First Bike Test with PowerMeter: Observations & Questions
So I did my first ride & bike test this morning with my new Powertap installed - this was an indoor test on the trainer using TrainerRoad.
Here are the ride files - if any of you guys who understand all this data have five minutes and are willing to take a look; I'd love any feedback that might be helpful in wrapping my brain around what all this means:
- TrainerRoad: http://www.trainerroad.com/cycling/...min-20-min
- Garmin: http://connect.garmin.com/activity/499307312
A couple of observations:
- I didn't feel great about the way I tested. I felt a little more fatigued this morning which I assume is totally normal as the volume in the IM plan the last two to three weeks has been ramping up. I feel like my test results weren't as great as they could have been if I were totally rested..but that's life & I'm okay with it. At least now I have a number that I can begin to use on my long rides.
- I found it very, very difficult to zero in on any one power number. I have TrainerRoad set to 3 second power smoothing to try and get the line so settle down. If you look at the file I'm all over the place in terms of my application of power. At least, that's how it looks to me.
- I tested back on 4/29 using the virtual power from TrainerRoad. Which I've heard from everyone that the VP is an overstated number & that was certainly true for me. My NP using VP was 301 vs. today's test showing an NP of 250 - which converts to an FTP of 238 - which is kind of a buzz kill, but life is full of disappointments!
A couple of questions:
- I have updated my FTP in Garmin Connect in the settings/zones/cycling area. I assume that will get passed to the device next time I download a workout. Correct?
- I don't have an Edge or any other head for the bike...so for now the 910 will be the vehicle I use to view the data. That being said - will the functionality of the 910 limit me in terms of the data that I should be looking at OR are the 25 or so power fields available to me the same 25 that I'd get using an Edge or Joule?
- Can someone confirm that I am correctly reading the EN protocol which is to set a box (15 minutes / 5 miles / etc...) and focus on hitting my % of FTP for that individual segment and then move on to the next, rinse repeat for 112 miles. And that data point is represented through the NP - Last Lap field
- I assume like most things in life, the more time I have working with the PT the better I'll get at riding constant without surges. But in the meantime, while I'm learning what is the best way to not go crazy seeing the number jump all over the place? I don't want to spend my entire ride looking at my Garmin...so without constantly looking down, what's the best way to get a sense of how I"m doing while I'm riding? The 30 second average field?
- What's something you wish you had know before your went out for your first long ride with a powermeter?
Thanks!
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Comments
2. I use the box approach you describe. 3s power is really hard to go by, I end up under shooting the watts. When I use trainer road I hit the lap button on the watch and look at lap power for each segment. I wish trainer road showed this instead of just the dot on the bar.
I wish I had known not to go by 3s power, I totally screwed up a race rehearsal and was way off target because of it.
Also, you can clear all your records in trainer road and start fresh. This will help get some mojo back by getting to earn new power records! I had about the same reduction in watts when I got my power meter.
I do have my watch cycle thru other pages automatically where I get time, lap time, heart rate.
The one thing that I don't really use is speed. Al Truscott broke me of that. Its all about effort vs some arbitrary speed.
1. Power by its nature is stochastic. Provided you're not intentionally hammering, pay the second to second jumps no mind. What I do is set -ranges- e.g., "I don't want to see more than X, or less than Y." when working with a 3s average. Inside, with practice, you can hold that pretty close--usually within 20w. Outside, it's much harder b/c of changes in road grade. But it can be done. I use 3s, but for longer distances outside 10s works (for me anyway).
2. The easiest way to get an answer to your question of how jumpy you actually are is to look at the variability index (VI) for a given interval. When you go home and look at the graphs in your software, 1.00=perfect execution. The graph will be jumpy anyway. For example, all of the ones here were 1.0 or .99 when loaded into golden cheetah http://www.trainerroad.com/cycling/...-3x14-FTP. (No snickering at the numbers--been a rough winter). But if you look at them, they look pretty uneven. I think your graph looks pretty good.
