Proper nutrition can prevent negative health outcomes in young female athletes

Since the onset of Title IX, opportunities have dramatically increased for female athletes, largely to their benefit. However, some negative health outcomes such as disordered eating, chronic menstrual disturbances and low bone mass have been associated with high-level competition among some female athletes, particularly in sports such as gymnastics and cross-country running, where a slender physique or lean body build is important. Adolescent female athletes, in a rapid growth and development phase, may be at greatest risk. We sought to identify athletes at risk, understand the origin of possible negative outcomes and recommend behavioral modifications that promote participation in competitive sports while supporting lifetime health. This review discusses the development and impact of disordered eating and menstrual dysfunction on bone mass in young, competitive, female athletes and provides nutrition recommendations for their energy, carbohydrate, protein, vitamin and mineral intake

Fluctuating temperature modifies heat-mortality association around the globe

Studies have investigated the effects of heat and temperature variability (TV) on mortality. However, few assessed whether TV modifies the heat-mortality association. Data on daily temperature and mortality in the warm season were collected from 717 locations across 36 countries. TV was calculated as the standard deviation of the average of the same and previous days’ minimum and maximum temperatures. We used location-specific quasi-Poisson regression models with an interaction term between the cross-basis term for mean temperature and quartiles of TV to obtain heat-mortality associations under each quartile of TV, and then pooled estimates at the country, regional, and global levels. Results show the increased risk in heat-related mortality with increments in TV, accounting for 0.70% (95% confidence interval [CI]: −0.33 to 1.69), 1.34% (95% CI: −0.14 to 2.73), 1.99% (95% CI: 0.29–3.57), and 2.73% (95% CI: 0.76–4.50) of total deaths for Q1–Q4 (first quartile–fourth quartile) of TV. The modification effects of TV varied geographically. Central Europe had the highest attributable fractions (AFs), corresponding to 7.68% (95% CI: 5.25–9.89) of total deaths for Q4 of TV, while the lowest AFs were observed in North America, with the values for Q4 of 1.74% (95% CI: −0.09 to 3.39). TV had a significant modification effect on the heat-mortality association, causing a higher heat-related mortality burden with increments of TV. Implementing targeted strategies against heat exposure and fluctuant temperatures simultaneously would benefit public health

Proper nutrition can prevent negative health outcomes in young female athletes

Since the onset of Title IX, opportunities have dramatically increased for female athletes, largely to their benefit. However, some negative health outcomes such as disordered eating, chronic menstrual disturbances and low bone mass have been associated with high-level competition among some female athletes, particularly in sports such as gymnastics and cross-country running, where a slender physique or lean body build is important. Adolescent female athletes, in a rapid growth and development phase, may be at greatest risk. We sought to identify athletes at risk, understand the origin of possible negative outcomes and recommend behavioral modifications that promote participation in competitive sports while supporting lifetime health. This review discusses the development and impact of disordered eating and menstrual dysfunction on bone mass in young, competitive, female athletes and provides nutrition recommendations for their energy, carbohydrate, protein, vitamin and mineral intake

Proper nutrition can prevent negative health outcomes in young female athletes

Since the onset of Title IX, opportunities have dramatically increased for female athletes, largely to their benefit. However, some negative health outcomes such as disordered eating, chronic menstrual disturbances and low bone mass have been associated with high-level competition among some female athletes, particularly in sports such as gymnastics and cross-country running, where a slender physique or lean body build is important. Adolescent female athletes, in a rapid growth and development phase, may be at greatest risk. We sought to identify athletes at risk, understand the origin of possible negative outcomes and recommend behavioral modifications that promote participation in competitive sports while supporting lifetime health. This review discusses the development and impact of disordered eating and menstrual dysfunction on bone mass in young, competitive, female athletes and provides nutrition recommendations for their energy, carbohydrate, protein, vitamin and mineral intake

