Heather Fell: Most of us want to run faster. In order to do that, we spend several hours
training. We also measure various metrics such as our pace, our distance ran, our heart rate,
but how about ground contact time? Yes, that's what we're looking at
today. [music]
GCT, ground contact time is measuring the time from when the first part of your foot actually
makes contact with the ground to when the last part of your foot leaves the ground.
For normal runners, it tends to be just under 300 milliseconds, but for faster runners, it's seen
around 175 to 200 milliseconds. It doesn't really matter where you are right now, but there is
evidence to show that reducing that ground contact time is going to actually help with your overall
running performance. How do we measure it? Why is it important and what can we do to improve it?
Well, measuring it manually is a little bit tricky, but luckily for us,
the technology to measure ground contact time has actually become relatively affordable.
You'll find that most top-end sports watches will automatically measure it when you're on
run setting. Some of them will require you having a foot pod or sometimes even heart
rate monitor straps have a motion sensor built in that can measure that ground contact time.
Then that leads us on to why is it important. [music]
Simply put, when your foot is on the ground, you're not moving forwards. You're only moving
forwards when you're airborne. The more time you're spending in the air, the less time on the
ground, in theory, the faster you're going to be moving. It's not just that, that we need to look at
when we can measure ground contact time because it can also give us an indication to your efficiency.
Research has also shown that the shorter the contact time, the less energy required.
That's indicating you'd be more efficient runner with a shorter ground contact time.
Then it can also give an indication to any potential misbalances or imbalances
between your right and your left foot as you can compare the time that each foot
is spending on the ground which could give you an idea if you're predisposed to any injuries.
[music] It turns out that
a fairly simple metric can actually give you a huge amount of information about your running
stride. There are other metrics to consider such as vertical oscillations, stride length,
and cadence. If you put them all together, you really will see the complete picture.
Ground contact time is a great area to focus on to hopefully see some improvement in your
running. That is a lot of information. I could go on, but it's enough for now. What better way
to learn about something new then go out and try it. It's very time to go and put a watch on
and head out for a run. [music]
All right. I've got my watch on and it's running. Now, I'm just going to jog at tempo for 10
minutes. I'm not going to be thinking about my running a talk. Well, I'm trying to do you guys,
to start with, but after this 10 minutes, I'm then going to run 10 minutes at tempo. Then I'm going
to have a little bit of a rest, I'm about to easy jog. Then I'm going to do one minute as fast as I
can and then we'll correlate all of those results. [music]
Well, during my warm-up, I spent 10 minutes running at around
5 minutes per kilometer pace and it looks like my contact time was an average of 260 milliseconds.
Just to confirm this, when I ran my all-out one minute effort,
my contact time decreased even further to 170 milliseconds. That's 90 milliseconds quicker than
in the warm-up. Then at the end, I was running the same pace as I was in a warm-up but obviously,
a little bit more tired and the ground contact time reflects this as at an average of 280
milliseconds. It was roughly 20 milliseconds longer than when I was running at the start.
[music] Then we talked about the imbalance between
each leg earlier on and I'm pleased to say that mine are fairly balanced, notably more balance
for the easy warm-up bit and it was a little bit of discrepancy as I got to the faster work. I
don't think it comes as any surprise that as my speed increased, my foot contact time decreased.
That doesn't really tell us anything because that would be the same for everybody. We need
to be able to understand the mechanics and what those limiting factors are so we can address them
and improve our ground contact time. [music]
Ground contact time is determined by three main factors. Your ability to apply force downwards to
the ground quickly which is power, then you've got your leg stiffness so the amount of energy return
you can get from the ground and finally, it's the biomechanics. A heel striker, for example,
will have a longer ground contact time than someone who runs mid or forfeit. We don't want
you guys to get too bogged down on focusing purely on the ground contact time and said got a couple
of suggestions that you could try which will help improve it overall. Hill sprints are great because
they're going to address the aspect of power. If you can find a fairly steep hill of about
50 meters in length and then focus on trying to do eight lots of really good form but running faster,
you've got the resistance of gravity and then walk or just do a light jog back down. Then you could
try to add in some plyometrics. Plyometrics have been proven along with lifting heavy
weights to actually work on your leg stiffness. If you're going to do some heavy weights make sure,
you've got the correct technique and you build into it. If you want to try some plyometrics,
again, you want to be thoroughly warmed up, but it's basically doing explosive actions/ You can
do this as double leg or single leg using boxes. You might see people in the gym experimenting
with this. If you want to do it simply just outside or wherever you do your normal running,
you can incorporate some hoppings. Again, I would probably put it in
after you've done a very good warm-up and just start off by doing 20-meter stretch of hopping
and trying to think about spending as little time on the ground as you can. Do 20 meters on one leg,
20 meters back on the other, have a bit of a rest, and try and repeat it four times.
You can look to increase that in distance or repetitions or move it onto a variety using
a box. Practicing hopping on one leg up onto a box is much harder than it looks. Trust me.
Then you could even go jumping off the box, so just stepping off and trying to jump up as soon
as you hit the ground so you're really focusing on touching and leaving the ground as quickly
as possible. [music]
As we've touched on ground contact time, it's just one of many metrics when it comes to running,
and you can't segregate one. They all influence each other but hopefully, it's giving you some
ideas on another area of your running you can focus on and just another metric that's quite
interesting. If you have enjoyed this insight, give this video a like. Remember, you can find us
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