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VO2 and all that jazz

Mon, Jul  27, 2009 - By Edward McCarthy

Ed is a Canadian racer who writes for the excellent XC Ottawa web site.

As my big bro never tires of pointing out, I've been doing some running this summer. This led to a couple of good races in the spring and a big blow-up in Canmore, despite which I now have a ticket (currently one-way) to Italy to complete in the World Mountain Running Championships, and then probably the Commonwealth Mountain Running Championships in England's Lake District. These will be - by far - the highest-level running races I have ever competed in, and relatively speaking are probably higher-level than any ski races I've ever done. Good thing that this is the year that I am training with no team and no coach, with the exception of Tom working hard to fill both categories. Ottawa's very own Eamonn Watson has also offered his services if I need any help throwing frisbees for training.

Science, however, has just begun an attempt to come to my rescue. In the first 5 Peaks race of the season, my prize (sadly, not cash this time) was a gift certificate for a full VO2 max, lactate, and energy efficiency assessment at the Peak Centre for Human Performance in Vancouver (but founded and headquartered in Ottawa!). Two months after winning this test, I have finally overcome my procrastinatory inertia and gone for my test and follow-up assessment and consultation.

First, the test, which I did for running. In the words of one of the employees: "You start out pretty easy. It gradually gets faster, then it starts to suck, and then it's over." Suck it does. The test involves running on a treadmill at a set speed which is raised by 1 km/hr every 3 minutes, until the testee decides they've had enough. I avoid treadmills at the best of times - this is, I think, the fourth time in my life I have been on one - and they are even less fun when I have a headset holding a plastic snorkel in my mouth and my nose plugged. In addition, the joys of doing a tandem VO2 max/lactate test mean that every 3 minutes, I had to put a hand down on the rail and keep it still, while still running, so that I could be pricked for a lactate sample. I try to be stubborn and mentally tough, but I still had to pull the plug 2 minutes through the 19 km/hr stage. I felt like a pansy, but there was no way I was convincing myself (or my legs) to keep going, and looking back at that, and at the testing that came before, I guess it was a reasonable place to stop. With the painful part over, all I had to do was look forward to my consultation!

Ok, ok: the numbers. There are a lot of numbers, but these are the salient ones:

Aerobic threshold (speed): 15.1 kph
Lactate threshold (speed): 17.3 kph
VO2 max (at 19 kph): 75.7 ml/kg/min

So, what does this all mean? First, VO2 max. In brief, it's the rate at which the body can use oxygen, from the lungs to the bloodstream to the muscles. For more information, you can refer to my old standby. When it was first developed as a test, it was seen as the single most important factor in determining results; Bjorn Daehlie and Miguel Indurain are examples of individuals whose high VO2 max results have passed into legend. More recently, though, testing has shown that VO2 max is not as much of a determining factor as the speed attained at VO2 max. VO2 max is largely genetic (thanks mom and dad!) and largely set by the age of 20, but speed can be improved. The upshot? Apparently I've got a pretty high VO2 max, but that doesn't seem to matter as much as...

Thresholds! The aerobic threshold is the pace I can maintain for long periods without tiring due to the buildup of lactates. The lactate threshold is the pace at which lactates start to REALLY suck. Both of these are in ranges, respectively 80%-85% and 90%-95% of pace at VO2 max, at which the speed at VO2 max can act as a limiting factor. So what does this mean? I'm supposed to work on improving my speed at VO2 max, and in the meanwhile should maybe work on improving each of those thresholds. To do this, these are the intervals I'm told to do:

For improving VO2 max, sets of intervals 2-3 minutes long with 4-6 minutes rest in between. I'm supposed to do these with a good performance marker, such as the track (the track doesn't lie!) to be sure that I'm maintaining my pace - in this case, faster than 3:03 min/km. Happily, I've been doing this - km repeats last week in 2:58, 2:57, 2:59, 3:00, 3:05 (and that's why I stopped after 5), and 800s in 2:18ish, but these intervals hurt - and I'm supposed to do them more often, once a week now. Ok. So much for my 200s and 400s.

For improving lactate threshold, over/under workouts. These sounds like they will suck. Essentially, I'm supposed to alternate 5 minutes just above my lactate threshold pace and 5 minutes just below, for about an hour. In the absence of a good treadmill, to judge pace, I'll have to do it on the track - apparently heartrate starts to drift too much to be an accurate predictor. Essentially, this means running close to my 10k pace, with ups and downs but no recovery, for an hour - in a 400m oval. Maybe I should find a longer track.

For the aerobic threshold? Nothing too new, but according the the Peak Centre my normal z1 pace is significantly slower than the threshold. I might try a few hour runs at a higher pace, and see what happens.

So, with 7 or so weeks to go before Worlds, I finally have a training program! Well, kind of. Fortunately, there are no radical changes, but a bit of confidence in what I've been doing, and a bit of direction as to how to focus my intervals. It's time to try it out, and we'll see how it works! Thanks to the Peak Centre guys for their good work and some good training discussion.