Friday, February 04, 2011

Evaluating the Eval Run (part 2)

To summarize from the last post the eval run should be about 25 minutes long  at a pace about 30 beats lower than your peak heart rate.

One other aspect of the eval run should be recorded, the time it take the heart rate to drop about 30 beats (twenty-five to thirty beats). Heart rate recovery has two distinct phases, the first phase has a time constant of 70-90 seconds and a secondary phase with a time constant of about an hour. The first phase reading can give you an indication of effort and fatigue.

To see how this works go out on a comfortable run and stop after 15 minutes and see how long it takes your heart rate to drop 30 beats (or 25) then continue the run for another 15 minutes and take another reading, continue with a few more 15 minutes segments and readings.  At first your heart rate will take longer and longer to drop the 25-30 beats as you get fitter you’ll see that your heart rate will continue to drop at a rapid rate for a larger number of the 15 minute segments. You may not run a faster pace but your system becomes more efficient at staying in a steady state.

For real world example of how the eval run works during the a build, below are the results from Thomas'  who writes the  Diary of a Rubbish Marathon Runner blog.

Marathon build phase October 2010 – January 2011:

Average Heart Rate

161.75

160.75

161.00

161.50

Days from Start

0

28

56

84

Date

19-Oct

16-Nov

14-Dec

11-Jan

         

Mile 1

6:40

6:44

6:51

6:44

Mile 2

6:55

6:57

6:53

6:47

Mile 3

7:14

6:59

6:56

6:49

Mile 4

7:16

7:02

6:55

6:52

Time to 130

0:42

0:39

0:36

0:39

As you can see Thomas’ first two miles changed very little (from an average of 6:48/mile to 6:46/mile) but his last two miles made a big improvement in his ability to maintain a steady state ( from 7:15/mile down to 6:51/mile, a 24 second per mile improvement). 

This is the type improvement in stamina that runner should look for during the Marathon conditioning phase. It will serve you well in your recovery from hard workouts.

The next post will cover the  methods of building speed without eroding the stamina that you have built.