"There's only one hard and fast rule in running: sometimes you have to run one hard and fast."

Wednesday, October 3, 2018

Quick Guide 6: Intervals

A lot of runners think interval workouts are both intimidating and boring, which is a contradiction if you think about it. "I hate this, I'm bad at it and all it does is make me tired and sore" - if this is what you're thinking, I'm planning another post in this series on how to get around some things one doesn't like.

Other than races, interval workouts will be the most challenging workouts I'll discuss. I think one of the problems with them is that runners don't have an idea of exactly what they should be doing or why they're doing it. There are two "whys" - these workouts are practice at race pace for some runners and also these are specific workouts for increasing maximal oxygen uptake (all workouts I'll talk about throughout this series will increase maximal oxygen uptake, but these are focused on that one aspect). Most runners can run at their maximal oxygen uptake rate for no more than 5-10 minutes before dipping into oxygen debt, at which point it becomes a lactic acid tolerance workout and I prefer to leave that to the time trials I covered in the last post. The plan is to run at a pace that brings one to the point where they're taking in air as quickly as possible and holding there for a bit, but stopping before it becomes too uncomfortable, then pulling back a bit to recover, then running hard again - and so on - until one has run as long as possible at the maximum uptake.

There are two workouts I'll give, with a ton of guidelines for each, so you can figure out just what you should do. These should be alternated, one per week.

First workout: 3-5x800-1600m@80-95%(5K/10K)in 3-5w/400-800m(2:1D)in3-5.

Here's how to decipher that.
1) Run repeats of 800 to 1600 meters
2) Run these at 80 to 95 percent effort, which should be between your 5K pace and your 10K pace.
3) In between these, do recovery runs of half the length of the hard sections.
4) Do the recovery runs in the same amount of time as the hard parts (so at half the pace).
5) Do 3 to 5 hard repeats, to total no more than 8% of your week's mileage.

Second workout:5-8x200-400m@85-100%(1.5K/5K)in 1/2-2w/400m in 3-5.
The pattern is explained as in the first workout, with some additional guidelines:
1) Run a total of 6-12 minutes hard.
2) Run at least 1500m hard
3) Run the hard sections to total no more than 5% of your week's mileage.

To this, I add one more guideline, Pfitzinger's Rule: run 80% of your week's mileage easy and 20% fast. Along with the guidelines for all the other days, this should tell you exactly what to run.

Most runners, of course, simplify this. The first workout becomes repeat miles and distance runners always try to make it miles at their race pace, which is a bit too slow and usually too many repeats. The second workout becomes repeat quarter miles at mile pace, which is ideal if you're racing under 5K in distance, but is too fast otherwise. Ideally, what you want to do in these workouts is to let your heart rate drop only 20-30% during the easy sections, so that you quickly go back to maximum during the hard sections; during the last recovery sections, your heart rate may not drop at all, or only slightly, so even the slow sections seem hard.
It gets a lot less complicated from here on. Trust me.


Ben said...

If I recall correctly Pfitz suggests recovering 50-90% of the time an interval takes. When nearing peak shape 90% always feel like too long.

SteveQ said...

It depends upon what your aim is. If you feel ready early, go early, but you might not be as rested as you thought. There's an old adage that for MVO2 intervals, the rest should be half of what the hard part was, so that you don't really recover.

Ben said...

Any reputable marathoners ever try doing an extra interval session each week on a bike? The bike would allow an extra cardio session without the pounding and extra recovery time a run based speed session would require. The real question is how much interval training (heart rate based) is beneficial? At what point does it become counter productive?

SteveQ said...

The only one that comes to mind is Jack Foster, who ended up running three times a week and then doing a 4-5 hour hard bike ride on the weekends, but he was a competitive cyclist before taking up running. Triathletes do it, of course.

If you go beyond 12-15 minutes total at MVO2max, you tend to be training for lactic acid tolerance, rather than improving oxygen uptake. At that point, the next few runs become very difficult at any pace (personal experience).