Stan Reents, PharmD
05/06/2007 01:01 PM
Last Revision: 01/15/2016 08:25 AM
Walking is a great way to get daily exercise. Current recommendations from the CDC for adults are to walk 10,000 steps per day. This is the equivalent of about 5 miles. People who want to lose weight should strive for 15,000 - 20,000 steps per day. (see the related story on "Walking".)
Now, that may seem like a lot, but if you counted up all the steps you take during an average day, it might be more than you realize. For example, how many steps do you take while shopping, while at work, running errands, or, just working around the house?
This brings us to a discussion of pedometers, those little devices you wear on your belt to count steps and measure distance walked. But, are pedometers just another passing fad in the fitness industry?
It doesn't appear so. Consider the following:
• Between 1999 and 2007, the Walk4Life company has sold more than 1.5 million units of its brand of pedometers.
• In May 2004, McDonald's announced it would distribute 10-15 million step counters as part of its "Go Active! Happy Meal" plan.
DO THEY WORK?
The most important question to be answered is if pedometers actually motivate people to walk more. Do they? Research and usage data suggest that they do! Consider the following:
• In 1999, in an effort to get people walking, the non-profit Minnesota health care organization HealthPartners initiated an 8-month "10,000 Steps" program. Participants were given a pedometer and some printed information. The program was very well-received. Nearly all participants doubled their daily step counts, a vast majority felt like they increased their physical activity, and many claimed they lost weight on the program.
• A review of published studies in the November 21, 2007 issue of JAMA revealed that pedometers increased walking by an average of 2491 steps per day, and, increased physical activity by 26.9% over baseline (Bravata DM, et al. 2007).
• Researchers from Australia and New Zealand published a study in the May 2012 issue of Annals of Family Medicine showing that, at 3 months and 12 months after receiving a pedometer, subjects increased the time spent walking (Kolt GS, et al. 2012).
Have any health benefits been seen after giving people pedometers? Here again, the answer is "yes!":
• Lower blood pressure: In the study from Australia and New Zealand mentioned above, at 3 months and 12 months, a significant drop in blood pressure was seen (Kolt GS, et al. 2012).
• Weight loss: A meta-analysis of 9 studies assessing the impact of pedometers on walking and weight loss revealed that the amount of weight loss averaged 1.42 kg (= 3.1 lbs) after subjects were given pedometers. The amount of weight lost was statistically significant in 5 of these 9 studies (Richardson CR, et al. 2008).
The JAMA review mentioned above also shows that pedometer use was associated with weight loss and a lower blood pressure (Bravata DM, et al. 2007).
Thus, it appears that pedometers may be around for some time to come.
HISTORY OF PEDOMETERS
Although the invention of the pedometer has been attributed to US president Thomas Jefferson, apparently Leonardo da Vinci conceptualized a similar device in drawings from the 15th century. In the US, pedometers became popular in the 1930s as a result of the radio program "Jack Armstrong: All-American Boy" and his Hike-o-Meter pedometer, and again in the 1960s when the Japanese walking program known as "manpo-kei" was popularized. In Japanese, "manpo" means 10,000 steps. Yamasa produced a pedometer they called "manpo-kei", or, literally, "10,000-steps meter" (Sidman CL. 2002).
STEP-COUNTERS vs. PEDOMETERS vs. ACCELEROMETERS
The first distinction to make is the difference between a pedometer and a step-counter. A step counter simply tracks the number of steps taken. A pedometer counts steps too, but, in addition, determines distance walked. Most people use the term "pedometer" to refer to either type, and that's what we'll do, too.
Next, we need to differentiate pedometers from accelerometers. Pedometers work by detecting vertical (up-and-down) motion. Pedometers count a step each time they detect this vertical change in direction. A spring-suspended horizontal arm bounces up and down inside the unit. It takes about one-third the force of gravity to deflect the arm enough to register a click.
Accelerometers are more sophisticated: they are small computers that measure acceleration of movement in up to 3 dimensions (eg., up/down, right/left, and forward/backward). Accelerometers are very expensive and require expertise to use.
