We studied 21 ballet dancers aged 19.4 ± 1.4 years, hypothesizing that undernu-trition was a major factor in menstrual irregularity in this population. Menstrual history was determined by questionnaire. Eight dancers had always been regular (R). Thirteen subjects had a history of menstrual irregularity (HI). Of these, 2 were currently regularly menstruating, 3 had short cycles, 6 were oligomenorrheic, and 2 were amenorrheic. Subjects completed a weighed dietary record and an Eating Attitudes Test (EAT). The following physiological parameters were measured: body composition by anthropometry, resting metabolic rate (RMR) by open-circuit indirect calorimetry, and serum thyroid hormone concentrations by radioimmunoassay. R subjects had significantly higher RMR than HI subjects. Also, HI subjects had lower RMR than predicted by fat-free mass, compared to the R subjects. Neitherreported energy intake nor serum thyroid hormone concentrations were different between R and HI subjects. EAT scores varied and were not different between groups. We concluded that in ballet dancers, low RMR is more strongly associated with menstrual irregularity than is currentreported energy intake or serum thyroid hormone concentrations.
Kathryn H. Myburgh, Claire Berman, Illana Novick, Timothy D. Noakes and Estelle V. Lambert
João Pedro Nunes, Alex S. Ribeiro, Analiza M. Silva, Brad J. Schoenfeld, Leandro dos Santos, Paolo M. Cunha, Matheus A. Nascimento, Crisieli M. Tomeleri, Hellen C.G. Nabuco, Melissa Antunes, Letícia T. Cyrino and Edilson S. Cyrino
The aim of this study was to analyze the association between muscle quality index (MQI) and phase angle (PhA) after a program of progressive resistance training (RT) in older women. Sixty-six older women with previous RT experience (68.8 ± 4.6 years, 156.6 ± 5.3 cm, 66.0 ± 13.0 kg, and 26.7 ± 4.6 kg/m2) underwent 12 weeks of RT (3 ×/week, eight exercises, and 10–15 repetition maximum). Anthropometry, muscular strength (one-repetition maximum tests), and body composition (dual-energy X-ray absorptiometry and spectral bioimpedance) were measured pre- and posttraining. There were observed significant increases for PhA, MQI, muscular strength, muscle mass, and reactance, whereas no significant changes in body fat and resistance were found. A significant correlation was observed between the RT-induced relative changes in PhA and MQI (r = .620). We conclude that improvements in MQI induced by RT are associated with increases in PhA. Therefore, PhA may be a valid tool to track changes in MQI after 12 weeks of RT in older women.
Aaron P. Crombie, Pei-Yang Liu, Michael J. Ormsbee and Jasminka Z. Ilich
To examine relationships between changes in body weight, body composition, and fitness level in male students of the general population and those in the Army Reserve Officer Training Corps (ROTC) program during the freshman year of college.
Thirty-seven (18.4 ± 0.7 yr) healthy, nonsmoking, first-semesterresident male students were divided into 3 groups: low active (LA), high active (HA), and ROTC. Baseline (beginning of freshman year) and 6-month follow-up measurements included anthropometry, body composition (by DXA), 3-day food records, and physical activity (PA) assessment.
Weight and body-mass index did not change significantly within or among groups. HA participants compared with LA and ROTC had a significant decrease in body fat (–1.6% ± 2.5% vs. 1.9% ± 1.2% and 0.8% ± 2.2%, respectively). They also had a significant increase in lean mass compared with LA and ROTC (1.8 ± 1.1 kg vs. –0.2 ± 2.0 kg and 0.2 ± 1.7 kg, respectively). All p values were <.05. ROTC and LA participants were similar in all measures of body composition and PA and had significantly lower PA levels than the HA group. No significant relationships were observed between dietary variables and body-composition changes.
These results suggest that higher PA was the most powerful determinant in achieving favorable body-composition outcomes. In addition, current physical training conducted by ROTC at Florida State University (which seems to be a practice nationwide) might not be sufficient to offset gains in body fat.
Megan E. Holmes, Jim Pivarnik, Karin Pfeiffer, Kimberly S. Maier, Joey C. Eisenmann and Martha Ewing
The role of psychosocial stress in the development of obesity and metabolic syndrome is receiving increased attention and has led to examination of whether physical activity may moderate the stress-metabolic syndrome relationship. The current study examined relationships among physical activity, stress, and metabolic syndrome in adolescents.
