Award Date

May 2019

Degree Type


Degree Name

Doctor of Philosophy (PhD)


Kinesiology and Nutrition Sciences

First Committee Member

James Navalta

Second Committee Member

Richard Tandy

Third Committee Member

John Young

Fourth Committee Member

Szu-Ping Lee

Number of Pages



The overarching purpose of this dissertation was to evaluate and analyze heart rate and/or step count measurements for six popular wearable technology devices: the Samsung Gear 2, FitBit Surge, Polar A360, Garmin Vivosmart HR+, Leaf Health Tracker, and the Scosche Rhythm+ in four separate conditions: free motion walking, free motion jogging, treadmill walking, and treadmill jogging. The four studies presented here utilized one test design and data collection protocol in which many measurements could be addressed simultaneously. Currently, there is no accepted standardized protocol to evaluate wearable technology devices. The test design utilized for this research series was introduced as a potential foundation for the establishment of a common procedure.

There were three purposes for the first study in this series of four research projects. First, this study looked at whether the tested devices that recorded heart rate were reliable and valid in each of the four stated conditions. Only the Garmin Vivosmart HR+ and the Scosche Rhythm+ were significantly acceptable for all four conditions. Secondly, while all the tested devices used photoplethysmography to record heart rate, this technique has not been thoroughly validated for this purpose. Limited research indicates that devices that use this method as a measurement technique and are worn on the forearm are more accurate than those worn elsewhere on the body. Results from our study supported this conclusion. The Scosche Rhythm+, being a fore arm worn device, did produce more significantly acceptable results than the wrist worn Garmin Vivosmart HR+. Third, a standardized heart rate testing protocol has been introduced by the Consumer Technology Association. However, their recommended measurement criteria (a measurement every 1-5 seconds which would require special software to record) can be viewed as financially prohibitive, restrictive, and over compensating. The protocol used in our research presented evidence that ours, which used an average of several minutes of heart rate values, was easier to implement and did not required a financial investment to perform.

The second study had two purposes. First, this study looked at whether the tested devices that recorded step count were reliable and valid in each of the four conditions. Only the FitBit Surge, Garmin Vivosmart HR+ and the Leaf Health Tracker were significantly acceptable for all four conditions. Secondly, the Consumer Technology Association has recommended a standardized step count protocol which would require the videotaping of an activity with separate tape reviews by two persons at a future time. This protocol is not feasible in certain conditions such as outside testing. Additionally, both reviewers would need to produce the exact same step count. Our testing used two manual counters where the mean of the two were used as the criterion measure. We provided strong evidence that this is an acceptable criterion measure for step counting that does not require additional time or resources.

The third study compared heart rate and step count values measured by the tested devices between the different conditions. Measurements taken during free motion walking were compared to treadmill walking and those taken during free motion jogging were compared to treadmill jogging. It is generally believed that most wearable technology device companies perform device testing on a treadmill in a laboratory. Our conclusion was that there was no significant interaction or main effects for walking heart rate value comparisons. Jogging heart rate values saw significant main effects from both the environment and between the devices. Walking step count values had a significant interaction between the devices and the environment. Jogging step count values had a significant main effect between the devices. When utilizing wearable technology devices for the measurement of heart rate during walking or jogging, the Garmin Vivosmart HR+ and Rhythm Scosche Rhythm+ provided acceptable measures both in the laboratory as well as in a free motion environment. The FitBit Surge, Garmin Vivo Smart HR+, and the Leaf Health Tracker produced similar results for step count.

The fourth study evaluated whether there was a correlation between both body composition percentages and body mass index values and the percent error calculated between a manual step count and that recorded by the wearable technology devices. Our results gave evidence that there are no significant correlations between body mass index and the calculated percent error. For body composition, only two conditions for the wrist worn devices had a positive significant correlation; the Samsung Gear 2 when free motion walking and the Garmin Vivosmart HR+ when free motion walking. The waist worn Leaf Activity Tracker had positive significant correlations for both treadmill walking and treadmill jogging. Even though our study produced four conditions with significant correlations, all were low to moderate in value.


Body composition; Body mass index; Heart rate; Reliability; Step count; Validity


Kinesiology | Medicine and Health Sciences

File Format


Degree Grantor

University of Nevada, Las Vegas




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