Evaluation of the Accuracy of a Triaxial Accelerometer Embedded into a Cell Phone Platform for Measuring Physical Activity.

Background: Physical activity is important in health and weight management. Several cell phone platforms integrate an accelerometer onto the motherboard. Here we tested the validity of the cell phone accelerometer to assess physical activity in a controlled laboratory setting.

Non-exercise physical activity in agricultural and urban people.

With evidence that urbanisation is associated with obesity, diabetes, hypertension and cardiovascular disease, this article compares daily physical activity between rural and urban dwellers. Specifically, it examines habitual daily activity levels, non-exercise activity thermogenesis (NEAT) and energy expenditure in agricultural and urban Jamaicans and urban North Americans. Ambulation was 60 per cent greater in rural Jamaicans than in the urban dwellers (4675 ± 2261 versus 2940 ± 1120 ambulation-attributed arbitrary units (AU)/day; P = 0.

An accelerometer-based earpiece to monitor and quantify physical activity.

Background: Physical activity is important in ill-health. Inexpensive, accurate and precise devices could help assess daily activity. We integrated novel activity-sensing technology into an earpiece used with portable music-players and phones; the physical-activity-sensing earpiece (PASE).

Sedentariness at work: how much do we really sit?

Sedentariness is associated with obesity. We examined whether people with sedentary jobs are equally inactive during their work days and leisure days. We enrolled 21 subjects of varying weight and body fat (11 men:10 women, 38 +/- 8 years, 83 +/- 17 kg, BMI 28 +/- 5 kg/m(2), 29 +/- 11 fat kg, 35 +/- 9% fat).

Activity-promoting video games and increased energy expenditure.

Objectives: To test the hypothesis that both children and adults would expend more calories and move more while playing activity-promoting video games compared with sedentary video games.

Study Design: In this single-group study, 22 healthy children (12 +/- 2 years; 11 male, 11 female) and 20 adults (34 +/- 11 years; 10 male, 10 female) were recruited. Energy expenditure and physical activity were measured while participants were resting, standing, watching television seated, sitting and playing a traditional sedentary video game, and while playing an activity-promoting video game (Nintendo Wii Boxing).

Energy expenditure and activity of transfemoral amputees using mechanical and microprocessor-controlled prosthetic knees.

Objective: To quantify the energy efficiency of locomotion and free-living physical activity energy expenditure of transfemoral amputees using a mechanical and microprocessor-controlled prosthetic knee.

Design: Repeated-measures design to evaluate comparative functional outcomes.

Setting: Exercise physiology laboratory and community free-living environment.

Changing the school environment to increase physical activity in children.

We examined the hypothesis that elementary school-age children will be more physically active while attending school in a novel, activity-permissive school environment compared to their traditional school environment. Twenty-four children were monitored with a single-triaxial accelerometer worn on the thigh. The students attended school in three different environments: traditional school with chairs and desks, an activity-permissive environment, and finally their traditional school with desks which encouraged standing.

The role of free-living daily walking in human weight gain and obesity.

Objective: Diminished daily physical activity explains, in part, why obesity and diabetes have become worldwide epidemics. In particular, chair use has replaced ambulation, so that obese individuals tend to sit for approximately 2.5 h/day more than lean counterparts.

Gait and balance of transfemoral amputees using passive mechanical and microprocessor-controlled prosthetic knees.

Background: Microprocessor-controlled knee joints appeared on the market a decade ago. These joints are more sophisticated and more expensive than mechanical ones. The literature is contradictory regarding changes in gait and balance when using these sophisticated devices.

An office-place stepping device to promote workplace physical activity.

Objective: It was proposed that an office-place stepping device is associated with significant and substantial increases in energy expenditure compared to sitting energy expenditure. The objective was to assess the effect of using an office-place stepping device on the energy expenditure of lean and obese office workers.

Methods: The office-place stepping device is an inexpensive, near-silent, low-impact device that can be housed under a standard desk and plugged into an office PC for self-monitoring.

Does Non-Exercise Activity Thermogenesis Contribute to Non-Shivering Thermogenesis?

We wanted to examine if spontaneous physical activity contributes to non-shivering thermogenesis. Ten lean, healthy male subjects wore a physical activity, micro-measurement system whilst the room temperature was randomly altered at two hourly intervals between thermoneutral (72°F), cool (62°F) and warm (82°F) temperatures. Physical activity measured during the thermoneutral, cooling and warming periods was not significantly different.

Nonexercise movement in elderly compared with young people.

The association between free-living daily activity and aging is unclear because nonexercise movement and its energetic equivalent, nonexercise activity thermogenesis, have not been exhaustively studied in the elderly. We wanted to address the hypothesis that free-living nonexercise movement is lower in older individuals compared with younger controls matched for lean body mass. Ten lean, healthy, sedentary elderly and 10 young subjects matched for lean body mass underwent measurements of nonexercise movement and body posture over 10 days using sensitive, validated technology.

Impact of endurance training on murine spontaneous activity, muscle mitochondrial DNA abundance, gene transcripts, and function.

We hypothesized that enhanced skeletal muscle mitochondrial function following aerobic exercise training is related to an increase in mitochondrial transcription factors, DNA abundance [mitochondrial DNA (mtDNA)], and mitochondria-related gene transcript levels, as well as spontaneous physical activity (SPA) levels. We report the effects of daily treadmill training on 12-wk-old FVB mice for 5 days/wk over 8 wk at 80% peak O(2) consumption and studied the training effect on changes in body composition, glucose tolerance, muscle mtDNA muscle, mitochondria-related gene transcripts, in vitro muscle mitochondrial ATP production capacity (MATPC), and SPA levels. Compared with the untrained mice, the trained mice had higher peak O(2) consumption (+18%; P < 0.

Laboratory measurement of posture allocation and physical activity in children.

Purpose: The purpose of this study was to validate the combined use of inclinometers and accelerometers to measure body posture and movement in children in a laboratory setting.

Methods: We performed two separate experiments. In the first experiment, we tested the hypothesis that four inclinometers (tilt sensors) could be used to capture body posture in children.

Precision and accuracy of an ankle-worn accelerometer-based pedometer in step counting and energy expenditure.

Background: Walking is a widely used approach to increase physical activity levels in obese patients. In this paper, we investigate the precision and accuracy of an ankle-worn dual-axis accelerometer (Stepwatch) and investigate its potential application as a predictor of energy expenditure.

Methods: Twenty healthy subjects (10 lean, 10 obese) wore spring-levered (Accusplit), piezoelectric (Omron HF-100), and Stepwatch pedometers.

Interindividual variation in posture allocation: possible role in human obesity.

Obesity occurs when energy intake exceeds energy expenditure. Humans expend energy through purposeful exercise and through changes in posture and movement that are associated with the routines of daily life [called nonexercise activity thermogenesis (NEAT)]. To examine NEAT's role in obesity, we recruited 10 lean and 10 mildly obese sedentary volunteers and measured their body postures and movements every half-second for 10 days.