Skip to 0 minutes and 2 secondsGait is essentially a style or manner of walking. Obviously, the general gait for humans is bipedal walking. Walking is controlled falling, and it always is. We are perpetually in danger of falling over. The adjustments we make to balance are to prevent us falling over. Essentially, the risks that we have in walking are mostly associated with the risk of falls. The biggest risk comes in turning. Turns are about 30% to 40% of all steps. In turns, we have to decelerate the body, accelerate the body, and we're doing this within about two steps. So in order to measure all this, we need high-speed cameras which are recording body motion, the motion of all segments.

Skip to 0 minutes and 53 secondsWe need to record actually not just the linear acceleration, changes in speed of the body segments, and where they're moving in space, but axial rotations - how a limb segment is rotating upon itself. All these things are telling us about how they body is moving. And then we need to look at muscle contractions, which are driving the motion, driving the balance. And then we need to look at the ways that we control that, with our vision, and the effect that listening to sounds in the environment has on our walking. In very common parlance, we talk about getting stiff as we get old. And indeed, that's absolutely true. That's one thing that's happening. Our ligaments are changing their properties.

Skip to 1 minute and 43 secondsThey're no longer as stretchy or as flexible as they used to be. For example, let's have a look now at how Ali walks. Look at the length of her stride. She's confident. She can look up. Her upper body is moving against her lower body, enabling very, very fine control of gait. If you watch her coming back again, she doesn't need to think about how her foot is making contact with the ground. She can feel her foot making contact with the ground. She can use her toes to detect ground irregularities. I cannot change the motion of my head from side-to-side and turning around independently of my shoulders.

Skip to 2 minutes and 29 secondsAnd certainly, I'm very poor at moving my pelvis independently of my thorax, because I'm old, I'm stiff, I move the whole of my trunk at the same time. And that's one of the reasons you see me waving my arms around simply in order to have something which balances the forces under my foot but in a very second-hand sort of way. We start to lose control - at a muscular level, at a force level - of our balance. So there isn't as much muscle around to control unwanted rotations of my body. The posh word for it is sarcopenia, which is loss of muscle fibre volume. Now looking from the front, you get another factor.

Skip to 3 minutes and 14 secondsLook at my lower legs, look at the position of my feet, and you'll see that I place my feet further apart than Ali. This is a natural reaction of elderly people to a feeling of instability. If you can see my whole body, essentially at this point, I'm balancing on one leg. I can't stay here very long, because at this point, I'm balancing - as you can see, I need to bring my foot down. And now, what's called my base of support is the space between my two feet. But watch me when I start walking, and you'll find I start doing that, because I'm insecure about my balance.

Skip to 3 minutes and 57 secondsAnd actually, this is the very worst thing that old people could do, but even I, who know something about it, make that mistake. What's driving gait, what's driving our control of walking, and driving our ability not to fall over when we're walking, is the application obviously of force to bones through muscles. Ultimately, there's one part of the body which matters in terms of walking, and that's the one down there. We move our trunk around, we move our head around, we move our legs around, but all that is doing ultimately is changing the interactions, the force interactions, the pressures between the foot and the ground. So that's all we're doing.

Skip to 4 minutes and 41 secondsEverything else is acting sequentially down the body, from top to bottom, to change the pressures under the feet, between the foot and the ground. For example, if I lean over sideways, or I feel unstable sideways, I will increase the pressure on the opposite side of my foot by changing the pressure under my toes. Again, if you're wearing shoes, and the shoes are stiff, well, you're not very good at doing that. And so your risk of falling is higher. The footwear that people have chosen or adopted is actually largely very bad for us. We obviously didn't evolve to walk around in shoes or boots.

Skip to 5 minutes and 24 secondsWe evolved to control in particular the lateral sway of the human body by using the lateral medial sides of the foot, by using the toes. And obviously, if the toes are bound together in the front by tight fitting shoes, that's gone. By the time people are say, 40 or thereabouts, the toes have been squashed together by fashionable shoes - for men and women - and again, in the case of women, high heel shoes are further disrupting the normal muscular function. So unfortunately, most of the effects of clothing is negative.

How does the way we walk change with age?

Gait disturbances are a common medical problem in old age. After the age of 70, 35% of people have abnormal gait and after 85, gait changes are found in the majority of people. In this video, we join Professor Robin Crompton in his gait lab at The University of Liverpool to find out what is happening to the musculoskeletal system when we walk.

Robin compares his own gait with that of a younger volunteer. As Robin walks, notice his slower gait speed and shorter stride length; these are common occurrences in older people.

Do you recognise any of the challenges that Robin highlights? What factors impact your own walking gait?

If you’d like to learn more about how our mobility is affected as we get older, you may like to watch the video under ‘SEE ALSO’ at the bottom of the page. In this video, Robin discusses the changes that happen in the brain as we age and how this affects our mobility.

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This video is from the free online course:

The Musculoskeletal System: The Science of Staying Active into Old Age

The University of Sheffield