Linear discriminant analysis for symmetric lifting recognition of skilled logistic experts by center of pressure trajectory.

GOAL: The main purpose of the present study was to propose a recognizing method to analyze characteristics of symmetric lifting of skilled logistic experts by center of pressure (CoP) trajectories. Although it has been known that good posture helps reduce the intradiscal loads on lumbar discs, the most significant problem was that most of logistic workers did not know whether the current posture was proper or not.

METHODS: The experiment of lifting was performed three times under 18 kg loads with closed eyes. Six skilled logistic experts and six unskilled beginners were participated in. The linear discriminant analysis (LDA) was designed by seven indices which were derived from measured CoP trajectories with the Wii Balance Board. The strong point of experimental system was practical, reliable, and cheap.

RESULTS: As a result, it was found that the designed LDA discriminated difference of symmetric lifting between skilled experts and unskilled beginners with the error rate of 0.005.

DISCUSSION: It was discussed that not only most of unskilled beginners had mainly characteristics of poor lifting posture, but also the proposed method showed a high possibility to self-evaluate the symmetric lifting in order to check whether the current posture of logistic worker is proper or not.