Gender and limb effects on adult normative data for the Biodex Balance System

Posturography normative data in healthy populations is crucial for several reasons including monitoring the independence issues related to activities of daily living (ADLs), fall and incapacity avoidance, and residual injury impairment. The Biodex Balance System requires updated normative data regarding healthy persons because of recent revisions to the Biodex Balance System. Further, this study aimed to determine and compare gender and limb performance in 161 adults aged 18-55 years (n = 80 males; n = 81 females). Assessments involved both static and dynamic stability tests such as double-leg and single-leg balance tests at platform stability which served as outcome measurements. Females performed significantly (p≤.05) better on double-leg static balance (p=.031), double-leg dynamic balance (p=.002), and single-leg dynamic balance on both the left (p=.003) and right legs (p=.013) when compared to males. The normative values and findings of this study not only enable the evaluation of individual performance regarding the balance of adults but also suggest the need to use gender-stratified normative data when using the Biodex Balance System to interpret double- and single-leg, static and dynamic balance test performance

Measurements of Heart Rate and Accelerometry to Determine the Physical Activity Level in Boys Playing Paintball

International Journal of Exercise Science 6(3) : 199-207, 2013. Paintball is a popular recreational sport played by 3.655 million Americans and may be sufficient physical activity to promote health. Paintball has been played as an organized sport since the 1980’s and is essentially a game of tag, except instead of touching an opponent by hand opponents are tagged by shooting them with a paintball that leaves a mark indicating who has been eliminated. A previous evaluation of paintball as physical activity had 13 subjects undergo a VO2max test to develop a heart rate (HR) /oxygen consumption relationship, and it was observed that heart rates during paintball were 68-73% of the measured maximal HR. The present study used accelerometry and HR monitors to evaluate the quantity and intensity of physical activity in boys playing paintball. Eleven boys (12.7 ± 1.0 y, 51.5 ± 11.3 kg, 161.8 ± 10.1 cm) engaged in a VO2max test to develop a HR/oxygen consumption correlation. On a separate day the boys played 7 games of outdoor paintball while wearing a HR monitor and accelerometer. The boys played paintball for 11.5 ± 6.2 minutes/game for a total of 80.6 ± 10.0 minutes of game play. Average HR during paintball play was 129.6 ± 6.6 beats/min, representing 39.9 ± 12.9% VO2max. Based on accelerometry, the boys accumulated 63.2 ± 15.6 minutes of moderate intensity activity and 2.6 ± 2.8 minutes of vigorous activity during paintball. These data suggest that playing paintball may be considered as physical activity that is \u3e 3 METs, and thus health promoting

Effects of Energy Drinks on Metabolism at Rest and During Submaximal Treadmill Exercise in College Age Males.

Energy drinks are widely available and popular among athletes and non-athletes. However, the effects of energy drinks on resting and exercise energy expenditure and metabolism remain largely unknown. On four separate occasions, baseline measurements of resting metabolic rate (RMR) and Respiratory Exchange Ratio (RER) were obtained in ten healthy males (21.4 ± 1.6 y, 77.60± 7.5 kg, 180.0 ± 7.1 cm). Then, in a randomly assigned cross-over design, the subjects consumed 473 ml of one of three commercially available energy drinks or a placebo and then RMR and RER were measured 1 hour later. The subjects then engaged in 15 minutes of treadmill exercise at 50% of V02max, during which RER and oxygen consumption (VO2) were measured. RMR was not changed by placebo, but increased (P\u3c0.05, means ± se) above baseline by 10 ± 2.5%, 15.0 ± 2.9%, and 15.3 ± 2.9%, following Energy Drink One, Energy Drink Two, and Energy Drink Three (respectively) with no differences between energy drinks. RER was reduced below baseline (P\u3c0.05) by 4.9 ± 1.5% in the placebo and increased (P\u3c0.05) above baseline by 12.8 ± 1.8%, 9.6 ± 1.3%, and 9.0 ± 1.3% following Energy Drink One, Energy Drink Two, and Energy Drink Three (respectively) with no differences between energy drinks. Oxygen consumption and RER during submaximal exercise were not different between placebo, Energy Drink One, Energy Drink Two, or Energy Drink Three. These data indicate that energy drink consumption increases RMR and carbohydrate use at rest, but metabolism during submaximal exercise remains unchanged

