Biological Maturation and Physical Activity in South Korean Adolescent Girls.

Introduction/purpose: To examine whether body fatness (i.e., body mass index and percent body fat) and psychosocial correlates of physical activity (PA) mediate the relationships between pubertal status and PA and sedentary behavior (SB) among South Korean adolescent girls.

Physical activity and sedentary behaviour of toddlers and preschoolers in child care centres in Alberta, Canada.

Objective: To describe duration of physical activity and duration and bouts of sedentary behaviour during child care in a sample of toddlers and preschoolers (19-60 months) from Alberta, Canada, and to examine whether duration and bouts differed among sex, age and parental immigration status groups.

Methods: One hundred and fourteen children aged 19-60 months from eight child care centres throughout Alberta participated. Data were collected at baseline of a study examining revised Alberta Child Care Accreditation Standards.

Assessment of Pre-Pregnancy Dietary Intake with a Food Frequency Questionnaire in Alberta Women.

Purpose: Pre-pregnancy is an under-examined and potentially important time to optimize dietary intake to support fetal growth and development as well as maternal health. The purpose of the study was to determine the extent to which dietary intake reported by non-pregnant women is similar to pre-pregnancy dietary intake reported by pregnant women using the same assessment tool.

Methods: The self-administered, semi-quantitative food frequency questionnaire (FFQ) was adapted from the Canadian version of the Diet History Questionnaire, originally developed by the National Cancer Institute in the United States.

Oral L-arginine before resistance exercise blunts growth hormone in strength trained males.

Acute resistance exercise and L-arginine have both been shown to independently elevate plasma growth hormone (GH) concentrations; however, their combined effect is controversial. The purpose was to investigate the combined effects of resistance exercise and L-arginine supplementation on plasma L-arginine, GH, GH secretagogues, and IGF-1 in strength trained participants. Fourteen strength trained males (age: 25 ± 4 y; body mass: 81.

The acute effects of L-arginine on hormonal and metabolic responses during submaximal exercise in trained cyclists.

L-arginine may enhance endurance performance mediated by two primary mechanisms including enhanced secretion of endogenous growth hormone (GH) and as a precursor of nitric oxide (NO); however, research in trained participants has been equivocal. The purpose was to investigate the effect of acute L-arginine ingestion on the hormonal and metabolic response during submaximal exercise in trained cyclists. Fifteen aerobically trained men (age: 28 ± 5 y; body mass: 77.

Reduced plasma glucose and leptin after 12 weeks of functional electrical stimulation-rowing exercise training in spinal cord injury patients.

Objective: To investigate the effects of exercise training with a functional electrical stimulation (FES) rowing machine on insulin resistance, plasma leptin levels, and body composition in people with spinal cord injury (SCI).

Design: Experimental study.

Setting: A fitness and research center for people with disabilities.

A comparison of fitness training to a pedometer-based walking program matched for total energy cost.

Background: Fitness and health variables were measured in 128 sedentary men and women randomly assigned to 6 months of fitness training (F), a walking program (W), or a control (C) group.

Methods: The F program gradually increased volume and intensity until 4 d/wk of training, at 70% of peak VO2 for 43 min/session was prescribed while the W group performed daily walking monitored with pedometers and increased until 10,000 steps x d-1 were prescribed. Total weekly energy expenditure was matched between the activity groups.

Effect of hydration status on high-intensity rowing performance and immune function.

Purpose: This study determined the effect of dehydration and rehydration (DR) on performance, immune cell response, and tympanic temperature after high-intensity rowing exercise.

Methods: Seven oarswomen completed two simulated 2000-m rowing race trials separated by 72 h in a random, cross-over design. One trial was completed in a euhydrated (E) condition and the other using a DR protocol.

A randomized controlled crossover trial of the effect of ginseng consumption on the immune response to moderate exercise in healthy sedentary men.

