Archive for the ‘speedwork’ Category


May 13, 2009

Well, my feet and legs are stopping me doing any real speedwork at the moment.  However, I’m looking forward to doing at least one session per week as soon as the legs will allow.  It struck me that a lot of people get confused about how to go about tackling speedwork, and that a lot of people are apprehensive about it.  So I thought I’d copy some very wise words penned by a friend on the topic.  I fully believe that what he has to say pretty much sums up everything you need to know to get you started!

“There are three basic types of intervals, each with a purpose:

1) 200-400m intervals with long recoveries: The purpose of this workout is to develop raw speed, working on strength, turnover, and fast-twitch muscle coordination. To achieve this, it is important to run each interval as fast as possible. Long recoveries are used to make sure you can run each interval near maximal pace. By definition, these intervals are limited to a max of 400m in length as you can’t sustain speed longer than this. If you are prepping for a 800m or 1500/1600m race, you may do 600-800m in this workout though you will likely no longer be at maximal speed, but doing more or a race simulation (ie running 800m at 1500m race pace). These workouts are actually not very fatiguing, because if you accumulate residual fatigue between intervals you can’t sustain the speed required in the workout. Of the three types, this will have the fewest number of intervals in a set.

2) 400m-1600m intervals with medium recoveries The purpose of this workout is to go into anaerobic debt on each interval and thereby stimulat building up your anaerobic capacity. This can also help somewhat with strength and speed tolerance. Moderate recoveries (say, 3+min for a 400m etc) are used to allow time to clear the lactic acid from your system and get HR back near baseline in order to be able to repeat the effort in the next interval. Comparing a 400m under this strategy to a 400m under #1 above, the time will be slower. This workout will actually feel much harder on you that #1 above, because you are working your anaerobic system so hard.

3) 400m-3000m intervals with short recoveries The purpose of this workout is to give your body an extended period of time at the very upper limits of your aerobic zone. This is probably also the best way to develop speed tolerance for 5K-10K paced races. This is the only one of the three types where your recovery will be shorter than your intervals. For example, I run 800m intervals in 2:22-2:30 avg depending on conditioning but only jog recover 90sec. Sets will also be longer than the other two types. (I do 8-10X800 or 6-8X1000 typically). The short recoveries bring you back just enough to be able to go out and do the next interval just as fast, or slightly faster than, the previous one (if you lose the ability to hit your target in the middle of the set, start slower the next time!). Using this strategy, you spend the whole workout at a very high aerobic capacity, with each interval inching you closer and closer to anaerobic. Due to the constant demand, this is probably the most demanding of the types.

Say you run a 5K in 16:00. While races are always good for development, you will rely heavily on the anaerobic component in the end stages of the race so you expose your body to high-end aerobic effort less than that 17:00. However, say you do 8X800 in 2:30 avg with 90sec recoveries. That workout will take you 32 minutes to complete, and the only time you tap anaerobic is if you try to blow out the last interval fast. You’ve just gotten yourself nearly twice the amount of time at sustained high-end aerobic effort! Think what that does for your development and the ability to hold high-end aerobic paces in your next race.

The bulk of my speed workouts are #3. I will use #2 as a sharpening tool 2-3 times going into a key race under 10K. The only time I have used #1 post-college was when I was picked to run an 800m leg at the USATF Indoor Championships on a distance medley relay team. It only took 3 weeks of doing two #1 workouts per week to find speed I hadn’t known I had since high school.

#1 gives up its gains in just a few weeks. #2 takes a bit longer. I’ve successfully continued to gain by #3 for up to 4 months. But they should be ideally applied in the reverse order (#3 followed by #2 then #1 time-wise).

When using #3, I suggest those newer to intervals start out at 2 miles of total intervals and work their way up. A well-conditioned and relatively quick runner should be able to get in 4 miles of these intervals in a session (not counting recoveries). When I was peaking out I could get 5 miles of intervals in a workout but I would not recommend that unless you are winning races and runnin 90+ mpw.

I have experimented with longer intervals, all the way up to 3200m. 3X3200m with 5min recovery is a great workout but the pace is getting too slow to consider it in any of the groupings above. The two last interval workouts I ran before my 10K PR were 4X2000m then 3X3000m workouts at 10K goal pace. I always dreamed of running 3X5000m with 7min recovery in 16:00 or faster but it never worked out.


Let me add that I think people use #2 (the interval workout type, that is!) too often. They enjoy the rush of running fast, but do not want to take on the associated discomfort of doing #3. What results is a hybrid where they do the recoveries of #2 with the pace of #3, which sub-optimizes the benefits. If you recover too long, HR drops, lactic acid clears, and you’re not getting all the benefits you could.

There is nothing wrong with it if your primary goal is to have fun or get some experience with speed. But if you are really trying to wring the most benefit out of the workout, you have to decide what the goal is.”

Let me know what you think of his ideas!  I think it is just about all you really need to know about running intervals.