memorial University

Less back pain, better sitting posture, enhanced blood flow!

Sitting has become the most common work posture in the developed world. Evidence has been steadily accumulating showing that sedentary behaviours, which include prolonged sitting, increases the risk of cardiovascular disease, cancers and early death. Seated postures also involve significant amounts of spine and hip flexion: postures that are related to the development and aggravation of low back pain. The high prevalence of back pain, paired with the high prevalence of seated postures, highlight the importance of considering chair interventions that can address both the broader health implications of seated postures but also the impact on back pain itself: ideally with the goal of prevention.

The ability of a chair to provide optimal occupant posture, stability and whole body movement would theoretically have the potential to address both the posture and movement risk factors that affect both overall health and low back pain. The CoreChair has a multi-axis seat pan that allows the user to move in all directions without sacrificing stability paired with a unique backrest design that targets the low back and pelvis. Studies conducted on the CoreChair have shown the seat pan to be stable while providing a large range of movement and comparable to a standard office chair in terms of seat pressure. However, it is not known how well occupants utilize the movement capabilities of the seat pan, if the design affects perceived ratings of back pain and/or whether the design improves lower limb venous return in a healthy population.

To address these questions, this study exposed a population of healthy male participants to 2-hours sitting while completing a standardized typing task in the CoreChair and a control chair. The study design utilized two separate data collections, in a randomized order, at the same time of day to control diurnal variation and separated by a 24-hour washout period. Variables compared between chair conditions included: spine posture, seat pan pressure, seat pan movement, calf circumference, low back muscle activity, and perceived low back pain. Qualitative data capturing perceived back stiffness, physical tiredness, chair support, chair movement and beliefs surrounding the concept of a typical office chair were gathered with an informal questionnaire at the end of each session.

The results of this study suggest that the CoreChair design facilitates more upright spine postures, greater lower limb venous return and increased seat pan movement compared to sitting in a control chair. Participants were less likely to be classified as a low back pain developer and reported lower perceived back stiffness and whole body fatigue compared to the control chair. While participants found both chairs could be more supportive, the CoreChair was rated as providing comparatively more support than the control.

Nearly all participants reported that the CoreChair did not fit their belief of what a typical office chair should be. However, this may be a positive finding, as the typical office chair design has not provided solutions in terms of improved health and wellbeing in sitting to date. Thus, it appears that the CoreChair has the
potential to positively affect both general cardiovascular health and back pain. However, larger, field-based, longitudinal studies would be needed to determine if this was the case.