes with ROM and those without ROM. Percent weight gain was identified as a significant positive predictor of ROM, OR (95% CI) = 1.25 (1.01, 1.56), p < .05. Nonpharmacologic intervention in college athletes with menstrual disturbances can restore regular menstrual cycles, although ROM may take more than 1 yr. Weight gain or an increase in BMI may be important predictors of ROM.

Bone, Jan 9, 2007

During adolescence, skeletal integrity of girls is largely dependent on menstrual function and im... more During adolescence, skeletal integrity of girls is largely dependent on menstrual function and impact exercise, yet currently there is limited research regarding the interaction between menstrual status and type of mechanical loading associated with various high school sports. Our purpose was to examine associations of menstrual status, type of mechanical loading, and bone mineral density (BMD) in female high school athletes participating in high/odd impact or repetitive/non-impact sport. Participants were 161 female high school athletes (15.7 ± 1.3 years; 165.3 ± 6.9 cm; 59.4 ± 8.7 kg) representing high/odd impact (n = 93, including soccer, softball, volleyball, tennis, lacrosse, and track sprinters and jumpers), or repetitive/non-impact sports (n = 68, including swimmers, cross-country and track distance runners who participated in events ≥ 800 m). Areal BMD was measured by DXA at the spine (L1-L4), proximal femur, and total body. Menstrual status was determined by selfreport. Athletes with primary, secondary or oligomenorrhea were combined into a single group (oligo/amenorrheic) and compared to eumenorrheic athletes. Analysis of covariance (ANCOVA) with Bonferroni post hoc comparisons adjusted for age, BMI, and gynecological age were used to compare BMD of athletes in combined mechanical loading and menstrual status groups. We found significantly greater total hip (p = 0.04) and trochanter (p = 0.02) BMD (g cm − 2 ) among eumenorrheic high/odd impact compared to eumenorrheic repetitive/non-impact athletes, and greater spine (p = 0.01) and trochanter (p = 0.04) BMD among high/odd impact eumenorrheic athletes compared to repetitive/nonimpact oligo/amenorrheic athletes. Chi-squared analysis of BMD Z-scores adjusted for gynecological age showed a significantly greater percentage of repetitive/non-impact athletes (33.9%) compared to high/odd impact athletes (11.8%) with low spine BMD for their age (BMD Z-score ≤ −1 SD) (p = 0.001), indicating that a high percentage of female high school athletes participating in repetitive loading sports, and especially those with oligo/amenorrhea, may not be accruing bone at the expected rate. Female adolescent athletes should be evaluated periodically and advised of the possible negative effects of oligo/amenorrhea on bone health.

Sports medicine (Auckland, N.Z.), Jan 26, 2015

Participation in sports offers many health benefits to athletes of both sexes. However, subsets o... more Participation in sports offers many health benefits to athletes of both sexes. However, subsets of both female and male athletes are at increased risk of impaired bone health and bone stress injuries. The Female Athlete Triad (Triad) is defined as the interrelationship of low energy availability (with or without disordered eating), menstrual dysfunction, and low bone mineral density. The Triad may result in health consequences, including bone stress injuries. Our review presents evidence that an analogous process may occur in male athletes. Our review of the available literature indicates that a subset of male athletes may experience adverse health issues that parallel those associated with the Triad, including low energy availability (with or without disordered eating), hypogonadotropic hypogonadism, and low bone mineral density. Consequently, male athletes may be predisposed to developing bone stress injuries, and these injuries can be the first presenting feature of associated Tr...

International journal of sports physical therapy, 2014

During the 2013-14 school year, over 763,000 female athletes participated in interscholastic runn... more During the 2013-14 school year, over 763,000 female athletes participated in interscholastic running sports in the United States. Recent studies have indicated associations between the female athlete triad (Triad) and stress fracture or other musculoskeletal injuries in elite or collegiate female running populations. Little is known about these relationships in an adolescent interscholastic running population. The purpose of this study was to determine the associations between Triad and risk of lower extremity musculoskeletal injury among adolescent runners. Eighty-nine female athletes competing in interscholastic cross-country and track in southern California were followed, prospectively. The runners were monitored throughout their respective sport season for lower extremity musculoskeletal injuries. Data collected included daily injury reports, Eating Disorder Examination Questionnaire (EDE-Q) that assessed disordered eating attitudes/behaviors, a questionnaire on menstrual histor...

