Saturday, September 29, 2007

"Body" -> Part I: The History Of Modern Endurance Training Tracking

Measurement is key to improvement.

Every endurance athlete knows that world class athletes track their training, and modify it to gain greater endurance and strength. However, with new technology, you can track and modify better than ever before. The following post is the first of three posts. In this and future posts, I will cover three main areas.

I. My view of the history of measurement
II. Current Tools
III. Ways of Using and Issues


One of the challenges of training correctly in endurance is one of overload. Everybody knows that overload is required to get strong in both anaerobic and aerobic workloads, once you have done base training. The question becomes "how do I manage the overload that I am doing?"

As an example of the difference in training between aerobic and anaerobic: in endurance activities this becomes very difficult due to the wide variation in training. While in lifting you may have some variation in sets, in endurance training you may go all the way from 60s tempo runs or sprints to 6 hour bicycle rides. Also, the specific nature of the workload is very, very different. In aerobic activities you do not train to failure or to the point of almost failure, which is common in weights.

For many, many years the measure of intensity for working out was distance per week. Even today, many running journals are kept that speak of "distance for the year" or "weekly distance."

However, not all distance is created equal.

For example, lets say that you had two work out weeks, and you ran all your miles on the same course at the same heart rate.

Week 1: 18 miles of running: 3 sessions of 6 miles = 2.57 miles/day
Week 2: 18 miles of running: 6 sessions of 3 miles = 2.57 miles/day

Are both workloads the same?

In reality, the Week 1 is harder. If you have run for any number of year, you will be familiar with the person that goes out to run for 1/2 hour six days a week, but would struggle with making for a whole hour. The opposite is not a problem. A person running for 1 hour three times a week could easily run 6 session of 3 miles a week.

Shorter session are easier. How would you come up with a formula to describe this?

An intuitive way (for those with an electrical engineering degree) to deal with this is to add a RMS (root mean square) method of weighing the series. Using an RMS formula against the above workload, you would get:

Week 1 rms: equivalent to 3.92 miles/day
Week 2 rms: equivalent to 2.78 miles/day

In other words, by placing your run through the RMS filter, you get an average mileage per day. For the 3x6 run session, it was equivalent to running almost 4 miles a day for a week. Over 1 mile more per day!

However, a straight RMS formula is weak in that it doesn't capture variability in heart rate. Most people run shorter distances at faster hearts rates.

So, in the 80s, we started to see the the movement toward quantifying the workloads that endurance athletes were doing. This was at the emergence of low cost heart rate monitors that were EKG accurate from such companies such as Polar.

Eric Bannister can up with "Training Impulse" or TRIMPS (1982, Physiological Testing of the Elite Athlete). This was a simple calculation using heart rate and time of exercise to come up with a formula. The formula was as follows:


You can see that "duration time" is the proxy for distance. Heart rate is now introduced to help with intensity level. However, Bannister left out any type of RMS calculation.

More than this, heart rate can vary significantly from a series of different factors. For instance, heat can notoriously impact one's heart rate for a variety of factors including dehydration.

In bicycling circles, the advent of low cost power meters (Powertap, SRM, Ergomo) has allowed a direct measurement of muscle power. By measuring power, we can set up models that show the energy wattage or power of the muscles working. Thus we bypass the heart as an indirect measure of muscle work, and get very, very close directly to the stress on the muscles.

There is no direct measurement of power while running, thus other tools must be developed to deal with running man.

In the next post, we'll talk about some of the tools available to the average consumer.