David L. Nichols

Bone density and young athletic women : An update

High-school girls and collegiate women have tremendous opportunities to participate in athletic teams. Young girls are also playing in club and select teams at an early age and often, year-round. There are many benefits for participating in sport and physical activity on both the physical and mental health of girls and women. Decreased risk for heart disease and diabetes mellitus, along with improved self-esteem and body-image, were among the first reported benefits of regular physical activity. In addition, sport participation and physical activity is also associated with bone health. Athletes have a greater bone mineral density compared with non-active and physically active females. The increase in bone mass should reduce the risk of fragility fractures in later life. There appears to be a window of opportunity during the development of peak bone mass in which the bone is especially responsive to weight-bearing physical activity. Impact loading sports such as gymnastics, rugby or volleyball tend to produce a better overall osteogenic response than sports without impact loading such as cycling, rowing and swimming. Relatively little is known about the impact of retiring from athletics on bone density. It appears that former athletes continue to have a higher bone density than non-athletes; however, the rate of bone loss appears to be similar in the femoral neck. The positive impact of sports participation on bone mass can be tempered by nutritional and hormonal status. It is not known whether female athletes need additional calcium compared with the general female population. Due to the increased energy expenditure of exercise and/or the pressure to obtain an optimal training bodyweight, some female athletes may develop low energy availability or an eating disorder and subsequently amenorrhoea and a loss of bone mineral density. The three inter-related clinical disorders are referred to as the ‘female athlete triad’. This article presents a review of the relationship between sports training and bone health, specifically bone mineral density, in young athletic women.

Impact of Detraining on Bone Loss in Former Collegiate Female Gymnasts

Undesirable changes in health-related parameters are thought to occur in retiring female athletes, but this has not been examined in longitudinal studies. The purpose of this study was to examine longitudinal changes in bone mineral density (BMD), body composition, and dietary intake in gymnasts and controls. Nonathletic, college-age women (n = 9) were selected as a control group for comparison to the gymnasts (n = 10). Initial BMDs for the gymnasts were determined by using dual energy X-ray absorptiometry (Lunar, DPX) at the beginning of their final competitive year. Initial BMDs for the controls were measured during a similar time-frame. Follow-up measurements were made at least 1-year after the initial measurement. Gymnasts had significantly greater BMD of the femoral neck (1.262 versus 1.058 g/cm2, respectively), Ward’s triangle (1.230 versus 1.008 g/cm2), greater trochanter (1002 versus 0.822 g/cm2), and total body (1.232 versus 1.145 g/cm2) than controls while still competing (P < .05). Following retirement from competition, (mean years of retirement, 4 years), BMD of the gymnasts remained significantly greater than controls at total body, femoral neck, trochanter, and Ward’s triangle (P < .05). Significant declines in femoral neck, Ward’s triangle, and greater trochanter BMD were found in both gymnasts and controls (0.72% to 1.9% per year), but only gymnasts had a significant decline at the lumbar spine (0.87% per year). In conclusion, BMD changes in former gymnasts appear to be site-specific, and gymnasts continue to have greater proximal femur BMD than controls, despite their decreased exercise, which may help postpone or prevent osteoporosis later in life.

Dissimilar Spine and Femoral Z-Scores in Premenopausal Women

Abstract. The purpose of this study was to determine if differences exist in premenopausal women between z-scores for lumbar spine and proximal femoral bone mineral densities (BMD). Participants were 237 women ranging in age from 20 to 45 years. BMDs of the lumbar spine and proximal femur (femoral neck, Wards area, and trochanter) were assessed using dual-energy X-ray absorptiometry (Lunar DPX). Mean (±SD) age, height, and weight of the participants were 29.4 ± 6.9 years, 164.4 ± 6.1 cm, and 64.9 ± 12.1 kg, respectively. Lumbar spine BMD and BMD at the femoral neck, Wards area, and trochanter were significantly correlated with large SEEs (r = 0.59–0.65; SEE = 0.09–0.11). No positive correlation with age and BMD at any site was seen in this population but a significant negative correlation with age was seen in the proximal femur beginning at age 30. Twenty to 24% of the 20–29-year-olds exhibited a difference in z-scores of greater than 1 between the spine and sites in the proximal femur. This percentage increased to 32–46% in the 30–45-year-olds but the nature of the observed differences changed. The differences in spine and proximal femoral z-scores that are seen in the older age group appear to be the result of the earlier onset of bone loss in the proximal femur rather than an initial difference in peak bone mass which has been maintained.

Bone mineral density and dietary intake in patients with Crohn's disease.