Pedometers are typically worn at the waist, while accelerometers can be worn on the foot or ankle. Pedometers should not be worn at ankle level, however. In this position, the pedometer receives too much shock during each stride causing it to register an excessive number of steps (Cyarto EV, et al. 2004).
There are a wide variety of pedometers on the market. The most basic models sell for around $10 and do nothing more than count steps (ie., step-counters). Other models display speed, elapsed time, calories burned, steps per minute, pulse-rate. Some include a stop-watch, alarm, 7-day history and more.
REALLY UNIQUE FEATURES
Some pedometers have some really unique features:
• Ability to Up-Load Data: Some brands allow you to connect your pedometer to your computer. You can then upload your daily data and generate a variety of charts and graphs. This helps you to track your progress.
• On-Demand Voice Read-Outs: Some models, such as the SportLine 343 Talking Pedometer, have this feature.
• Variable Music Tempo: The SportLine 343 Talking Pedometer will increase or decrease the tempo of the music to match your walking pace.
Like many products on the market, you get what you pay for. In general, pedometers are most accurate in counting steps, less accurate in calculating distance, and very poor at estimating energy expenditure (Crouter SE, et al. 2003) (Schneider PL, et al. 2003). Nevertheless, with regard to counting steps, some relatively-inexpensive pedometers perform extremely well.
In 1996, researchers at U. Tennessee evaluated 5 different brands of pedometers and found a high degree of variability (Bassett DR, et al. 1996). None of these models are still on the market, so, in 2003, they repeated the test with 10 newer models (Crouter SE, et al. 2003) (Schneider PL, et al. 2003). The results are summarized below:
In terms of counting steps accurately, the best performing models were:
- Kenz Lifecorder ($200)
- New-Lifestyles NL-2000 ($45)
- Yamax Digi-Walker SW-701 ($29)
Four additional models were "moderately accurate" (defined as a step count error of less than 10 steps over a 400-meter walk):
- FreeStyle Pacer Pro ($22)
- SportLine 345 ($15-20)
- Walk4Life LS-2525 ($29)
- Yamax Skeletone EM-180 ($15)
The worst performing models were:
- Omron HJ-105 (underestimated step count by 19 steps)
- Oregon Scientific PE316CA (overestimated step count by 13 steps)
- SportLine 330 (underestimated step count by 25 steps)
Research over the last 10 years has documented a very high accuracy rate for pedometers made by Yamax (Bassett DR, et al. 1996) (Schneider PL, et al. 2003). Yamax is a Japanese company. Japanese manufacturing standards specify an error rate for pedometers no higher than 3% (Crouter SE, et al. 2003). No such standard currently exists for pedometers made in the US.
FACTORS THAT REDUCE STEP-COUNTING ACCURACY OF PEDOMETERS
Very Slow Walking:
Several studies show that very slow walking (54 meters/minute) can impair the performance of pedometers substantially. In one study of nursing home residents, even the very accurate Yamax DigiWalker SW-200 pedometer underestimated step count by 74% during slower walking (Cyarto EV, et al. 2004). The "shuffling gait" (see below) in these subjects also contributed to the low accuracy. In another study, pedometers underestimated actual step count by 20-33% (depending on the wearing position) at a walking speed of 54 meters/minute (Swartz AM, et al. 2003). But, at more typical walking speeds between 67 and 107 meters/minute (the textbook value for walking speed by healthy adults is 84 meters/minute), the Yamax SW-200 has been shown to be highly accurate (LeMasurier GC, et al. 2003).
Pedometers depend on a slight "bump" or "jolt" to register a step. Thus, pedometers are less accurate in people who "shuffle" their feet, such as elderly nursing home residents who lean on a walker (Cyarto EV, et al. 2004).
Accuracy in Children:
The accuracy of 2 pedometers was evaluated in children, ages 5-11 yrs, while they walked around a track ("self-paced walking") and on a treadmill. Two additional brands were also tested on the treadmill. The Yamax Digi-Walker SW-200 and SW-701, and the Walk4Life 2505 all performed well and their measurements were in high agreement. The SunTrek LINQ performed noticeably worse at speeds of 67 meters/minute and slower (Beets MW, et al. 2005).
