Target Watts Adjustments for VI???
When I look at my historical data I see that my ability to ride steady, as measured by VI, is different for flat courses and rolling or hilly courses. This seems consistent with the race execution targets that the coaches give us (VI ≤ 1.02 for flat courses and VI ≤ 1.04 for hilly courses).
We measure our FTP as normalized power and we plan our races using the fatigue loading / TSS tables, which are also expressed as normalized power.However – our power meters collect data and send it to our Garmins (or other display devices) as averages. Depending on the devices, different numbers of samples are taken, averaged then transmitted via ANT+.
Some of us display that data directly; others average that data (for example, 3-Sec moving average) to smooth it. This averaged power is what we use as a target as we ride. This is, at least, how I do it and how I believe most of us approach riding with power.
Do any of you account for variability in your target wattage?
As an example of what I am asking, consider my data:
- FTP = 250 watts-normalized
- Assume full-course IF = 70% = 175 watts-normalized.
- VI = 1.02 → 175 ÷ 1.02 = 172 (no big deal) but,
- 175 ÷ 1.05 = 167 will start to add up over time.
Some courses are just harder to ride than others (at least for me) and my variability is worse. One of my Garmin screens display’s P-Norm & VI from the previous lap so that I can maintain a sense of how the ride is developing.. if my VI is running higher, should I target a lower number on the display as an adjustment?
I’m curious to see how (if) anyone accounts for this during their race planning / execution.
0
Comments
Hey Rich,
Not really sure I'm tracking you 100% but here are some notes:
So the short answer is to (1) watch your current watts, (2) do your best to ride within the guidance we give you, (3) create an interval every ~20-30' on your GPS, doing your best within that interval, (4) save the VI calcs for post-race analysis.
Do any of you account for variability in your target wattage? NO
EN says we can increase this target by 10% for long climbs… but should we reduce it by 1.04 for variability also? NO
If my VI is running higher, should I target a lower number on the display as an adjustment? NO
Hypothetical ride data comparison on 2 rides. If the NP for both rides is the same , and the ride time is the same , then the TSS would be the same, and then the stress to your body or how the ride felt would be the same , regardless of VI... This isnt an exact science since the ride with a lower VI would probably be faster/shorter and therefore have a lower TSS than the ride with the same NP higher VI being slower/longer due to how the power was applied.
The beauty of working off lap NP is it resets the data so you can work it in smaller increments...IMO the last lap or previous data is no longer important... Focus on current interval...The less data , and screens to look at and think about the better.... I use 3s power, lap NP auto 5miles, and time... Thats it... Having a high VI because of power spikes or overbiking is bad , having a high VI because you coasted a lot and never went over your target watts is not bad its just slower.... AP / average power is what moves us down the road and NP / normalized power is how the execution of that power was applied and how it felt to us.... The ride with the higher AP will be faster/smoother/steadier, and that is why the focus on lower VI....
All this should be sorted out on your RR's , making sure your NP/IF target is correct, TSS correct , and able to run well after!
If I follow you correctly, I think that I am tracking the right data... but would appreciate guidance.
My main Garmin screen during rides always has:
- Power (no averaging)
- Heart rate
- Cadence
This is the info that I see 99% of the time... trying to keep watts & cadence on target and using heart rate as a control indicator.
I have a second screen setup to capture Lap Data (each five miles for me) that contains:
- Normalized Power (lap)
- Average Cadence (lap)
I glance at this data from time to time to make certain that my normalized power is about where it should be and that my cadence isn't slipping.
Maybe 5 miles is too short an interval to get a good read on Normalized power?
I also have a screen setup to summarize the entire Ride that has:
- Normalized Power (ride)
- TSS (ride)
- IF (ride)
I only check this screen when starting each lap of a multi-loop ride, or when I reach the half way mark, etc. I use it to get an estimate of how the race numbers are unfolding vs the targets I used while planning.
At Tahoe, for example, I planned about 6.5 hours with IF 69% and TSS ˜ 300. Half way through the race, TSS was 181! I made some adjustments and rode the second have at 149 - ending at 330 total, but was still able to pull out ˜4:30 on the run. Pretty sure that wouldn't have happened if I had ended with TSS of 362.
Each time I think I understand this subject I overthink it and confuse myself again!
If I only had three data points per screen to play with, and I wanted to follow the thinking of Coach R and Tim above, then my main screen would include 3 (or 5) sec power, and Normalized Power (I prefer IF if available - same thing as N expressed as % which is the actual target) for my current lap. And the third one is … huh, let me think here a minute, ummm … whoops!
