How to Determine Anaerobic Threshold ( AT )
Introduction What You Need The Test The Zen of Testing
Other Krebs Cycle Plot and Use the Data Disclaimer
Introduction GO TO TOP
    Training for bicycle racing is making the best use of limited resources. It does not matter whether you are a Cat5, or a contracted Professional. The situation is always the same: how to make the best use of your resources. The easy way out is to believe: they are faster because they have more money/opportunity. No matter where you are in cycling, the name of the game is efficiently managing your resources
Those who are good at it advance, those who are not do not
    Everyone, at some time in their life, starts at the bottom. This article talks about bike racing - an athletic event - so genetics matters, but not as much as you have been taught to believe. Actually, each persons decision's, the efficiency of those decisions, is the main determenant of success or failure.
    For example, if you have an IQ of 200, but you cannot read or write....Are you smart, or dumb? Using this anaolgy in cycling, if you have all the gifts, but do not workout, are you fast or slow? The next level up from that question is; if I chose to do it, how effective can I be at being 100% of my potential?
    "Power Based" Training is the most effective way to train for cycling. Power based training combines:
  1. Cadence
  2. Heart Rate
  3. Power output
to make workouts 100% efficient. If you have an extra $2500.00, then purchase the SRM Professional. It is the hot setup for training.

    "AT Based" Training - For less than 1/10th the cost of an SRM, you can achieve at least 95% of the efficiency of power based training with Anaerobic Threshold based training. AT based training combines:
  1. Cadence
  2. Heart Rate
  3. Perceived level of exertion
Clearly the difference is:
  • Power Based: the watt meter is displaying actual watts ( about every 2.5 seconds )
  •       AT Based: more experience = more accurate information
In other words, the difference in efficiency between "Power based" and "Anaerobic Threshold based" training is how accurately workload is presented as feedback.
This article presents the method to determine Anaerobic Threshold ( AT ) for AT based training.


What You Need for the Anaerobic Threshold Test GO TO TOP
  1. Your bike and a wind/mag trainer, or an ergometer
  2. Heart rate monitor
  3. Cadence monitor
  4. A friend for timing the steps in the AT test, and to record information
  5. Pen and notepad
  6. PRACTICE! PRACTICE! PRACTICE! being on an RPM for 30 seconds and then in less than (at worst) 2 seconds, be locked on to a cadence exactly 5 rpm higher. The quality of the data is directly related to your ability to change immediately from one RPM to the next, and to 'sit' on that RPM.
  7. Set up the bike and trainer so with the rear wheel going 30mph, it coasts to a stop in exactly 2 seconds
  8. Do this test when you are 100% rested ( for example, before Tuesday morning's intervals )

The Anaerobic Threshold ( AT ) Test GO TO TOP
Do the Anaerobic Threshold ( AT ) test when you meet these criteria:
  1. You are race fit and in good health
  2. You have practiced the AT test and you are very good at "sitting on" a specific RPM
  3. You are 100% rested
  4. The bike/trainer/ergometer are properly setup
  5. There is a person to time and record the test
    • Record the data
    • Keep an eye on the RPMs and encourage you to stay on plan
    • When the test gets tough, More incentive!
The Anaerobic Threshold ( AT ) Test
    After warming up, you must ride in the same gear for the entire test.
    The test ends the second time you cannot maintain an rpm for 30 seconds. For example, if you are at 115 rpm, but it is getting alittle ragged, your rpms are varying up and down by 2 or more rpm, that is the first miss. If you cannot sit on 120 rpm in the next 30 second segment, then you are finished.
  1. Warm up with easy spinning for about 10 minutes
  2. Stretching
  3. Get on the bike and ride at 60 rpm for 30 seconds in an easy gear
  4. Continue for another 30 seconds at 60 rpm in the gear you will be using for the entire test
  5. Now record heart rate
    ( You are still at 60 rpm for another 30 seconds )
  6. From now, until you fail, do this every at the end of each 30 second segment:
    • Count down: 5 seconds to 90 RPM, 4 seconds, 3,... 1, 90 RPM
    • Record heart rate at 1 second to go
    • Increase rpms by exactly 5 rpm in less than 2 seconds

