The effect of variety on physical activity: a cross-sectional study.

It has been repeatedly demonstrated that increasing the variety of available food and purchasing options reliably increases eating and consumer spending behavior, respectively. However, the potential probehavioral effect of increasing the variety of exercise equipment options on the amount of exercise individuals perform is very limited. The purpose of this investigation was to compare the amount, enjoyment (liking), and effort perception of resistance training exercise vs. sedentary alternatives during a high-variety (HV) resistance-exercise equipment condition (10 choices) vs. a low-variety (LV) equipment condition (2 choices). During each condition (HV) and (LV), children (8-12 years), young adults (18-26 years), and older adults (≥60 years) had free-choice access to both resistance-exercise equipment and sedentary activities for a total of 20 minutes. The amount of time allocated to resistance exercise, the total number of repetitions performed, and session liking were measured during each condition. The participants significantly (p ≤ 0.05 for all) increased: repetitions performed (126.4 ± 71.7 vs. 88.0 ± 48.8), the amount of time allocated for exercise (14.3 ± 6.3 vs. 12.1 ± 6.5 minutes) and liking (8.1 ± 1.5 vs. 7.1 ± 2.1 cm) during the HV condition relative to the LV condition. The rating of perceived exertion was not significantly (p = 0.13) different from HV (4.2 ± 2.4) to LV (3.8 ± 2.3). Increasing the variety of exercise equipment available to children, young and older adults increased their exercise participation and enjoyment of that exercise without altering their perceived exertion. The practical application from this research is that increasing the variety of exercise equipment available to one's clients may increase their exercise adherence.

Fifty-three hours of total sleep deprivation has no effect on rewarming from cold air exposure.

OBJECTIVE: Sleep deprivation and cold air exposure are both experienced in occupational and military settings but the combined effects of these 2 stressors is unknown. The purpose of this study was to determine the effects of 53 hours of total sleep deprivation on thermoregulation during the rewarming phase (25°C air) after acute cold air exposure (10°C air). METHODS: Eight young men underwent 2 trials in which they either received 7 hours of sleep at night or were totally sleep deprived. On 3 consecutive mornings, the subjects underwent 2 hours of cold air exposure followed by 2 hours of rewarming. Rectal temperature, mean skin temperature, oxygen consumption, and thermal sensation were measured. RESULTS: Rewarming from acute cold air exposure caused a decline in rectal temperature (~0.5°C) each day but this was not different between subjects who were totally sleep deprived and subjects who received 7 hours of sleep at night. During this same period, mean skin temperature increased (from ~22°C to 27°C), oxygen consumption decreased (from ~7 to 4 mL·kg(-1)·min(-1)), and the participants felt warmer. CONCLUSIONS: Under the conditions of the present study, sleep-deprived persons are not at a greater risk for a decline in rectal temperature (ie, a hypothermic afterdrop) during rewarming from cold air.

Exercise is Medicine®: Knowledge and Awareness among Exercise Science and Medical School Students.

The purpose of this exploratory study was twofold: to determine whether exercise science and medical students are aware of the Exercise is Medicine® (EIM®) program and to construct a tool that would permit assessment of EIM® variables with students enrolled in both programs. The study consisted of a quantitative, cross-sectional design, using a self-report electronic questionnaire. An Exploratory Factor Analysis (EFA) using principal component analysis extraction method with Varimax factor rotation was employed to validate the survey instrument based on the expected constructs, which posited five (5) contending factors: Value, Familiarity, Preparedness, Curricular Perceptions, and Opinions. A pairwise comparison was then performed to compare elements of the EIM® scale identified from the factor analysis by student type (medical and exercise science student) using multiple independent sample t-tests. Based on the pairwise comparisons, there were statistically significant differences of all EIM® factors by student type with the exception of Opinions (p = 0.109). Based on the trends observed in the data, exercise science students had a more positive report for each EIM® factor compared to medical students. These findings suggest a discrepancy in the delivery, acceptance, and implementation of the EIM® initiative between exercise professionals and medical healthcare providers. Future investigation is warranted to validate this experimental instrument and study the differences in EIM® factors among current medical and exercise professionals.

Seven-site versus three-site method of body composition using BodyMetrix ultrasound compared to dual-energy X-ray absorptiometry.

Obesity is a steadily growing epidemic affecting all segments of the population including college-aged students. The weight gain that is evidenced amid the transitional stage of college years increases the risks associated with cardiovascular and metabolic diseases. The BodyMetrix® BX-2000 (ULTRA) using a seven-site method has been evaluated against dual-energy X-ray absorptiometry (DXA) for estimation of body composition, which has yielded conflicting results. To date, no studies have compared the three-site method Jackson and Pollock three-site method to DXA. PURPOSE: The purpose of the study was twofold (i) to compare agreement between Jackson-Pollock seven site (JP7), Jackson-Pollock three site (JP3) and Pollock three site (P3) to predict body fat (%BF) using ULTRA and (ii) and to compare the three ULTRA methodologies against DXA. METHODS: Seventy-six healthy college-aged subjects (ages = 22·08 ± 2·50 years) participated in this study. DXA and ULTRA body composition assessments were performed following manufacturer's instructions to estimate %BF. Paired sample t-tests were used to assess agreement between JP7, P3 and JP3. Additionally, a two-tailed sample t-test was performed by sex. ULTRA and DXA results were also performed for agreement and bivariate correlation. RESULTS: No significant differences between JP7 and P3, P = 0·38, were observed. In males, no significant differences were observed between JP7 and P3, P = 0·18. Significant differences were observed in all other pairs, P≤0·001 and between ULTRA and DXA. CONCLUSIONS: The Pollock 3-site method estimates body fat percentage with comparable accuracy to JP7 using ULTRA.

