Based on well-documented research studies over several decades, Yamax DigiWalker pedometer series are generally considered a gold standard in step measurement devices for research purposes. Since 2020, several Yamax models have been discontinued or are no longer available for sale in the USA. With this in mind, which pedometer model is a preferred replacement when precision and reliability are paramount?
Since 2006, Pedometer Express has supplied pedometers for more than 354,000 users in research studies, wellness programs, schools, hospitals, rehab facilities, institutions, and individual walkers. During that time we have accumulated extensive feedback based on real world usage.
By analyzing anecdotal evidence in adjunct with published research studies, Pedometer Express offers a more complete picture of expectations and limitations of pedometers for use in research compared to either entity alone.
Since the pedometer was first introduced in 1780 and popularized in the 1970’s, the primary method for measuring step counts has been through use of a mechanical device in the form of a pendulum, the same type of movement used inside grandfather clocks. Attached to the pendulum is a flexible wire which acts as a spring. The sensitive pendulum and spring mechanism must be precisely calibrated for accuracy. Yamax models featured in most research studies utilize a mechanical pendulum.
While the pendulum is generally considered an accurate method of measuring steps, there are drawbacks. The number one complaint about pedometers is inaccurate step counts. The number one cause of inaccurate step counts is failure of the sensitive pendulum-and-wire system.
The invention of the piezoelectric motion sensor and eventual integration with the pedometer has revolutionized precision step counting. The pendulum was replaced by an electronic motion sensor, which has no moving parts to jam, bend, stretch, or break if dropped.
Both pendulums and motion sensors do have a similar accuracy rate on studies with participants who are healthy, relatively fit and volunteer to be part of a study. However, few of those studies include a cross-section of real world body types, age ranges, or those with physical limitations. As far as we can tell, no pedometer studies take into consideration diverse factors such as level of education, cognitive ability, or participants on medications.
So while technology has advanced, how well does the Yamax compare to the SimpleStep in the real world?
Yamax: For accurate step counts, pendulum pedometers including Yamax must remain relatively perpendicular to the body as well as parallel to the ground. Some models stop counting if tilted as little as 15 degrees off level positioning. An inadvertent brush of the arm or hand may skew the pedometer and affect accuracy until repositioned correctly.
SimpleStep: Because a motion sensor is electronic and not mechanical, SimpleStep’s accuracy is not affected by position on the body. The SimpleStep works on the hip regardless of vertical or horizontal positioning. It also works in the pocket, as well as around the neck on a lanyard. For greatest accuracy, most pedometer manufacturers recommended a motion sensor be placed against the body in a relatively stable position.
Conclusion: Pendulum pedometers require continual monitoring by each user to maintain correct positioning for accurate data collection. This requires a level of cognitive awareness and engagement which will vary from user to user. Accumulated data reliability may vary.
The SimpleStep utilizes a medical-grade motion sensor which operates consistently in any position. It requires minimal instruction for implementation, with little or no user monitoring or special knowledge to use properly. The SimpleStep has the advantage here.
Yamax: For a pendulum to swing freely and count accurately, the pedometer must be positioned perpendicular to the ground. Some pendulum pedometers skip counts or stop counting altogether when tilted as little as 15 degrees off vertical. The orientation of the waistline in users with larger body mass indexes may not allow a pendulum pedometer to be worn on the waist perpendicular to the ground. This can negatively affect pedometer accuracy.
SimpleStep: A motion sensor has no moving parts, so the SimpleStep does is not required to be placed vertically on the body. It also may be worn in other positions if affixing to the waistline is not desirable.
Conclusion: For some body types the waistline is not the vertical position on the body and a pendulum pedometer requires reasonably vertical positioning to swing freely. The SimpleStep is more reliable for a wider variety of body types and waistline positions.
Yamax: Pendulum pedometers measure hip movement. In studies, some Yamax models are shown to be less accurate as speed decelerates below 2.5 mph. While this is typically not an issue for an average healthy walker, accuracy may be reduced for elderly users, those with a short gait, slow gait, shuffle, or walk with minimal hip movement.
SimpleStep: Based on studies, motion sensors count more accurately for users with a slower walking pace. A motion sensor will detect and count motion beginning at appx. 1.5 mph. This may be advantageous for participants who are less ambulatory and for patients in clinical recovery / rehabilitation settings. The SimpleStep has three options for body placement, making it more adaptable for slower walkers. First and or last steps may or may not register as step motion, a feature relatively consistent with both pendulum and motion sensor pedometers.
Conclusion: The SimpleStep’s motion sensor is more accurate than a pendulum model at slower walking speeds.
Yamax: A majority of studies utilize Yamax models with built-in clips. The Yamax must be affixed to the waist during use. While viewing the display on the hip may not be an issue for a majority of users, for those with neck, shoulder and other range of motion limitations, real time viewing may not be possible. Additionally, Yamax models in the same studies are designed with a clamshell cover. Real world usage has shown clamshell covers are difficult and sometimes impossible to open for those with dexterity issues such as arthritis and Parkinsons.
