Physical activity and physical fitness in African-American girls with and without obesity

Lack of physical activity and low levels of physical fitness are thought to be contributing factors to the high prevalence of obesity in African-American girls, To examine this hypothesis, we compared habitual physical activity and physical fitness in 54 African-American girls with obesity and 96 African-American girls without obesity residing in rural South Carolina, Participation in vigorous (greater than or equal to 6 METs) (VPA) or moderate and vigorous physical activity (greater than or equal to 4 METs) (MVPA) was assessed on three consecutive days using the Previous Day Physical Activity Recall, Cardiorespiratory fitness was assessed using the PWC 170 cycle ergometer test, Upper body strength was determined at two sites via isometric cable tensiometer tests, Relative to their counterparts without obesity, girls with obesity reported significantly fewer 30-minute blocks of VPA (0.90 +/- 0.14 vs. 1.3 +/- 0.14) and MVPA (1.2 +/- 0.18 vs. 1.7 +/- 0.16) (p<0.01), Within the entire sample, VPA and MVPA were inversely associated with body mass index (r=-0.17 and r=-0.19) and triceps skinfold thickness (r=-0.19 and r=-0.22) (p<0.05), In the PWC 170 test and isometric strength tests, girls with obesity demonstrated absolute scores that were similar to, or greater than, those of girls without obesity; however, when scores were expressed relative to bodyweight, girls with obesity demonstrated significantly lower values (p<0.05). The results support the hypothesis that lack of physical activity and low physical fitness are important contributing factors in the development and/or maintenance of obesity in African-American girls.

Invasive activity and chemotactic response to growth factors by Kaposi's sarcoma cells

Kaposi's sarcoma (KS) is a relatively low grade neoplasm, classically occurring in the skin of elderly men. A more virulent and invasive form of Kaposi's sarcoma has been described in patients with acquired immune deficiency syndrome (AIDS). The origin and identification of the tumor cells in these lesions is controversial. Here we have studied the behavior of cells derived from KS lesions in an in vitro assay which measures the ability of cells to invade through a reconstituted basement membrane. In agreement with previous work, KS cells obtained under selective culture conditions were invasive showing activity comparable to that of malignant tumor cells. Normal fibroblasts, smooth muscle cells, and endothelial cells did not demonstrate invasive behavior under the same experimental conditions. To characterize further the nature of the KS cells we tested the chemotactic response of cells from the most invasive line to a variety of growth factors and compared their response to those of fibroblasts, smooth muscle, and endothelial cells. These studies suggest that normal cells respond to a unique repertoire of chemotactic factors. The chemotactic response of the KS cells most closely resembled that of smooth muscle cells and was quite distinct from endothelial cells. These results indicate that the KS-derived cultures contain invasive cells with a smooth muscle cell-like phenotype.

Physical activity and overweight in children aged 3-5 : relationship to parental activity and obesity

OBJECTIVE To compare the physical activity levels of overweight and non overweight 3- to 5-y-old children while attending preschool. A secondary aim was to evaluate weight-related differences in hypothesized parental determinants of child physical activity behavior. DESIGN Cross-sectional study. SUBJECTS A total of 245, 3- to 5-y-olds (127 girls, 118 boys) and their parent(s) (242 mothers, 173 fathers) recruited from nine preschools. Overweight status determined using the age- and sex-specific 85th percentile for body mass index (BMI) from CDC Growth Charts. MEASUREMENTS Physical activity during the preschool day was assessed on multiple days via two independent objective measures direct observation using the observation system for recording activity in preschools (OSRAP) and real-time accelerometry using the MTI/CSA 7164 accelerometer. Parents completed a take-home survey assessing sociodemographic information, parental height and weight, modeling of physical activity, support for physical activity, active toys and sporting equipment at home, child’s television watching, frequency of park visitation, and perceptions of child competence. RESULTS Overweight boys were significantly less active than their nonoverweight peers during the preschool day. No significant differences were observed in girls. Despite a strong association between childhood overweight status and parental obesity, no significant differences were observed for the hypothesized parental influences on physical activity behavior. CONCLUSIONS Our results suggest that a significant proportion of overweight children may be at increased risk for further gains in adiposity because of low levels of physical activity during the preschool day.

Advances in the science of objective physical activity monitoring : 3rd International Conference on Ambulatory Monitoring of Physical Activity and Movement

Editorial: This theme issue of BJSM presents key papers from the 3rd International Conference on Ambulatory Monitoring of Physical Activity and Movement (ICAMPAM). The July 2013 conference was hosted by the University of Massachusetts and was attended by researchers, clinicians, students and technology vendors for North America, Europe, Australasia and Asia...