Biological Trace Element Research, 2005

Serum iron levels have been shown to decline both with fever and with strenuous exercise, leading... more Serum iron levels have been shown to decline both with fever and with strenuous exercise, leading to the supposition that the decrease might be the result of a rise in core body temperature. To evaluate this hypothesis, the serum iron response to an exercise-induced 1.5 degrees C rise in core body temperature was measured. To increase core temperature, five females and two males exercised in an environmental chamber heated to 41 degrees C with a relative humidity of 40%. Blood samples were taken before exercise and immediately after body temperature increased approximately 1.5 degrees C. Blood was also collected 1 h, 6 h, and 24 h postexercise. Results showed that the core body temperature significantly increased (p<0.001) from a mean baseline value of 36.5 +/- 0.1 degrees C to 38.1 +/- 0.1 degrees C following exercise. A one-way repeated measures analysis of variance was used to examine the effect of increased core body temperature on serum iron levels over the five time periods: preexercise, immediate postexercise, and 1 h, 6 h, and 24 h post exercise. The results indicated that there were no significant differences in serum iron levels among time periods. This suggests that the previously reported depression of serum iron levels that occurs with fever and after prolonged exercise is not the result of hyperthermia. Rather, the change in serum iron occurs in response to biological or physiological stressors, such as bacterial infection, muscle damage, or unusual trauma. Further studies are needed to explicate the mechanisms responsible for these changes.

Current Sports Medicine Reports, 2014

The female athlete triad is a medical condition often observed in physically active girls and wom... more The female athlete triad is a medical condition often observed in physically active girls and women and involves three components: (1) low energy availability with or without disordered eating, (2) menstrual dysfunction, and (3) low bone mineral density. Female athletes often present with one or more of the three triad components, and early intervention is essential to prevent its progression to serious end points that include clinical eating disorders, amenorrhea, and osteoporosis. This consensus statement presents a set of recommendations developed following the first (San Francisco, CA) and second (Indianapolis, IN) International Symposia on the Female Athlete Triad. This consensus statement was intended to provide clinical guidelines for physicians, athletic trainers, and other health care providers for the screening, diagnosis, and treatment of the female athlete triad and to provide clear recommendations for return to play. The expert panel has proposed a risk stratification point system that takes into account magnitude of risk to assist the physician in decision making regarding sport participation, clearance, and return to play. Guidelines are offered for clearance categories, management by a multidisciplinary team, and implementation of treatment contracts.

British journal of sports medicine, 2014

Medicine & Science in Sports & Exercise, 2006

Medicine & Science in Sports & Exercise, 2006

Medicine & Science in Sports & Exercise, 2008

Identify the prevalence of and traits that may increase the risk of low bone mineral density (BMD... more Identify the prevalence of and traits that may increase the risk of low bone mineral density (BMD) among 93 female adolescent competitive endurance runners. Participants were 93 high school runners, ages 13-18 yr, from southern California. Eating attitudes and behaviors were assessed using the Eating Disorder Examination Questionnaire (EDE-Q). Menstrual and sports participation history were evaluated using an interviewer-assisted, self-report questionnaire. Bone mineral density (BMD) of the spine (L1-L4), total hip, and total body were measured by dual-energy x-ray absorptiometry. The -2 and -1 BMD age-matched, gender-specific z-score cutoffs were used to categorize girls as having low bone mass for age. Among the female runners, 11.8% and 28% met the -2 and -1 BMD z-score cutoffs, respectively, whereas 25.8% reported menstrual irregularity (MI). Total hip BMD, lumbar spine BMD, and lumbar spine BMD z-score were significantly lower in runners with MI after adjusting for body mass index (BMI) and lean tissue mass. Runners that participated in five or more compared with three seasons of endurance running exhibited a significantly lower total body and lumbar spine BMD z-score after adjusting for BMI, lean tissue mass, and number of menstrual cycles in the past year. Multiple regression analysis indicated that MI, participation in five or more seasons of endurance running, BMI, and lean tissue mass were independent predictors of low BMD. Female adolescent endurance runners may represent a population with an increased risk of low bone mass. Future studies are necessary to further understand the factors contributing to low bone mass in young runners and to identify behavioral strategies that will promote optimal bone mineral accumulation during the adolescent years.

Medicine & Science in Sports & Exercise, 2004

Medicine & Science in Sports & Exercise, 2010