Science of Sport: BMX

Every time you try to explain that

you race BMX to somebody they always

say, Oh, I used to do that as a kid.

I think people underestimate the amount

of power and force that BMX riders put out.

In BMX, off the start lines, we go from zero

to about 35 miles per hour in around two seconds.

BMX riders get up to like 280 RPMs a minute.

There's only one gear, so you have

to learn to accelerate that quickly.

We're often producing upwards of 2500 watts

coming off of an eight meter tall starting hill.

When we go from the downhill slope of the ramp to flat,

we're pulling close to five G's.

That's only the first two seconds of the race.

The physics of what we're doing on our bike,

like the biomechanics of all that, are huge.

It's very important because we

don't have any shock absorbers.

If you're on a mountain bike, or a dirt bike,

you've got something to help you absorb

those landings if you're not perfect.

We have to be so precise, and all

of that comes from your body position.

There is absolutely nothing natural

about the positions that we're put in

when we're riding a BMX bicycle, so we

often have to do a lot of preventative care on our bodies.

Different stretching, treatments, things like that.

We're a sprint sport, so the power-to-weight

ratio is really important.

We have to be extremely explosive

and really quick out of the start to jockey for position.

The heavier you are, the stronger you're

gonna have to be to get off the start.

We only have two-and-a-half seconds

to get into position, or you might get shot

out the back, or end up on the ground.

You're not on tiny little hills

that you could jump over on your feet anymore.

The jumps are up sometimes to 40 feet.

The starting hill is three stories high.

When you actually see an Olympic-level BMX

track in person, it's a spectacle.

Another thing we have to be careful with

is just making sure not to overdo it

because we're playing with limits here

with jumping 40 feet, and only having

a small window of where to land.

When you're tired and your brain is not

functioning as fast, it does become really dangerous.

I guess it's (2 second pause) survival of the fittest.