A multilevel examination of gender differences in the association between features of the school environment and physical activity among a sample of grades 9 to 12 students in Ontario, Canada

<p>Abstract</p> <p>Background</p> <p>Creating school environments that support student physical activity (PA) is a key recommendation of policy-makers to increase youth PA. Given males are more active than females at all ages, it has been suggested that investigating gender differences in the features of the environment that associate with PA may help to inform gender-focused PA interventions and reduce the gender disparity in PA. The purpose of this cross-sectional study was to explore gender differences in the association between factors of the school environment and students' time spent in PA.</p> <p>Methods</p> <p>Among a sample of 10781 female and 10973 male students in grades 9 to 12 from 76 secondary schools in Ontario, Canada, student- and school-level survey PA data were collected and supplemented with GIS-derived measures of the built environment within 1-km buffers of the 76 schools.</p> <p>Results</p> <p>Findings from the present study revealed significant differences in the time male and female students spent in PA as well as in some of the school- and student-level factors associated with PA. Results of the gender-specific multilevel analyses indicate schools should consider providing an alternate room for PA, especially for providing flexibility activities directed at female students. Schools should also consider offering daily physical education programming to male students in senior grades and providing PA promotion initiatives targeting obese male students.</p> <p>Conclusions</p> <p>Although most variation in male and female students' time spent in PA lies between students within schools, there is sufficient between-school variation to be of interest to practitioners and policy-makers. More research investigating gender differentials in environment factors associated with youth PA are warranted.</p

Effects of self-paced interval and continuous training on health markers in women

This is the final version of the article. Available from Springer Verlag via the DOI in this record.PURPOSE: To compare the effects of self-paced high-intensity interval and continuous cycle training on health markers in premenopausal women. METHODS: Forty-five inactive females were randomised to a high-intensity interval training (HIIT; n = 15), continuous training (CT; n = 15) or an inactive control (CON; n = 15) group. HIIT performed 5 × 5 min sets comprising repetitions of 30-s low-, 20-s moderate- and 10-s high-intensity cycling with 2 min rest between sets. CT completed 50 min of continuous cycling. Training was completed self-paced, 3 times weekly for 12 weeks. RESULTS: Peak oxygen uptake (16 ± 8 and 21 ± 12%), resting heart rate (HR) (-5 ± 9 and -4 ± 7 bpm) and visual and verbal learning improved following HIIT and CT compared to CON (P  0.05). No outcome variable changed in the CON group (P > 0.05). CONCLUSIONS: Twelve weeks of self-paced HIIT and CT were similarly effective at improving cardiorespiratory fitness, resting HR and cognitive function in inactive premenopausal women, whereas blood pressure, submaximal HR, well-being and body mass adaptations were training-type-specific. Both training methods improved established health markers, but the adaptations to HIIT were evoked for a lower time commitment.The study was supported by FIFA-Medical Assessment and Research Centre (F-MARC)

EFFECTS OF CHEMOTHERAPY REGIMENS ON SKELETAL MUSCLE MITOCHONDRIAL FUNCTION IN BREAST CANCER PATIENTS MEASURED BY NEAR INFRARED SPECTROSCOPY

Chloe W. Caudell1, Shannon Smith1, Randy Hutchison2, Jennifer Trilk, FACSM1. 1University of South Carolina School of Medicine Greenville, Greenville, SC. 2Furman University, Greenville, SC. Background: Cancer patients undergoing chemotherapy are known to develop skeletal muscle mitochondrial dysfunction and subsequent cachexia due to massive treatment related oxidative stress, increasing the risk of chemotherapy-related morbidity and mortality. The timeline is unknown as to when this dysfunction starts to occur and is traditionally measured via invasive muscle biopsy. This adds additional burden to the patient and makes tracking of cachexia throughout treatment difficult.Purpose: To assess the effects of differing chemotherapy regimens on skeletal muscle mitochondrial function throughout treatment in breast cancer (BC) patients using near infrared spectroscopy (NIRS). Methods: Non-metastatic BC patients will be recruited prior to the initiation of chemotherapy treatment involving taxanes and/or anthracyclines. Mitochondrial function of the vastus lateralis muscle will be measured during activation, noninvasively, by assessing changes in oxygenated and deoxygenated hemoglobin using a NIRS PortaMon device. Within 5 days prior to every infusion, participants will perform moderately intense exercise on a stationary ergonometric bike while wearing the PortaMon device. Data collected in real-time by the NIRS will be analyzed using a one-way ANOVA to detect differences in mitochondrial oxidative capacity between different chemotherapy regimens as well as between treatment time points within each individual regimen. Between treatment differences will be considered statistically significant at α \u3c 0.05. Results: Throughout chemotherapy treatment, it is anticipated that the time constant (Tc) it takes the vastus lateralis muscle to reoxygenate will increase indicating skeletal muscle mitochondrial dysfunction. It is also anticipated that there will be between treatment differences in mitochondrial oxidative capacity. Discussion: The results of this project will further provide insight into how different chemotherapy regimens impact mitochondria at a cellular level, potentially further informing oncology practice regarding the costs and benefits of a chemotherapy regimen. This is a novel way to noninvasively assess mitochondrial function during treatment in a cancer population, which has not yet been previously studied