Stan Grant

Fundamental movement skills and habitual physical activity in young children.

PURPOSE To test for relationships between objectively measured habitual physical activity and fundamental movement skills in a relatively large and representative sample of preschool children. METHODS Physical activity was measured over 6 d using the Computer Science and Applications (CSA) accelerometer in 394 boys and girls (mean age 4.2, SD 0.5 yr). Children were scored on 15 fundamental movement skills, based on the Movement Assessment Battery, by a single observer. RESULTS Total physical activity (r=0.10, P<0.05) and percent time spent in moderate to vigorous physical activity (MVPA) (r=0.18, P<0.001) were significantly correlated with total movement skills score. Time spent in light-intensity physical activity was not significantly correlated with motor skills score (r=0.02, P>0.05). CONCLUSIONS In this sample and setting, fundamental movement skills were significantly associated with habitual physical activity, but the association between the two variables was weak. The present study questions whether the widely assumed relationships between motor skills and habitual physical activity actually exist in young children.

Total energy expenditure and physical activity in young Scottish children: mixed longitudinal study

Childhood obesity has been attributed to a decline in total energy expenditure (TEE). We measured TEE, physical activity, and sedentary behaviour in a representative sample of young children from Glasgow, UK, at age 3 years (n=78), and we did a follow-up study at age 5 years (n=72). Mean physical activity level (TEE/resting energy expenditure) was 1.56 (SD 0.39) at age 3 years and 1.61 (0.22) at age 5 years. Median time in sedentary behaviour was 79% of monitored hours at age 3 years (IQR 74-84) and 76% (71-80) at age 5 years. Median time spent in moderate to vigorous physical activity represented only 2% of monitored hours at age 3 years (IQR 1-4) and 4% at age 5 years (2-6). Modern British children establish a sedentary lifestyle at an early age.

Control strategies for integration of electric motor assist and functional electrical stimulation in paraplegic cycling: utility for exercise testing and mobile cycling

Aim: The aim of this study was to investigate feedback control strategies for integration of electric motor assist and functional electrical stimulation (FES) for paraplegic cycling, with particular focus on development of a testbed for exercise testing in FES cycling, in which both cycling cadence and workrate are simultaneously well controlled and contemporary physiological measures of exercise performance derived. A second aim was to investigate the possible benefits of the approach for mobile, recreational cycling. Methods: A recumbent tricycle with an auxiliary electric motor is used, which is adapted for paraplegic users, and instrumented for stimulation control. We propose a novel integrated control strategy which simultaneously provides feedback control of leg power output (via automatic adjustment of stimulation intensity) and cycling cadence (via electric motor control). Both loops are designed using system identification and analytical (model-based) feedback design methods. Ventilatory and pulmonary gas exchange response profiles are derived using a portable system for real-time breath-by-breath acquisition. Results: We provide indicative results from one paraplegic subject in which a series of feedback-control tests illustrate accurate control of cycling cadence, leg power control, and external disturbance rejection. We also provide physiological response profiles from a submaximal exercise step test and a maximal incremental exercise test, as facilitated by the control strategy. Conclusion: The integrated control strategy is effective in facilitating exercise testing under conditions of well-controlled cadence and power output. Our control approach significantly extends the achievable workrate range and enhances exercise-test sensitivity for FES cycling, thus allowing a more stringent characterization of physiological response profiles and estimation of key parameters of aerobic function. We further conclude that the control approach can significantly improve the overall performance of mobile recreational cycling.

ENERGY REQUIREMENTS OF PREGNANCY IN SCOTLAND

Measurements of energy intake, basal metabolic rate, body weight and composition, and physical activity were made on 88 women throughout pregnancy. Mean weight gain (from 10 wk to 40 wk gestation) was 11.7 kg, birthweight 3370 g, and placental weight 641 g. Maternal fat gain (from 10 wk) calculated by three methods was 2.1 kg. The total rise in basal metabolism for the whole of pregnancy was calculated to be 126 MJ (1 MJ = 239 kcal). The total increase in energy intake was estimated as 88 MJ. There was little evidence of any changes in either the energy cost of physical activity or the time spent in these activities. The total energy cost of laying down fetal and maternal tissues and the increased metabolism was 281 MJ, which was offset by a possible increase in energy intake of only 88 MJ. The most likely explanation for the deficit of 193 MJ is that many small reductions in energy expenditure occurred which were not detectable by the methods used.

