Itís NOT all about the bike
As athletes we spend a lot of money on speed suites, the latest aero gear for our bikes and the latest and greatest running shoes, all in an attempt to shave a few seconds or even minutes off our race times. While investing in a speed suite may shave 2-3 seconds off a half ironman swim, would it not be more beneficial to spend the money on improving your technique in the water? Along these same lines, purchasing race wheels can shave 10-15 minutes of an ironman bike, but if you are not physically fit you will loose a lot more time than this. If the engine (ie your fitness) is not maximized, all theses technological advances will not help in the end.
What most athletes neglect is the fact that our bodies provide the majority of the forward propulsion that makes us go faster and improve our PRs no matter what distance we race. Focusing on technique in the water, on the bike and run will improve our times no mater what we wear or what we ride. Similarly, maximizing our fitness will provide the biggest gains in time regardless of the equipment. This is what I would like to focus on today.
How many of us have taken the time to assess out physical fitness? Not only to gauge our fitness level but also to assess whether out training is doing what it is supposed to do. At the end of the season are you faster than when you started? Probably, but have you actually improved on your fitness from last year? We put in a lot of time during the year training and it would be nice to have a way to gauge whether what we are doing is actually working. When we are training, are we going hard enough to maximize our time or are we going too hard placing us at risk for overtraining? Finally, come race day, how are we tempering our effort? Are we just going all out only to crash and burn on the run or are we finishing the race with too much left in the tank and not getting the best out of our fitness?
Knowing your fitness level (VO2max) and anaerobic threshold (or lactate threshold) in my opinion is just as important as proper swim technique, proper bike fit, aero wheels and proper running form. By maximizing the output of our engine we will get the most out of our training and racing. While there are many different ways to estimate your VO2max and lactate threshold (LT) the best way to get this data is by direct measurement. Before we talk about this, lets get some terminology clarified.
VO2max is the maximal oxygen that you body is capable of consuming at maximal exertion. This correlates directly with overall fitness. VO2max is determined by many factors including age, sex, genetic makeup and body composition. Most measurements for VO2max are expressed in ml O2 per kilogram per minute to normalize VO2max for weight. So simply loosing weight will drive your VO2max higher. VO2max will decline with age but can be improved anywhere from 5-20% with proper training. VO2max ranges anywhere from 30-40 in sedentary individuals, 40-50 in recreational cyclists and over 70 in elite athletes (Joan Benoit 78.6 ml O2/kg/min, Lance Armstrong 84.0 mlO2/kg/min). Too many athletes focus on VO2max as a badge of honor or bragging rights, however this is only part of the equation.
Anaerobic threshold (AT) and lactate threshold (LT) are a major determining factor in how well we are able to race and train. These terms refer to the point in our exercise where the body accumulates lactic acid faster than it is able to clear lactic acid. Once this starts to occur we are limited in how much longer we can continue at that speed. This is actually the limiting factor to how fast we can race as opposed to VO2max.
For example, athlete A has a VO2max of 70 ml O2/kg/min (HR 180) and an AT/LT of 45 (HR=115). Athlete B has a VO2max of 65 ml O2/kg/min (HR 180) and an AT/LT of 55 (HR 153). Assuming everything else about the athletes are the same including size, efficiency, etc athlete B will actually be able to race faster despite having a lower overall VO2max. Why ? Because athlete B can use a much higher proportion of his VO2max than athlete A prior to becoming anaerobic. Athlete A, while having a higher overall fitness is only able to use 64% of his potential while athlete B is using 84% of his potential and can therefore go faster/harder prior to entering in to his anaerobic zone.
AT and LT essentially tell us the same thing but are measured differently. More on this below. For all intents and purposes these two measurements are equivalent when it comes to monitoring our efforts. It should be noted that what is also essential to have is the heart rates that correspond with these numbers, as most of us will train and race with a heart rate monitor and will not be directly monitoring our AT or VO2max with routine exercise. Once we have our VO2max, AT/LT and corresponding heart rates we can monitor our effort with heart rate. We use these numbers to gauge our effort in order to avoid overtraining and avoid bonking at the end of a race.
So how do you get these numbers? As I stated above there are some field tests that you can do to estimate your LT/AT and corresponding heart rate but these have inherent difficulties. It is relatively easy to replicate testing conditions in the lab but we are not ably to control weather, wind, rain, humidity, etc when testing on the road. As a result I believe measured values provide more consistent and reproducible data.
Metabolic carts are able to directly measure the amount of oxygen we consume during exercise. By measuring the ambient air temp, humidity, CO2 and O2 content and measuring every breath expired during testing these machines can calculate exactly how much oxygen our bodies are extracting during exercise. Based on this we can calculate our VO2max and AT. The AT is measured by calculating the point where CO2 begins to rise. This corresponds with a rise in lactic acid and therefore the AT. There are also devices that measure blood lactate directly and can then calculate a LT and corresponding heart rate. These two measurements are essentially the same and will not likely differ very much form each other.
The test is a graded exercise test on the bike or treadmill. The activity is usually started very slowly and then the intensity is increased at specified intervals to a point of voluntary maximal exertion. Remember that this is a voluntary test and is only as good as the effort put into the test. With a submaximal effort we can still calculate your AT and the VO2max can be extrapolated from this. This is obviously not as good as a maximal test. The other value that can be obtained from this type of test is the aerobic threshold, which corresponds to the level where we are burning predominantly fat. This is helpful to know especially for the longer distance racers. Ideally a VO2max test should be done within 6-12 minutes. Also, in an ideal situation you would like to have values on the bike and treadmill as the heart rates with be slightly different between the two activities given that running is a more weight bearing activity.
Finally, remember that this is only one of the many tools, albeit important, that we use to assess our fitness and direct our training. Every test we do has inherent difficulties when we try to extrapolate this to race day. As I like to say, all bets are off on race day. Through experience we learn how our bodies respond to training and racing and many of us perform well above the numbers we would expect to see based on testing. Nevertheless, I feel that having these numbers (especially the AT/LT) is a valuable tool to put in your arsenal to avoid overtraining, maximize your interval sessions and assist with pacing for longer races.
As members of the Berkshire Triathlon Club you all have access to discounted testing. Please contact me for further information.
Train smart, Race hard, Make a difference.