Why negative splits?

How do you attack a race?  Do you believe in ‘banking time’ up front or starting slow and building up as you go?

I’ve always been a believer in training at a certain pace until that speed becomes my ‘forever pace.’  Of course, I can do that because I’m not aiming to break world records.  All I have to do is focus on cadence and stepping lightly during training, and that lets me ‘go zombie’ during a race, zoning out and maintaining that familiar pace.

But I had a race a couple of years ago where I unexpectedly and unintentionally went with the negative split approach.  It was amazing!

fb-stopwatch2.pngScience is against trying to ‘bank’ time early in a race.  The point is this:  If you’re running at a speed faster than what your body typically trains at, your body enters its anaerobic metabolic zone.  While in that zone, your body uses carbs to fuel your effort level, and not oxygen.  When your body burns carbs, it produces higher amounts of lactic acid.  That acid builds up in your muscles and other tissues and blocks enzymes from breaking down more carbs.  Additionally, cell membranes are damaged and electrolytes build up inside cells, causing swelling.

In short, operating at high intensity will drastically inhibit performance over time.  And that’s just the physical effect.  Of course, the psychological effect might be even greater.  While there’s no greater high than passing people and pulling away from your competitors, there’s also no greater low than knowing your competitors are closing in, seeing and hearing them getting closer and finally watching them go by, knowing there’s nothing you can do about it.

glycosisA slower early pace helps the body conserve its supply of glycogen.  If you’re not burning it at a prodigious rate, you’re also not building up that evil lactic acid early on.  If you’re running a half marathon, starting off a race at 20-30 seconds off your normal pace and staying in that range for the first mile or so, and then settling into your goal pace will pay benefits down the line.

By mid-race, you should still comfortably be running within yourself.  Now it’s time to start increasing the pace – but not all at once.  Slowly build your tempo, speeding up only a little at a time.  The increase should be hard to notice.  Soon, you’ll notice your splits are slowly falling.

Regardless of how well you pace yourself, you’re going to feel fatigued around the last third of the race.  Focus on form and cadence, and forget about the clock.  At this point, you should start to see the people who bolted out of the gate in an effort to bank time coming back to you.  That will be a motivator in itself, and your confidence will increase, too.

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