Dental professionals sit during many if not all procedures. The seated posture is an inactive position. While there is a very low level of muscle activity during sitting as compared with dynamic activities, Nachemson found in sitting a 40 percent increase in intra-discal pressure as compared to standing22 making pain inevitable for those who engage in prolonged static sitting. Even standing postures can contribute to increased disc loading, especially if there is any forward lean. In addition, inactivity can cause an accretion of metabolites that contributes to both disc degeneration and disc herniation in both the cervical and lumbar spines.17 Table 1 shows the percentage comparison of disc pressures in the third lumbar disc in various positions.
Table 1. Disc Pressures in Varied Positions.
Recognizing the effects of various positions is crucial when choosing a working posture. Replace the pain and fatigue from static unstable positioning with a muscular framework, a structurally stable sitting alignment, and fluid movements. In Practice in Motion: Part II, we ask you to consider the 6 Components of Posture and various movement strategies that can minimize stress to pain sensitive tissue.