Some thoughts on older adult bathtub slips and falls

Filmed during Inside Edition production in mid-September, 2026 by ASU media team. Thurmon Lockhart (00:00): When I see an older adult going into a bathtub, it worries me a great deal because that floor surface, or bathing surface, has not been carefully designed or carefully standardized as of now. And, and because of that, we really don't know what type of floor surface, or slippery surface, that is in the bathtub. So, when the older adult, you know, slips in the bathtub, it's not just the fall accidents and breaking hips and, you know, bones and things like that, but also, they have a great deal of traumatic brain injury. You know, we usually think about, like, athletes, you know, having traumatic brain injury. But if you look at the statistics, the majority of traumatic brain injury (happens to) older adults and is caused by the bathtub — associated bathtub injuries. So, currently, bathing surface friction standard has been obsolete since 1978. Thurmon Lockhart (01:06): You know, the first thing that we were asking when we were doing this research was why do older adults fall more than younger adults? So, by looking into elderly capabilities, we could see clearly why older adults are falling more than younger adults; because with the aging, we have a sensory degradation. Our visual, vision, vestibular, proprioceptive system, all degradate. When we're looking at the statistics from the Consumer Product Safety Commission, we could see clearly that bathing tub was an associated, related variable to TBI, traumatic brain injury. And then when we look at that, and then looking at the population, we saw older adults, you know, having much of these kind of accidents. With increasing in older population, the next few decades, we're going to be seeing a significant amount of these type of injuries, and, unless we do something about it. And so, that's what we're trying to do right now, is to try to understand the mechanism related to slips and falls, related to the bathtub, and then come out with a, an intervention, solution that can actually reduce this type of slip-and-fall injuries. Thurmon Lockhart (02:32): You know, in order for a slip to occur, your friction demand has to be greater than what is available. So what it, what that means is as we walk across, we demand certain friction, and that is basically horizontal force divided by the vertical force. For the young person, that demand is about .2, OK? And if you put a soapy water, let's say for example on this surface, it becomes about .10, OK? Thurmon Lockhart (02:59): So if you got an available coefficient of friction with a .10, with a soapy water, and then your demand is .2, physics tells you that you're going to, you're going to slip, because you, you're demanding more than what's available. Those older adults have a higher friction demand, and maybe perhaps this is the reason why they are slipping more than younger adults and falling more. What happens is, you know, we demand certain friction, and then if there's ... friction is not available, then physics tells you, you slip. So what happened in this case is that you walked normally, you know, without really knowing that there was a slippery surface, and then you stepped in just like walking normal, demanding about .2. But unfortunately, on that surface, there was a, some slippery medium there that reduced the coefficient of friction to about .001. And so, then you got a .001, you stepped in normally .2, physics tells you that you slipped. And so that's what we saw. Thurmon Lockhart (04:06): My name is Thurman Lockhart. I'm a professor at the School of Biological and Health Systems Engineering at Arizona State University. COPYRIGHT & USAGE Copyright Holder: Please credit: Thurmon Lockhart, Arizona State University Copyright Notice: Provider: Arizona State University Usage Restrictions: This content is intended for editorial use only. For other uses, additional clearances may be required. Please credit: Thurmon Lockhart, Arizona State University