This blog's turned 10! You've endured dating stories, cooking experiments, poetry and enough training theory to earn a doctorate. Time for the post-doc. I'm starting on a new project which will be of little interest to most people, but I think I can supply some grist for the windmills of curious minds (and there's the worst metaphor ever). As I do some workouts, I'm going to explain their history and that might be of some interest.
On Tuesday, I went to the track and ran 20x100m in 19.5 seconds (800m pace) with recoveries of 100m in 1 minute. There were 75 year-old women running laps and a functional fitness class doing whatever they do, but I had the inner lanes to myself. This is a workout that's never been popular, but keeps coming back because, empirically, it works for some. I called it "extensive low volume," which became E.L.V., then ELV and finally "The Elf."
In the 1950's, a standard work-out for milers was 10x400m (440 yds then) at 1 mile pace, with 3 minute recoveries. For those whose pace kept dropping at the end of repeats, they started the season with 20x400; some thought about doing 40x100 first, but forty of anything seemed drudgery and the workouts became too long - they also discovered that the workout seemed to be different in essence; there was something physiologically different, but no one could say what it was.
When Lydiard was king, his high mileage runners did "leg speed" repeats and "wind sprints" which were a large number of short repeats, somewhat like my workout. The idea was to keep the legs fresh with some fast running, to work on form, to get a feel for a fast pace. This message ultimately got lost among those who did high mileage.
Doing a lot of short repetitions worked for a few runners, such as Jim Ryun and Ralph Doubell, 800/mile specialists, but it never caught on. Physiologically, there's a delay before your body reacts to moving fast and the energy used comes from stored creatine phosphate; after 5-20 seconds (5 for most runners), the body starts using glycogen anaerobically and recycles the creatine, so one can do a lot of short bursts. After a large number of repeats, it becomes a matter of producing lactic acid (I'm going to ignore some facts in favor of convention here). Your body adapts to the workout by storing more creatine phosphate, by increasing the speed you have to run to deplete the creatine stores and by increasing tolerance to levels of lactic acid (actually, of ADP).
There were a group of East German coaches that developed an engineering approach to training. They would look at this in the following way: if you allow the heart rate only 1/3rd the time required to return to normal after a repeat, then the training stimulus comes from the heart having to start from a higher rate with each interval until one is running largely near maximal heart rate, even during the recoveries, but a large number of repeats is required.
In the late 90's, a version of this workout was rediscovered by Veronique Billat and became a favorite of high intensity interval training aficionados. This workout consisted of 30 seconds run at a pace that could be maintained for 6 minutes, followed by 30 seconds done at half that pace, repeated until one could not continue. The best runners ended up managing 12 minutes run at their maximal oxygen uptake.
It's never going to be a favorite of long distance runners, but it's a good weapon to keep in one's arsenal.