Plot and Use the Data GO TO TOP
  1. Use this equation to convert RPMs to miles per hour
       Speed = ( Gear * RPMs ) / 347
       where  Gear = (Front Ring / Rear Cog ) * 27
  2. For each speed number, calculate: speed cubed
  3. Graph Heart Rate to Speed cubed. Heart rate is on the vertical axis, speed cubed across the bottom of the graph
  4. The graph will look similar to the sample below. Your AT is the heart rate at the "deflection point"
       ( the arrow is pointing at the AT heart rate )
          HR vs. Speed Cubed
    After reading many books about heart rates, I came to the conclusion that all those zones and all those names, and all the extra fluff in the books was mostly information that cannot be used in real life.
To a point, less information is more useful because, if workload changes
  • it can take as long as 30 to 60 seconds for heart rate to catch up and stabilize at the new workload
  • in the real world, the wind, the road, the group cause changes in workload in in time frames less than 30 seconds
I use these zones:
  • Recovery Rides: keep heart rate about ( AT * .66 )
  • Long Slow Distance: keep heart rate above ( AT * .82 ) and below ( AT * .90 )
  • Intervals and TTs: heart rate at or above ( AT * 1.12 )
For recovery rides and long slow distance rides, shift gears to maintain about 105 rpm and be in the target zone. For intervals, it's party time! Light it up and play!

Other Information GO TO TOP
    I first did this test in a 53x12 in October of one of the years I was District Road Champion. My guess is you should first try a 53x14. You cannot shift gears during the test so you must find a gear that is easy at 60rpm and evil north of 100rpm. You need a gear that causes you to 'fail' between 125 and 135 RPM.
    This test requires you to be exactly on a specific RPM for 30 seconds. And at the end of that 30 seconds, within ( at worst ) 2 seconds, increase RPMs by exactly 5 RPMs. And so on. The result from this test is only as good as your ability to hit and maintain exact RPMs.
    Use the Tuesday and Thursday morning trainer rides to practice the above RPM requirements and to figure out which gear you need, the proper resistance setting, amount of rest to be ready for the test.

Krebs Cycle GO TO TOP
    There are 3 different parts to Krebs cycle.
1. Aerobic - a.k.a. "Long Slow Distance", or riding at 70% - you remove all lactic acid produced
2. Pyruvate/Creatine - on the gas, but not a full sprint
3. Lactic Acid - sprinting, kilo rides, bridging a gap,....

Training for any endurance sport, in our case; cycling, means planning workouts and cycles of workouts, to maximize your performance in each of these 3 parts of the Krebs cycle.

The Zen of Anaerobic Threshold Testing GO TO TOP
    Anaerobic Threshold is only relevant when you are fit. Some people say that your AT number comes down over time. From my experience, AT does not really exist before you are reasonably fit because when you are fit, your body is optimized for cycling. But that adaptation takes time. When you are fit and adapted to cycling, you have only one anaerobic threshold number that defines where your body changes energy cycles.
    In 1984, my AT was tested to be 158. At that time, I had won District Roads once and won other races, and there were more wins in my future. I stopped racing after the 1986 season and after many years of being fat, and after moving to Colorado in 1994, I got back on the bike. A year later, at the end of 1995 after racing the 1995 season, my AT was tested again. The numbers from the 1984 and 1995 tests were
exactly the same.
  • The same max heart rate: 187
  • The same AT: 158
  • The same if I am between 180-182bpm, then I have about 5 minutes
  • The same if I am between 183-187bpm, then I have about 30 seconds
And those numbers also stood up in racing.
    But during the years I was not training and mostly off the bike - 1987 through 1994, my max heart rate was about 210 and I could easily hang out at 190bpm. During those years I was not fit and my Anaerobic Threshold of 158 and my maximum heart rate of 187, did not apply because I had no fitness.
    Another example, Greg Lemond and I have the same AT, 158. Greg won Nationals, Worlds and a few other races. My only claim to fame is winning District Roads a couple times, and setting some time trial course records.
    The point is: Anaerobic Threshold is a person specific tool that is very effective at maximizing workout efficiency. There is no good or bad number. It is what it is. Use your anaerobic threshold number to make the most effective use of your time on the bike.