I find the second key run workout, the tempo run, to be the easiest of the three RLRF runs. The tempo run usually begins with an easy mile or two, followed by 3 – 6 miles at a 10-K pace or slightly slower. This run is intended to improve endurance by raising the runner’s lactate threshold. Lactate is a by-product of anaerobic activity. As exercise intensity increases, the body cannot keep up with removing lactate from the muscles, resulting in fatigue. The tempo runs aim to raise the lactate threshold so that the runner is less limited by muscle fatigue, resulting in the ability to maintain a faster pace.
I’m very interested to see how increasing my lactate threshold affects my marathon performance this year. The heavy, leaden legs I experienced in the last half of the race may have been largely caused by a build-up of lactic acid. (I’m sure glycogen depletion played a part in my muscle fatigue, as well.)
I’m a little afraid that I’ve run my tempo runs at too slow a pace to see results from this run. According to RLRF, the same 5K pace should be used to determine the paces for all three key runs. While my 2011 half marathon time indicates that I should use a 5K time of 26:50, I used a 28:00 time in order to handle the first key run paces. A 28:00 5K has the following tempo runs associated with it:
Short tempo: 9:18 minutes/mile
Mid-tempo: 9:33 minutes/mile
Long tempo: 9:48 minutes/mile
I worry that these are too slow, since I ran a 2011 half marathon at an average of 9:30 minutes/mile. I don’t find even the short tempo run pace to be uncomfortable. But RLRF doesn’t recommend moving up a pace bracket unless all three tempo runs can be completed “easily.” Since, I can barely (and sometimes not at all) complete the first key run at the 28:00 5K times, I’ve stuck with the that bracket.
I do most of my tempo runs along River Road/Eastern Avenue. I do simple out-and-back runs and I know where all the mile markers are. It’s flat, so I can achieve consistent times across the tempo miles. It’s also the final portion of the marathon course. As Sun Tzu says, “know thy enemy.” I like to be familiar with the course, especially the part at which I’ll be most fatigued.
The tempo runs are good reminders that, for short distances, I can run faster than the 10-minute mile I usually think myself capable of. I have never raced a distance shorter than a half-marathon, but the tempo runs make me think that a fast 5K might be kind of fun.
Even if the runs don’t raise my lactate threshold, they are good pacing practice. I’m becoming very familiar with the “feel” of the different speeds. This will come in handy on marathon day, when I start slow and finish faster.
Sporty Sunday is a recurring feature in which I share my fitness routine and offer and solicit advice. While this content might seem a little out of place in an outfit diary, a healthy, strong body is the foundation of my wardrobe. I hope to inspire my readers to be fit as well as stylish!