Garmin connect is useless for this kind of analysis; you have to download different software. I strongly recommend Golden Cheetah; it uses many of the same metrics as WKO+ (TSS, NP, VI, etc), is mac-native, and it's free. To me, that interval actually looks pretty good. Your indoor intervals ought to be at 1.00 or 1.01. I try to keep my outdoor ones below 1.05, and view anything higher as a failure. GC is available here: http://goldencheetah.org. I've heard good things about WKO, but never used it as we have a mac at home.
3. Don't be a total slave to the power meter. What you want to keep constant is the cadence and the RPE--you will learn the feel--what tempo feels like, what z4 feels like, and what z2 feels like. The PT is a tool to help you do that; that's why RnP say that riding steady is a skill. (Plus the data is like crack once you get into it). Besides, when you get outside, it's nice to look around every so often.
Looking @ the TR graph, a few observations - yeah, that doesn't look very smooth. On the plus side, the HR in the 20 min interval shows a steady rise from 150 >> 160, indicating a fairly good metering out of effort. But, the first minute or so of the 5 min interval looks WAY too high, might have led to some of the later issues. And, the first 3 minutes or so of the 20 min interval starts out around 265, and drops to 245 - just the OPPOSITE of what you should be doing in a TT or testing protocol. The best results in a TT come when you start out a little less than your anticipated effort level. Using RPE, the suggestion is to be doing a perceived effort during the first 10-15% of the test @ 15% less than your anticipated effort level in the last half.
As to changes from one mode to another - I hear ya. 4 years ago when I switched from an older power meter to PowerTap, I dropped from 262 to 232. So be it - I didn't race any slower, which is the only number which really means anything to me.
What do I wish someone had told me when I first started using my new power meter? Mount it as far forward on the aerobars as possible, and look at it for nano-seconds. Don;t wear it on your wrist. Keep your eyes on the road! When I first started using my Joule/PowerTap, I had one very minor crash (only tore my shorts, no real injuries) and one major crash a week later - spent 9 days in the ICU, multiple trauma, argh. Because I was looking for an extended time at my power #s 3 weeks before an IM, on what I THOUGHT was a deserted road. The time for leisurely analysis of the #s is after you get home.
Yeah, no matter how steady you ride, the current (3sec) watts will always be bouncing around. Usually within a range of +/- 10-15 or less is you are riding steady. You get used to that, and try to live within a range, not stick to a single number. Again, reviewing the data after the fact and looking at VI is a good way to learn about things.
Wow. I have never been able to do that outdoors for anything more than a few seconds. VI turns out OK, but the readings do not. Good on you.
David- I have Joule 2.0 that is sitting on my desk at home (i use a garmin 810). If you want to use it for CdA I can ship it to you. I also made a mount that attaches to the left aero bar and positions my Garmin right between the aero bars in between my hands. To look at it all I have to do is drop my eyes about 4 inches. My eyes never have to leave the road. If interested I can give you some build tips.
David- I had it in the classified section for $100 + shipping ($6). But you can use it for CDA for free. If you like it then buy it. If you don't like it send it back and I'll list it on ebay.
Thanks
David
Settings > Bike Settings > Bike 1 > Power Zones
It is pretty buried. I guess some people have different FTPs on different bikes and the watch can handle it.
@ David...I got my PT about a year ago. I had the same questions/concerns you do. While I'm still not perfect at riding "steady" outdoors (and even on the trainer really), it does get easier to stay steady the more you ride outside with power. Think of it as numerical feedback for what your feet/legs are telling you. That is, as you ride more and more with it, you will be able to tell pretty accurately what your current watts are before you glance at the screen. Once I've been riding along in Z2 for 20-30 mins, I can look much less often because my legs/brain know what the effort is supposed to feel like.