Design, fabrication, and characterization of a micro fuel processor

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Chemical Engineering, February 2008.Includes bibliographical references (p. 171-174).The development of portable-power systems employing hydrogen-driven solid oxide fuel cells continues to garner significant interest among applied science researchers. The technology can be applied in fields ranging from the automobile to personal electronics industries. In order for fuel cell systems to outperform batteries, a method of chemically converting high-energy-density combustible fuels to hydrogen while maintaining high thermal efficiency must be developed. This thesis focuses on developing microreaction technology that minimizes thermal losses during the conversion of fuels - such as light end hydrocarbons, their alcohols, and ammonia - to hydrogen. Critical issues in realizing high-efficiency devices capable of operating at high temperatures have been addressed: specifically, thermal management, the integration of materials with different thermophysical properties, and the development of improved packaging and fabrication techniques. A new fabrication scheme for a thermally insulated, high temperature, suspended-tube microreactor has been developed. The new design improves upon a monolithic design proposed by Leonel Arana. In the new modular design, a high-temperature reaction zone is connected to a low-temperature package via the brazing of pre-fabricated, thin-walled glass tubes. The design also replaces traditional deep reactive ion etching (DRIE) with wet potassium hydroxide (KOH) etching, an economical and time-saving alternative. A glass brazing method that effectively accommodates the difference in thermal expansion between the silicon reactor and the glass tubes has been developed. The material used in this procedure is stable at temperatures up to 710 °C. Autothermal combustion of hydrogen, propane, and butane in excess oxygen has been demonstrated in ambient atmosphere and under vacuum. Hot spot temperatures of up to 900 °C have been measured during autothermal combustion of propane in ambient and vacuum conditions.(cont) Experimental temperature measurements have been compared to steady-state temperature estimates, and show good agreement. Finally, a computational fluid dynamics (CFD) model has been developed to study the heat transfer properties of the microreactor. Using simplified reaction schemes from the literature, the model has successfully reproduced the results observed in the laboratory.by Brandon S. Blackwell.Ph.D

Wii, Kinect, & Move. Heart Rate, Oxygen Consumption, Energy Expenditure, and Ventilation due to Different Physically Active Video Game Systems in College Students.

International Journal of Exercise Science 7(1) : 22-32, 2014. Nintendo Wii, Sony Playstation Move, and Microsoft XBOX Kinect are home video gaming systems that involve player movement to control on-screen game play. Numerous investigations have demonstrated that playing Wii is moderate physical activity at best, but Move and Kinect have not been as thoroughly investigated. The purpose of this study was to compare heart rate, oxygen consumption, and ventilation while playing the games Wii Boxing, Kinect Boxing, and Move Gladiatorial Combat. Heart rate, oxygen consumption, and ventilation were measured at rest and during a graded exercise test in 10 males and 9 females (19.8 ± 0.33 y, 175.4 ± 2.0 cm, 80.2 ± 7.7 kg,). On another day, in a randomized order, the participants played Wii Boxing, Kinect Boxing, and Move Gladiatorial Combat while heart rate, ventilation, and oxygen consumption were measured. There were no differences in heart rate (116.0 ± 18.3 vs. 119.3 ± 17.6 vs. 120.1 ± 17.6 beats/min), oxygen consumption (9.2 ± 3.0 vs. 10.6 ± 2.4 vs. 9.6 ± 2.4 ml/kg/min), or minute ventilation (18.9 ± 5.7 vs. 20.8 ± 8.0 vs. 19.7 ± 6.4 L/min) when playing Wii boxing, Kinect boxing, or Move Gladiatorial Combat (respectively). Playing Nintendo Wii Boxing, XBOX Kinect Boxing, and Sony PlayStation Move Gladiatorial Combat all increase heart rate, oxygen consumption, and ventilation above resting levels but there were no significant differences between gaming systems. Overall, playing a “physically active” home video game system does not meet the minimal threshold for moderate intensity physical activity, regardless of gaming system

Rare Event Extinction on Stochastic Networks

We consider the problem of extinction processes on random networks with a given structure. For sufficiently large well-mixed populations, the process of extinction of one or more state variable components occurs in the tail of the quasi-stationary probability distribution, thereby making it a rare event. Here we show how to extend the theory of large deviations to random networks to predict extinction times. In particular, we use the theory to find the most probable path leading to extinction. We apply the methodology to epidemic models and discover how mean extinction times scale with epidemiological and network parameters in Erdos-Renyi networks. The results are shown to compare quite well with Monte Carlo simulations of the network in predicting both the most probable paths to extinction and mean extinction times.Comment: 5 pages 6 figure