What a runner is really trying to accomplish through training are the following.
(I) Improve the body’s ability to transport blood and oxygen,
(2) Increase the ability of the running muscles to effectively utilize their available oxygen (to convert carbohydrate and fat fuel into useful energy),
(3) Increase V02max, which is a sum of #1 and #2, above,
(4) shift lactate threshold to correspond to a faster running speed,
(5) improve speed, and
(6) lower the energy demand of running (improve economy).
Lest you are up to now clueless or is not sure of what you are doing, ride along. Ready your towel for some nosebleeds
Types of Training
Easy (E) and Long (L) Runs. When you do easy E runs to recover from strenuous periods of training or to carry out a second workout on a particular day, and when you do your long L runs, you should run at a pace which is very close to E (easy-run) velocity, which is about 70% of V02max. Long runs L, improve cell adaptation, and lead to glycogen depletion and fluid loss (important considerations for distance runners), but should not be demanding in terms of the intensity (pace) being utilized.
Be advised that the benefits of “E-pace” running are more a function of time spent exercising than intensity of running, and 70% V02max, which corresponds to 75% vVO2max and 75% of HRmax, is all the harder you need to go to get the benefits you want at the cellular level and in the heart muscle.
Marathon Pace (MP) Running. The next faster intensity of training (faster than E pace) is MP (marathon race pace) and is pretty much limited to marathon training. MP is as it suggests — the pace at which you plan to race (or run, as the case may be) in your next marathon, and is about 20 to 30 seconds per mile slower than T (threshold) pace, described below. Non-marathoners can ignore this.
Threshold (T) Runs. Threshold pace is about 88% of V02max (90% of VO2max or of HRmax). Subjectively, T (threshold) pace is “comfortably-hard” running. For many people it is slower than I race pace and for most people it is about 24 seconds per mile slower than current 5K race pace.
In the case of T-pace training, it is important to stay as close as possible to the prescribed speed; neither slower nor faster velocities do as good a job as does the proper speed. Here is a case where going too fast — which many runners automatically try to do — is simply not as good as running at the right pace. T-pace training improves your lactate threshold.
Interval (I) Pace. The next important training velocity is the one that stresses and improves V02max V02max-interval (I) velocity. The intensity here should be equal to vVO2max- I believe most people should shoot for 98% – 100% of HRmax, rather than always demanding a 100% value, if using heart-rate as a guide. This is suggested because if maximum heart rate coincides with a pace of 6:00 per mile, for example, then certainly 5:50 or any pace faster than 6-minute pace will also elicit maximum heart rate, but is too fast for the purpose of the training session — optimum result with the least possible stress. No single run, which makes up a series of Intervals, should exceed 5-minutes.
Interval (I) training is demanding, but by no means is it all-out running. In the case of I pace, the harm of going too fast is that no better results are obtained and the excessive pace will probably leave you over stressed for the next quality-training session.
Repetition (R) Pace. Repetition (R) velocity is faster than I pace, at the very least, but, unlike I and T, is not based on V02max. Rather, R pace is to a great extent, based on the race for which you are training; it is more designed for good mechanics at a pretty firm pace. A runner, in training for a I, with a vVO2max of 300 meters per minutes will have the same threshold velocity and V02max (I) velocity as any other runner whose vVO2max is also 300, but who may be training for a 1500-meter race. This is because T and I paces are related to the same vVO2max value, and any runners with a 300 vVO2max would have identical training speeds for I and T training. On the other hand, R pace would differ for the two runners cited above, because one is running for a faster race than is the other, and needs good economy and speed for that faster pace. Keep in mind that the purpose of Rep-pace training is to improve economy and speed; it is not to benefit V02max or lactate threshold. It is important to always have set in your mind what every workout is designed to do for you, even if that benefit is pure relaxation.
No-man’s Land. Training intensities that fall into ‘No man’s land,” are either too easy or too hard to reap the benefits you want. You are not, as may sometimes be assumed, achieving the purpose of training the two systems on either side of the chosen intensity. What you are doing might be termed, “Quality-junk” training. At the least, it is training aimed at accomplishing an unidentifiable purpose. Always have a purpose for every training session; ask yourself the following questions: “What system do I hope to improve by doing this workout,’ and ‘What am I really trying to accomplish?”
* E — up to 2-½ hours steady
* T — 20 min steady or up to 10% cruise intervals
* I — up to 5 min per workout & up lesser of 8% or 6 miles total
* R — up to 2 min per workout & up lesser of 5% or 4 miles total