4. Critical Power in Cycling
โข Prescribe an appropriate power
output for a new interval
session
โข Use shorter tests to predict the
maximum sustainable power
for longer efforts
โข Analyse changes in a riderโs
fitness over time
โข Compare ridersโ performances
โข Identify strengths, weaknesses
and areas for improvement
โข Predict the effect of changes in
performance at one time
duration, relative to another
7. Example 1 โ using Empower Oarlock
Date Distance Duration Power
Target
Power
Actual
500m
Pace
Comment
Sep
17
9.5k 43:57 190W 202W 2:18
Sep
19
9k 39:50 >202W 205W 2:12
Sep
23
8k 35:07 >205W 212W 2:12
Sep
25
7k 32:00 >212W -- 2:17 Hardware issue
Oct
2
6k 26:26 >212W 217W 2:12 Target set at
220W for race
Oct
7
RACE 6k 24:19 220W
๏จ
225W
230W 2:01 Target adjusted
to 225W
โข Gave rower a +5W target increase because of nice flat water and strong current
โข Work per Stroke constant at 480J (i.e. 240W at 30spm)
โข Race was WON
8. Optimizing Head Race Pacing
โข Use CP chart to find power level you can hold for
10k
โข Row 10k at that level. โEmpty the tank in second
half of rowโ
โข Update Critical Power Chart โ find maximum
sustainable power for 8k
โข Row 8k at that level. Make sure to empty the tank
โข Repeat until you are at your race distance
โข You can use other sessions (like 4x2km) as well
โข Algorithm converges very fast
โข Helps you get the โfeelโ for the right power level
โข Avoid athletes relying on โrace day inspirationโ โ
Train to race at your worst performance
Editor's Notes
In this second part of the talk I am going to use data to enhance training at race pace. For this, I will use the Critical Power Concept
As a result, we can tell you where you stand in terms of absolute power at different distances, but also tell you whether your data suggest youโre a Sprinter or a Stayer. So this guy, a 40 something lightweight rower, is not really world class but he is better than 90% of his age group. From his stayer score he looks to be an allrounder.
Since we now have power measurements in the boat, I thought that the CP chart would be very useful for on the water training. I found that there were a number of challenges because of wind and other conditions. I developed an algorithm that finds the highest power โpiecesโ in a large number of logged workouts, and then a smooth profile is fit to the data. The green line to find your โevery dayโ performance, and the red line indicating where your peak performance lies.
So here is a 2017 season preparation for a head race over 6k. The sequence started with a 9.5k hard distance trial. Look how we shorten the trial distance gradually and increase the power target. Again, you need to have access to a power number in the boat.
Do also take a look at the pace column. You can see that sometimes the pace does not correlate with the power. Pace depends on external factors like wind and choppy water.
On September 25th, there were hardware issues preventing the measurement of power. In a sense, this was a good test to see if the โfeelโ for power was there. The pace value was influenced by a very stiff headwind in the second half of that row.
Eventually, we came to the conclusion that 220W would be a good target for the race. The race was held on a river about 70km from our boat house. Arriving there on race day, we noticed a pretty strong tail current and nice flat water. This race would perhaps be a minute shorter than anticipated. On the spot, accessing the data online through the cellphone, we decided to add 5W to the power target. Eventually, a strong sprint in the final 1k got the average power up to 230W. The race was won.
Here is how you can use power to โderiveโ a optimal race pace.
This approach really counts on having power data available in the boat and on having a data platform to quickly determine averages. It replaces the stopwatch and is insensitive to wind and other external influences.
Basically, you start with a guessed power level that you can hold for a distance that is longer than the race distance. Itโs good to start at a longer than the race distance. Itโs less intimidating for the athlete than a test at the race distance. In the next slide I will give you an example.