Ginseng is a popular herbal remedy that is reputed to increase resistance to stress and improve immune function. Regular exercise results in acute physiologic stress that affects the immune response. This study was conducted to investigate the effects of daily consumption of a standardized ginsenoside-containing North American ginseng (Panax quinquefolius) extract on immune function before, during, and after a moderate-exercise protocol in healthy sedentary men.

Effects of aerobic exercise training on estrogen metabolism in premenopausal women: a randomized controlled trial.

Background: Regular physical activity may alter estrogen metabolism, a proposed biomarker of breast cancer risk, by shifting metabolism to favor production of 2-hydroxyestrone (2-OHE1). Few studies, however, have examined this question using a randomized controlled trial.

Purpose: To examine the effects of 12 weeks of aerobic exercise training on 2-OHE1 and 16alpha-hydroxyestrone (16alpha-OHE1) in premenopausal women.

Lower excess postexercise oxygen consumption and altered growth hormone and cortisol responses to exercise in obese men.

Context: Obesity is associated with altered patterns of substrate utilization at rest and during exercise.

Objective: The relationship between obesity and fat oxidation during recovery from exercise was examined.

Hypothesis: The postexercise shift toward fat oxidation is blunted in the obese state, reflected by higher respiratory exchange ratio (RER), blunted GH, and increased cortisol values compared with lean controls.

Effect of elk velvet antler supplementation on the hormonal response to acute and chronic exercise in male and female rowers.

To examine the effects of elk velvet antler supplementation (EVA) combined with training on resting and exercise-stimulated hormonal response, male (n = 25) and female (n = 21) rowers ingested either EVA (560 mg/d) or placebo (PL) during 10 wk of training. VO(2max), 2000 m rowing time, leg and bench press strength were determined before and after 5 and 10 wk of training. Serum hormone levels were measured prior to and 5 and 60 min after a simulated 2000 m rowing race.

Associations between aerobic fitness and estrogen metabolites in premenopausal women.

Unlabelled: Chronic physical activity may alter estrogen metabolism, a proposed biomarker of breast cancer risk, by causing a shift toward higher 2-OHE1 and lower 16alpha-OHE1 levels.

Purpose: To investigate the association between an objective indicator of chronic exercise, aerobic fitness, and 2-OHE1 and 16alpha-OHE1 in premenopausal women.

Methods: Women with high aerobic fitness (N=17; VO2max>or=48 mL.

Energy balance and reproductive function in active women.

Athletes engaged in rigorous training programs expend large amounts of energy and require appropriate energetic compensation to maintain or improve performance. If these exercise regimens are not fueled sufficiently, a negative energy balance will likely emerge and lead to a broad spectrum of menstrual cycle disturbances and less than optimal performance. This review examines the theory and evidence surrounding energy availability and reproductive function.

Leptin response to short-term fasting in sympathectomized men: role of the SNS.

We studied plasma leptin levels in six people with high-lesion spinal cord injury [SCI; body mass index (BMI) 25.9 +/- 1.5 kg/m(2), age 37 +/- 3.

Intact sympathetic nervous system is required for leptin effects on resting metabolic rate in people with spinal cord injury.

Compared with able-bodied (AB), people with spinal cord injury (SCI) have a 3- to 5-fold higher risk of developing type 2 diabetes mellitus, which may be associated with increased fat mass. Evidence suggests that leptin regulates body adiposity through the sympathetic nervous system, which is impaired in people with high lesion SCI. The purpose of this study was to determine the relationship among leptin levels, body composition, and resting metabolic rate (RMR) in people with high lesion SCI and body mass index-, weight-, height-, and waist circumference-matched AB subjects.

Energy balance and luteal phase progesterone levels in elite adolescent aesthetic athletes.

Menstrual abnormalities are associated with negative energy balance and reduced energy expenditure (REE). To examine this relationship in elite adolescent aesthetic athletes, 3 groups of females (aged 15-18 years) were studied: 10 oligo/amenorrheic athletes (OA), 11 eumenorrheic athletes (EA), and 8 non-athlete controls (C). Components of energy balance, body composition, dietary restraint, pubertal maturation, and luteal phase salivary progesterone were assessed in all groups.