Individuals diagnosed with Crohns disease are at an increased risk for developing low bone density. The exact cause of low bone mineral density in Crohns disease patients has not been determined. The purpose of this study was to assess the incidence of low bone mineral density in premenopausal women with Crohns disease and to determine the role diet plays in bone mineral density for this population. Bone mineral density of the lumbar spine (L2-L4), proximal femur, and forearm was measured in 51 female controls and 50 females with Crohns disease using dual energy X-ray absorptiometry (Lunar DPXPlus, Madison, WI). Dietary intake for all Crohns disease participants was analyzed using both 3-d dietary records and a food frequency questionnaire. When compared to healthy controls, bone mineral density values of Crohns disease participants were decreased for all sites, particularly the spine (1.169 +/- 0.114, p = 0.054), Wards area (0.831 +/- 0.128, p = 0.052), and the femoral neck (0.927 +/- 0.100, p = 0.01). Factors associated with lower bone density in Crohns participants were weight, corticosteroid usage, length and age of diagnosis, history and length of resection, and dietary intakes of magnesium, copper, magnesium, vitamin K, and zinc. The results of this study indicate for the first time that diet plays a role in the development of low bone density in premenopausal women with Crohns disease.

Evaluation of the Nutrition Knowledge, Attitudes, and Food Consumption Behaviors of High School Students Before and After Completion of a Nutrition Course

Adolescents may lower their risk of becoming overweight and lead a healthier lifestyle by improving their nutrition knowledge and attitudes towards nutrition and health. A quasi-experimental design was used to assess nutrition knowledge, attitudes, and food consumption behaviors of students 14 to 19 years old before and after a nutrition course in a North Texas high school. The intervention group (n = 45) was enrolled in elective family and consumer science courses and received nutrition and health education, whereas the control group (n = 30) received no nutrition education. Identical pre- and posttest questionnaires were completed at the beginning and the end of a semester by students in both groups. Descriptive statistics, cross-tabulation with chi-square analyses, and independent and paired-sample t tests were calculated using SPSS. No differences in the dependent variables existed between the two groups before the intervention, but after the intervention, only the intervention group significantly improved in nutrition knowledge, some attitude scores, and milk and breakfast consumption behaviors. The findings of this study indicate that nutrition education may positively influence the knowledge, attitudes, and eating behaviors of high school students.

Effect of exercise on postprandial insulin responses in Mexican American and non-hispanic women

Postprandial insulin responses (integrated area under the curve) to an oral glucose load after a period of aerobic exercise and no exercise (control) were compared in sedentary normoglycemic Mexican American and non-Hispanic women pair-matched (n = 9) on total body fat mass (21.8 +/- 3.5 kg). The age (27.4 +/- 3.0 years), body mass index (BMI) (23.6 +/- 1.4 kg/m2), waist to hip ratio (WHR) (0.85 +/- .02), waist circumference (83.5 +/- 4.5 cm), lean mass (36.2 +/- 1.5 kg), and maximal O2 consumption ([VO2 max] 32.9 +/- 1.6 mL x kg(-1) x min(-1)) were similar, although the centrality index (subscapular/triceps skinfolds) was significantly greater in Mexican Americans (0.88 +/- 0.06 v 0.70 +/- 0.05, P < .01). Exercise (treadmill walking for 50 minutes at 70% VO2 max) and control trials were performed 4 weeks apart and 5 to 12 days after the onset of menstruation. A 75-g oral glucose load was administered 15 hours after the completion of each trial, with the subjects 12 hours postprandial. Blood samples were drawn prior to glucose ingestion (fasting, 0 minutes) and at minutes 15, 30, 60, 90, 120, and 150 postingestion. The postprandial insulin response was calculated using a trapezoidal method. In Mexican Americans, significant (P < .02) reductions in the postprandial insulin response (exercise v control, 6.5 +/- 1.0 v 8.5 +/- 1.4 pmol/L x min x 10(4)) and fasting insulin (exercise v control, 77.4 +/- 7.0 v 88.5 +/- 10.3 pmol/L) occurred after exercise compared with the control condition. In non-Hispanics, neither the postprandial insulin response (exercise v control, 7.2 +/- 1.0 v 6.2 +/- 0.9 pmol/L x min x 10(4)) nor fasting insulin (exercise v control, 77.0 +/- 8.2 v 82.9 +/- 8.9 pmol/L) were significantly different between trials. The postprandial insulin response in the control trial was significantly correlated with the change in the insulin response (control minus exercise) in the 18 women (r = .56, P = .01). No trial or group differences were found for postprandial glucose and C-peptide responses. Mexican American women have a high risk of developing type 2 diabetes, and aerobic exercise may be valuable in the prevention or delay of onset of diabetes by reducing peripheral insulin resistance.

