The Sensor Medica Treadmill – High Tech Gait Assessment

Technology in Diagnosis

As a registered podiatrist, we need to have studied for at least 4 years at university, on top of that we must keep up with professional development every year to keep our knowledge current.

At Dynamic Podiatry we will always strive to get even better at diagnosing lower limb problems and how will treat them. Read about the history of our practice here.

Whether it’s going to courses or getting a new piece of technology that can improve our diagnostic skills, we’ll give it a try.

Diagnostic gait analysis has been a huge part of podiatry for decades, and now technology is taking us much further than ever before.

Previously we could watch people walk, slow it down and break down the steps, but we didn’t know exactly how much pressure was being exerted onto the soft and hard tissues in the feet. This is crucial because excess pressure frequently causes pain and breakdown of tissue.

At first there were stationary force plates which you could measure one or two steps on. But it didn’t work well for running, and there was never enough space to get a good rhythm up. As well as the fact that you couldn’t quickly repeat the step 20 or 30 times to make sure that it was a persistent score.

So when they started building treadmills with force plates inside, wer really stood up and took notice! This innovation means that we can measure many steps whilst the patient is walking or running in a straight line.

I first saw these treadmills at QUT a few years back but the use of them was mainly reserved for research and not very often as a clinical diagnostic tool.

So as soon as I was able to buy one, I did, keen to help our patients even more effectively using this technology. Now our gait analysis has gone to the next level. 

Below I breakdown some of the most common features of gait analysis that we’re able to breakdown with this bit of kit.

 

High Speed Gait Assessment

The still photos to the right show a very clear change in gait with shoes and orthotics on as opposed to off.
These photos are actually of me running (yes, I know!).

The one at the top shows a massive bulk on the inside of my ankle as I pronate during mid-stance.
This type of over-pronation can cause all kinds of compensation from other parts of my body which can lead to pain and injury.
On the right is me in a pair of running shoes and my orthotics.
The difference in the size of the medial bulge is quite obvious.

Two screens the one at the top shows a mans foot as he is running without shoes and on the bottom shows with shoes

Here’s where the Sensor Medica Treadmill gets really exciting!

For many years we’ve been able to map pressures of people using a fixed force plate. 

But it could only measure one step at a time as you walked over the plate.

Now we can actually measure those pressures whilst our patient is walking, running and standing, capturing every step they take, which makes this piece of tech a real game changer in gait assessment.

 

A screen with a lot of data including a pair of feet with pressure maps

The Breakdown

The picture above tells much more than a thousand words!

In the three sections below I discuss how the different parts ot the window help us with a diagnosis.

Overall Pressure:

The left part of the screen displays a general picture of the gait. It gives some information on where the most amount of pressure is applied, the angle of each foot, and the width of the gait, and a centre of pressure line.

Symmetry in Gait Assessment:

The central area with green, orange, and red bars break down each little stage of gait and tell us how similar the left and right are at each time. 

A very common finding from this part of the report is that one foot may be more turned in or out than the other, or that more time is being spent moving through a certain joint on the left foot compared to the right.

Why is Symmetry important? 

When gait is efficient, your joints are free to move, without pain and there is no compensation going on, there will be symmetry.
When on the other hand there is something wrong on one side of the body E.g. a restriction in the big toe joint, or pain in the knee joint from a torn meniscus, or tight external rotators of the hips – it will show up as an assymetry.

This is great news for us as clinicians because it helps us to use gait assessment to hone in on where the problem might be. A restricted big toe joint can lead to over-compensation through the mid-foot in the form of collapse or pronation, which in turn will rotate the knee inwards causing uneven pressures on cartilage and tension on ligaments and muscles. 

Because we know that everything in the lower limb is interconnected, getting a clue from one area can really help us work on a treatment plan for the area that’s actually causing you the pain.

 

Centre of Pressure Line (COP):

The area on the far right side of the screen also gives us a lot of information.

The Centre of Pressure line or COP shows us exactly which way your weight is moving throughout each step.

One of the things we’ll often notice are tiny little deviations in the path that the COP takes, these deviations or “hesitations” indicate times where there was a restriction, whether it’s from the joint, muscle tightness or other factors, that causes the body to slightly change direction in order to continue to drive you forward. 
It’s as though on a tiny scale the body “moves around” a road block.

This again will help us to direct our testing to the correct area, so that we can find out the root cause of the pain that you present with so that we can help you to get better.

 

Loading Areas:

The right of the screen area also shows parts of the foot that are loading and parts that aren’t loading during gait assessment.

In some people their big toes don’t take any load at all, and in others they take an inordinate amount of load. This can lead to overuse injuries and tissue breakdown.

Some people will load right throughout their foot including the arch, and some will only load on the very lateral (outside) border.

Still others will have no heel strike at all, but start by landing in the middle of their foot.

This information can tell us a lot about the type of foot you have and what shoes or insoles might be best to cause you the least amount of pain.

Balance and Stance

A pressure map of two feet

Another test that we can do with this technology is stance and balance testing.

We all know how important it is to avoid falls as we age, and how devastating a single fall can be. Prevention is definitely much better than the cure in this case.

Read my falls prevention post here.

One of the first things you can see in the above report is that there is zero pressure on the toes, they don’t appear at all.

This can be a problem for balance as the toes play a critical role in keeping us from falling over. They are constantly making tiny changes based on the information that they get from the Cerebellum – that part of the brain responsible for balance and telling us where we are in space.

We can also see that the centre of balance (denoted by a “C” on the graph) is very slightly to the left. In some people it may be much further to the left or right.  This is also noted at the percentages at the bottom of the screen – 51% to the left and 49% to the right.
This can indicate that there is: a leg length difference; a hip imbalance; one foot pronating (rolling in) more than the other; a scoliosis or a variety of other conditions.
Our job as clinicians is to then go seeking the source of the imbalance, work out if it’s a problem (pathological) and treat if necessary.

In another plane we also notice that more pressure is being placed on the balls of the feet than the heels. This is shown by the percentages in each corner denoted as R/A%.

Almost 60% of the weight is on the front of the feet. This can also be caused by several different factors, one of them being very tight posterior muscle groups, the hamstrings and calves.

 

Collaboration

Three podiatrists analysing some information on a screen

As a clinical team we will often take a look at interesting gait patterns. 

This collaboration can have multiple benefits including a new set of eyes spotting something that the clinician didn’t notice at first.

It also helps us to grow our knowledge base. The more feet and gait patterns that we look at, the better we become at gait assessment, diagnosis and treatment of lower limb conditions.

If you have any lower limb aches or pains or would just like to have a full gait assessment using our latest technology by our skilled clinicians, click on the button below to book in or call (07) 3351 8878.

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