Carlibration of an instrumented couch with a motion capture system in measuring force applied and distance

Abstract

The objectives of this study were (i) to describe an instrumented couch which would be able to synchronize with the motion capture system in details; (ii) to calibrate this device. The criterion-related validity and test-retest reliability of the couch were investigated in two conditions: empty couch and a couch with dead weight of known mass of 70 kg. Both conditions were investigated in three directions: vertical, medial-lateral and caudad-cehalad directions. The motion capture system was also investigated by using the grid paper size 40× 40 cm2. The criterion-related validity of both the couch and motion capture system were analyzed by Pearson’s product moment correlation. The test-retest reliability of the couch was analyzed by Intra-class correlation coefficients [ICC(2, 1)]. The percentage error was calculated for both the couch and motion capture system. The Pearson’s product moment correlation of this study showed 1.00 (p<0.05) in both the couch and motion capture system. The ICC(2, 1) of the couch was 1.00 (p<0.05). The percentage error of the couch showed average percentage error to be ranged from 0.41-1.12%. The percentage error of the motion capture system showed 0%. In conclusion, the instrumented couch and the motion capture system are appropriate to investigate both amount of force applied and displacement during manual therapy.