M2 IM Pace & Fueling Test Ride

Recently I did a test ride to measure my IM cycling fitness and fuel-burning efficiency.

My training approach followed standard M2 training protocol:

  • Finite training hours – generally 6-7hrs per week
  • Quality versus quantity – focus on improving 20min watts
  • Indoor classes at M2 Revolution or road equivalent using Powertap
  • Delaying fueling (other than sports drink) on outdoor rides for the first 90min to induce fat-burning
  • Longer rides done at very end of training period (these were few however)

To the extent that actual performance matters in evaluating training efficacy and fitness…

4hr Steady-state Ride to test the following:

  1. IM pacing wattage
  2. Fueling efficiency and limits

M2 current Fitness:

  • 20min watts 345w +- 2-3 watts
  • 1hr watts 325w +- 3-5 watts
  • Current weight 165 pounds
  • Race weight 156 pounds

Recent Training Background:

  • Longest previous ride was 4hr 45min.
  • Most long rides were 2hr 50 – 3hr 10min duration; most weeks, sometimes not.
  • Indoor sessions at high intensity or road equivalents; indoors would be 70min duration, outdoors up to 2hrs. 2-3 of these weekly.
  • Weekly ride hours: 6-8hrs
Wattage Target for 4hr ride

Objective was to ride Steady-state uninterrupted ride at a standard Ironman race pace, 75-80% of maximum sustainable 1hr watts.

Test fueling efficiency and limits

I wanted to test my body’s ability to perform on existing fuel stores – fat. To that end, I ingested sparse carbs the day before and morning of, and virtually no calories during the ride itself.

  • Dinner the night before saw few carbs – Cheese plate, nuts, buffalo burger and salad, beer & wine.
  • Breakfast was similar in its paucity of carbs – fruits, juice, coffee. Rode 2hrs later.
  • Riding fuel – 1.5 bottles of Accelerade – approximately 200 calories.
Ride Observations

Pace graduated from very comfortable to moderately stressful at end. Estimate another hour at this sustained effort would not have been a problem – IM race ride would be sub 5hrs.

Weather was cool, so hydration needs were not great. No dips in energy and was not hungry post-ride. Given the paucity of carbs the day before and morning of, I thought I might run on fumes, but this was not the case – no energy issues.

Ride Wattage
  • Hour 1   243ap 247np
  • Hour 2   230ap 243np
  • Hour 3   244ap 253np
  • Hour 4   241ap 249np (52min)


  • Wattage indicates a very steady effort.
  • Hour 2 AP/NP discrepancy due to stop signs getting through Petaluma and two downhills where pedaling not possible.
  • AP/NP very close elsewhere indicating constant effort.
  • Mood was right for a metronome type ride; constant and very even.

Gently rolling by California standards.
Lucas Valley Road > Nicasio > Petaluma > Bodega Hwy > Fallon Two Rock > Chileno Valley > Wilson Hill > return Nicasio

Take-away Items from M2 Training Model and IM PacingTest
  1. Strong 1hr fitness as objectively measured by watts
  2. Ability to translate shorter intense base into sustained IM performance, again as demonstrated by watts.
  3. Ability to burn fat and thus simplify race day nutrition
  4. All of the above accomplished with modest weekly training hours
1. Strong 1hr fitness

325-330w is a respectable number for a 160lb rider. The primary workouts that contributed to this fitness were 60-70min indoor sessions at M2, or road equivalents. 6-7hrs/week.

2. Strong IM fitness
  • Ability to ride long and steady at a solid IM intensity factor, 248 NP, IF = 76%.
  • I was able to execute my 2nd longest ride (more than 50% of my weekly volume) at an unerring steady-pace and where RPE only grew to moderately stressful.
  • Another hour at this pace would have seen RPE grow another tick, but did not appear to be daunting.
  • Based on the ease at which I completed this ride, I would estimate current IM target watts would be a bit higher, approximately 260 watts, and where IM ride duration would be comfortably less than 5hrs
  • It would be easy to drive this 260w number higher with a month of focused long/hard riding, similar to my standard IM model where long rides are done close to the event.
3. High degree of fat-burning efficiency
  • A low carb dinner, breakfast, 2hr wait period before beginning ride, and approximately 200 calories consumed during the ride, YET, a measured sustainable performance with modest RPE, ability to continue beyond, and a comfortable not particularly hungry post-ride state.
  • The low-intensity training crowd that prattles endlessly about teaching the body to burn fat, (racing fast often seems secondary) ought to take note that there are more efficient and effective ways to reach their professed fat-burning fitness nirvana, while also getting fast. How else to explain an upbeat and sustained 4hr ride on virtually no carbs?
  • Note also that the higher intensity workouts which characterize most of the training that enabled the above fitness example also breed fuel-burning efficiency, where despite the higher intensity, the workouts are by definition still largely aerobic, a term that the low-intensity crowd often throws around without fully understanding its meaning.
  • Of course in a race event I would take in more calories, but my caloric need has been trained to be much less than the low-intensity eat carbs (gels, bars, perpetuem) all along the way athlete. Having to cram less fuel into the stomach reduces potential for nutritional issues and means less blood diverted to digestion and more to legs and arms.
4. High Level of fitness with modest training hours

People will be motivated to train for different reasons. Myself, I like to see improved performance and have a demonstrated time-efficient recipe for accomplishing such. Most people are challenged by finding the time they are told is necessary to train using generic traditional models.

I also enjoy having an objective measurement of fitness – how many watts for what period of time – yes or no. Too often, volume-oriented riders confuse process with results, and measure fitness by how much they are training instead of the most straightforward and meaningful measurement – how many watts can I sustain.

On the other hand, many of these same folks I observe appear less concerned with demonstrable results than they are with process, checking off a workout, etc., so perhaps spending more time to achieve less performance, and even fat-burning efficiency, is not really a matter.

The low-intensity volume crowd can tell you how many hours they trained and what their low intensity HR zone is, but they can’t tell you what their fitness was when they began, and what it is now. Perhaps if they were to see how little it had changed, they might reevaluate their commitment to a process that produces so little return relative to time invested.

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