Going Long Part I:  How Can Testing Help You Prep for Your 70.3 or IM Bike

Chatt is coming, Chatt is coming!  Wasn’t it just winter?  Triathlon season is finally here in the southeast US!  As the target races of the year near or serious prep for them begins, testing your VO2 and threshold power and heart rate can give you valuable information for your training and race prep.

We’ll start with the bike today because this is often where the race plan can start going off track, especially in longer events.  Even when triathletes approach me for help with the run portion of the race, we’ll at least start with a good discussion about the bike effort and pacing.  The swiftest runners can quickly turn into walkers if they overdo it on the bike.  Despite our best intentions, it can be very easy to misjudge your effort in the early stages of the bike.  You’ve just come through the screaming crowds heading in and out of T1, you’re happy to be out of the water, and you may have even just seen a dinosaur eating a donut and screaming your name at the top of its lungs.  Who wouldn’t feel great?  In fact, you may feel so fantastic that it seems easy to hold a heart rate or power close to your FTP for the first part of the bike.  Or it may just feel SO easy to spike near your VO2 max power on those early hills.  If this continues, though, things start to come apart at the end of the bike or early in the run.  Cramping is a big sign of overdoing it (AND more research is pointing to the cause of cramping as “altered neuromuscular control” and poor pacing…NOT nutrition.  But nutrition plays into development of fatigue, so stay tuned…that is for another blog post!).  Poor run performance could also be another sign of an overaggressive bike.  So what can you monitor on the bike to help you keep things in check but not hold back so much as to sacrifice performance?

Using Test Results in Your Race

When most people think of VO2 testing, they want to take their numbers and compare it to competitors and to elite athletes.  While that VO2 max values does give you an indication of your aerobic fitness ceiling, that number alone won’t help you in training.  Finding the physiological thresholds beneath that value along with the heart rates and powers that occur there, however, can be very valuable in planning your training and racing.  CES does this by collecting data from the air you breathe out during a test of progressively increasing intensity.  We can then analyze that for physiological thresholds relative to training and racing.  The most important values we find are your power and heart rate at ventilatory threshold 2 (VT2), which is closely related to your power and heart rate at lactate threshold and reflects an all-out effort of 30-60 minutes.  The other meaningful value is VT1, which is reflective of the first notable increase in respiration and beyond which your respiration and energy consumption continually rise with increasing power output.  This number reflects the heart rate and power you can hold for hours.  Finding the heart rates and powers at each of these thresholds can all be done in one test, and knowing how to apply each of these is incredibly important to your individual race pacing and training.  VT values can range between 60-88% of an athlete’s VO2 max, so knowing where you fall in that range is important.  VT1, which is more predictive of long course performance, can have great variability among athletes with similar VT2 powers.


Ok, you speaking in many weird words.  How do I practically use my test results in a race?!?

I was hoping you’d ask that.  Here’s an example:

Susie Q VO2/threshold test results:


  Power Heart rate
VT1 195 watts 153bpm
VT2 242 watts 168 bpm
VO2 max 308 watts 182 bpm


Susie Q is racing Chatt 70.3 next week and using these numbers as a guide.  The combo of heart rate and power is especially valuable for pacing as the power gives you the instantaneous effort you’re putting on the pedals while heart rate allows you to know how your body is responding to that and the environment and other stressors from a physiology stand point.  You’ll want to respect both of these!

Flat sections:  use VT1 power of 195 watts and heart rate of 153 bpm as ceilings and minimize time above these values.  Above VT1 you start expending more energy than just below it, so this will help keep things in check for the run.

Climbs:  there are no long, sustained climbs in Chatt, so the time of increased intensity is short enough (< 3 minutes) that heart rate will not be a good guide as it takes several minutes to fully respond to an increase in intensity.  Power will give you an instant reading, though, that your body will eventually respond to!  Keep the power between VT1 and VT2 when possible, preferably closer to VT1.   Too much time above VT2 will create metabolic waste that will slow you down later in the race, so resist the urge to punch it up the hills!

Rules of thumb:

*Respect heart rate above power.  Heart rate is going to help you in every environmental condition (wind, heat, changing hydration status, etc.).  Chasing the power and ignoring your heart rate is a costly mistake many make.

*Practice with these values.  Some athletes can ride at a VT1 heart rate for a longer duration (closer to IM distance) while for most it is more appropriate for a 70.3 bike.  You can also start to become more self-aware about how environmental conditions and hydration affect you individually.

We hope this helps you create your pacing plan for your next race!

Stay tuned this week for more info how to use these values in training and info on run testing!

Leave a Reply

Your email address will not be published. Required fields are marked *