In the so-called Dortmund Lumbar Load Study (DOLLY), the load on the lumbar spine was quantitatively monitored for complete shifts in diverse fields, i.e. for the materials handling tasks in construction and metal-processing industries as well as in a meat-processing factory and for dustbin removal. Video recording of 8 shifts was performed, actual posture was described and the action forces applied at the hands were determined for each work situation. Based on the respective data for posture and handforces, lumbar load was calculated applying the 3D biomechanical model The Dortmunder for each working situation, in total between approx. 4 and 22 thousands per shift. Shift-monitored temporal profiles for several load indicators - trunk flexion and torsional moments, compression and shear forces with respect to the lumbosacral joint - describe the load on the lumbar spine. Comprehensive results with regard to posture, handforces and lumbar load are available. Several load indices regarding load level, duration and the cumulative effects were defined and applied for assessing the analysed jobs.
In relation to recommended limits for the maximal disc compression, lumbar load is exceeded in numerous situations during a shift, in particular, with regard to persons of higher age. In a “dose model” developed in this study, the cumulative effect of single-task exposures was considered by superproportional weighting of the compressive force with respect to the corresponding duration of a working task, based on the higher injury potential of high loads compared to - although longer effective - low loads.