A comparison of dual-energy X-ray absorptiometry, air displacement plethysmography and A-mode ultrasound to assess body composition in college-age adults.

BACKGROUND: There is currently a dearth of scientific literature exploring the agreement of A-mode ultrasound (US) body composition analysis with dual-energy X-ray absorptiometry (DXA) and air displacement plethysmography (ADP). OBJECTIVE: To investigate the agreement of US with DXA and ADP for estimating fat mass (FM) and fat-free mass (FFM). METHODS: College-age men (n = 33) and women (n = 41) volunteered to participate in this study. Participants were instructed to adhere to the following pretest protocol: refrain from food and drink 12 h prior to testing and wear tight fitting clothing. Body composition (BCA) was assessed using US, DXA and ADP in accordance with the respective manufacturer's guidelines. Two-way mixed-model AVOVA and Bland and Altman techniques were applied to explore agreement for FM and FFM among the three methods: US, ADP and DXA and by sex. RESULTS: There was no statistically significant effect by sex for either FM or FFM across all BCA comparisons (P = 0·504 and 0·510, respectively). US was not statistically different from ADP for FM and FFM (P ≈ 1·00). However, for FM and FFM, there were significant differences between DXA and both US and ADP (P≤0·001). The Bland and Altman analyses revealed large individual differences for all BCA. CONCLUSION: There was statistical agreement between US and ADP for FM and FFM but lack of agreement for US and ADP when compared to DXA. However, the large limits of agreement between methods warrant caution in generalizing these findings.

The Effect of Increasing Autonomy Through Choice on Young Children's Physical Activity Behavior.

BACKGROUND: Increasing autonomy by manipulating the choice of available physical activity options in a laboratory setting can increase physical activity in older children and adults. However, the effect of manipulating the number of physically active choices has yet to be examined in young children in a gymnasium environment. METHODS: Twenty children (n = 10 girls, 6.1 ± 1.4 years old) individually participated in 2 [low choice (LC), high choice (HC)] free-choice activity conditions for 30 minutes in a 4360 square foot gymnasium. Children had access to 2 or 8 physical activity options in the LC and HC conditions, respectively. Physical activity behavior was measured via accelerometry. RESULTS: Children's 30-minute accelerometer counts increased (P < .03) from the LC (2675 ± 294 counts·min-1) to the HC (3224 ± 280 counts·min-1) condition. CONCLUSIONS: Providing greater autonomy through choice of a greater number of physically active options increased young children's physical activity participation by 20.5%.

Agreement between ultrasound and dual-energy X-ray absorptiometry in assessing percentage body fat in college-aged adults.

BACKGROUND: The BodyMetrix(®) BX-2000 Ultrasound device (ULTRA) shows prowess in being an effective alternative to the expense and technicality of dual-energy X-ray absorptiometry (DXA). However, this technique has not been investigated using a seven-site methodology. SUBJECT/OBJECTIVE: To employ a cross-over design to investigate the agreement between ULTRA using a seven-site methodology and DXA in assessing body fat (%BF) in a normal-weight sample of college-age men and women. METHODS: Subjects (n = 84, BMI = 23.6 ± 3.6 kg m(-²), age = 23.0 ± 4.7 years) participated in this study with %BF measurements following the manufacturer's specifications. RESULTS: Significant differences were observed between methods with ULTRA less than DXA (difference = 4.4 ± 0.8%, t-statistic = 7.27, P<0.001) with no difference between men and women. CONCLUSION: The current study showed that ULTRA using a seven-site methodology did not agree with DXA in measuring %BF. Thus, this investigational ULTRA methodology might not be appropriate in estimating %BF in this population.

Validity of Borg Ratings of Perceived Exertion During Active Video Game Play.

During physically interactive video game play (e.g., Nintendo Wii), users are exposed to potential distracters (e.g., video, music), which may decrease their ratings of perceived exertion (RPE) throughout game play. The purpose of this investigation was to determine the association between RPE scores and heart rate while playing the Nintendo Wii. Healthy adults (N = 13, 53.5 ± 5.4 years old) participated in two exercise sessions using the Nintendo Wii Fit Plus. During each session participants played a five-minute warm-up game (Basic Run), two separate Wii Fit Plus games (Yoga, Strength Training, Aerobics or Balance Training) for fifteen minutes each, and then a five-minute cool down game (Basic Run). Borg RPE and heart rate were assessed during the final 30 seconds of the warm up and cool down, as well during the final 30 seconds of play for each Wii Fit Plus game. Correlation analysis combining data from both exercise sessions indicated a moderate positive relationship between heart rate and RPE (r = 0.32). Mixed-effects model regression analyses demonstrated that RPE scores were significantly associated with heart rate (p < 0.001). The average percentage of age-predicted heart rate maximum achieved (58 ± 6%) was significantly greater (p = 0.001) than the percentage of maximum RPE indicated (43 ± 11%). Borg RPE scores were positively associated with heart rate in adults during exercise sessions using the Wii Fit Plus. However, this relationship was lower than observed in past research assessing RPE validity during different modes of exercise (e.g. walking, running) without distracters.