How does one know if they are durability limited? One of the best ways to get your arms around this concept is to observe HR data from yours or your athletes (if you are a coach) races…the higher the HR relative to threshold HR, the better. One could say, I work with my athletes to try and produce the highest HR possible while racing. If I can do that, I’ve been successful. This may sound silly, ridiculous, and counterintuitive however; it actually captures a lot of information, physiology and is pretty darn close to the truth. Now of course HR is a parallel indicator of other things going on at the muscle, but in most cases it’s a pretty good metric to use in evaluating a very complicated system. Let’s take a look at two scenarios:
1) The significantly durability limited athlete: this guy does his IM and due to peripheral system limiters, is forced to walk the second half of the marathon (assuming nutrition wasn’t the limiter). Now, while he’s walking along the marathon “RUN” course his HR is 85 bpm. Of course this significantly reduces the average HR for the day and he might end up with a 120 avg for the day (just picking numbers from the sky).
2) The non-durability limited athlete: this guy is able to run the whole marathon and continue to produce high HR’s throughout the day. Of course his average HR will be higher (maybe 130 for comparison sake), and his overall time much better.
What you find is that pros are able to continually fire their HR all day long using their peripheral system as the driver. Note, I like to include the head (mental game) in the peripheral bucket. We need to be mentally tough in order to continue telling the muscle to fire, which in turn demands more blood and increases HR. Another interesting limiter that HR is good for tracking is nutrition related limiters. If an athlete “bonks” on the course due to improper fueling or is forced to slow down due to cramping, his HR will be much lower during that episode and end up dragging the HR average down for the day.
Based on this qualitative theory, your job as an athlete/coach is to take the best strategy you can in both preparation and execution to produce the highest HR avg for the day. How do we do that?
1) Meet critical volume through aerobic intensity exercise which insures adequate durability.
2) Avoid nutritionally limited HR on race day by having a solid and practiced fueling plan.
3) Use a pacing strategy that gives you the best shot at a high HR average. This means knowing what average to shoot for and staying there all day (respectively in each sport).
4) Don’t stop on the course! Bathroom breaks for instance would pull down the HR average quite a bit.
As a coach, one approach is to known what ratios of race day HR avg versus TH for each race distance are good. From that, you can than evaluate how a particular athlete is racing and whether or not there are peripheral, nutrition, or pacing limiters on race day. If you turn all the dials properly (fix all of the issues), you should start to see higher and higher HRs on race day.
What’s the difference between pro level and amateur level athletes in IM racing? You’ll find pro level Ironman athletes have the ability to continuously push their core system and stimulate HR to high levels throughout the whole day.
Bottom line: do whatever it takes to achieve the highest HR average throughout your day of racing whether it is from better preparatory activities, or better execution on D day.
Just another way to look at things…