Validity of wireless device measuring velocity of resistance exercises

Document Type

Journal Article


Active Aging Research Center

Place of Publication



Faculty of Health, Engineering and Science


School of Medical and Health Sciences




Sato, K.,, Beckham, G. K., Carroll, K., Bazyler, C., Sha, Z., & Haff, G. G. (2015). Validity of wireless device measuring velocity of resistance exercises. Journal of Trainology, 4(1), 15-18. Available here


Objectives : The purpose of the study was to identify the level of accuracy in velocity measurement from a newly developed inertia sensor. Design and Methods : Five subjects performed two dumbbell exercises for total of four sets of ten repetitions with a light intensity. Velocity data were taken and considered for analysis from two devices; the inertia sensor, wirelessly connected via Bluetooth™ to a smartphone, and a motion capture system. Both data were taken at the sampling frequency of 200 Hz. Identical data sets of peak and average velocity were analyzed with Pearson product-moment zero-order correlation using total 200 data points (5 subjects, 4 sets, and 10 repetitions) on both exercises with p value of 0.05. Data were also analyzed using the same statistical procedure for left and right side to ensure the device-device data consistency. Results : Results showed high correlations in both exercises between the two velocity measurement methods (0.80 - 0.92), indicating the accuracy of the data from the inertia sensor is supportive. Left and right side correlations were also high from the inertia sensor (0.90 - 0.93) indicating that the data were similar with relatively identical movements between the two limbs. Conclusions : With the accuracy of the velocity measurement, this would potentially replace currently used, wired devices to accommodate user-friendly, accessible to more exercises to measure velocity.

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