Question: Could you explain me a little bit more about those "reflective dots" you use to tell you where bits of our body are and what they are doing you talked about at your profile? I'm pretty amazed to know and understand how such technology works.

LauraAnne Furlong answered on 9 Nov 2016:

sure 🙂 it is a technique which we call motion analysis. The reflective dots are also reflective balls, about the size of your thumb nail. We can track where they are in a room using what we call infrared cameras, which reflect back off the markers. We put them onto different parts of the human body to tell us where that part of the body is in the room, so for example when I am doing an experiment, I place some on the outside of your big toe, on the outside of your little toe, on your ankle bone, at your knee and at your hip.

By doing this, I would be able to tell where your leg is in the room, how fast it is moving, and what angles each of your joints are at. I would also be able to tell you what one bit of your leg is doing relative to another bit, and this sort of information has been shown to be very important when working with people who are injured or are recovering from things like stroke or have Parkinson’s disease or multiple sclerosis.

If you take a look at the work photos in my profile, you will see pictures from two studies I have done, the one on the right is from the markers I have just mentioned during a running experiment, and the middle photo is where we had lots and lots of markers attached to a person’s leg. This told us not only where the bony bits of the leg were, but also the actual shape of the leg itself around the muscle so you can quite clearly what the person’s leg really looks like. Hopefully you can see this link, it was taken recently at the opening of the building I work in – 42 seconds in, you will see a skeleton bowling a cricket ball – that is what we see on screen during testing. At 58 seconds you will see a man running up with orange cameras lighting behind him, that is what we use to see the reflective markers and dots, and you see it again at around 1 minute 49 seconds, where it used during arm cycling.

We have another piece of kit called a force plate, and that allows us to measures the forces on your body during tasks like walking, running or jumping. When we combine this force plate with the measurements from the reflective dots, we can estimate what the force is at each of your joints which is very useful for both maximising someone’s performance, as well as reducing their chance of injury. I can also use another piece of equipment (ultrasound) which tells me which muscles your body is using, and how they are being used, as well as take videos of the muscle working during movement, so when we use all of them together, we get a really cool insight into how your body works during a task like running or jumping, and why it does that.