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Part 1: Changes Heading into 2019

Instead of doing something like a 10,000 word paper on everything I have changed over the past 5 weeks heading into the 2019 season (cause it's a lot of stuff), I thought I'd split things up a little over a series of posts. From physically changing how I run, to the numerous accessory exercises/activities to support the new technique (which both require their own post), my training has a very different feel and shape all in the hopes that it leads to a healthy and successful year. Overall the year will have a slightly different focus, and most of the changes are geared towards that but I'll get to that later. So I thought I start things off with just a minor thing I've inserted into my program to give a little more insight into my training going forwards. Even though it is very minor it may be slightly more useful to for readers compared to me going on and on about how I have physically changed how I run. This first thing on the other hand is something you can pretty easily insert into your program [with some devices].

So as you may know I've been running to power with the Stryd foot-pod* for about half a year now. I believe it is a incredibly valuable tool in terms of pacing efforts regardless of terrain, and for me I find it also gives me a much more accurate representation of the training stress inflicted by a particular run compared to TrainingPeaks' default rTSS which goes simply by running pace relative to your threshold. In terms of pacing, it is a much much better tool than heart rate since it is instantaneous. The second you stamp your foot at the base of the hill the power meter reacts (just like on a bike), whereas with heart rate there is a lag. Because of the sluggish response of heart rate I've never really consistently used it for running, or cycling (except in zwift races where you are forced to use heart rate to have your results count). However, over the past month I've thought of a way to combine running power and heart rate into my run training. If I thought it was useless before why now incorporate it? Well, it is a metric just like power, or pace, and I'm of the school that the more numbers the better. Especially with being in the off-season, with true performance tests (races) far off in the distance, the more data I have the better and helps give insight into whether or not I'm on the right path and in fact improving.

*A disclaimer: Stryd provided me with the foot-pod 100%, however they are not paying me or giving me anything in return to give a positive review. I simply reached out after reading up on running with power in May, and they sent me the unit and said see how you like it.

So how am I incorporating heart rate? On training peaks there is a metric called Efficiency factor (EF). It is simply a measure of your normalized power (NP)/heart rate (HR). The theory is if your power from a bike ride goes up, and your heart rate has stayed the same or lowered than your aerobic efficiency has improved. Stryd Power allows that same metric to be carried over onto the run, and will still just be measured as NP/HR to give insight into aerobic efficiency. Now to be a reliable measure you need to account for as many variables as possible meaning doing the workout at same time of day, similar pre-workout nutrition (especially in terms of caffeine), weather, etc. Reason being if for example, you have a few cups of coffee prior to a run your heart rate will naturally be higher thus making your aerobic efficiency appear to be lower. Having said that if you drink the same amount of coffee and run at the same time of the day everyday then although it would be difficult to compare your efficiency factor to another person who maybe hasn't consumed the same caffeine (and is heavier or lighter body weight, less or more habituated to the effects of caffeine), the number is meaningful to you [and that is all that is important] and could be used to track changes over time.

Now that I've been running with power, I have the ability to gage aerobic efficiency on the run. Does that mean I just strap on the heart rate monitor each and every time I head out the door and measure EF. I could but no I don't. I have carefully thought about how and when I want to use it. So here's the scoop and what I'd recommend doing. Just like keeping the variables like caffeine and pre-workout nutrition as consistent as possible (which is pretty easy for me since I eat and drink the exact same thing every day at the exact same time almost down to the minute), I wanted to keep as many things on the actual run as consistent I could. So first off, I only measure heart rate to get efficiency factor for easy shorter runs (but I use power on every single run). You might say I thought the purpose is to track your efficiency so wouldn't you want to really stress the system and see how it perform as race paces. Well, going back to what EF is it is supposed to be a measure of aerobic efficiency, so with that I use it on runs that are at an easy enough pace that I know I can keep my cadence and running form perfectly consistent so that the stress on the aerobic system is consistent. Easy enough that fatigue doesn't become a factor. Think of it like when you are on a bike. If you hold say 300W at 100RPM I'll bet that your heart rate is significantly higher than 300W at 65RPM. High cadences shift more of the stress to the aerobic system, and low cadence is shifted more to strength work at the muscle level. So with running, if I said I'm going to track my aerobic efficiency of a 1 hour long tempo run, problem is that after say 45 minutes I may start fatiguing, my form and cadence may start deteriorating both which will impact my heart rate and my efficiency factor. I may be able to grind it out to keep my power and pace the same, but the heart rate may increase with extra effort (poor form). That increase in heart rate would indicate that the aerobic efficiency has decreased, however, was the limiting factor on that run the fact that aerobically I was unable to maintain my form/cadence, or was it that I was over-reaching a bit from a muscular standpoint with the hour long tempo when maybe a 45min tempo was more realistic to my current fitness? Not sure. So I measure on easier runs where I know fatigue will not be a factor, and I'll be able to maintain very consistent cadence and technique thus keeping the stress on the aerobic system as consistent and reliable as possible.

