The differences in physical activity levels in preschool children during free play recess and structured play recess.

BACKGROUND/OBJECTIVE: Physical activity (PA) is important in reducing childhood obesity, yet a majority of children are not meeting PA guidelines. Schools have been identified as a place to promote childhood PA. The purpose of this study was to determine the best type of physically active recess period to increase preschool-aged children's PA. METHODS: PA was measured via accelerometers in preschool-aged children (n = 29) during three, 30-min recess conditions (control; structured play; free play) on separate school days. Tertile splits were performed based on PA during the free play condition and children were divided into three groups: highly, moderately and least active. RESULTS: For the aggregated sample, children were more (p ≤ 0.001) active during the free play (1282 ±â€¯662 counts. min-1) and structured play (1416 ±â€¯448 counts. min-1) recess versus the control condition (570 ±â€¯460 counts. min-1) and activity was not different between the free play and structured conditions. However, children who were the most active during free play (1970 ±â€¯647 counts·min-1) decreased (p ≤ 0.05) activity during structured play (1462 ±â€¯535 counts·min-1), whereas children who were moderately active (1031 ±â€¯112 counts·min-1) or the least (530 ±â€¯239 counts·min-1) active during free play increased activity during structured play (1383 ±â€¯345 counts·min-1 moderately active, 1313 ±â€¯413 counts·min-1 least active). CONCLUSION: Providing a physically-active recess period will contribute to preschool-aged children meeting the recommended PA guidelines; however, different children may respond in a different way based upon the structure of the recess period.

Bone Mineral Density in Collegiate Dance Majors Compared to Healthy Controls.

INTRODUCTION: The bone mineral density (BMD) status of dancers is currently unknown. Some research indicates that female dancers have no difference or higher BMD than non-dancers. Other evidence indicates they have lower BMD, predisposing them to osteoporosis and fractures later in life. These differences among studies may be due to differences in dancer type, age, level, and lack of control of confounding variables. Few studies have been completed on college-level dancers. PURPOSE: To evaluate BMD in female college-level dance majors. METHODS: 20 female multi-genre collegiate dance majors and 12 female non-dancer control subjects participated in the study. Each participant underwent three consecutive dual energy x-ray absorptiometry scans to determine BMD of the total body, dual femurs, and lumbar spine. Statistical analysis was completed by an independent samples t-test. RESULTS: The lumbar spine demonstrated a significant difference between groups (p=0.011), with dancers showing greater BMD (1.32±0.10 vs 1.21±0.12 g/cm2). There was no significant difference between groups for total body or dual femur BMD (p=0.104 and 0.175, respectively). CONCLUSION: College-level dancers may have higher BMD of their lumbar spine than non-dancers, but not in other areas. This area may have increased BMD due to loading from dance activity and warrants further investigation.

The influence of ethnicity on thermoregulation after acute cold exposure.

OBJECTIVE: It is well established that a combination of factors, including ethnicity, may influence an individual's response to cold stress. Previous work from our laboratory has demonstrated that when faced with a cold challenge, there is a similar response in heat production between Caucasian (CAU) and African American (AA) individuals that is accompanied by a differential response in core temperature. The objective of this study was to evaluate the influence of ethnicity (CAU vs AA) on the thermoregulatory response after acute cold exposure (ACE-REC, 25 degrees C air). METHODS: Five AA males (20.8 +/- 0.5 years) and 10 CAU males (25.6+/-4.9 years) underwent pre-experimental testing to determine Vo(2max) (AA = 37.2 +/- 0.1 mLxkg(-1)xmin(-1), CAU = 44.3 +/- 8.7 mLxkg(-1)xmin(-1)) and body composition (AA = 14.6 +/- 5.4%, CAU = 19.2 +/- 5.0%). Participants underwent acute cold exposure that consisted of 120 minutes of exposure to 10 degrees C air (ACE) followed by 120 minutes of recovery in 25 degrees C air (ACE-REC). Rectal temperature (T(re)) was measured via a rectal thermistor. Mean skin temperature (T(sk)) was assessed with thermistors. Oxygen consumption (Vo(2)) was assessed via indirect open circuit spirometry. Rectal temperature and T(sk) were measured continuously, and if T(re) < or = 35 degrees C, testing was terminated. RESULTS: Analysis of variance for ACE-REC revealed a significant main effect for T(sk) across time (P < .001), T(re) across time (P < .001), and Vo(2) across time (P < .001). In addition, a significant time x ethnicity interaction was revealed for T(re) (P = .008), T(sk) (P = .042), and Vo(2) (P = .019) during ACE-REC. CONCLUSIONS: Based on these data, there is a differential response between CAU and AA across time for Vo(2), T(re), and T(sk) ACE-REC.