QUANTIFYING STAIR GAIT STABILITY AND PLANTAR PRESSURE IN AN AGING COMMUNITY, WITH MODIFICATIONS TO INSOLES AND LIGHTING

IntroductionStair gait falls are a common concern especially for older adults aged 65 years and older (1). Recently falls have become the most common cause of injury-related deaths in individuals over the age of 75 years old (2). During stair descent falls account for 75% of stair falls and also present a greater injury severity (2). Factors such as poor shoes or insoles, lighting condition, or stair design can contribute to an increased risk of falls during stair ascent and descent. (3) Stability, which is the ability for an individual to control the body’s center of mass (COM) over their base of support (BOS), can be measured during normal gait using the COM-BOS ‘stability margin’ relationship (4)(5)(6). Plantar pressure, a measure of weight distribution on the plantar surface of the foot, is an important indicator of gait pattern efficiency (7).

Aim We aim to measure the COM-BOS ‘stability margin’ (Fig. 2) and plantar pressure patterns of individuals in stair ascent and descent, while wearing different insole conditions in combination with two lighting conditions. This research will potentially identify certain aspects of stair gait that increase the risk of falls.

Methods• 10+ young adults and 10+ older adults • Ascend and descend a 4 level staircase (Fig. 1)• Two imbedded force platforms ( ) will record force• Two levels of lighting conditions (low and normal). • Standardized footwear will be fitted with pressure

insoles and varying insole hardnesses (Fig. 3).• Optotrak motion capture system will record 12 IRED

markers placed on the individual in descent

Expected Results Participants will demonstrate a greater lateral displacement in the single support phase during dim lighting as opposed to normal lighting. Older adults will demonstrate a more cautious stair gait pattern under dim lighting as opposed to younger adults. The stability of older adults will be compromised in comparison to the young adults. Under soft insoles, participants will demonstrate a lower peak plantar pressure in the most common contact location, the metatarsal heads. Lastly, under soft insoles, we expect the rate of change of plantar pressure will be lowest in older adults. References1)Statistics Canada (2012) Retrieved from www.statcan.gc.ca. Accessed Nov. 16, 20112)Masud & Morris (2001) J Age and Ageing. 30 (S-4): p.3-73)Templer, John. The staircase. MIT Press, 19924)Shumway-Cook et al. (1988) Arch Phys Med Rehabil. 69 (6): p. 395-4005)Pai & Patton (1997) J Biomechanics. 30 (4): p. 347-3546)Perry et al. (2008) J Gerontol: Med Sci. 63 (6): p.595-6027)Rosenbaum & Becker (1997) J Foot and Ankle Surgery. 3: p.1-14

Patrick Antonio, Stephen D. PerryDepartment of Kinesiology and Physical Education, Wilfrid Laurier University, Waterloo, Ontario, CANADA

Figure 1: Experimental staircase (2.13m x 1.3m x 0.72m; Rise :18 cm, Run : 30 cm)

Figure 2: ‘Stability margin’ measurement

Figure 3: Insole hardnesses (hard, typical, soft)