Racing flats

So, I'd like to talk about the different things that have worked for me over the last few years to make me faster.  More specifically, I'd like to focus on WHY they worked, because some really are interesting.  Today, I'm talking about racing flats.

There's an interesting word involved here; biomechanics.  Biomechanics refers to the body's use of forces.  Leverage, momentum, drag, inertia, that sort of thing.  And that makes a big difference.  Stick with me.

Now, I bought racing flats this year for the first time.  A racing flat is a running shoe used for, well, racing.  It sacrifices large amounts of cushioning and durability to achieve a massive weight reduction, and the lighter you are, the faster you run, fair enough?  Of course, but it's really interesting when you get to WHERE the weight loss is.

So, a racing flat is about half the weight of an endurance training shoe.  We're talking 125 grams instead of 250.  The thing is, if you told a runner to lose 125 grams of body weight (about 1/4 of a pound), the maths says they would be a about 1/4 of a second faster per mile.  Neglible.

However, when you put that weight loss into a shoe, the experiments show a pair of racing flats makes you about 2 seconds per mile faster, a full 4 times speed gain over body weight loss!  Why?  Our friend biomechanics.

It turns out that because the weight from the shoe is positioned right at the end of your leg, it is much harder to move that weight through space (the same principle as trying to hold a weight away from your body-the further away, the harder it gets) than if the weight was spread evenly through your body.  Therefore, it isn't just about the weight saved from the shoe, but the effort needed to propel the shoe through the running cycle.  The reduced leverage required from the muscles to move the lighter foot results in a huge decrease in energy use and the result?  You speed up!

The first time I wore my racing flats, I couldn't believe the difference.  For the record, they are a pair of Asics Gel Hyperspeed 6.  You only get 250 miles or so out of them, but they're worth it.  If you're a runner, and you're reading this, I recommend investing in a pair.  They could save you half a minute or so on a half marathon!

There are other biomechanical forces in play during running, and if you're a runner, check out the studies on wind resistance and hill climbing.  It really can help you.

I'm off to see the new Star Wars movie tonight.   With that in mind, if I could give my fellow runners one piece of advice?

Use the force.