I’m in hard training for my sixth half marathon, and I’m running slower than I ever have before. Much slower. As in, almost 2 minutes per kilometre slower. I’m also running without a pace group – as much as I love the comeradierie, they all go too fast for me.
That’s right, I’m running slower, it’s hard work, and I’m doing it alone and I’m doing it so I can get faster.
It’s all about heart rate zones, and lactate thresholds. I’m wearing a heart rate monitor and paying attention to my body – it’s the most personalized training I’ve ever had.
Also the first heart rate monitor chafing I’ve ever had, but I can deal.
Warning: I’m about to blind you with science.
A couple of Saturdays ago I gave myself a birthday present: a trip to the Peak Centre in Burnaby so they could put me on a treadmill and run me ragged while taking a drop or two of blood from my pricked finger every three minutes.
Yeah, I know, bling would have been nice, or a weekend getaway, but there was no one around to spoil me so I got myself something I could really use. Something that would give me back my running, get me back to training and return me to sanity.
Alex at Peak Centre explained that my heart rate is an indication of the lactate in my blood produced by exercise. The harder you work, the more lactate is produced. A lower intensity – about 70% of maximum heart rate, your body is able to get rid of all the lactate it’s producing. Go faster, and lactate builds up, it fills up like a sink and eventually overwhelms the body’s ability to deal with it, producing lactic acid and the attendant cramping, fatigue, and inability to continue running (or biking, or whatever).
The goal of training is to “widen the drain” at the bottom of the sink – to train the body to handle increasing amounts of lactate. Translation: if you’re training based on your lactate threshold profile, you don’t get tired as easily and can perform better.
It also has to do with fast twitch and slow twitch muscles. the faster you go, the more you’re using fast twitch. The slower you go, the more you’re using slow twitch.
My training heart rate is now determined by five zones the Peak Centre guys figured out for me using data from my lactate threshold test.
BUT here’s where my eyes opened wide: there are “intermediary” fast twitch muscles that can act as slow twitch, and handle all that lactate for longer periods. It’s really important for endurance athletes to “recruit” those intermediary fast twitch to act more like slow twitch. By continually pushing my “easy” pace into Zone 2 all those years, I was encouraging my intermediary fast-twitchers to stay fast twitch, I wasn’t increasing my aerobic treshhold or my lactate threshold and I was hitting a wall in terms of performance. I got frustrated and started to lack motivation.
(Those extra ten pounds I gained since the last fall haven’t helped either, but that’s another matter.)
As it turns out, my 6:30/km (or faster) pace – the pace at which I did all my long and “recovery” runs for the last three years, was probably in Zone 2, “junk mile” territory. Also, I’m not doing enough training in zone 3 – lactate threshold pace, and therefore not training my body enough to handle faster running.
(Yes, I missed nearly every Wednesday night track workout while I was training last summer and fall).
Alex explained that 10-15% of my training should be at lactate threshold, Zone 3, between 6:23 and 5:56 per kilometre; but the other 85-90% should be under aerobic threshold, Zone 1, under 150 bpm – or about 8 minutes per kilometre. When I first started doing it I had to stop and walk frequently to keep my heart rate down. It’s getting ever so slightly better, but I really need to concentrate on running at these paces.
What’s the upshot of all this for me? By running slower according to my own body chemistry, I can train my body to run faster at the same heart rate.
So today my 70% HR is 8:00 per km, but in a few months it might be 7:00, and my race pace will be faster yet.
I won’t be hitting my goal of a 2-hour half marathon this May during the Vancouver Half Marathon. I’ll be lucky to break 2:17 – close to a personal worst. However, if I keep at it, consistently training in my correct zones, I can expect to push my Zone 1 to faster paces and set a personal record in the fall.