Research Institute

University of waterloo

Dr. Callaghan’s research compared the posture of individuals sitting in the CoreChair versus a high end ergonomic office chair, as well as a comparison between CoreChair and a properly fitted exercise ball in the recruitment of core stabilizing muscles.

The outcome concluded that CoreChair is just as effective at providing general postural support while being significantly more effective in providing pelvic support and preventing slumping of the pelvis and ascending spine. CoreChair was also determined to be equal to an exercise ball in the ability to recruit core stabilizing muscles thereby showing that the CoreChair is more efficient at introducing desired movement and an exercise opportunity, while providing optimal support.

Research Team:

Jack P. Callaghan PhD, CK, CCPE

The CoreChair is more efficient at introducing desired movement and an exercise opportunity, while providing optimal support.

The subsequent report presents data collected from 16 participants (8 males, 8 females) and compares the physiological responses to the CoreChair and an ergonomic control chair during two hours of simulated office work. Four different office tasks were examined (mouse dominant work, typing, a combination of the two and reading). Other focuses of the study were: insure that the CoreChair meets minimum mechanical stability guidelines; evaluate the stability and seat pan movements during reaching tasks within the primary through tertiary zones; and assess the torso muscle recruitment while undergoing a series of basic seated exercises on the CoreChair compared to a stability ball.

When the CoreChair was used as a standard ergonomic task chair for office work, it always performed at least as well as a leading ergonomic task chair. Postural responses, muscle activity patterns, both the magnitude and time varying measures assessing muscle rest time were similar between the two chairs. Subjective discomfort, rated by each of the 16 participants throughout the prolonged office work did not show any significant differences between the CoreChair and
the control chair. These findings alone support the potential for the CoreChair to function very well as a task chair. In addition to performing to the same standard as an established ergonomic task chair, the CoreChair also had a significant impact on the postures assumed by the participants over the 1 hour of sitting. The control chair exhibited a well-documented trend of postural creep, with lumbar spine flexion and posterior pelvic rotation increasing over time. These two physiologic responses result in a shift away from a neutral lumbar spine posture. In contrast the CoreChair facilitated more neutral spine postures that persisted over the one hour period. The seat pan was easily controlled by the participants and maintained a neutral average position within 1° of level yet they used the dynamic feature encompassing a range of 3-4° of seat pan rotation in all directions.

The CoreChair passed the front and rear stability tests outlined by the American National Standards Institute. While there are currently no lateral tipping stability tests, when the same test criterion were applied to lateral seat pan rotations the CoreChair also exhibited no potential to tip over. In conjunction with the results from the extended reaching tasks performed by all 16 participants, the centre of mass of the seated user was well within the base of support of the chair
and the stability in these tests confirm that the CoreChair does not present any undue risk for lateral tipping when used for typical office related work tasks. The rotation ability of the seat pan accommodated participants reaching and rotated to a maximum of 8° for the maximum distances.

An additional feature of the three-dimensional rotation capability of the CoreChair is that it can be used for light exercises at a workstation. The muscle recruitment for four exercises were compared against a stability ball and in all cases produced comparable or higher levels of muscle activity indicating it performed very well in targeting the torso or core musculature. The adjustable stiffness control for seat pan rotation in the CoreChair provides varying resistance and can be used to accommodate both different usage (office tasks versus exercise) and well as differing demands during seated exercises.

The one potentially negative finding from this investigation was related to seat pan pressures, which were higher in the CoreChair compared to the control chair. This did not impact subject evaluations, and even the exit survey results scored the seat pan as not having uneven pressure. This is an area that could be targeted for improvement and alternative foam densities and materials should be considered.

Subjective evaluation of the CoreChair during an exit questionnaire was very favourable with scores falling in the 70-80 range on a 100 point scale. This positive response coupled with the fact that this study sought to test a wide range of participant sizes (the heights tested represented 99% of the North America male height range and 75% of the female height range) suggests that the CoreChair will be suitable for a large range of the general population.


Additional Key Points