Since I have up to 8 data points per screen on my Joule (plus whatever I choose to display on my Garmin watch which I wear as a back-up), I don't have to scrimp on data. I do look at cadence, HR, even mph, but 95 times out of 100, I only make changes in my current effort level based on three pieces of data: my current lap IF, my current watts, and the % grade I'm on (barometric, not GPS based). So that would be my third data point. But I can see arguments for HR and cadence.
Argument for adding cadence: if your current cadence is "too low", but your current lap NP is "just right" are you going to start pedaling faster? Maybe you would switch to an easier gear, and try to hit the same watts, OK, that's a reason to observe cadence. How about HR? Again, might be useful, as a reason to figure out why it might be off…if your HR is too high relative to your NP, maybe you're dehydrated. But those are both secondary considerations to the primary metric of power.
I prefer to manually start intervals hitting the interval/lap button. I don't want to pollute the IF I see that the possibly 5% lower effort I'd be making at the start/end of say, a 10 minute long hill.
I prefer to not use auto lap, but to hit my interval/lap button manually based on the terrain I'm in. EG a longish hill which might take me 12 minutes to climb … I don't want to pollute the IF I see with the 5% lower effort I might have made on the downhill preceding or following.
I prefer to not use auto lap, but to hit my interval/lap button manually based on the terrain I'm in. EG a longish hill which might take me 12 minutes to climb … I don't want to pollute the IF I see with the 5% lower effort I might have made on the downhill preceding or following.
I prefer to not use auto lap, but to hit my interval/lap button manually based on the terrain I'm in. EG a longish hill which might take me 12 minutes to climb … I don't want to pollute the IF I see with the 5% lower effort I might have made on the downhill preceding or following.
Good advice from Al and Tim.
I haven't raced yet with a Garmin, just the older Joule. If I were to set up the Garmin for racing:
Main Screen:
Summary Screen:
Other notes:
I started riding in 2012 and thought that I needed to get stronger - I was thinking of my legs, not my brain. This is like trying to drink through a firehose!
I did not list all the fields on my main screen earlier- just the ones related to related to Power/VI. I ride with an Edge 500 (910xt is my backup). My screen are set as follows:
Main:
- Power (I have determined that my Power2Max averages a few samples before transmitting, so I do not use 3-sec moving average. The response is too slow when I do)
- Cadence (I'm still a novice / newbie rider - focusing on cadence / power combo keeps me in the right gear, allows me to react to RPE changes etc...)
- % Grade (Same reasons Coach R described - lots of climbs/descents will confuse me about how steep the next grade/descent really is)
- Heart rate (two reasons:secondary indicator or RPS, and Early warning indicator for all things nutritional)
- Speed (something to focus on while tweaking body position, descending, etc.)
Second:
- NP Lap
- Avg Speed (lap)
Tertiary
- NP Lap
- IF
- TSS
Sumary
- Distance
- Time
- Avg Speed
- Temperature
At the end of the ride, even though I had exceeded my Pnorm targets for the ride and the variability wasn't great, I felt awesome! I felt really strong the last 30 miles of the ride and by buddies were suffering (they are really strong guys, but they just hammer, none are riding with power). I was ready to run. I felt like this was a HUGE step in the right direction.
I will do the last long ride before IMMT this weekend, this time riding on my own so that I can practice the pacing and the steadiness of the ride.
Thank you all a ton for the advice. I think that I am starting to understand how to sue these numbers to help execute better.
Nice work! FYI, group rides, especially a hammerfest with stronger riders, are not the best venue to learn how to ride steady. They can be useful if you're riding with similar riders / you're one of the stronger ones out there, as you can do your thing (ride steady, focus on applying power where they aren't), they do their thing, and you can observe how this riding strategy plays out on the course -- how little net gain they get for spiking power, backing off, etc, vs your style of riding.
It's even more valuable of they are different body types. Over time you'll develop a 6th sense of estimating the FTP, w/kg of the riders around you and being able to anticipate how the moves they make will play out over time.
However, there's a difference between the "key" data and how much data you have in front of you. With some units, you can display 8 or 10 fields if you want to.
I like Rich's 7-field mail display for race day, but I might have something different for training. For purely psychological reasons during the race, I like to be able to glance at how far I've gone. I know that you get that information every 5 or 10 miles anyway, but it's just something that makes me feel good to look at sometimes. I think there's some worth to the "make me feel good" field once you've got the basic real data covered. If that's time or distance or whatever, don't feel bad about having it. :-)
For the record, going back to the original question...there was one instance in which an adjustment to Ave Power is worthwhile...if you have one of the now-pretty-old units that doesn't display NP and ONLY will do AP, then knowing that you will ride at about 1.04 or 1.05 VI would suggest that you'd want to lower the target Average Lap Power reading by 4-5%. With NP available, there's no need to display AP.