Participants (N = 126; 57 girls, 69 boys) were assessed for anthropometry, psychosocial stress, physical activity, and metabolic syndrome variables; t tests were used to examine sex differences, and regression analysis was used to assess relationships among variables controlling for sex and maturity status.
Mean body mass index approached the 75th percentile for both sexes. Typical sex differences were observed for systolic blood pressure, time spent in moderate and vigorous physical activity, and perceived stress. Although stress was not associated with MetS (β = –.001, P = .82), a modest, positive relationship was observed with BMI (β = .20, P = .04).
Strong relationships between physical activity and stress with MetS or BMI were not found in this sample. Results may be partially explained by overall good physical health status of the participants. Additional research in groups exhibiting varying degrees of health is needed.
Daniel P. Bailey, Louise A. Savory, Sarah J. Denton and Catherine J. Kerr
It is unclear whether cardiorespiratory fitness (CRF) is independently linked to cardiometabolic risk in children. This study investigated a) the association between CRF level and presence of cardiometabolic risk disorders using health-related cut points, and b) whether these associations were mediated by abdominal adiposity in children.
This was a cross-sectional design study. Anthropometry, biochemical parameters and CRF were assessed in 147 schoolchildren (75 girls) aged 10 to 14 years. CRF was determined using a maximal cycle ergometer test. Children were classified as ‘fit’ or ‘unfit’ according to published thresholds. Logistic regression was used to investigate the odds of having individual and clustered cardiometabolic risk factors according to CRF level and whether abdominal adiposity mediated these associations.
Children classified as unfit had increased odds of presenting individual and clustered cardiometabolic risk factors (P < .05), but these associations no longer remained after adjusting for abdominal adiposity (P > .05).
This study suggests that the association between CRF and cardiometabolic risk is mediated by abdominal adiposity in 10- to 14-year-old children and that abdominal adiposity may be a more important determinant of adverse cardiometabolic health in this age group.
Kaisu Marjut Kaikkonen, Raija irmeli Korpelainen, Mikko P. Tulppo, Hannu Sakari Kaikkonen, Marja Liisa Vanhala, Mika Antero Kallio, Sirkka M. Keinänen-Kiukaanniemi and Juha Tapani Korpelainen
Autonomic nervous system (ANS) dysfunction and obesity are intrinsically related to each other. In normal-weight subjects physical activity (PA) and fitness are related to cardiovascular autonomic regulation, providing evidence that aerobic training may improve ANS functioning measured by heart rate variability (HRV). The goal of this study was to investigate the association between lifetime PA, aerobic fitness and HRV in obese adults.
Participants included 107 (87 females) volunteers (mean age 44.5 years, median BMI 35.7) who completed health and lifestyle questionnaires and measurements of maximal aerobic performance, anthropometry and 24 h HRV.
In the multivariate linear regression analyses, lifetime physical activity explained 40% of the variance in normal R-R intervals (SDNN). Each 1-category increase in the activity index increased SDNN by 15.4 (P = .009) and 24% of the variance in natural logarithmic value of ultra-low frequency power (P = .050). High measured VO2max explained 45% of the variance in natural logarithmic value of high-frequency power (P = .009) and 25% of the variance in low frequency/high frequency ratio (P < .001).
Lifetime physical activity and aerobic fitness may reduce obesity-related health risks by improving the cardiac autonomic function measured by HRV in obese workingage subjects. This research supports the role of lifetime physical activity in weight management strategies and interventions to reduce obesity-related health risks.
Laura Banks, Cedric Manlhiot, Stafford W. Dobbin, Don Gibson, Karen Stearne, Jolie Davies-Shaw, Nita Chahal, Amanda Fisher and Brian McCrindle
Background: Moderate-to-vigorous physical activity (MVPA) has been negatively associated with cardiometabolic risk. We sought to determine if MVPA interacts with body-mass index (BMI) and waist circumference (WC) in determining cardiometabolic risk in adolescents. Methods: This cross-sectional study included cardiometabolic risk (blood pressure [BP], nonfasting lipids) screening and a 7-day recall physical activity questionnaire in 4,104 adolescents (51% male; mean age: 14.6 ± 0.5 years old). WC- and BMI- percentiles were used to define anthropometric categories (including obese adolescents: 390th WC, 385th BMI). Results: Obesity in adolescents was associated with lower levels of high-density lipoprotein (HDL cholesterol (Estimate [EST]: -0.28(0.07) mmol/L, p < .001) and higher non-HDL cholesterol (EST: +0.38(0.14) mmol/L, p = .008). Each additional day with 320 min of MVPA was associated with lower non-HDL cholesterol (EST: −0.014(0.005) mmol/L/days/week, p = .003), independent of anthropometric category. Each additional day with 320 min of MVPA was associated with an increased odds ratio (OR) for higher BP category in obese adolescents (OR: 1.055, 95% CI: 1.028−1.084, p < .001) and a lower odds ratio for higher BP category in presumably-muscular adolescents (OR: 0.968, 95% CI: 0.934−0.989, p = .005). Conclusions: An increase in MVPA was associated with an increased likelihood for higher BP category in obese adolescents. The dose-response relationship between physical activity and cardiometabolic risk needs to be evaluated in adolescents of varying anthropometry categories.