IS NUTRITIONAL STATUS ENDANGERED BY VIRTUALLY NO EXTRA INTAKE DURING PREGNANCY

In the course of a multinational study on energy requirements in pregnancy and lactation, the food intake of 67 pregnant women in Glasgow was measured by the use of the individual weighed inventory technique, for 3 or 5 consecutive days every 6 weeks (in 21 women), every 4 weeks (in 23 women), or every 2 weeks (in 23 women). Data were obtained in the pre-pregnant state in 12 women. Rises in energy intakes were small and gradual in the first 34 weeks of pregnancy, the mean being about 50 kcal (210 kJ)/day, but in the remaining weeks of pregnancy, intakes rose by about 150 kcal (630 kJ)/day. The total extra energy intake therefore represented less than 20 000 kcal (84 MJ), as opposed to theoretical estimates of requirements of 80 000 kcal (335 MJ). Energy-saving mechanisms may have resulted in reductions in physical activity, but this was not obvious in the study population. However, there was depression of basal metabolic rates in the first half of pregnancy, which could produce considerable energy savings.

Validation of energy intake by 24-hour multiple pass recall: comparison with total energy expenditure in children aged 5-7 years.

Accurate measurement of energy intake (EI) is essential in studies of energy balance in all age groups. Reported values for EI can be validated against total energy expenditure (TEE) measured using doubly labelled water (DLW). Our previous work has indicated that the use of the standardized 24 h multiple pass recall (24 h MPR) method produces slight overestimates of EI in pre-school children which are inaccurate at individual level but acceptable at group level. To extend this work, the current study validated EI by 24 h MPR against TEE by DLW in sixty-three (thirty-two boys) school-aged children (median age 6 years). In both boys and girls, reported EI was higher than TEE, although this difference was only significant in the girls (median difference 420 kJ/d, P=0.05). On analysis of agreement between TEE and EI, the group bias was an overestimation of EI by 250 kJ/d with wide limits of agreement (-2880, 2380 kJ/d). EI was over-reported relative to TEE by 7 % and 0.9 % in girls and boys, respectively. The bias in the current study was lower than in our previous study of pre-school children, suggesting that estimates of EI become less inaccurate as children age. However, the current study suggests that the 24 h MPR is inaccurate at the individual level.

Control approach for high sensitivity cardiopulmonary exercise testing during stimulated cycle ergometry in spinal cord injured subjects

Abstract Aim People with complete lower-limb paralysis resulting from spinal cord injury (SCI) can perform cycle ergometry by means of functional electrical stimulation. Here, we propose and evaluate new exercise testing methods for estimation of cardiopulmonary performance parameters during this form of exercise. Methods We utilised a customised ergometer incorporating feedback control of stimulated exercise workrate and cycling cadence. This allowed the imposition of arbitrary workrate profiles with high precision with the potential for improved sensitivity in exercise testing. New incremental exercise test (IET) and step exercise test (SET) protocols for determination of peak and steady-state performance parameters were assessed. Results The IET protocol allowed reliable determination of the ventilatory threshold, peak workrate and oxygen uptake-workrate relationship, but gave unrepresentative peak oxygen uptake values and highly variable measures of oxygen uptake kinetics. The SET protocol gave reliable estimation of steady-state oxygen uptake and metabolic efficiency of constant load exercise, but high variability in the estimation of oxygen uptake kinetics. Conclusion The feedback-controlled testbed and the new IET and SET protocols have the potential for estimation of cardiopulmonary performance parameters with improved sensitivity during stimulated cycle ergometry in subjects with SCI.

Comparison of carbon monoxide levels during heating of ice and water to boiling point with a camping stove.