With that I also keep the runs where I'm measuring EF shorter. Shorter because I don't want hydration levels to skew the efficiency factor. From a physiological standpoint cardiac output (how much blood your heart is pumping out every minute) is a product of Heart Rate x Stroke Volume (how much blood is pushed in every beat). During something like a 2 hour long run, as you begin to become dehydrated your overall blood volume will decrease (as blood plasma is mostly water). As your blood volume decreases your stroke volume will decrease. However, your muscles are still demanding the same amount of blood as before, so to maintain the same cardiac output your heart rate must increase to compensate. This is known as cardiac drift. So going shorter and easier will minimize the impact of hydration (since you'll have less time to become dehydrated and of course just be sweating less by going easier), and in the end you'll get truer measure. Of course, you can use EF on a long run, and sure that would give a good indication of fatigue and hydration status, and could be nice to compare the EF in the first half of the run compared to the second half of the run to get a measure of that deterioration (something called training peaks dubs aerobic decoupling), but that's not what I'm interested in at that moment. Since I'm currently in the final week of a 5 week "base phase" [I'll explain in the next post] I simply am interested to see if on I'm becoming more aerobically efficient during sub-maximal efforts.

And finally, my last point on how to have EF be as accurate/reliable as possible is to make sure to go on a route where you'll have, if it's possible, zero interruptions (zero traffic lights). If you have to stop and wait a minute for the light to change, your heart rate will come back down, and will take another minute or two once you've started running again to get back to steady state effectively lowering the average heart rate (and "improving" the EF). Of course the other option is running on a treadmill and that will be perfectly consistent/controlled with no interruptions, but seriously 12C at the end of December, doesn't get any better than this I say run outside while you can.

So to sum up how to use EF and make it as reliable as possible:

1. Measure it on short runs to minimize the impact of hydration levels and cardiac drift

2. Measure it on easy runs where fatigue will not be an issue, easy enough that you can maintain the exact same form and cadence start to finish

3. Pick routes with minimal interruptions

4. Try to measure on runs done at the exact same time of day, with the same pre-workout nutrition/hydration to account for as many variables as possible.

For this final point, obviously some people just aren't able to do the exact same thing every day due to various life commitments, but point is if you know every Wednesday for example you'll be able to run a 6:30am every single week then measure it then. The whole point of what I've been saying really is that for any measure to be reliable and therefore give you an indication as to whether or not you are actually improving or not then you need to keep as many variables as possible consistent. Heart rate, in my opinion at least, is a completely useless measure if just used at random, but when you use it systematically it can for sure give insights into you aerobic performance.

In terms of whether or not I'm aerobically improving, well in week one of measuring across 3 of the shorter easier runs the EF was an average of 1.87. In week 2 it was 1.90, in week three 1.92, week four 1.92, and this week so far in two run I've measured an EF of 2.0. So over 5 weeks, that is approximately a 6.5% improvement in aerobic efficiency. Those are just the numbers, but am I actually feeling the difference subjectively? Absolutely. On these very easy runs around 285W which is about 4:12-4:17/km I'm now barely breaking a sweat, and feeling like if I wanted to I could probably breath through my nose (in and out) start to finish (but I don't to keep things consistent). Anyways overall, adding the heart rate into the power data is another great way application of the Stryd footpod. If you were to try to get a measure of EF via pace instead of power it just wouldn't be nearly as reliable. There are too many factors that could effect pace such as a tailwind or headwind whereas for power running at 285W into a headwind will require the same effort as running at 285 with a tailwind. Just like on a bike, power is power and speed is not the best metric to gage improvements.

So that's it for now, I'll update in couple days with more detail on what I'm actually doing now in terms of running, and what I'm currently working towards.