A review of preschool children's physical activity and sedentary time using objective measures

CONTEXT: Identifying current physical activity levels and sedentary time of preschool children is important for informing government policy and community initiatives. This paper reviewed studies reporting on physical activity and time spent sedentary among preschool-aged children (2-5 years) using objective measures. EVIDENCE ACQUISITION: Databases were searched for studies published up to and including April 2013 that reported on, or enabled the calculation of, the proportion of time preschool children spent sedentary and in light- and moderate to vigorous-intensity physical activity. A total of 40 publications met the inclusion criteria for physical activity and 31 met the inclusion criteria for sedentary time. Objective measures included ActiGraph, Actiwatch, Actical, Actiheart, and RT3 accelerometers, direct observation, and Quantum XL telemetry heart rate monitoring. Data were analyzed in May 2013. EVIDENCE SYNTHESIS: Considerable variation in prevalence estimates existed. The proportion of time children spent sedentary ranged from 34% to 94%. The time spent in light-intensity physical activity and moderate to vigorous-intensity physical activity ranged from 4% to 33% and 2% to 41%, respectively. CONCLUSIONS: The considerable variation of prevalence estimates makes it difficult to determine the "true" prevalence of physical activity and sedentary time in preschool children. Future research should aim to reduce inconsistencies in the employed methodologies to better understand preschoolers' physical activity levels and sedentary behavior.

Exploring parents' beliefs about their young child's physical activity and screen time behaviours

Drawing on the belief-based framework of the theory of planned behaviour, 20 adults living in Queensland, Australia participated in semi-structured interviews to elicit salient beliefs regarding their young child’s physical activity (PA) and screen time behaviours. Data were analysed separately for PA and screen time with a range of beliefs emerging that guided parents’ decisions for these important health behaviours. Underlying advantages (e.g., improve family interactions, improve child behaviour), disadvantages (e.g., mess and noise factor, increase in parental distress), barriers (e.g., lack of time, parental fatigue), and facilitators (e.g., access to parks, social support) to engaging their child in adequate PA and limited screen time emerged. Normative pressures were also identified as affecting parents’ decisions for their child in these contexts. Parents experience unique difficulties in engaging their child in adequate PA and limited screen time that interventions can draw on when designing and implementing programs aimed at modifying these important child health behaviours.

Quantifying physical activity and the associated barriers for women with ovarian cancer

Objective The purpose of this study was to quantify physical activity levels and determine the barriers to physical activity for women with ovarian cancer. Materials and Methods Women with ovarian cancer from 3 oncology clinics enrolled in the cross-sectional study. Physical activity and barriers to physical activity were measured using the International Physical Activity Questionnaire and Perceived Physical Activity Barriers scale, respectively. Demographic, medical, and anthropometric data were obtained from medical records. Results Ninety-five women (response rate, 41%), with a mean (SD) age of 61 (10.6) years, a body mass index of 26.5 (6.8) kg/m2, and 36.6 (28.2) months since diagnosis, participated in the study. The majority of the participants had stage III (32%) or IV (32%) ovarian cancer, were undergoing chemotherapy (41%), and had a history of chemotherapy (93%). The majority of the participants reduced their physical activity after diagnosis, with 19% meeting recommended physical activity guidelines. The participants undergoing treatment reported lower moderate-vigorous physical activity compared with those not undergoing active treatment (mean [SD], 42 [57] vs 104 [119] min/wk; P < 0.001) and less total physical activity barriers (mean [SD], 49 vs 47; P > 0.4). The greatest barriers to physical activity included fatigue (37.8%), exercise not in routine (34.7%), lack of self-discipline (32.6%), and procrastination (27.4%). Conclusions Women with ovarian cancer have low levels of physical activity. There are disease-specific general barriers to physical activity participation. The majority of the participants reduced their physical activity after diagnosis, with these patients reporting a higher number of total barriers. Behavioral strategies are required to increase physical activity adherence in this population to ensure that recommended guidelines are met to achieve the emerging known benefits of exercise oncology.

Active aging: Exploration into self-ratings of "being active," out-of-home physical activity, and participation among older Australian adults living in four different settings

We examined whether self-ratings of “being active” among older people living in four different settings (major city high and lower density suburbs, a regional city, and a rural area) were associated with out-of-home participation and outdoor physical activity. A mixed-methods approach (survey, travel diary, and GPS tracking over a one-week period) was used to gather data from 48 individuals aged over 55 years. Self-ratings of “being active” were found to be positively correlated with the number of days older people spent time away from home but unrelated to time traveled by active means (walking and biking). No significant differences in active travel were found between the four study locations, despite differences in their respective built environments.The findings suggest that additional strategies to the creation of “age-friendly” environments are needed if older people are to increase their levels of outdoor physical activity. “Active aging” promotion campaigns may need to explicitly identify the benefits of walking outdoors to ambulatory older people as a means of maintaining their overall health, functional ability, and participation within society in the long-term and also encourage the development of community-based programs in order to facilitate regular walking for this group.

