I have read ‘Training with power’ but am still not sure on how to pace with power. I have mainly been looking at 3 sec avg power when I ride but it bounces around a fair bit… 30 sec avg is too delayed.
Any suggestions? Should I be using NP or IF?
Thanks in advance
Read this:
http://forum.slowtwitch.com/gforum.cgi?post=4917466;
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NP and IF are equivalent, one is just NP expressed as a percentage of your FTP.
Whether you use a rolling average, lap average, or both is up to you. Most people would do something like a 5 second rolling average power and then the NP for the whole ride.
For triathlon set power goals from training rides, not as % of FTP, at least not until you learn from experience what % works for you.
Depends on your purpose. TT/Triathlon? I agree that I’d like a 5s average since 3s is still a bit noisy. But you can put both 3s and 30s (at least on most Garmin head units). Once you get a good feel for pacing, just the 30s should be fine. By race day you should already be pacing mostly by feel rather than needing the power display as a constant crutch. I glance a few times in the first few miles just to be sure I’m not too amped up.
NP and IF are mostly useful in post-ride analysis/planning/forensics. Normal average power is just fine for use in pacing.
Trying to use it to pace a 1/2 and then full IM tri.
I have 3sec and 30sec showing on my screen at the moment but will have a play with 5sec too. I guess I just need to get a feel for the power I am putting out so I am not riding with my head down looking at the stem the whole time. Though this seems to work for Froome!
For training 3s avg. Doesn’t matter if it bounces around a bit, it’s natural. Just not too much.
For TT’s, longer efforts 3s/30s (keep the two relatively even).
Budget for a TSS of about 270 for the bike for an Ironman.
I answered the wrong question
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Go by feel and try to keep a constant power for what feels right. It’s that simple. The advantage the power meter provides is that it allows you to manage power spikes and ensure that you can keep the power up in the second half of a long race when the mind starts to wander and the power becomes mentally difficult to maintain.
Which head unit do you have? If it is a Garmin best you will get is 3s and 30s since there is no 5s.
I didn’t see but maybe I missed it, but how much are your numbers jumping around? 3-5 watts or 10-20 on the 3s ave? If you are on a flat or trainer, you shouldn’t see that variation if cadence is consistent.
As for pacing the more you ride the better it will get. You don’t have to stare at the number but an occasional glance is highly suggested. And knowing the HR equivalents is a good idea as well as you never know when your PM battery will die. Like 10 minutes into an IM. Oops.
Lots of good information about using live power data so far. After your ride, check out your variable index (VI). This is calculated by dividing normalized power by average power (NP/AP). Shoot for as close to 1.00 as possible on flat courses for most even pacing, aim to keep it under 1.05 on most other hilly courses. NP is basically how hard your ride felt with surges for hills, coming out of corners, etc, so it taking these into account changes the physiological cost of the ride more than average power alone might indicate.
Lots of good information about using live power data so far. After your ride, check out your variable index (VI). This is calculated by dividing normalized power by average power (NP/AP). Shoot for as close to 1.00 as possible on flat courses for most even pacing, aim to keep it under 1.05 on most other hilly courses. NP is basically how hard your ride felt with surges for hills, coming out of corners, etc, so it taking these into account changes the physiological cost of the ride more than average power alone might indicate.
OK, thinking out loud here as I don’t claim to have the answer, but… couldn’t the approach of trying to keep the VI not too high on hilly courses potentially result in going too hard on the downhills? I think the biggest surprise I had when getting a PM was how low my power output was on long gradual downhills, and how hard it is to actually keep the power up on a downhill. If you can go pretty fast on a gradual downhill on low power during an IM, why not, given how much harder you have to work to get small gains on a downhill? Sure, on a 40K TT you need to keep the power up but an IM isn’t a 40K TT. If you’re very aero you can go pretty damn fast on a gradual downhill on really low power, almost like resting, really, saving most of your energy for the flats and uphills. Note that I’m not talking about steep downhills where there’s no real reason to pedal for most of us.
At any rate, given I’m doing my first IM this August one of my biggest goals for my long rides is to experiment with different power strategies and see what works for me, especially on the uphills. I’m pretty confident my strategy will remain to use the gradual downhills as “active recovery” and my main job is to figure out the rest of it.
I just got through the “triathlete” chapter on “Training & Racing with Power” and it gives recommendations for power ranges depending on the length of the hill. MY understanding is one of the most critical elements of a downhill when it’s a rolling course, is to get back up to speed when cresting the hill fairly quickly, then settle back into your goal power. Yes, you won’t make up times on the downhills, but you also can give up time going too easy. Ultimately going very easy still results in a larger VI that WILL increase your TSS and physiologically drain you more than a steady effort. There plenty of examples when reviewing pwoer files, that unless you run very well off a hard bike effort, those with good IM runs held a VI at 1.03 or better. I think what kills you isn’t a 90% effort for 5 minutes, a 105% effort for 1 minutes or 115% for 30 seconds, its standing up and without realizing it spiking to 150% for 10 seconds.