ACCURACY OF OTHER MEASUREMENTS
Tracking Steps vs. Tracking Distance:
As summarized above, some pedometers are excellent at recording steps. However, determining distance is highly variable. The sports medicine community generally states that 2000 steps are roughly equal to 1 mile. But this conversion applies only to walking. A study of adult women using the Yamax Digi-Walker step counter showed average step counts varied depending on whether they walked, jogged, or ran (Welk GJ, et al. 2000):
||STEPS PER MILE
Pedometers are really pretty primitive devices. They simply tabulate a step when the lever arm inside is jolted up or down. They have no way of adjusting for factors that can greatly affect calories used, such as, the difference between walking on a level road vs. walking on a hilly trail. Obviously, uphill walking burns more calories than walking on a level surface.
TIPS WHEN PURCHASING AND USING A PEDOMETER
When purchasing a pedometer, make sure it's held securely in place. Some models clip on a belt and some are hung around the neck. The pedometer should remain in a vertical position during use.
Purchase a pedometer with a protective cover. This helps to prevent accidentally resetting the count.
The display should be easy to read without having to take the step counter off your belt.
You should first calibrate the device for your average stride. Adjust your pedometer by walking or jogging a measured distance, with the stride setting in the middle; the standard setting is 2.2 ft. for women and 2.5 ft. for men. Then adjust this setting up or down. Cover the same distance again in the same mode, and fine tune the setting until you are recording accurately the distance covered.
Another way to check the accuracy of your pedometer is this quick test (from ACSM):
- Put on pedometer and find a space where you can walk at your typical walking pace.
- Reset your pedometer so it reads "0" and carefully close pedometer cover.
- Walk 20 steps.
- Carefully open pedometer (rough handling can cause erroneous steps).
|• 20 steps
|• 19 or 21 steps
|• 18 or 22 steps
|• <17 or >23 steps
Note that different pedometers have different sensitivity thresholds. Some pedometers allow you to adjust the sensitivity threshold. Examples of pedometers that have this feature are the Omron HJ-105 and the Oregon Scientific PE316CA, however, both of these models performed poorly in recent evaluations of step-counting accuracy (Crouter SE, et al. 2003) (Schneider PL, et al. 2003).
Q: What is the best placement for a pedometer?
ANSWER: In one study, the accuracy of electronic pedometers was no different if worn at waist level on (a) the anterior mid-line of the thigh (aka: "front", manufacturer-recommended placement), (b) the mid-axillary line (aka: "side"), or (c) the posterior mid-line of the thigh (aka: "back") (Swartz AM, et al. 2003).
Q: Are pedometers less accurate when used by obese persons?
ANSWER: It appears that pedometers work as well on obese subjects as they do on normal weight subjects (Swartz AM, et al. 2003)...as long as the pedometer remains in a vertical position. If the person's abdomen is large and causes the pedometer to tilt forward when wearing it on the front of the waistline, then it should be moved to the side (hip).
Q: Does the road surface affect the accuracy of pedometers?
ANSWER: No differences were seen when walking on a sidewalk was compared to walking on a rubberized outdoor track (Bassett DR, et al. 1996). However, users should also note that pedometers can't make any distinction between level walking and walking on an incline. In other words, while step-counting might be accurately recorded while walking inclines or hills, calories burned may be way off.
Q: Do pedometers lose accuracy if you use them a lot?
ANSWER: In one study, the pre-use error rate of one model was 1%. After 7 weeks of heavy use in a research setting, the error rate was 3% (Sidman CL, et al. 2001).
SUMMARY AND GUIDELINES
• Features: Decide if you only want a pedometer that counts steps, or, if some of the other features described here are also important. You can spend anywhere from $9 to over $200 for a pedometer.
• Accuracy: Prior to each use, check the pedometer's accuracy by counting off 20-50 paces and seeing if the unit registers the correct number. Also, make sure your waistband isn't so loose that the pedometer bounces around; this will reduce accuracy. But don't get too hung-up on which model of pedometer is most accurate. If a pedometer gets you exercising on a more regular basis, then it is doing its job.
• Walking vs. Running: If you want to use your pedometer during both walking and running, find one that allows you to adjust the sensitivity setting.
