Running, training and racing with power (Read 177 times)

 

I use a Stryd foot pod everyday simply for the accurate pace/distance measurement once calibrated.  For this it is valuable for daily running and is irreplaceable for indoor running (track or treadmill) or areas with challenging GPS (i.e. Chicago Marathon, canyons, tunnels).   Mine measured 26.24 miles at CIM last month which was close enough to report the same pace to my watch as my official pace on CIM's website.  Accurate pacing is... nice.

 

I never look at the stride length, vertical oscillation, etc.  That stuff is neat for post run analysis but it's variable with effort/speed and it's unlikely that you will be thinking about that while running.  You should be focusing on relaxing, your breathing, how your legs feel, etc rather than worrying about that stuff.

 

What most people that use the power meter use it for is to pace themselves to common target efforts (EZ, Tempo, MP, CV, 10K, 5K) over hilly courses.  To do this you perform a short, maximal test that estimates your threshold.  This is in units of "power" which you then put in terms of percentages.  For an easy run, you would check your watch and make sure you're running at say 75-80% of threshold power.  For a Threshold run you'd run very close to or just below 100% of threshold power.  10K and 5K pace would be higher than 100%.  This is very similar to running to HR except for the power number starts to go up immediately as you hit an uphill.  So it's great at keeping your effort even.  In fact, to me, it's nothing more than a rock solid Grade Adjusted Pace meter.

 

Hope this helps.

This is how I use mine. Pace/distance always from Stryd (just for recording, I don't have pace as a metric on my watch screens), then I use the power number to guide my runs. I use a CIQ data field I've configured to show 3 sec power, lap power, total average power (or perhaps last lap average) and usually HR. 
It's awesome to be able to focus on one single number for a workout and concentrate on hitting that regardless of the terrain or wind. 330W for a tempo run is the same intensity uphill and against the wind as it is on flats running with the wind. No guessing at adjusting pace when I'm running on anything except a track or super-flat trail is just glorious.

I have a question about the styrd which is really unrelated to this post, but I can't find the search feature and I don't know anyone who has one. I'm really intrigued by the idea of using power to guide my pace during trail running, but, if the metric basically corresponds to heart rate, why not just train by heart rate. I don't actually train by heart rate, but maybe it is something to consider. I don't care about GPS. My garmin is good enough for my needs as far as measuring distance.

Stryd does correlate quite well with HR so long as you're running at a very constant effort - basically on flats. And that you aren't sick, stressed, dehydrated, it's not really hot/cold, etc. (all the things that impact HR).
HR lags behind the effort that you're putting out, while power is essentially instant (usually an average over 3-5 seconds is used to smooth things out, but even then that's a really quick reaction). Hills are a great example of this - if you start up a hill with a power meter you can see right away if your wattage climbs and you need to ease up a bit. HR will take a while to show that same increase. And by that time you've already been running up the hill too hard for a while before HR says you need to slow down.

Something I've found interesting is doing hill sprints and tracking HR during the sprints and recoveries (using individual laps to separate sprints and recoveries). Even using a 3 second average for power, I can see quickly if my power is where it needs to be. But my HR won't actually peak until after the sprint is over - and even if I jog/walk to the base of the hill and let my HR get down to a certain level the average HR of the recovery will be higher than the average HR of the sprint. So looking at peak or average HR the recoveries will look more intense than the sprints, while power would be just the opposite.

Here's an old blog post from Stryd that details this as well, along with some graphs for illustration.

I've started to write a program that takes Garmin .fit files to analyze them. In my case, I have Styd paired with my Garmin, so I get all power data in the file.

Runalyze already does a whole lot of analysis on runs, and is totally free, but it analyzes power data for the workout as a whole. I like to see my data split by split.

Stryd Power Center only shows a few metrics in the split by split view.

So my software is now at a stage that I can import data and I am starting to add ways to analyze it. To make this post short, I added Running Efficiency (RE) which is the speed (in meters/second) divided by the power to weight (in kg) ratio. A good RE is a value of 1. The lower the RE, the worse you're doing (you're running slower for a given power value), and, of course, the higher the RE the better. For what it's worth, I almost never hit a RE of 1. I'm usually in the 0.92 to 0.99 range.

Today I did a workout on the indoor track. no wind, no elevation change. Did 3 x (2K  / 1 min jog).

• 2K is about 1.25 miles
• I ran by feel, not looking at pace at all.
• First 2K does not count in my analysis, because it always take me a while "at pace" for my stride to become fluid. (pace 6:33 mpm)
• Second 2K counted. I kept my natural cadence, which turned out to be 183. (pace 6:26 mpm)
• Third 2K, I forced myself to lower my cadence. Managed a split at avg cadence 180. (pace 6:23 mpm)

Post run analysis shows that Vertical Oscillation (VO) went up by 0.4 cm (from Stryd, didn't use Garmin values) and RE went down, even though my last split was a tad faster than the second one. Usually, the faster I run (within pace ranges I handle well) the more efficient I become.

So even though it is far too soon to conclude anything, this experiment points in the direction that if I lower my cadence by trying to make bigger steps, my RE drops.

Many more tests to come in the future.

That begs the question you and I use data but don't train by Stryd standards. What would Otter1 think of the Stryd? Good tool or go for old fashion strength conditioning to help increase elastic strength???

Since the more elastic strength you have, the more energy you can store and release in the muscles and tendons and so your technique will improve and you will become more efficient and faster.

If some people are interested, I might share the program with a couple of people on a person to person basis. There will be nothing fancy about it, but if others would do some tests like I'm doing, maybe it would benefit me also.

But it is not ready yet. It only supports metric (although Imperial is in the plans) and it is way too sketchy to use. I am focusing on workability, and if conclusive, then I will focus on usability.

I know myself and maybe Madison are working on form over time. Is it possible to use Stryd data from say a workout done  before  vs one done after and look at RE and other metrics if weight hasn't changed?

Yes. It is possible without my program or with my program. All my program does is calculate whatever I want, actually. I pull the data from a fit file I export either from Garmin Connect or from Stryd Power Center if Stryd gets its data from syncing with Garmin Connect, that is. My program does not support the Stryd native .fit file support.

But I disgress...

If an activity was recorded by a Garmin watch with a Stryd paired to it, you're good. You pull the .fit files, and the program reads it and adds custom calculations.

You could do it manually also. Just lots of calculations and conversions.

Otter1, from just wearing it on my shoes and looking at the data from time to time, I would describe the Stryd's power pretty much as grade and wind adjusted pace, given in watts. On flat ground, with little wind, Stryd's power is proportional to pace. Simple as that ( I'm in no way an expert ).

I am not the one who's going to argue against your post. I agree with your thoughts  on the subject.