11.3.2 Assessing risk from unsuitable postures using the LUBA method

The LUBA method66F¹ (Loading on the Upper Body Assessment) is a technique for assessing static postural load on the upper body. It assigns relative discomfort scores to movements of the hand and wrist, elbow, shoulder, neck, and torso joints according to their angular deviation from the neutral position. Each movement is classified into angular intervals or postural classes associated with an experimentally obtained discomfort score, as shown in the Joint-Motion Discomfort section of Figure 61. The sum of the scores for a posture constitutes the Postural Load Index, which is inversely related to Maximum Holding Time (MHT): the higher the index, the shorter the time for which the posture can be expected to be sustained without a substantial increase in discomfort. Ergoniza Intelligent performs this calculation independently for the right and left sides of the body.

Based on the relationship between the Postural Load Index and Maximum Holding Time, LUBA defines four action categories (I, II, III, and IV) indicating the need and urgency for corrective measures. Ergoniza Intelligent calculates one category for the right side and another for the left and presents the action corresponding to the less favorable result as the overall action.