Power faded but speed increased ?
http://connect.garmin.com/activity/199185628
108 mile ride done as 4 loops of Mooseman OLY course 27 mile per and interval. Was targeting IF .75 and ended up at IF .745. Interestingly though my power faded a little as it usually does over that kind of distance but well within acceptable levels for me anyway but my splits and speeds were faster on the last two loops than they were on the first two essentially negative splitting 108 miles on lower power. Each lap is essentially the exact same thing give or take a tenth due to where I started the split in the parking lot. Traffic was only a minor factor in all 4 loops.
Splits
1:24:07 NP 176 19.3mph
1:25:12 NP 172 19.2mph
1:23:28 NP 170 19.6mph
1:23:18 NP 167 19.4mph
I came up with some observations and some thoughts.
Why did I have higher power on first two laps?
1. It was earlier and cooler
2. I was rested .
3. I stopped 4 times to pee in the first 54 miles and a 5th time at 54miles to refuel allowing for micro breaks.
Why was my times and speed slower on the first two laps?
1. Because I stopped to pee/refuel 5 times . Even though I stopped the clock I did record the stopping and speeding back up time.
2. Possible wind negative component although wind felt negligible all day.
Why did my power fade on the last two laps?
1. It was later and warmer.
2. I was becoming fatigued.
3. After my refuel stop at mile 54 I rode continuous for the second 54 with no need to stop to pee or refuel so no breaks.
Why was I faster on the second 54 miles with lower power?
1. Because I didnt stop but rode continuous.
2. Possible wind postive component but again felt negligible all day.
My thoughts are this. Riding a normal long day or race rehearsal one would normally stop to pee and refuel. This introduces micro breaks allowing you to continue longer at a higher intesity. But this also lowers your speeds and times do to slowing down and speeding back up. Now in reality during an IM race most people will not stop this introduces more fatigue due to no microbreaks and one could expect a bit lower NP or IF than a normal long ride day or a RR.
I have read alot of Race Reports where target NP or IF was not met as it was in the Race Rehearsal. Could this be the reason why? Can we actually expect to execute a continuous IM ride at the same NP or IF as in our Rehearsal or should we target a few watts lower? I have also read the argument about stopping on the bike to pee would actually give you a break and that you would regain the time lost with the added rest but after my observations its best to keep moving even if its at a slightly lower wattage!
Thoughts or comments?
Comments
As I know the course...first let me say..nice ride.
A key missing piece of informatoin is your VI.
Within the power/speed range you recordd I believe your Speed would improve with lower power if you VI were lower...just a thought.
Thats pretty steady riding on a hilly/rolling course...again good job.
As I have only been on power since April/May I continue to pile up personal data and learn...I have noticed that Speed and Power are nt the same thing...as has been noted elsewhere...wind, aero position etc. all affect speed...and this probably most account for the difference....
even marginal wind makes a big difference.
I actually did have something to say... Maybe you could eliminate the "slowing and speeding up" phenomenom of the first two laps by creating some intervals of the times when you were constantly moving in each lap. Eg you'd look just at mile 10-20 of each lap and compare speed and power among the four over the same sections of the course when you were constantly moving, to see if there was and "power fade" or speed increae during those times.