Triathlon and Chris Froome

It is difficult to probe (not proof) whether high cadence at certain rpm will decrease the resistance of the chain and chainring.  We just know the cadence of Froome at Mont Ventoux, the last 15km, 97 rpm.  I would like to probe that increasing inertia force by increasing velocity of the object (increasing cadence) less power is needed.  My guess from Armstrong and Froome measures is that an exponential curve starts above 90 of rpm; the force of inertia of the chainring increases and less power is needed to move the bike.  The more cadence, the less power needed to increase speed on the bike.  Based on that reasoning, oval chainrings are more useful to increase the moment of inertia:

http://hyperphysics.phy-astr.gsu.edu/hbase/mi.html

That is why the racing wheels have most of the weight at the most outside part of the rim.  The equation for the centrifugal inertial force, as a function of mass, velocity and radius is:

F = mv²/R.

https://www.youtube.com/watch?v=NMBM0PKJdDQ

Why is so difficult to probe?

1) Except for Froome, there are not riders able to go at that rpm for so long, 41 minutes 30 seconds. 

2) Armstrong was close to 90 when going uphill.

3) Except for Team Sky, there is not data regarding the top 10 riders going uphill.  Nairo Quintana would be a good rider to compare to.

4) Most of the data is calculated and once again, we just have Team Sky data measured with instruments which are more accurate to quantify the phenomenon.

5) The data have some errors but still useful for this exercise.

Saying the above, I will venture in this exercise.  We have done a preliminary exercise few years back.

26 août 2013

Chris Froome Coaching and Triathlon Coaching

Before a race in Veracruz this past weekend, we had the regular chat with the team before the race and an exercise to boost our athletes’ egos.  I am careful not to inspire cynicism in our competitors when we do this exercise because of the “excess of ego.” But unfortunately, that is a risk we take when giving information without full background.  In this case we discuss the graph of Froome during the time trial in La Vuelta a España (2011), http://www.trainingpeaks.com/av/Z3JDD63H2UVGP77YSXNITPULAE

  

And the question was: “How would you help Froome to be better cyclist if you were the coach?” What they discover was that Froome has room to improve from what we saw; but during the triathlon race, they did not do their best effort to do things right, not even what they discover reading the graph.  The study of the graph and how they perform has nothing in common; they were in automatic mode from the life they have known at home and school.  Whatever they learned from the graph was remotely related to their performance.  This is a problem we constantly encounter in our population, what they learn is not considered useful and is out of mind when performing (it happened in this competition).  We have seen that unless specific learning is generalized after years by team members, it does not belong to them.

The selection from the graph below is when Froome is going downhill and his heart rate increases.  Nine pulses as an average compared to his going uphill.  Increasing three pedals per minutes does not explain the increased heart rate, unless Froome is not trained to go higher than 100 rpm (something that I do not believe).  Froome is a climber and it appears that going downhill is not what to practice as a climber.  Normally, the pulse increases even when we keep the same rpm over time.

Selection
0:42:48 - 0:56:32

Total Time: 0:13:44

Distance: 13.18 km

Energy: 330 kJ

TSS: 20 (0.96)

NP: 412

VI: 1.02

Pw:HR 1%

EF: 2.69

Gain: 12 m

Loss: - 121 m

Grade:-0.8 %

VAM:52

W/Kg:5.9

	Min	Avg	Max
Power (Watts):	0	402	766
Speed (km/h):	35.7	57.6	71.4
Pace (min/km):	01:41	01:02	00:50
HR (bpm):	138	153	167
Cadence (rpm):	22	95	110
Elev (m):	832	861	953
Temp (C):	<29	30	31

First Half: 414w
0:00:01 - 0:29:16

Total Time: 0:29:15

Distance: 22.98 km

Energy: 726 kJ

TSS: 45 (0.97)

NP: 415

VI: 1.00

Pw:HR 5.6%

EF: 2.88

Gain: 210 m

Loss: - 36 m

Grade:0.8 %

VAM:431

W/Kg:6.1

	Min	Avg	Max
Power (Watts):	0	413	598
Speed (km/h):	31.5	47.1	73.6
Pace (min/km):	01:54	01:16	00:49
HR (bpm):	91	144	149
Cadence (rpm):	26	93	114
Elev (m):	835	934	1031
Temp (C):	<28	30	35

What would be our recommendations?

1)   Practice downhill speed.

2)   Practice cadence above 100.

A year ago we wrote another article.  We jokingly said that Froome followed our advice:

28 juil. 2015

Triathlon and Froome’s Tour de France 2015

We have studied the numbers given by Team Sky regarding Froome’s climbing when he practically won the tour de France.

Chris Froome’s performance data from Stage 10 [Tarbes to La Pierre-Saint- Martin]

Analysis of final 15.3km of the stage

(It is difficult to identify the exact start point of the climb as there is no clear landmark defining the start)

Time: 41min 28sec

Average power: 414 watts

VAM: 1602

Chris’s weight: 67.5kg

Corrected power/weight for the whole climb - 5.78w/kg

When used in conjunction with osymetric chainrings, power meters over-report power by approximately 6%. The above figure of 5.78 w/kg is corrected to take this into account. Without making this correction, the power/weight would be 6.13w/kg. All other power values stated here are the actual reported power values - i.e. not corrected.

Gearing:​ 52-38/11-28

Average Cadence:​ 97rpm

Average heart rate: 158

Froome improved his cadence 5 rpm since the Vuelta a España 2011.  His power output is quite similar from 2011 with the difference that he pedaled after a long ride before hitting the mountain where the power output was 366 watts:

Froome’s 60-minute power figure, which includes the flat kilometres before the climb, was 366 watts.

This is, by the way, the wattage produced in an Olympic Distance World Series Triathlon, measured by Vidal and Frodeno.

Froome´s downhill speed really improved this year at the tour de France.  He won the race going downhill showing how to race going downhill like nobody.

https://www.youtube.com/watch?annotation_id=annotation_3552594811&feature=iv&src_vid=Wxf21yCUUjM&v=4Z59bvf_0Hc

They say that it is not the best way to descent but I think it was the best for him and better than the others.