Responses of Blood Lipids and Lipoproteins to Extended-Release Niacin and Exercise in Sedentary Postmenopausal Women

Niacin and exercise positively alter blood lipids and lipoproteins via different mechanisms. However, the effects of niacin combined with exercise on blood lipid and lipoprotein profiles have not been investigated in sedentary postmenopausal women. The current study examined the responses of blood lipids and lipoproteins to niacin and exercise in 18 sedentary postmenopausal women, who underwent four conditions: no-niacin rest, no-niacin exercise, niacin rest, and niacin exercise. Participants ingested 1,000 mg/day of extended-release niacin for 4 weeks during the niacin condition. As an exercise treatment, participants performed a single bout of exercise on a treadmill at 60% heart rate reserve until 400 kcal were expended. Extended-release niacin without the exercise intervention significantly (p < .001) increased high-density lipoprotein cholesterol and high-density lipoprotein-2 cholesterol by 12.4% and 33.3%, respectively, and decreased the total cholesterol to high-density lipoprotein cholesterol ratio by 14.8%. Thus, 4 weeks of 1,000 mg/day of extended-release niacin can improve the blood lipid and lipoprotein profiles in sedentary postmenopausal women.

Prevalence of overweight and obesity among students with intellectual disabilities in Taiwan: A secondary analysis

PURPOSE The study aims to investigate the prevalence and likelihood of overweight and obesity in a large sample of students with intellectual disabilities (ID) from Taiwan. METHOD A secondary analysis of a cross sectional study was employed to examine the body weight status among 7 to 18 year-old students with ID enrolled in public special education schools in 2013. The students were divided into three age groups (7-12 yrs, 13-15 yrs, and 16-18 yrs), four ID levels (mild, moderate, severe, and profound) and six comorbidities of ID (ID only, ID caused by genetic disorders, ID with physical disability, ID with multiple disabilities without physical disabilities, ID with autism spectrum disorders, and others with rare diseases). RESULTS The sample represented 34.8% of students with ID attending public special education schools in Taiwan. Within this sample, 35.2% were identified as being overweight or obese. The 16 to 18 year-old age group were approximately two times (AOR=2.02, more likely to be obese than the 7-12 year-old group. Students with ID caused by genetic disorders such as Down syndrome (AOR=2.00) appeared to be more overweight or obese in comparison to those with ID only. Students with moderate (AOR=1.64) and severe ID (AOR=1.49) were more overweight/obese compared to those with profound ID. CONCLUSION The findings not only highlight the high prevalence of overweight/obesity but also stress the need for health promotion initiatives to address issues of overweight/obesity within this population.

The Effect of Whole-Body Vibration on Lower-Body Resistance Detraining in College-Age Women

ABSTRACT Purpose: This study explored the effect of whole-body vibration (WBV) using accelerations of 2.56 g to 7.68 g on lower-body detraining. Methods: All participants (N = 20) were trained using a lower-body resistance-training program for 30 min twice per week from Week 0 to Week 6. At the end of the program, they were randomly assigned to a control group that performed no further training or a WBV group that performed a progressive static WBV program. Data for the 5-repetition-maximum (5RM) squat and extensors and flexors of the knee and ankle were collected at Weeks 0, 6, 8, 10, and 12 for all participants. Results: Two-way (condition vs. time) analysis of variance revealed that although the WBV group maintained strength in the 5RM from Week 6 through Week 8 and the control group had a lower 5RM in Week 8 from Week 6, no differences in the 5RM squat existed between the groups at Week 8. Two-way factorial multivariate analysis of variance revealed no differences between the groups at any of the time for torque of knee flexion, dorsiflexion, or plantar flexion. Conclusion: Static WBV of 2.56 g to 7.68 g did not attenuate detraining of the flexors and extensors of the knee and ankle.

Use of technology to facilitate physical activity in children with autism spectrum disorders: A pilot study

Deficits in social behavior and communication skills are correlated with reduced gross motor skills in children with autism spectrum disorders (ASD). The ExerciseBuddy application (EB app) was designed to communicate these motor skills to those with ASD and integrates evidence-based practices such as visual support and video modeling supported by The National Professional Development Center on Autism Spectrum Disorders. The purpose of this study was to determine the effectiveness of the EB app in facilitating increased physiologic responses to physical activity via a continuous measurement of energy expenditure and heart rate versus practice-style teaching methods in children with ASD. Six children, ages 5 to 10years, diagnosed with ASD were recruited. Each participant performed a variety of locomotor or object control skills as defined by the Test of Gross Motor Development-2 once per week for 4weeks. Motor skills were communicated and demonstrated using either practice-style teaching methods or the instructional section of the EB app. Energy expenditure and heart rate were measured continuously during each 12-minute session. A Wilcoxon signed-rank test was performed to assess any differences between the use of the app and practice-style teaching methods. The use of the EB app elicited greater values for peak energy expenditure (p=0.043) and peak heart rate response (p=0.028) while performing locomotor skills but no differences were observed while performing object control skills. Similarities were observed with average physiologic responses between the use of the EB app and practice-style teaching methods. The use of the EB app may allow for a greater peak physiologic response during more dynamic movements and a similar average cardiovascular and metabolic response when compared to practice-style teaching methods in children with ASD.