SImpleStep: The motion sensor’s design allows it to function in any position, whether affixed to the hip like a traditional pedometer; carried in a pocket; or around the neck on a lanyard. Three options provide a wider range of flexibility for users with physical limitations. In addition, the SimpleStep does not have a cover.
Conclusion: Both styles may be worn on the hip. For the Yamax, this is the only choice. The SimpleStep may alternatively be carried in a pocket or on a lanyard. The SimpleStep requires minimal dexterity to operate. In addition the SimpleStep is ergonomic, with a slim, rounded cornerless case. The SimpleStep is a better choice for users with dexterity limitations.
Yamax: Flat screen LCD display numeric characters are appx. 3/8″ tall.
SimpleStep: Enhanced LCD display numeric characters are 1/2″ tall with blue backlight display when button is pressed. Display illuminates for about 3 seconds.
Conclusion: Both models are easy to read. The SimpleStep’s bright backlight display is readable in low or no light conditions. The SimpleStep display is 25% bigger than the Yamax, a feature which is useful for users with diminished eyesight or any conditions which are not well lit.
Yamax: Most pendulum-based Yamax models use an LR-44 / AG-13 battery. Yamax’s own specifications state this battery has a 3 year life. However, under real world conditions, battery life will vary from 1 to 3 years depending on number of hours the pedometer is worn per day.
SimpleStep: The most unique feature of the SimpleStep is the USB recharge feature. Battery life is indefinite, so users will never have to change a battery. Recharging takes appx. 2 hours and plugs into a computer’s USB port, or a USB A/C adapter. A single charge lasts about 3.5 months.
Conclusion: While the Yamax battery may last longer than a single charge of the SimpleStep, at some point the battery on a Yamax will eventually have to be replaced. This requires users to purchase a new battery at their own expense, as well as open the pedometer and replace the battery. Experience has shown many users are uncomfortable, unwilling or unable to take a pedometer apart to replace the battery.
According to the manufacture, using the SimpleStep 8 hours a day and using the backlight 10 times per day, the charge will last 3.5 months. The long life lithium battery can be fully recharged over 300 times, which is a battery life of 75 years. There are no batteries to replace, and recharging costs just pennies. The SimpleStep is a clear winner when it comes to battery life and cost.
In the large volume of papers published about pedometer accuracy, one critical factor has never been studied: the shipping process. Pedometer Express has shipped and re-shipped nearly 1/3 of a million pedometers. We are experts in this area.
Based on the assumption each pedometer passes quality testing by the manufacturer, there is nevertheless a defect rate for all pedometer models. Real world experience shows anywhere from 2% to 25% of pedometers shipped from the manufacturer are either fast or slow, or do not count at all. This is the number one complaint about pedometers. The number one cause of inaccurate step counts is failure of the sensitive pendulum-and-wire system.
The simple fact is a majority of defects are caused DURING THE SHIPPING PROCESS. Pendulums are designed to swing freely with movement. When a pedometer leaves the manufacturer’s location, shipping cartons are loaded onto one or more air cargo flights, shipping trucks, delivery vehicles. The shipping process revolves around economy and speed. “Handle with care” is a desired but often unrealistic goal. During shipping, the mechanical mechanism can get hung up. Delicate springs pop off their mounts. Pendulum pedometers have a large failure rate caused by mishandling during shipping. The same thing applies to a pendulum based pedometer like the Yamax SW-200 and Yamax CW-701.
Motion sensor pedometers do not count mechanically. They have no moving parts, so failure of the pendulum system is not an issue.
Conclusion: The SimpleStep’s motion sensor is not affected by rough handling during shipping. This gives the SimpleStep a huge advantage over a pendulum pedometer.
The Yamax and SimpleStep are equally accurate, with an error rate of plus / minus 2 steps per hundred under controlled conditions with reasonably physically fit participants.
However, under real world conditions the SimpleStep displays numerous advantages. The SimpleStep requires less monitoring with no special knowledge to operate correctly. It can be worn in multiple positions on the body, unlike the Yamax single positioning, making the SimpleStep compatible for a wider range of physical body types, ages and abilities.
The SimpleStep is more adaptable for walkers who are overweight, who have a slower gait, and those with physical limitations.
The SimpleStep has a 25% larger display than the Yamax, and illuminates for use in varying light conditions. The electronics are sealed in an ergonomic case design. While not immersible in water, it is more water resistant than the Yamax and can withstand rain and water splashes. The SimpleStep never needs a battery and costs just a few cents to recharge, with a 75 year life span that is unrivaled.
Probably the SimpleStep’s greatest advantage is durability. The ability to ship with fewer issues is a major advantage. Most pedometer defects are caused by rough handling during the shipping process and/or when a user drops the unit. Unlike the mechanical pendulum in the Yamax, the SimpleStep’s medical-grade motion sensor has no moving parts, resulting in a lower defect rate and higher user satisfaction.
Whether for research or everyday use, the SimpleStep is simply the best overall step counter we’ve seen in years, a recommended alternative to the Yamax SW-200.
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