I remember reading one IMWO race reports from a pro that had a poor race and he mentioned looking down comming out of some corners and seeing 600Watts! Yes, about 170% power effort. As a result, he was completely spent destroyed by mile 90 and ran a good 20-25 minutes or more off his run pace.
I bet the guys you see walking IM’s runs with hilly bike courses, if you reviewed their power file, they likely went out fast, and there’s tons of spikes at 150%+ all over the place the first 50-70 miles.
Not sure wich unit you are using, but the latest firmware for Garmin 500 also has 10s smoothing.
This is a great point, and I would love to share my power data from Ironman Lake Placid to help with this point-
http://connect.garmin.com/activity/350040907
Yes, when you are going incredibly fast, such as the 40 mph downhill at the start of each loop on this course, the benefit to maintaining your power is minimal, maybe a fraction of a mph. Meanwhile, the benefit of coasting or tucking away aero for this stretch can be tremendous energy saving. You’ll notice my variable index was almost exactly 1.05, because there was coasting through the fast stretches, a little bit of extra power on the steeper climbs, and typical power hovered around 190-200 for the rolling terrain. Compare this to my race at Eagleman that has almost zero gain-
http://connect.garmin.com/activity/326325612
VI is less than 1.01, because there is never a place where you can coast to maintain speed, and no hills that require extra power. The point of lower VI isn’t to maximize speed on the bike, but rather to maximize the gains from energy expenditure. Physiologically, it is much easier on your body to run after an evenly paced ride than a ride with lots of big accelerations. You need to find a balance between the fastest possible bike split and not frying yourself before the run.
I think you have to remember the physological changes that occur at different power levels. At some point you start using more and more fast twitch muscles which burn glycogen less efficiently. You also fatigue quicker at higher intensities, yet you can’t fully recover from those efforts even at a zone 2 pace.
Look at it this way, your goal is to reach a TSS of around 250-280. More than that and you toast for the run. The fastest split will likely be from having the highest average wattage. How do you achieve the highest average power output (total work performed) while having the lowest TSS? By having a VI of 1.00.
I think everyone is answering the wrong question (except maybe Jack)…
I display 3sec, NP, and lap average on my Edge 500/Quarq. The 3sec will bounce but you can sort of predict the average if you keep a steady cadence. Then watch lap average/NP to see if its trending up/down away/towards your target power. It simply takes practice and will be frustrating to begin with but you’ll pick it up in a dozen or so rides.
The fastest split will not be with a VI of 1.0 on a hilly course. This is just physics, it won’t be.
The degree to which you raise power on uphills is not that huge though, most people raise it too much.
BestBikeSplit.com will do the math for you and give you a pacing plan constrained to a given normalized power. Additionally you can set max power limits. A reasonable approach for ironman might be, set a goal Normalized Power, and then set a max power of around your FTP. This would ensure no undue cooking of the legs but save you a lot of time going uphill.
Or you can just go “a little harder” on the ups and “a little easier” on the downs and achieve very nearly the same thing.
I think you have to remember the physological changes that occur at different power levels. At some point you start using more and more fast twitch muscles which burn glycogen less efficiently. You also fatigue quicker at higher intensities, yet you can’t fully recover from those efforts even at a zone 2 pace.
Look at it this way, your goal is to reach a TSS of around 250-280. More than that and you toast for the run. The fastest split will likely be from having the highest average wattage. How do you achieve the highest average power output (total work performed) while having the lowest TSS? By having a VI of 1.00.
I think everyone is answering the wrong question (except maybe Jack)…
I display 3sec, NP, and lap average on my Edge 500/Quarq. The 3sec will bounce but you can sort of predict the average if you keep a steady cadence. Then watch lap average/NP to see if its trending up/down away/towards your target power. It simply takes practice and will be frustrating to begin with but you’ll pick it up in a dozen or so rides.
What distance do you set your “laps” at for an IM and a HIM?
for me - the lap is 1 lap for the whole race.
I think everyone is answering the wrong question (except maybe Jack)…
I display 3sec, NP, and lap average on my Edge 500/Quarq. The 3sec will bounce but you can sort of predict the average if you keep a steady cadence. Then watch lap average/NP to see if its trending up/down away/towards your target power. It simply takes practice and will be frustrating to begin with but you’ll pick it up in a dozen or so rides.
What distance do you set your “laps” at for an IM and a HIM?