Most runners think that speed work is a key to gaining fitness and being race ready. While it’s true that you need to do some race pace work (use that term rather than speed work) to race to your potential, you need to have done weeks and months of challenging aerobic workouts first. Aerobic repeats are done entirely below your anaerobic threshold, which is different than workouts such as 10 x 400m with 60 seconds of walking, where you are maxing out the aerobic metabolism plus dipping into the anaerobic metabolism. The aerobic repeat workout is entirely aerobic and it’s the type of workout you want to be doing regularly in the foundational phase of your training.
4 x 8 minutes with 3 minutes steady is the first aerobic repeat workout I use with athletes. Totaling 41 minutes of high level aerobic running, this is a challenging workout, so long as you run steady rather than easy for the 3-minute segment. Yes, it’s slower than the 8-minute segment, but don’t think of it as a full recovery. By the end of the 3 minutes you should be thinking, “I wish I had another minute at this pace.” Do a 10-minute warm-up and a 10-minute cool-down to get 61 minutes of total running.
What paces should you run? I have no idea. I have no idea what your fitness is, so I can’t tell you what paces you should be able to run for this workout. What I can tell you is if you run by feel you’ll be able to execute this workout on the second or third try. The keys to this workout are as follows.
First, you need to make the first 8-minute segment very conservative. Do that and you give yourself a great chance of running faster on the next three 8-minute repetitions.
Second, you need to make your last 8-minute repetition your fastest repetition. If you do that then you’ll have done a workout that has a slight progression to it, aka a negative split workout, where the second half of the workout is faster than the first half of the workout.
Third, you must be able to say, “I could have done one more 8-minute repetition. I wouldn’t have wanted 5 minutes of steady running rather than 3 minutes, but I could have done it.” If you can say that at the end of the workout then you’ve done a great job executing this workout.
Just like the fartlek workout there is no shame in bombing this workout the first or second time you do the workout. All that means is that you’re learning the skill of running by feel, which is a challenge if you’ve been running all of your workouts based on pace.
Final thought. This is basically an extended version of the fartlek workout, and for that reason, this is the next workout you should do after you have a couple of fartlek workouts under your belt. The difference is that you have to focus for 8 minutes, which is much more difficult than focusing for 4 minutes.
Feel free to do 5 x 8 minutes with 3 minutes steady for 52 minutes of challenging aerobic running (so 72 minutes with a 10-minute warm-up and 10-minute cool-down). That’s the longest most of my athletes will do in their training, moving to progression runs and progression fartleks as the next step in their training.