About the only thing Coach P told me when I got mine about 6wks before a HIM was to not stare at it and drive into a tree! It comes around pretty fast, honestly. You are doing it right. I had the same "disappointment" with a drop in FTP when I switched from virtual power to PT as well. It doesn't matter though....you didn't get slower just because you got a powermeter! If you could use virtual power outdoor somehow, with your old FTP of 300, you'd race at 220W or something....but you'd go the same speed as if you race at 170W (true power) with your PT. It's just a number....just like weighing yourself on two different scales, one of which is off by 10lbs.
As I checked my bike in for IMTX today, I was shocked at how few people have a powermeter (I may have missed a few pedal based units, but saw no PT or crank based meters on the ~100bikes I saw). They have the fancy wheels, aero cockpits, etc...but not the most important piece of equipment!
As for your power profile, I agree it's a little "jumpy", but an FTP test is not the best judge of how "smoothly" you can ride. I hate the FTP tests and mine are never as pretty/ideal as what Al described....it's hard to "start low" and gradually build (mentally hard to swallow that pill is what I mean). I'm sure Al is right that that is the best way to test, but I haven't been successful yet! What really matters is how steady you can ride Z2 or Z3 for RR and race day. It's much easier to ride smooth when you're not on the edge of exhaustion/lactate pain.
When the coaches say we should dial it in at such and such % of FTP - is the metric I use to track that is NP? Or am I confused?
You are not confused. You are indeed looking for your NP to be a % of FTP; of course, you are ALSO looking for you current ("3 sec") power to be @ the same % of FTP, to the greatest extent possible. So: during a ride, you are looking @ current power, and maybe a 15 min/5 mile interval NP/IF. AFTER the ride, when analyzing, you are looking at your total NP, and maybe checking out your VI, and any spikes or drop-offs in power.
Al - I thought about this today in my race and I thought, I wish someone else would've told me how to keep my Garmin on when I left transition for the swim.
So, I finally remembered to have my Garmin charged up the morning of the race for my second sprint tri of the season. So, I get the Garmin (edge 500) set up and calibrated and leave transition and all is well. I come back and it is off and I try to turn it on as exit. So, at the mount line, I finally get a good poke on it and now it wants to calibrate. So, I poke it again with "no" since I already did that before I left for the swim and now it says "motion detected - hit start", so I hit start. Now it keeps showing that and I keep hitting it and now I'm trying to get feet in bike shoes and because I'm pushing the start button so hard it is like going under the handlebar. I gave up and then the screen appears with my power data. No crash, but a loss of about a minute and some pretty reckless driving. I now understand the importance of turning the "auto-off" function off for race day!
I've now how the opportunity to use the PT on two outside rides. Saturday was a 5 hour / 90 mile ride & today was a 100 minute / 30 mile ride. I know you mentioned that the power meter provides some good look back data - which is what I'm trying to do now. Based on that I've got a couple of questions:
When I pull the same file into Golden Cheetah I have no idea what I'm looking at. Here is the summary section from GC. In the CG FAQ document they say that "NP and xPower are largely the same, whilst Daniels EqP place a much higher emphasis on upper intensity work." I can't even find NP in GC and the xPower score is 187 - which is about a 7 point swing from Garmin Connect. At 187 I'm at an IF of .74 - much closer to what I was trying to do during my ride.
Average power is the simple average of all your power over the entire ride. NP is the cost of that power, not all power comes at the same cost. If you do an entire ride on a flat course, you might average 200 watts and have a NP of 205 on one ride. Then do another ride and have some monster hills but you average 200 watts you'll have a NP of 220 watts over the entire ride, your cost for the second ride was be higher.
VI is the relationship of Avg Power to Norm Power. The closer your AP to NP, the smoother you rode. (No big spikes)
David--
Which version of GC are you using? 3.0? There should be fields in the preferences/settings that allow you to put TSS, VI, time in zone and a bunch of other stuff that you might need. Given the small difference (10w) between AP and xPower, you probably did well. XPower is a very similar metric, but I find that it runs 8-10w lower. In any event, you should be able to select VI and a bunch of other fields for this screen. If you're having problems, let me know and I'll try to post a screenshot or something.
Cheers.