Are you still guessing for your TT's and Bike Splits?

Technology, September 19, 2016

The use of a power meter, weather forecasting, elevation profiles and Best Bike Splits. The use of a knowledgeable coach and some slick software and your time trial performance and triathlon bike splits no longer have to be a guessing game.

Are you still wishing and hoping for a good time in your time trials and on your bike splits? There is no reason you need to leave this to "guessing" with the technology and coaching that exists today.

Coaching isn't a guessing game. Good coaches plan workouts, sure, but ultimately it is a good coaches job to verify that the plan (or what is actually being done compared to the plan) is truly working. If your steady state power is something you are planning and working on improving and on race day (or test day) that is not happening then it is time for a change.

It has been said, the best predictor of performance is past performance. This is where the use of a power meter starts to help. You see a power meter is measuring your work capacity in cycling. If you are capable of holding 300 watts for two hours in practice then you can easily predict that in the race this will also be possible. Sounds simple right? Well, getting athletes to hold 300 watts for 2 hours isn't so simple but very possible. The training MUST be effective and optimized for the individual response to the exercise. This is another advantage of the power meter. With this knowledge my athletes KNOW what they are capable of "holding" in races. They are not hoping or guessing. They KNOW it because we have VERIFIED it in practice and training. When I tell my athlete and Ironman Professional, Scott Bradley, we are shooting for 305 watts on the bike split today he isn't thinking "boy I hope I can hold that". If he is thinking anything, other than "I am going to crush this" it is probably, "jeez coach, I did that in practice, shouldn't we shoot higher?"

So, how does this prediction stuff work? Why do I say, your bike splits and time trials no longer have to be a guessing game? Well, it starts with the power meter but goes further. You start by KNOWING what the athlete is capable of. This weekend I told Scott Bradley we need 305 watts on the bike split, and I told my wife, Traci, we need 170 watts in their 55 mile bike split at the Barrelman Triathlon. I know they are capable of those numbers. Then using a .gpx file of the course (turn by turn and elevation profile) I go to my software, Best Bike Splits. This allows me to create a virtual aerodynamic and rider profile model of each rider. I will not go into the creation of the model in this article as there is some work that is needed to develop a SOLID model. Once you have a aerodynamic and rider profile model you are confident is accurate and you now know the riders work capacity for the duration needed in the race you are  MOST of the way there.

Now, leading into race day it is time to look at the weather forecast and the course. Sometimes finding a .gpx of the course is a little difficult but more and more it is easy to find these files for racers. In fact, many promoters are supplying them on their web site. Taking this file and placing it into Best Bike Split, the software now knows where the course is located (and can then check the weather forecast) and knows the elevation profile. This allows the software to check the forecast weather and use it, along with the aero and rider profile models you created in the prediction model. It might sound like a long way around but actually it is pretty straight forward.

So, I had two athletes race this weekend, how did it work for us? Well, when you know what you are doing it works pretty AWESOME. This weekend, as I mentioned, I told my athletes Scott and Traci to hold 305 and 170 watts respectively. So, first check, how did I do knowing my athletes? Scott held 300 watts and 303 watts Normalized, while Traci held 167 watts or 168 Normalized. Way to go Coach and athletes. We were only off by 1% or so. 

What about the prediction models? Did they hold up? Well, at pre-race our models suggested Scott would complete the bike portion of the triathlon in 2:03:51 while Traci's model suggested she would complete the bike portion in 2:32:09 if they were capable of hold the power I suggested (which we now know they did to within 1% of goal) AND the weather forecast held up. The weather hardly varied at all from forecast and the models held up. Their official bike splits were 2:03:12 and 2:31:47!! That is a grand total for the margin of error on two athletes over 110 mile of combined racing of 61 seconds! So, in seconds, we predicted the two riders would need a total of 16,500 seconds to complete the bike portion of the race and their actual time, in seconds, actually was 16,439. That is LESS THAN 1% margin of error. No Guessing here.

If you aren't using a power meter and a knowledgeable coach you are probably guessing at not only you racing but your training. Reliable power meters are no i the $600 range. Entry fee in that triathlon was $200. Add gas, and hotel costs and you can quickly rationalize the purchase of a power meter. 

Don't guess in training and racing, KNOW what you are doing.


Best Bike Splits is copyrighted and a product of Trainingpeaks, LLC.