Utility of the Actiheart Accelerometer for Estimating Exercise Energy Expenditure in Female Adolescent Runners

There is a growing need to accurately assess exercise energy expenditure (EEE) in athletic populations that may be at risk for health disorders because of an imbalance between energy intake and energy expenditure. The Actiheart combines heart rate and uniaxial accelerometry to estimate energy expenditure above rest. The authors' purpose was to determine the utility of the Actiheart for predicting EEE in female adolescent runners (N = 39, age 15.7 +/- 1.1 yr). EEE was measured by indirect calorimetry and predicted by the Actiheart during three 8-min stages of treadmill running at individualized velocities corresponding to each runner's training, including recovery, tempo, and 5-km-race pace. Repeated-measures ANOVA with Bonferroni post hoc comparisons across the 3 running stages indicated that the Actiheart was sensitive to changes in intensity (p < .01), but accelerometer output tended to plateau at race pace. Pairwise comparisons of the mean difference between Actiheart- and criterion-measured EEE yielded values of 0.0436, 0.0539, and 0.0753 kcal . kg(-1) min(-1) during recovery, tempo, and race pace, respectively (p < .0001). Bland Altman plots indicated that the Actiheart consistently underestimated EEE except in 1 runner's recovery bout. A linear mixed-model regression analysis with height as a covariate provided an improved EEE prediction model, with the overall standard error of the estimate for the 3 speeds reduced to 0.0101 kcal . kg(-1) . min(-1). Using the manufacturer's equation that combines heart rate and uniaxial motion, the Actiheart may have limited use in accurately assessing EEE, and therefore energy availability, in young, female competitive runners.2.230 JCR (2010) Q2, 33/70 Nutrition & dietetics, 20/80 Sport scienceUE

Utility of the Actiheart Accelerometer for Estimating Exercise Energy Expenditure in Female Adolescent Runners

There is a growing need to accurately assess exercise energy expenditure (EEE) in athletic populations that may be at risk for health disorders because of an imbalance between energy intake and energy expenditure. The Actiheart combines heart rate and uniaxial accelerometry to estimate energy expenditure above rest. The authors' purpose was to determine the utility of the Actiheart for predicting EEE in female adolescent runners (N = 39, age 15.7 +/- 1.1 yr). EEE was measured by indirect calorimetry and predicted by the Actiheart during three 8-min stages of treadmill running at individualized velocities corresponding to each runner's training, including recovery, tempo, and 5-km-race pace. Repeated-measures ANOVA with Bonferroni post hoc comparisons across the 3 running stages indicated that the Actiheart was sensitive to changes in intensity (p < .01), but accelerometer output tended to plateau at race pace. Pairwise comparisons of the mean difference between Actiheart- and criterion-measured EEE yielded values of 0.0436, 0.0539, and 0.0753 kcal . kg(-1) min(-1) during recovery, tempo, and race pace, respectively (p < .0001). Bland Altman plots indicated that the Actiheart consistently underestimated EEE except in 1 runner's recovery bout. A linear mixed-model regression analysis with height as a covariate provided an improved EEE prediction model, with the overall standard error of the estimate for the 3 speeds reduced to 0.0101 kcal . kg(-1) . min(-1). Using the manufacturer's equation that combines heart rate and uniaxial motion, the Actiheart may have limited use in accurately assessing EEE, and therefore energy availability, in young, female competitive runners.2.230 JCR (2010) Q2, 33/70 Nutrition & dietetics, 20/80 Sport scienceUE

Correlation of MRI grading of bone stress injuries with clinical risk factors and return to play: a 5-year prospective study in collegiate track and field athletes.

