Ground contact time in sprinting is how long your foot stays on the ground each stride. At top speed it's about a tenth of a second, and that tenth is the whole window you get to put force into the floor. Anywhere from 100 down to 90 milliseconds is a strong target when you're flat out. The 80s to low 90s is really rapid. Whatever force you get into the ground inside that window is your speed.
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What ground contact time in sprinting actually is
Every stride, your foot lands, takes the force, and leaves. That's one contact. It opens, it shuts, and that's it. I've measured athletes at 118 milliseconds. That's the entire window they get.
It changes as you speed up. Out of a standing start, your first contact can be upwards of 200 milliseconds. Second, third, fourth contact keeps coming down. By about the fifth and sixth stride you're in the 110 to 100 millisecond range. So the start and the top end are almost two different jobs.
And here's why it matters on the pitch: every millisecond on the ground is half a yard the other player gets on you.
Why a 300 kg deadlift doesn't make you fast
I assessed a man who deadlifts 300 kilos. He was stronger than almost every athlete I've ever put through a session, and he could not get out of his own way.
Here's the arithmetic nobody does. A heavy deadlift takes you two seconds, maybe three. Your foot is on the ground for about a tenth of a second. So you can spend years training a slow way of producing force, and then ask your body to produce it twenty times faster. It can't, because nobody ever taught it to.
That's not a strength problem. That's strength that can't get out fast enough. And another year under the bar doesn't fix it, because the bar isn't where it's broken. See?
Springs, not muscle
Strength and elasticity are not the same quality. A heavy squat is slow force output. You've got time to produce it. Running in behind or chasing a loose ball, you don't.
In a 90 millisecond window there's no time to push with muscle. The force has to come from your tendons, and tendons act like springs. They stretch when your foot lands and recycle that energy straight back into the ground. It's why the Mbappés of the game look like they're not even trying.
Here's the catch. A stiff, reactive system returns that energy. A tense, muscular system absorbs it. So the harder an athlete tries, the more he tenses up, and the more energy leaks out on every single contact. It's not about trying. It's about letting the elastic system do what it's built to do.
That's also why strength without elasticity keeps you on the ground longer. For a lot of players, getting stronger past a certain point doesn't just stop helping. It can make them slower.
How to test it: the 10 bound test
Elasticity has to be trained as its own quality, with fast, reactive, short contact work. And it has to be measured, not guessed. The two numbers I use are ground contact time and RSI, the reactive strength index, which is how much distance you produce against how long you spend on the ground.
You can get close to that on any training pitch with the 10 bound test. A 5 metre run-in, then 10 continuous bounds, and you measure the distance. Every bound feeds the next one, so it shows how well you return energy. If you're well under 30 metres, it's usually not your strength. It's your elasticity holding you back.
The trap: recovery looks like poor elasticity
This is where it gets tricky, because two problems hide behind each other.
A nervous system that hasn't recovered blunts your reactivity. You come off the ground slower, which looks exactly like poor elasticity. So you add more plyometrics, which costs more nervous system recovery. It works the other way too. Poor elasticity means you're making speed with effort instead of elastic return, and effort is expensive for the nervous system. So now you look under-recovered, you rest more, and nothing changes.
For context, after one flat-out session where you ran a personal best, our own figures from around 1,000 athletes show 7 to 24 days to full neurological recovery, and up to 50 if you were pushed past your max. Those are days to 100% neurological freshness, not days until you can train. Your legs will feel fine long before then.
So how do you tell them apart? If your bound distance is good when you're fresh but falls away across the week, that's a recovery issue. If it's short even when you're fully recovered, that's elasticity that needs work. Does that make sense? More on this in legs feel fresh, nervous system isn't.
Find the bottleneck, then train it
Ground contact is one of the 100+ subcategories under speed, and we treat it as its own block: measured, given a target, given its own work. We film at 240 frames a second, which is fast enough to see the exact moment your foot hits the ground and what happens in the tenth of a second after.
A ceiling is permanent. A bottleneck isn't. If you're stronger than ever and still can't get away, read how to increase top speed next.