Biomechanical Analysis of Spinal Load in Motor-Manual Cutting

摘要

Two Norwegian cutting instructors have been used as models for demonstration of "correct" and "poor" working postures in motor-manual cutting. This enabled estimation of the intervertebral disc compression forces at L5/Sl-level. The results/when related to defined lifting hazard levels shows that the compressive forces are greater in all "poor" postures compared with corresponding "correct" postures. Furthermore, relating to the lifting hazard levels, it becomes obvious that even correct working techniques in the felling and bunching sequences entails hazardous compressive forces in the lumbar column. This is probably one of the main causes of the high incidence of lower back injuries among loggers. Training courses for better technique and adminstrative or engineering controls to eliminate the peak loads are still needed in forestry.