Part 5: Interval Running and "Speed" Work

What's in a Name

So many people will tell you they're going to do some speed work, then go on to describe an interval workout.  I think I'm learning not to begrudge people the little shorthand means that they use to describe their running, even if their mislabeling is misleading.  When I discuss these topics, I will reserve the term "speed work" for workouts that focus on raw speed - how fast you can go at your absolute top speed, full-out sprinting.  Interval workouts are not speed workouts for me.

Interval Running

So what are intervals?  Intervals are repeated efforts at faster than race pace, with some sort of rest between.  The objective of interval work is to repeatedly exceed the anaerobic threshold, allowing your body to recover enough between each effort so that you can put in a substantial distance at a faster pace than you could running continuously.  During each interval, metabolic waste will accumulate faster than your body can eliminate it - if you just kept going, your body would force you to slow down.  Then you back off during the recovery period, allowing your body to catch up on the waste removal.  This teaches your body to deal with high levels of wastes more efficiently, and conditions the muscle cells to operate for longer periods of time anaerobically.  What does this mean to you and your running?  It means the ability to run at a faster pace than before, for longer.

As I said in Part 4, I do these in blocks, just like my tempo runs.  They are an intense workout, and you can only do them a couple of times per week at most - may people will only do one workout like this per week.  A person can only sustain the work load of intervals for a month or two at most before they need to switch things up.

The bread and butter interval workout for middle-to-long distance runners are 400m repeats (1/4 mile repeats).  The mistake that many runners (especially our misguided high school cross country athletes) make is to set a pace for interval workouts that is absolute murder.  They try to give their best 400m on ever rep, and so their times steadily get slower as the workout progresses, or they have to do a shorter, less effective workout.  I prefer to do intervals at a pace which is 20-30 seconds/mile faster than race pace - really anywhere from 5-10 seconds per 1/4 mile faster than my 5k pace works for me.  While it is uncomfortably fast, the discomfort only lasts for a few minutes, and it isn't so fast that I burn out early in the workout - I like to do 10-15 intervals for a workout, anything less feels lazy, anything more is just ridiculous, even when training for longer races.  I used to hate intervals, because we always did them too fast, and our recovery was too stationary, making my legs feel heavy at the start of the next interval.  My recovery is a combined walk/jog for 200m, always trying to jog the last 20 or 30 seconds of it to loosen my legs back out.  My recovery goal is to get my heart rate back down to 140 beats per minute, which takes about 90 seconds or so for me.  When I'm in good shape, I like to hit this workout twice a week, when I'm just getting back into things, I only do one hard workout per week.  While they may sound tailored more to shorter distances, intervals benefit marathoners too.  There will always be times when your body needs to sneak past the anaerobic threshold, even for a short distance like climbing a hill.  Spending a little time working on your body's ability to efficiently deal with this makes those efforts easier to recover from during the big race.


Speed Work

Speed, you're either blessed with it or you aren't, right?  Well yes and no.  While your genetics do play a huge part, it is probably unlikely that many of us are at our full potential when it comes to sprinting.  And it doesn't matter greatly to us longer runners - the kick is only the last 2% of a 5k, right?  Which is why I really only give speed work about 2% of my time.  If you can force yourself to sprint at the end of your race with no thought to the consequences (mainly, how it is going to feel when you cross the line), you'll probably out kick most people anyway.

Speed work requires much high intensity effort.  Sprinting is almost entirely anaerobic, and is more about strength and explosiveness than conditioning your muscle cells to do certain things.  I might do one or two speed workouts all year - some 100m repeats, with long recovery between maybe.  Good enough.


My own interval work continues to go well.  I didn't want to run today, but forced myself to, and ended up with a pretty good workout.  My heart rate is still recovering quickly, and my legs are dealing with the intervals better each time.  This tells me that next week I'll be doing longer interval workouts (probably 15x400m), and then it's on to a tempo block.  I mention this just to highlight the importance of listening to your body and your results, and using what they tell you to adapt your schedule so that you get the most out of it.  And your life won't be complete unless you hear about the sandwich that I just ate for lunch - peanut butter with chocolate and caramel syrup and marshmallows.  The 2nd best sandwich I've ever eaten (I'll leave you writhing in suspense about my favorite until a later date when I need something to post about).

I also wanted to highlight this week's edition of Running with the Kenyans (the index of articles can be found here, with a new post each Tuesday).  They call the workout they are doing a fartlek, but the rigid schedule, the length of the hard runs, and the shortness of the easy recoveries, this all screams INTERVAL to me.