Tuesday, August 31, 2010

I'm back at it.....it's a long one this time!

Welcome back! I hope that in these last 2 weeks you have managed to find activities that have been able to fill the blank void created by my lack of blog entries. Thank you for returning to the site every so often to check if anything has been added – your perseverance has now been rewarded!

I jest, however, you may indeed be wondering what I have been upto for the past few weeks. Resting. With one exception, which I shall shortly address, I did not run a step since my cooldown following the 1500m at the provincial champs. The rest was good, and I enjoyed it, however, a funny thing happened to my body as the days passed. I became injured. It seemed that as the rest progressed old injuries that I had suffered in days gone by resurfaced. My hamstring began to ache as I sat at my desk, my shin got sore as I watched movies, my left hip feels locked, and my heel (site of an Achilles problem) became too sore to walk on. Absolutely incredible, and ridiculous at the same time. I began to itch to get back running before anything worse befell me. And, following my first run yesterday….I feel completely fine. Apparently my body was rebelling against the lack of exertion.

The one thing that I did do in the past 2 weeks, the exception that I alluded to above, was a VO2 Max test. This is a measurement of the maximum amount of oxygen that your body can extract from the air as you run at progressively increasing speeds and/or elevation on a treadmill. The result is given as either an absolute value measured in L of O2/minute or as a relative value measured in mL of O2/kg body mass/minute. The relative value means the amount of oxygen used by a kg of muscle per minute. The more O2 you can use the better you can break down glucose into a usable energy form that the body can use. Therefore, the higher your VO2, the better your aerobic fitness is. However, it is not the only indicator of fitness and cannot stand alone as a predictor of something as multifaceted as race performance. There are several factors that contribute one’s VO2 including strength and efficiency of the heart (to pump oxygenated blood around the body), the efficiency of the gas exchange in the lungs (swapping CO2 for O2), the gas exchange at the site of the muscle, the network of minute blood vessels that supply the muscles, and the amount of enzymes and cellular bodies inside the muscle cells themselves that help to process the oxygen. All of these things have a genetic component (ie some people have a naturally superior aerobic capacity), yet these can all be increased (up to a certain point by) endurance training. Due to such factors as increased muscle mass, bigger lungs, and bigger hearts, at comparable age and fitness levels, men will have a higher VO2 than women. The range can be from 20mL/kg/min in a sedentary person to 96ml/kg/min, which is the highest Vo2 ever, recorded in a male Swedish cross-country skier.

The testing process can be best explained as I describe my own test. I started running on the treadmill at 9miles/hr and 0% elevation for 3 minutes. At 3:00 the elevation increased to 5% and from then on increased by 2% every 2 minutes. Speed would remain constant until 15:00 when the elevation would hit 15% and the speed would be increased by 0.2mi/hr every minute. I am pretty sure that is what would happen, however, I only made it to 15:00 when I had to stop due to exhaustion. One’s VO2 increases as the test progresses and it is necessary to run to exhaustion in order to ensure one hits their max. My VO2 peaked at 5.2ml/min or 74.5ml/kg/min at 12:00. This is a very satisfactory number, however, there were other aspects of the test that I was more pleased with. For 4mins, between 9:30 and 13:30 I held an average VO2 of 71.3ml/kg/min. This is very close to my max, indicating that I was running close to my max aerobic capacity for 4 minutes – essentially the time within which I would run a mile. From 13:30 to the end of the test I had a lower VO2, but still managed to keep the pace for that remaining 1:30. With this decreased aerobic efficiency I was relying on anaerobic mechanisms of creating energy – the method used when sprinting. This may be a physiological indicator of why I am able to kick at the end of a 1500m to good effect.

However, this is as far I am willing to look into my results. I am happy with 74.5 but what does it mean? If that is my genetic max, then what more can I do? Besides more training the only way to increase my VO2 would be to lose weight (thereby decreasing my relative value, but not my absolute value) but I’m not willing to go that route. Racing and training are comprised of complex physiological and psychological components that go beyond the factors involved in the VO2 test. It’s interesting to know, but unless I can test myself every week and tailor my training to improving it, a costly and futile effort, then it really has no tangible value for me. That being said, I probably will get retested at the end of the XC season to see how it has changed!

Did that all make sense? Nod once if yes.

Anyway, I do have more to write I believe I have taken up enough of your time for this particular occasion. Plus, I am off shortly for my second run of the day. I put in an easy 3 miles this morning and will do another 8 or so with Kevin and another friend of mine, Clay. I am going to take this week and next running easy, gradually increasing my mileage. I might try to peak at 80miles/week this season but will probably average 60. However, that is some time away. One run at a time!
Be Easy.

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