The Effect of Stool Design on Sitting Postural Control in Older and Young Adults

Effective balance control while performing daily activities in sitting is an important component of everyday life of many older adults. The ability of older adults to withstand external perturbations declines with age in both sitting and standing positions. While previous research has shed light on older adult’s balance maintenance in standing, limited evidence exists for sitting balance. Therefore, the focus of this dissertation was on the investigation of anticipatory and compensatory postural adjustments in sitting balance control of young and older adults. Moreover, we sought to determine the role of stool design and aging in the presence of external perturbations. First, we demonstrated that seated older adults exposed to frontal or lateral body perturbations showed diminished ability to generate anticipatory postural adjustments compared to young adults, regardless of seat inclination, availability of leg support, or directions of perturbation. Second, we demonstrated that irrespective of the direction of perturbation, young adults utilized reciprocal activation of muscle while older adults largely utilized co-activation of muscles as their main mechanism of postural control. The outcome of the dissertation provides evidence that sitting older adults have diminished ability to generate anticipatory postural adjustments. This dissertation also provides a background for future investigation of sitting postural control in older adults.