Q: what factors can contribute to the machine reading’s inaccuracy?
A: Bodily factors, including weight and body fat percentage,
monitors reliable indicators of energy expenditure as well?
A: pedometers: A 2009 study in Medicine & Science in
Sports & Exercise found that pedometers, when worn around the hip, in a shirt pocket, or around the neck, yielded little error in the number of steps walked, suggesting that placement of the pedometer (other than when worn around the pocket area of pants) had little effect on accuracy.3 However, a 2012 study in the European Journal of Applied Physiology revealed that while the pedometer was relatively accurate in step-count measurement, it was not as accurate in reading distance and energy expenditure.4
purchasing?
A: In addition to counting steps, pedometers can be used
accelerometers: A 2010 study in Measurement in Physical
to reduce sedentary behavior and motivate physical activity in individuals, according to a 2008 study in the International Journal of Behavioral Nutrition and Physical Activity.12
heart rate monitors: A 1998 study in the Journal of
Yet, the quality of such machines, as well as their prices, may give buyers second thoughts. Low-end machines can cost as little as $2, but tend to run out of power soon. High-end models, which can cost as much as $350, have longer lifespans than their low-end counterparts, but may also offer features such as predicting the weather or calculating barometric pressure that may not be necessary for a workout.13
Education and Exercise Science showed that the accuracy of accelerometers (devices used to measure speed changes) varied greatly. As a result, further studies are necessary to examine the usefulness and limitations of these devices.5
Sports Sciences found that professional equipment like the electrocardiogram and Holter devices (both of which measure heart beat regularity) were accurate. However, due to cost, size, and complexity, these machines are not appropriate for everyday wear. The study also showed that lightweight heart rate monitors were just as accurate as the ECG and Holter devices.6
Q: with the growth of media technology in recent years, just how reliable are mobile applications in determining energy expenditure?
A: A 2008 conference published in the Sensor, Mesh and total wellness ▪ winter 2014
Q: Are pedometers and heart rate monitors worth
Ad Hoc Communications and Networks tested the 3-axis accelerometer mobile device application, which was designed to measure energy expenditure. The study showed that the mobile device application was just as accurate when compared to another reference device, a medical calorie counter.7 Furthermore, a 2009 study from Association for Computing Machinery tested BALANCE, another mobile-phone system that calculates caloric expenditure while walking or jogging on the treadmill. The test determined that the accuracy of the system was within 87% of the actual value.8
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Overall, exercise machine readings can sometimes be inaccurate, since aspects such as age, weight, and muscle mass may distort readings. Yet, considering these as ballpark measures during the next gym session will contribute to a rewarding workout. tw
References 1. “Validity of Seven Commercially Available Heart Rate Monitors.” Meas Phys Educ Exerc Sci. (2002). 2. “A Comparison of Three Models of Elliptical Trainer.” Nav Health Res Ctr. (2006). 3. “Validity of the Omron HJ-112 Pedometer During Treadmill Walking.” Med Sci Sports Exerc. (2009). 4. “The validity of two Omron pedometers during treadmill walking is speed dependent.” Eur J Appl Physiol. (2012). 5. “Technical Reliability Assessment of the Actigraph GT1M Accelerometer.” Meas Phys Educ Exerc Sci. (2010). 6. “Heart rate monitors: State of the art.” J Sports Sci. (1998). 7. “A Calorie Count Application for a Mobile Phone Based on METS Value.” Sensor, Mesh Ad Hoc Comm. (2008). 8. “BALANCE: towards a usable pervasive wellness application with accurate activity inference.” Assoc Comp Mach. (2009). 9. “Calories Burned on a Treadmill.” healthstatus.com. (2013). 10. “Metabolism and weight loss: How you burn calories.” mayoclinic.com. (2011). 11. “Energy cost of walking and running at extreme uphill and downhill slopes.” J Applied Physiol. (2002). 12. “The effect of a pedometer-based community walking intervention ‘Walking for Wellbeing in the West’ on physical activity levels and health outcomes: a 12-week randomized controlled trial.” Int J Behav Nutr Phys Activity. (2008). 13. “How Much Does a Pedometer Cost?” livestrong.com. (2009).
right: squaredpixels/istockphoto; aldra/istockphoto
Q: are pedometers, accelerometers, and heart rate
as well as external conditions like machine incline and stride length, all contribute to possible inaccuracy. The more the individual weighs, the more calories he or she will burn.9 › Individuals with more muscle or more body mass in general burn more calories, even when resting.10 › Walking or running uphill burns more calories than on level surfaces. Even going downhill, according to a 2002 study in the Journal of Applied Physiology, results in more expended energy, due to changes in body movements in order to compensate for the incline.11 › A shorter stride indicates that the individual is moving the legs more in order to cover the same distance, thus burning more calories.10