Mobile application found less accurate for measuring gait

SAN ANTONIO — Although strides have been in its efficiency, the Dartfish Express — an iPad application used to measure gait — was less accurate than the Vicon 3-D Motion Capture System, according to a data presented here at the American Orthotic and Prosthetic Association National Assembly.

Lee Childers, PhD, MSPO, CP, director of the Biomechanics and Motor Control Laboratory at Alabama State University, conducted a comparative study of both platforms. The Vicon and Dartfish systems concurrently recorded the same walking trial. Videos were then analyzed by a group of master’s and doctorate students, as well as high-level O&P professionals.

Results showed the Dartfish Express was less accurate than the Vicon due to lens distortion, motion blur, parallax and user error. However, the mobile application showed results similar to the Vicon in measuring peak hip extension pre-swing and peak knee flexion during swing.

“It is accurate plus or minus 7°, as long as it is perpendicular to the line of progression,” Childers said. He added that with cameras and accelerometers, smart devices could change the future of clinical practice. “But, there is room for improvement regarding efficiency,” he said.

“For now, this can be a good educational tool for patients. Mobile applications have enabled devices to potentially provide a method to measure gait. We just have to keep improving their validity.” – by Shawn M. Carter


Childers L. Paper #C58. Presented at: American Orthotic and Prosthetic Association National Assembly; Oct. 7-10, 2015; San Antonio.

Disclosure: Childers reports no relevant financial disclosures.

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