Variation in the Kinematic Response of Cervical Spine, Proprioception and Muscle Activity During Anterior Load Carriage-An Experimental Study

Abstract

Background: Front load carriage is a common occupational task in some industries (e.g. agriculture, construction). Previous studies were conducted to examine the effects of load carriage on changes in thoracic and lumbar spine rather than the effects on the cervical spine. The focus of this study was to explore kinetic and kinematic response of cervical spine the during anterior load carriage and, specifically, to examine the effects of load height on neck muscle activity and neck posture. Despite the evidence linking between load carriage and kinetic and kinematic response, previous studies to examine lumbar spine rather than the effects on the cervical spine. Methodology: 30 female participants participated in this front load-carriage experiment. The experiment called for carrying a barbell (with weight corresponding to 10% of body weight of the participant) at three heights (knuckle height, elbow height and shoulder height) at a constant horizontal distance from the spine. In this experiment, the participants performed this task while standing still. As they performed this task, the activity level of the upper trapezius was sampled. Craniovertebral angle and proprioception of cervical spine were also quantified using photographic method and magnetic inclinometer respectively at these three heights. Results: The results showed a significant effect of load height on muscle activity, craniovertebral angle and proprioception (flexion) of cervical spine levels in the barbell experiment but insignificant effect for proprioception (extension) of cervical spine. Conclusion: These results provide insight into muscle activation patterns, proprioception and kinematic response of cervical spine especially (load) carrying biomechanics, and have implications in industrial settings that require workers to carry loads in front of their bodies.