Chapter 6 Estimation of low - back moments from video analysis a validation study . P . Coenen

Estimation of low-back moments from video analysis a validation study. 78 79 Chapter 6 Validity of a video analysis method 6 ABSTRACT This study aimed to develop, compare and validate two versions of a video analysis method for assessment of low-back moments during occupational lifting tasks since for epidemiological studies and ergonomic practice relatively cheap and easily applicable methods to assess low-back loads are needed. Ten healthy subjects participated in a protocol comprising 12 lifting conditions. Low-back moments were assessed using two variants of a video analysis method and a lab-based reference method. Repeated measures ANOVAs showed no overall differences in peak moments between the two versions of the video analysis method and the reference method. However, two conditions showed a minor overestimation of one of the video analysis method moments. Standard deviations were considerable suggesting that errors in the video analysis were random. Furthermore, there was a small underestimation of dynamic components and overestimation of the static components of the moments. Intra-class correlations coefficients for peak moments showed high correspondence (>0.85) of the video analyses with the reference method. It is concluded that, when a sufficient number of measurements can be taken, the video analysis method for assessment of low-back loads during lifting tasks provides valid estimates of low-back moments in ergonomic practice and epidemiological studies for lifts up to a moderate level of asymmetry.