BackgroundBone stress injuries are common in track and field athletes. Knowledge of risk factors and correlation of these to magnetic resonance imaging (MRI) grading could be helpful in determining recovery time.PurposeTo examine the relationships between MRI grading of bone stress injuries with clinical risk factors and time to return to sport in collegiate track and field athletes.Study designCohort study (prognosis); Level of evidence, 2.MethodsA total of 211 male and female collegiate track and field and cross-country athletes were followed prospectively through their competitive seasons. All athletes had preparticipation history, physical examination, and anthropometric measurements obtained annually. An additional questionnaire was completed regarding nutritional behaviors, menstrual patterns, and prior injuries, as well as a 3-day diet record. Dual-energy X-ray absorptiometry was performed at baseline and each year of participation in the study. Athletes with clinical evidence of bone stress injuries had plain radiographs. If radiograph findings were negative, MRI was performed. Bone stress injuries were evaluated by 2 independent radiologists utilizing an MRI grading system. The MRI grading and risk factors were evaluated to identify predictors of time to return to sport.ResultsThirty-four of the athletes (12 men, 22 women) sustained 61 bone stress injuries during the 5-year study period. The mean prospective assessment for participants was 2.7 years. In the multiple regression model, MRI grade and total-body bone mineral density (BMD) emerged as significant and independent predictors of time to return to sport. Specifically, the higher the MRI grade (P = .004) and lower the BMD (P = .030), the longer the recovery time. Location of the bone injury at predominantly trabecular sites of the femoral neck, pubic bone, and sacrum was also associated with a prolonged time to return to sport. Female athletes with oligomenorrhea and amenorrhea had bone stress injuries of higher MRI grades compared with eumenorrheic athletes (P = .009).ConclusionHigher MRI grade, lower BMD, and skeletal sites of predominant trabecular bone structures were associated with a delayed recovery of bone stress injuries in track and field athletes. Knowledge of these risk factors, as well as nutritional and menstrual factors, can be clinically useful in determining injury severity and time to return to sport

Healthy Runner Project: a 7-year, multisite nutrition education intervention to reduce bone stress injury incidence in collegiate distance runners.

OBJECTIVES: We evaluated the effect of a nutrition education intervention on bone stress injury (BSI) incidence among female distance runners at two NCAA Division I institutions. METHODS: Historical 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). RESULTS: The historical phase included 56 runners and 90.2 person-years; the intervention phase included 78 runners and 137.3 person-years. Overall BSI rates were not reduced from the historical (0.52 events per person-year) to the intervention (0.43 events per person-year) phase. Post hoc analyses demonstrated trabecular-rich BSI rates dropped significantly from 0.18 to 0.10 events per person-year from the historical to intervention phase (p=0.047). There was a significant interaction between phase and institution (p=0.009). At Institution 1, the overall BSI rate dropped from 0.63 to 0.27 events per person-year from the historical to intervention phase (p=0.041), whereas no decline was observed at Institution 2. CONCLUSION: Our findings suggest that a nutrition intervention emphasising energy availability may preferentially impact trabecular-rich BSI and depend on team environment, culture and resources

Healthy Runner Project: a 7-year, multisite nutrition education intervention to reduce bone stress injury incidence in collegiate distance runners

Objectives We evaluated the effect of a nutrition education intervention on bone stress injury (BSI) incidence among female distance runners at two NCAA Division I institutions.Methods Historical 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).Results The historical phase included 56 runners and 90.2 person-years; the intervention phase included 78 runners and 137.3 person-years. Overall BSI rates were not reduced from the historical (0.52 events per person-year) to the intervention (0.43 events per person-year) phase. Post hoc analyses demonstrated trabecular-rich BSI rates dropped significantly from 0.18 to 0.10 events per person-year from the historical to intervention phase (p=0.047). There was a significant interaction between phase and institution (p=0.009). At Institution 1, the overall BSI rate dropped from 0.63 to 0.27 events per person-year from the historical to intervention phase (p=0.041), whereas no decline was observed at Institution 2.Conclusion Our findings suggest that a nutrition intervention emphasising energy availability may preferentially impact trabecular-rich BSI and depend on team environment, culture and resources