Gillian K. Myburgh, Sean P. Cumming, Manuel Coelho E. Silva, Karl Cooke and Robert M. Malina
To evaluate relationships among skeletal maturity, body size, and functional capacities of elite junior tennis players.
Participants were 88 elite British Junior tennis players (44 male; 44 female), 8–16 years of age (12.4 } 1.9 years). Skeletal age estimated maturty. Anthropometry, grip strength, countermovement jump, squat jump, forehand agility, backhand agility, Yo-Yo, 5-m, 10-m and 20-m sprints were measured. Comparative analysis for each sex was performed, relating advanced maturers (Male: 15; Female: 29) to a combination of on-time and late maturers (Male: 29; Female: 31). ANCOVAs were used to determine absolute differences between male and female players and between the 2 maturity subgroups, with chronological age as the covariate.
Advanced maturity afforded male players advantages in absolute measures of grip strength, speed, upper and lower body power but not in acceleration, agility or aerobic endurance. Male players were significantly taller than females in the U13-U16 age group. Advanced maturity in female players afforded advantages in absolute measures of grip strength, agility and overhead power, but not in backhand agility, aerobic endurance or squat jump power.
It is important that talent identification protocols consider the maturity of youth athletes to more satisfactorily address athletic potential rather than transient physical capabilities.
Markus V. Nahas, Mauro V. G. de Barros, Maria Alice A. de Assis, Pedro C. Hallal, Alex A. Florindo and Lisandra Konrad
A cross-cultural, randomized study was proposed to observe the effects of a school-based intervention designed to promote physical activity and healthy eating among high school students in 2 cities from different regions in Brazil: Recife and Florianopolis. The objective of this article is to describe the methodology and subjects enrolled in the project.
Ten schools from each region were matched and randomized into intervention and control conditions. A questionnaire and anthropometry were used to collect data in the first and last month of the 2006 school year. The sample (n = 2155 at baseline; 55.7% females; 49.1% in the experimental group) included students 15 to 24 years, attending nighttime classes. The intervention focused on simple environmental/organizational changes, diet and physical activity education, and personnel training.
The central aspects of the intervention have been implemented in all 10 intervention schools. Problems during the intervention included teachers’ strikes in both sites and lack of involvement of the canteen owners in schools.
The Saude na Boa study provides evidence that public high schools in Brazil represent an important environment for health promotion. Its design and simple measurements increase the chances of it being sustained and disseminated to similar schools in Brazil.
Joyce E. Ballard, Lorraine S. Wallace, David B. Holiday, Cassandra Herron, Liberty L. Harrington, Karen C. Mobbs and Patricia Cussen
This study assessed differences in bone-mineral density (BMD) and lean and fat tissues between 5 age groups of White men age 65–93 years. Lean and fat tissues were measured with absorptiometry and anthropometry, and BMD, with dual-energy X-ray absorptiometry. Forearm, spinal, and femoral T scores were used to classify BMD as normal, osteopenic, or osteoporotic. A questionnaire evaluated previous physical activity, calcium intake, and bone fractures. Significantly lower values in body weight, lean tissue, and forearm BMD occurred in the older age groups. Significant, positive relationships were found between total lean tissue and radial, spinal, and hip BMDs. For the total group, osteopenic and osteoporotic T scores, respectively, were femoral neck 70.6% and 9.8%, radius 27.5% and 25.5%, and spine 25.5% and 7.8%. Differences in BMD values were found between levels of lifestyle factors (dietary calcium and history of previous fractures). In conclusion, elderly men should be encouraged to maintain adequate total lean tissue because of its association with BMD.