How Can Testing Help You?
First, measurements allow objectively derived training zones that are specific to your current fitness. We can thus tailor training in a way that's not possible without this information. Because your results are unique to you, and change over time as you train and improve, periodic re-testing allows these zones to be recalibrated to keep your training as targeted as possible. Test results also give clear-cut proof of the amount of performance improvement you have made since the last test.
Second, testing allows you to have very objective goals that are separate from your race results. From a fitness perspective, it is quite useful to have as a goal, "I want to improve my w/kg 20 percent over the course of my first year of training." For many people, this type of goal will serve as a significant motivator—and it will help you conquer the many tough workouts that coaches like me dish out.
Third, it is really helpful to know where you stand relative to your peers. While there is not a direct correlation between race results and test results (which is why Lance did not win every race he ever entered), in general, the better your testing numbers, the more likely it is that your race performance will be positive.
More: 7 Ways to Test Your Cycling Fitness
If you are attempting to compete in a particular race category, it is useful to know if you are in the middle of the range of performance numbers, or near the top of the heap. In other words, all other things being equal, it is better to have more w/kg to play with than less. But, regardless of where you fall in the range of your category, it is good to have realistic expectations; those expectations can be derived from your results on a performance test.
Performance testing is key to cycling, and training, smart. Get curious about what it can do for you: seek out a local coach, and get yourself tested. It is straightforward to do, and it can give you extremely valuable information that will almost certainly help you become a better cyclist.
I know that many people unconsciously avoid tests; these tests, though, are the worthwhile kinds that give us important insights. The athletes who test regularly show greater improvement over time than athletes who test infrequently. According to the couple hundred athletes I've tested, they've all been glad they did, and found it gave them a valuable edge.
More: How to Do Your Own Performance Testing
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