Wearing high-heeled shoes on a side slope makes standing balance unstable

Many women wearing high-heeled footwear are at high risk of falls. Past studies have examined the balance on level ground or balance during walking. We measured the standing balance on the ground and side slopes for 18 healthy women. Body sway was evaluated based on the center of pressure (COP) while participants stood on level ground on a side slope. The total locus length as well as rectangular and outer peripheral areas were then measured using a Zebris system. Measurements were compared under bare feet, normal shoe, and high-heeled shoe conditions. On level ground, there were no significant differences among the three conditions. On the side slope, the total locus length (TLL), rectangular area (RA) and outer peripheral areas (OPA) were significantly greater for the high-heeled shoes than for the bare feet and normal shoes. Standing on the side slope caused larger body sway than on the level ground, along with a higher risk of falling. In TLL, OPA, and RA, the COP moved outside substantially when participants stood on a slope in high heels than in shoes. High heels were highly unstable for standing on a slope since the ankle joint of one leg is in plantar flexion, the foot is pronated, and the other side is plantarflexed at the ankle with pronation of the foot. High-heeled shoes significantly alter a person's balance when standing on a side slope, suggesting a high risk of falling. •We compared standing balance in bare feet, normal, and high-heeled shoe condition.•Total locus length, rectangular area, and outer peripheral area were measured.•There were no significant differences among the three conditions on level ground.•High-heeled shoes were most unstable on slide slope.•Wearing high-heeled shoes on a side slope made standing balance unstable.