• Obtain medical clearance: Men over age 40 and women over age 50 should obtain medical clearance from their physician before beginning a new exercise routine.
FOR MORE INFORMATION
An excellent web site for general information on pedometers and reviews of specific models is www.Pedometers.com.
The web site www.New-Lifestyles.com not only sells quality pedometers, but, also educational kits for establishing an exercise program at the grade school level, a kit targeted to diabetics, and other exercise and activity-tracking materials. This site can also be accessed from: www.ThePedometerCompany.com.
The Walk 4 Life group (www.Walk4Life.com) has a superb web site. They have been promoting the use of pedometers to increase activity levels since 1999.
The Surgeon General's Report on Physical Activity and Health is located at: www.CDC.gov. The President's Council on Physical Fitness and Sports www.fitness.gov.
Readers may be interested in these related stories:
ONLINE FITNESS LOGS
There are many web sites that allow you to keep track of your own fitness log. Some of these include:
EXPERT HEALTH and FITNESS COACHING
Stan Reents, PharmD, is available to speak on this and many other exercise-related topics. (Here is a downloadable recording of one of his Health Talks.) He also provides a one-on-one Health Coaching Service. Contact him through the Contact Us page.
Bassett DR, Ainsworth BE, Leggett SR, et al. Accuracy of five electronic pedometers for measuring distance walked. Med Sci Sports Exerc 1996;28:1071-1077. Abstract
Beets MW, Patton MM, Edwards S. The accuracy of pedometer steps and time during walking in children. Med Sci Sports Exerc 2005;37:513-520. Abstract
Bravata DM, Smith-Spangler C, Sundaram V, et al. Using pedometers to increase physical activity and improve health. JAMA 2007;298:2296-2304. Abstract
Crouter SE, Schneider PL, Karabulut M, et al. Validity of 10 electronic pedometers for measuring steps, distance, and energy cost. Med Sci Sports Exerc 2003;35:1455-1460. Abstract
Cyarto EV, Myers AM, Tudor-Locke C. Pedometer accuracy in nursing home and community-dwelling older adults. Med Sci Sports Exerc 2004;36:205-209. Abstract
Kolt GS, Schofield GM, Kerse N, et al. Health steps trial: pedometer-based advice and physical activity for low-active older adults. Ann Fam Med 2012;10:206-212. Abstract
LeMasurier GC, Tudor-Locke C. Comparison of pedometer and accelerometer accuracy under controlled conditions. Med Sci Sports Exerc 2003;35:867-871. Abstract
Richardson CR, Newton TL, Abraham JJ, et al. A meta-analysis of pedometer-based walking interventions and weight loss. Ann Fam Med 2008;6:69-77. Abstract
Schneider PL, Crouter SE, Lukajic O, et al. Accuracy and reliability of 10 pedometers for measuring steps over a 400-m walk. Med Sci Sports Exerc 2003;35:1779-1784. Abstract
Sidman CL. Count your steps to health & fitness. ACSM Health Fit J 2002;6:13-17. (no abstract)
Sidman CL, Vincent SD, Corbin CB, et al. Digital pedometers: checking calibration prior to use in research. Med Sci Sports Exerc 2001;33:S299. (no abstract)
Swartz AM, Bassett DR, Moore JB, et al. Effects of body mass index on the accuracy of an electronic pedometer. Int J Sports Med 2003;24:588-592. Abstract
Welk GJ, Differding JA, Thompson RW, et al. The utility of the Digi-Walker step counter to assess daily physical activity patterns. Med Sci Sports Exerc 2000;32(suppl);S481-S488. Abstract
ABOUT THE AUTHOR
Stan Reents, PharmD, is a former healthcare professional. He is a member of the American College of Sports Medicine (ACSM) and holds current certifications from ACSM (Health & Fitness Specialist), ACE (Health Coach) and has been certified as a tennis coach by USTA. He is the author of Sport and Exercise Pharmacology (published by Human Kinetics) and has written for Runner's World magazine, Training and Conditioning, Club Solutions, and other fitness publications.
DISCLOSURE: Neither the author, nor AthleteInMe, LLC, has any financial relationships with any of the products or companies mentioned in this review.
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