OBJECTIVES To determine whether using a camping stove to bring a pan of ice to boiling point produces higher carbon monoxide (CO) concentration than would bringing a pan of water to boiling point. The hypothesis was that ice would cause greater CO concentration because of its greater flame-cooling effect and, consequently, more incomplete combustion. METHOD This was a randomized, prospective observational study. After an initial pilot study, CO concentration was monitored during 10 trials for each of ice and water. A partially ventilated 200-L cardboard box model was developed and then used inside a chamber at -6 degrees C. Ice temperature and volume, water temperature and volume, pan size, and flame characteristics were all standardized. Temperature of the heated medium was monitored to determine time to boiling point. Carbon monoxide concentration was monitored every 30 seconds for the first 3 minutes, then every minute until the end of each 10-minute trial. RESULTS There was no significant difference (P > .05) in CO production levels between ice and water. Each achieved a similar mean plateau level of approximately 400 ppm CO concentration with a similar rate of rise. However, significantly higher (P = .014) CO concentration occurred at 4 and 5 minutes when the flame underwent a yellow flare; this occurred only on 3 occasions when ice was the medium. CONCLUSION There were no significant differences for CO production between bringing a pan of ice or water to boiling point. In a small number of ice trials, the presence of a yellow flame resulted in high CO concentration. Yellow flares might occur more often with ice or snow melting, but this has not been proven.

Does Pan Diameter Influence Carbon Monoxide Levels During Heating of Water to Boiling Point With a Camping Stove

OBJECTIVES To determine whether pan diameter influences carbon monoxide (CO) concentration during heating of water to boiling point with a camping stove. The hypothesis was that increasing pan diameter increases CO concentration because of greater flame dispersal and a larger flame. METHOD This was a randomized, prospective study. A Coleman Dual Fuel 533 stove was used to heat pans of water to boiling point, with CO concentration monitored every 30 seconds for 5 minutes. The stove was inside a partially ventilated 200-L cardboard box model that was inside an environmental chamber at -6 degrees C. Water temperature, water volume, and flame characteristics were all standardized. Ten trials were performed for each of 2 pan diameters (base diameters of 165 mm [small] and 220 mm [large]). RESULTS There was a significant difference (P = .002) between the pans for CO levels at each measurement interval from 60 seconds onward. These differences were markedly larger after 90 seconds, with a mean difference of 185 ppm (95% CI 115, 276 ppm) for all the results from 120 seconds onwards. CONCLUSION This study has shown that there is significantly higher CO production with a large-diameter pan compared with a small-diameter pan. These findings were evident by using a camping stove to heat water to boiling point when a maximum blue flame was present throughout. Thus, in enclosed environments it is recommended that small-diameter pans be used in an attempt to prevent high CO levels.

A comparison of physiological responses and rating of perceived exertion between high-impact and low-impact aerobic dance sessions

Abstract The aim of this study was to compare the exercise intensity and rating of perceived exertion (RPE) of a high-impact (HIP) and a low-impact (LIP) university aerobic dance session. Ten women [mean (SD) age 22.9 (2.6) years] took part in the study. An incremental treadmill test was performed by each subject to determine maximum oxygen consumption (V˙O2max) and maximum heart rate (HRmax). The measured V˙O2max [mean (SD)] was 49.0 (7.5) ml · kg−1 · min−1. The subjects were randomly assigned to LIP and HIP sessions (i.e. five of the subjects participated in the HIP session first, and the other five participated in the LIP session first). In a laboratory, heart rate, oxygen uptake and RPE were measured throughout each session for each subject. Expired air was collected continuously throughout the sessions using Douglas bags (ten bags over a 30-min period). The sessions consisted of 20 min of aerobic exercise (bags 1–7) followed by 5 min of local muscular endurance exercise (bags 8 and 9) and 5 min of flexibility exercises (bag 10). The mean intensity of the aerobic section of the LIP and HIP sessions was 51.6% and 64.7% V˙O2max, respectively. Ninety-five percent confidence intervals for the average difference between the HIP and LIP sessions demonstrate that the %V˙O2max was between 12% and 14% higher for the HIP session. The mean %HRmax for the LIP and HIP sessions was 71.4% and 76.7%, respectively, with the %HRmax in the HIP session being between 5.4% and 7.2% higher on average than that of the LIP session. On average, the RPE for the aerobic section of the HIP session (12.1) was consistently higher than that of the LIP session (11.1). HIP activity has the potential to maintain/improve the aerobic fitness of its participants. According to the literature, the exercise intensity elicited by LIP activity may have a limited training effect for the population utilised in this study, and for some individuals may result in detraining. Conversely, LIP activities may be an appropriate mode of exercise for overweight and unfit individuals.