I received the 80/20 book for Christmas and have started to use the methods described in the book. I’m a slow runner so I’ll cover approximately 5k in a 30 minutes test – threshold pace 6 min/km. If I use the zone calculator and put in 30 minutes for 5k then threshold pace is given as 6:13 . Not a big difference, but I’m not clear why there is a difference?
First, remember that this is an estimate, it can’t replace an actual field test so there is always a likelihood of variation from actual results. Second, we are constantly tweaking our Pace calculator based on continual input from athletes and how they are training. Our new pace calculator is no longer linear. Meaning, we used to use a fixed multiplier for each distance. If your average pace for a marathon was X then we used multiplier Y. If your average pace for a 10K was A we used multiplier B.
Now, that multiplier varies by pace for each distance. A pace of X for a marathon will use multiplier Y, but a pace of X.1 will use a multiplier of 0.9Y. There are now many multipliers per for each distance instead of just one for each distance.
We feel that for some paces, a threshold estimate greater than a 30-minute base is best.
Additionally, particularly for athletes who are using a race result to estimate their zones, motivation in training does not equal motivation in racing, and 30 minutes observed racing will not equal 30 minute unobserved training.
In summary we feel that these new estimates will help you be more successful in training, but the estimate is no substitute for your actual field testing.