Age-related self-overestimation of step-over ability in healthy older adults and its relationship to fall risk

BACKGROUND: Older adults could not safely step over an obstacle unless they correctly estimated their physical ability to be capable of a successful step over action. Thus, incorrect estimation (overestimation) of ability to step over an obstacle could result in severe accident such as falls in older adults. We investigated whether older adults tended to overestimate step-over ability compared with young adults and whether such overestimation in stepping over obstacles was associated with falls. METHODS: Three groups of adults, young-old (age, 60-74 years; n, 343), old-old (age, >74 years; n, 151), and young (age, 18-35 years; n, 71), performed our original step-over test (SOT). In the SOT, participants observed a horizontal bar at a 7-m distance and estimated the maximum height (EH) that they could step over. After estimation, they performed real SOT trials to measure the actual maximum height (AH). We also identified participants who had experienced falls in the 1 year period before the study. RESULTS: Thirty-nine young-old adults (11.4%) and 49 old-old adults (32.5%) failed to step over the bar at EH (overestimation), whereas all young adults succeeded (underestimation). There was a significant negative correlation between actual performance (AH) and self-estimation error (difference between EH and AH) in the older adults, indicating that older adults with lower AH (SOT ability) tended to overestimate actual ability (EH > AH) and vice versa. Furthermore, the percentage of participants who overestimated SOT ability in the fallers (28%) was almost double larger than that in the non-fallers (16%), with the fallers showing significantly lower SOT ability than the non-fallers. CONCLUSIONS: Older adults appear unaware of age-related physical decline and tended to overestimate step-over ability. Both age-related decline in step-over ability, and more importantly, overestimation or decreased underestimation of this ability may raise potential risk of falls.