Reliability of the infrared motion-time acquisition system for each motion segment in the timed up-and-go test

[Purpose] This study aimed to investigate the reliability of an infrared motion-time acquisition system by measuring the time taken for five motion segments (sit-to-stand, forward gait, mid-turn, return gait, and turn-stand-to-sit) in the timed up-and-go test. [Participants and Methods] In total, 30 healthy adults (25.1 ± 4.6 years, 19 males and 11 females) were included in this study. Tester A and Tester B measured the time taken in the timed up-and-go test and its five motion segments with an infrared motion-time acquisition system, and two measurements were made by Tester A and one by Tester B. [Results] Intraclass correlation coefficients of the time taken for the five motion segments in the timed up-and-go test and the intra- and inter-rater intraclass correlation coefficients were greater than 0.9. [Conclusion] Infrared motion-time acquisition systems and its five motion segments are reliable and provide accurate measurements during the timed up-and-go test.