Manual material handling such as box lifting is a very common task that is used in the industrial and medical fields. It is widely accepted that manual lifting can lead to low back injury. Asymmetric lifting, which involves twisting of the trunk, shifts trunk muscle activation and can increase the lower back loading on the spine, thus further increasing the likelihood of injury. Other researchers have explored asymmetric lifting but have not considered the effects of handedness. This work aims to identify the effects of handedness on spinal joint moments and trunk electromyography (EMG) measurements during two-handed asymmetric box lifting so that safer lifting recommendations can be made for those tasks. Participants will perform box lifts with five different lift origins (two left lifts, one sagittal symmetric lift, and two right lifts) and two different box weights (light weight and heavy weight). Lift origins will remain consistent across participants, but box weights will vary according to the participant’s strength. Motion data will be collected using a motion capture system, force plates, and surface EMGs. We anticipate the collection of five left-hand-dominant and five right-hand-dominant individuals. The processed motion data results will allow us to compare the spinal joint moments and trunk EMG measurements between lifting scenarios to identify trends. In addition, we will conduct a statistical analysis using ANOVA to determine if handedness plays a significant part in the generation of spine moment during lifting. We expect our results to show that handedness does have an influence on the previously mentioned biomechanical measurements. Upon acquiring these results, it is possible to recommend new lifting strategies based on handedness. Additionally, this finding would further motivate our future work, which will incorporate the use of musculoskeletal modeling and finite element modeling to perform a deeper analysis of spine biomechanics during these lifts at the muscle and tissue levels, respectively.
Keywords: manual material handling, spine, low back, asymmetric lifting, electromyography
How to Cite:
Cruz, J. & Aguilar, I. & Yang, J., (2022) “The effects of sex and handedness on lumbar kinetics during asymmetric lifting tasks: A pilot study”, Proceedings of the 7th International Digital Human Modeling Symposium 7(1): 5, 10 pages. doi: https://doi.org/10.17077/dhm.31748
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