Physical activity and screen-time of childhood hematopoietic stem cell transplant survivors

Aim Reduced bone mineral density, impaired cardiovascular fitness, and increased risk of obesity are well-known late effects of Hematopoietic Stem Cell Transplantation (HSCT) in survivors of childhood cancer. These comorbidities can be mitigated through physical activity and limiting screen-time (ST). This study aims to increase the understanding of physical activity and ST behaviours for children following HSCT. Method Children were recruited from two oncology follow-up clinics and completed a questionnaire on their physical activity levels and screen-time. Children were classified as short (≤2yrs) and long term (>2yrs) survivors. Results Fifty-eight children were eligible, of whom forty children age 6 to 18 years (60% males) participated in the study. Less than half (47.5%) met the daily recommendations for physical activity and one third met the ST recommendations. Late survivors reported higher daily physical activity and less ST than early survivors. Among late survivors, females reported higher daily physical activity and less ST than males. Conclusions Our findings suggest that the majority of children following HSCT were not sufficiently active and had excessive screen-time; however this was comparable to healthy populations. Appropriately designed physical activity and screen-time intervention programs should be explored early following transplant for children undergoing HSCT.

Adolescent self-reported physical activity and autonomy: A case for constrained and structured environments?

The provision of autonomy supportive environments that promote physical activity engagement have become popular in contemporary youth settings. However, questions remain about whether adolescent perceptions of their autonomy have implications for physical activity. The purpose of this investigation was to examine the association between adolescents’ self-reported physical activity and their perceived autonomy. Participants (n = 384 adolescents) aged between 12 and 15 years were recruited from six secondary schools in metropolitan Brisbane, Australia. Self-reported measures of physical activity and autonomy were obtained. Logistic regression with inverse probability weights were used to examine the association between autonomy and the odds of meeting youth physical activity guidelines. Autonomy (OR 0.61, 95% CI 0.49-0.76) and gender (OR 0.62, 95% CI 0.46-0.83) were negatively associated with meeting physical activity guidelines. However, the model explained only a small amount of the variation in whether youth in this sample met physical activity guidelines (R2 = 0.023). For every 1 unit decrease in autonomy (on an index from 1 to 5), participants were 1.64 times more likely to meet physical activity guidelines. The findings, which are at odds with several previous studies, suggest that interventions designed to facilitate youth physical activity should limit opportunities for youth to make independent decisions about their engagement. However, the small amount of variation explained by the predictors in the model is a caveat, and should be considered prior to applying such suggestions in practical settings. Future research should continue to examine a larger age range, longitudinal observational or intervention studies to examine assertions of causality, as well as objective measurement of physical activity.

Underlying scaling relationships between solar activity and geomagnetic activity revealed by multifractal analyses

his paper identifies some scaling relationships between solar activity and geomagnetic activity. We examine the scaling properties of hourly data for two geomagnetic indices (ap and AE), two solar indices (solar X-rays Xl and solar flux F10.7), and two inner heliospheric indices (ion density Ni and flow speed Vs) over the period 1995–2001 by the universal multifractal approach and the traditional multifractal analysis. We found that the universal multifractal model (UMM) provides a good fit to the empirical K(q) and τ(q) curves of these time series. The estimated values of the Lévy index α in the UMM indicate that multifractality exists in the time series for ap, AE, Xl, and Ni, while those for F10.7 and Vs are monofractal. The estimated values of the nonconservation parameter H of this model confirm that these time series are conservative which indicate that the mean value of the process is constant for varying resolution. Additionally, the multifractal K(q) and τ(q) curves, and the estimated values of the sparseness parameter C1 of the UMM indicate that there are three pairs of indices displaying similar scaling properties, namely ap and Xl, AE and Ni, and F10.7 and Vs. The similarity in the scaling properties of pairs (ap,Xl) and (AE,Ni) suggests that ap and Xl, AE and Ni are better correlated—in terms of scaling—than previous thought, respectively. But our results still cannot be used to advance forecasting of ap and AE by Xl and Ni, respectively, due to some reasons

Muscular activity and fatigue in lower-limb and trunk muscles during different sit-to-stand tests

Sit-to-stand (STS) tests measure the ability to get up from a chair, reproducing an important component of daily living activity. As this functional task is essential for human independence, STS performance has been studied in the past decades using several methods, including electromyography. The aim of this study was to measure muscular activity and fatigue during different repetitions and speeds of STS tasks using surface electromyography in lower-limb and trunk muscles. This cross-sectional study recruited 30 healthy young adults. Average muscle activation, percentage of maximum voluntary contraction, muscle involvement in motion and fatigue were measured using surface electrodes placed on the medial gastrocnemius (MG), biceps femoris (BF), vastus medialis of the quadriceps (QM), the abdominal rectus (AR), erector spinae (ES), rectus femoris (RF), soleus (SO) and the tibialis anterior (TA). Five-repetition STS, 10-repetition STS and 30-second STS variants were performed. MG, BF, QM, ES and RF muscles showed differences in muscle activation, while QM, AR and ES muscles showed significant differences in MVC percentage. Also, significant differences in fatigue were found in QM muscle between different STS tests. There was no statistically significant fatigue in the BF, MG and SO muscles of the leg although there appeared to be a trend of increasing fatigue. These results could be useful in describing the functional movements of the STS test used in rehabilitation programs, notwithstanding that they were measured in healthy young subjects.