| Summary: | Low back pain is a common problem, which has been linked to repetitive lifting and highloading. Previous studies investigating the relationship between lifting and spinal load shave failed to consider the separate elements of the back. This study aims to compare different lifting techniques (weightlifting and manual handling) using a multi-segmental model of the spine. The loading and movement characteristics of the lumbo-pelvic joint during sagitally symmetric lifting were investigated. Kinematic and kinetic data were acquired with the 'Flock of Birds' electromagnetic sensors and a custom-built forceplate. Weighted boxes and Olympic barbells were used to simulate occupational lifting and athletic weightlifting respectively. The results indicate a shift to back-driven lifting and a reliance on the momentum of the upper body to move heavier weights. Over-extension of lumbar spine and pelvis during the heavy lifts implies the increased role of the hip and back extensors in force production. Moment did not increase significantly with load suggesting a physiological limit to the moment that can be generated by the muscles; other factors must affect lifting ability once this maximum has been reached. A simultaneous study investigated the potential of the 'balance board' method for measuring pelvic segment mass. Despite previous studies reporting the ease and accuracy of this method for measuring segmental mass, the results were not deemed to be sufficiently accurate for use. This is the first study that attempts to compare lifting technique between subjects with differing types and levels of training. Some training effects were seen to transfer between tasks. These findings would imply that a compromise might be reached, combining the advantages of manual handling and competitive lifting, which could result in a safer and more effective lifting technique. From a clinical perspective, this may be helpful in both treating patients and reducing healthcare costs.
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