Interactive effects of body position and perceived exertion during spinning exercises.

Spinning is a popular group exercise taught in health and fitness facilities worldwide. Throughout a Spinning workout session, intensity is variable and is controlled by body position on the Spinning stationary cycle and perceived resistance. This study examined the effects of 3 body positions and 4 levels of perceived exertion (RPE) on cardiorespiratory response and vastus lateralis normalized electromyographical activity (NrmsEMGVL). Eleven participants (24.4 ± 6.3 years) with 3.2 ± 2.2 years of Spinning experience completed twelve 3-minute randomly assigned Spinning conditions across 4 separate testing days after an 8-hour fast. Conditions were determined by body position (seated, running, and standing climb [SC]) and RPE (low, low-medium, medium-high, and high). Cardiorespiratory data and NrmsEMGVL were recorded continuously during each Spinning condition. Respiratory rate and oxygen consumption were significantly higher for running and SC than seated, and minute ventilation was significantly higher for running than seated. All cardiorespiratory values were higher at medium-high and high RPE, than low or medium-low RPE, and high RPE generated higher respiratory rate and respiratory exchange ratio than medium-high RPE. Significant body position × RPE interactions were observed for heart rate (HR) and NrmsEMGVL with running and SC producing higher HRs than seated at low and high RPE, and running producing higher NrmsEMGVL than seated at low RPE. Results indicate that running and SC provide the greatest cardiorespiratory responses, and maximal efforts are not needed for these responses. Additionally, HR seems to be a poor marker of oxygen consumption, especially at high RPEs.

Genomic signatures of a global fitness index in a multi-ethnic cohort of women.

The rates of obesity and sedentary lifestyle are on a dramatic incline, with associated detrimental health effects among women in particular. Although exercise prescriptions are useful for overcoming these problems, success can be hampered by differential responsiveness among individuals in cardiovascular fitness indices (i.e. improvements in strength, lipids, VO(2) max). Genomic factors appear to play an important role in determining this inter-individual variation. We performed microarray analyses on mRNA in whole blood from 60 sedentary women from a multi-ethnic cohort who underwent 12 weeks of exercise, to identify gene subsets that were differentially expressed between individuals who experienced the greatest and least improvements in fitness. We identified 43 transcripts in 39 unique genes (FDR<10%; FC>1.5) whose expression increased the most in "high" versus "low" pre-menopausal female responders. These 39 genes were enriched in six biological pathways, including oxidative phosphorylation (p = 8.08 × 10(-3)). Several of the 39 genes (i.e. TIGD7, UQCRH, PSMA6, WDR12, TFB2M, USP15) have previously reported associations with fitness-related phenotypes. In summary, we identified gene signatures based on mRNA analysis that define responsiveness to exercise in a largely minority-based female cohort. Importantly, this study validates several genes/pathways previously associated with exercise responsiveness and extends these findings with additional novel genes.

The effects of an incremental approach to 10,000 steps/day on metabolic syndrome components in sedentary overweight women.

BACKGROUND: Pedometer programs can increase physical activity in sedentary individuals, a population that is at risk for developing metabolic syndrome and each of its individual components. Although the popular 10,000 steps/day recommendation has shown to induce many favorable health benefits, it may be out of reach for sedentary individuals. This study observed the effects of incremental increases in steps/day on metabolic syndrome components in sedentary overweight women. METHODS: This study was a longitudinal, quasi-experimental design. Participants were recruited from a 12-week work-site pedometer program and grouped as either 'active' or 'control' after the intervention based on their steps/day improvement. Self-reported physical activity, pedometer assessed physical activity, BMI, resting heart rate, waist circumference, blood pressure, triglycerides, HDL-C, and fasting glucose were measured before and after the program. RESULTS: The active group showed significant within-group improvements in waist circumference and fasting glucose. Significant group differences were observed in resting heart rate, BMI, and systolic blood pressure; however, the changes observed in systolic blood pressure were not independent of weight loss. CONCLUSIONS: Incremental increases in steps/day induced favorable changes in some MetS components suggesting that this approach is a viable starting point for sedentary individuals that may find it difficult to initially accumulate 10,000 steps/day.