nectarinee wrote:
How do you know you are running the right intensity?
By a feel, and with the help of a heart rate monitor. These calculators by different people are very different.
For example "Tinman" advocates a rule of thumb for tempo runs of 5k race pace + 60s, which I believe takes into account the difference between race pace and "date pace."
Pfitz apparently recommends 4-6mi at 15k to HM pace and 8-10 mi at HM to M pace. These paces correlate to about 5k + 30s for the shorter tempos, and about 5k + 45s for the longer tempos, which seems to be a good bit faster than Tinman recommends to me.
McMillan recommends "steady state" runs (25-60 min) at 5k+35s and "tempo" runs (15-30 min) at 5k+25s. This is even a hair faster than Pfitz.
So what to believe? If I have to choose from these guys, I would say Tinman has it quite right. I don´t believe on tempos much less than 30+ minutes. I prefer that you progress to 40minutes. But when you run on different surfaces, snow, hilly, windy etc. You can´t run based on pace. Use the HR monitor. Since you don´t want to accumulate lactate too quickly, start the run running just at your LT-intensity. If you´re tired, even this HR can be quite hard to keep. If you have a good day and your clycogen stores are full, you have no problem on that pace, so you can go a bit faster. Feeling should be the famous comfortably hard. But even on a good day keep the HR under about 92% of MHR. You want to recruit also some of your fast glycolytic fibers but not too much of them, and keeping the HR under 92% is about right on that goal. But this depends also from a runner, how good your endurance is. If your lactate threshold is really low, you want keep the HR on the lower end of these figures.
So in summary, correct tempo intensity by HR is in about 87-92% of MHR. If you run so called lactate threshold run, the HR should be in about 80-87% of MHR. This should keep in mind about the differences between a lactate threshold and a tempo run.