Pacing the Bike for the Boulder Half Ironman Age Group Athlete

by Nadia Sullivan, June 2016
This year, the Boulder Half Ironman course was changed to 1 lap of the full course. That means athletes will get a chance to experience the rolling climb up Nelson Road that the 140.6 athletes love so much! And with that rolling climb, there’s a few fast descents and some long false flats to get you back to transition. So what does this mean for your bike pacing on this course? It means you shouldn’t be trying to hold a steady effort the entire way, even if you have the gearing for it!

So how should you ride it? Let’s look at an example male & female mid-pack age group triathlete. We’ll assume they’re on mid-range tri bikes with average wheels & a road bike helmet and we’ll pace them on the course using Best Bike Splits (BBS). To keep things simple, we’re going to say that they are from the area and are therefore adapted to the mile high elevation. Our example male athlete is 170 pounds and riding around an 80% average at 200 watts across the entire course. He may have the gearing to hold 200 watts at an aerobic cadence up the steeper sections of Nelson Road, but that means he may not have the best gearing for the fast descents on Highway 36. Using Best Bike Splits, we can plug in his stats and get a much better idea of where he can push the watts a little more and still maintain that 200 watt average over the course and still be set up for a solid run. We can see that while a there’s a nice little hill right out of transition, our athlete keeps the effort only a little above his target average at 210 watts. The first jog down the Diagonal Highway is a false flat so he’s cruising below his target average to keep his legs ready for the longer climbs. When he turns back up toward Highway 36, the watts are now at or just above his target average, peaking briefly at 240 watts which is still below his threshold. Niwot Road is another fun false flat so he can get some rest. N.63rd St. has rolling hills so he’ll hit the quick ascents at 200-210 watts & relax on the quick descents. He’ll be spiking the watts shortly after the turn onto Nelson Road where the grade gets steep but he’ll still keep it below threshold and average about 230 watts back up to Highway 36. There’s still some climbing to get the to highest point on the course, but from there he can let his legs relax again and spin around 180 watts all the way down to 73rd St. where the terrain gets a little more interesting again. For the last 5 or 6 miles, he’s back up to his target average pace of 200 watts up the false flat of the Diagonal as he preps for the run. For an average mid-pack woman at 125lbs, pacing will be very similar: relaxed on the long false flats and just below threshold on Nelson Road. But her time will be slower due to her lower power to weight ratio. Riding at 80% would have her averaging 135 watts, a little more than 1 watt/Kg lower than our example man. She’ll average about 18.5mph to his almost 21mph.

So if you’re racing the Boulder 70.3 this June, plan to take it a little easier on the false flats so you have more in the tank for Nelson Road. Just make sure you keep it below threshold because it’s tempting to stand up & hammer on some of those climbs but you’ll pay for those kinds of efforts on the run. Good luck & hope to see you out there!

Copyright, 2016, FasCat Coaching
To nerd out with FasCat coaches and athletes about your FTP, race data, power based training, or anything related to going fast on the bike, join our *FREE* athlete forum!