Running fast is fun. The lung busting satisfaction of a fast interval workout provides the immediate gratification we all crave. Part of it is the excitement of running fast. Perhaps part is the convenience of track work. However, I think most of the allure is the idea that the harder the pain the more the gain. Counterintuitively, this isn’t always the case in distance running. You must work hard to perform well, that much is true, but some of that effort is often misplaced. The value of “conversation paced” running cannot be overstated and should always comprise the majority of your training. However, as you get into the phase of training where you are doing harder workouts 1-2 times a week you will benefit greatly by focusing most of your hard days on improving your anaerobic threshold through the tempo run and similar workouts.
Anaerobic vs Aerobic
The biggest mistake I see people make is spending far too much time doing “speed work” that focuses on all-out running designed, intentionally or otherwise, on developing the anaerobic system. Have you ever had that quick jump in performance and then plateaued after doing consistent hard interval work? Or have you ever found yourself fatigued and worn out by the time your key race rolled around? Then a transition to more aerobically geared workouts might be right for you!
Infomercial personality aside, these are a couple of symptoms of overtraining the anaerobic system. Training the anaerobic system does have benefits, but it must be done sparingly. And those benefits are minimal when compared to the improvements you can gain by training the aerobic system through workouts like the tempo run.
The traditional tempo run is designed to improve your anaerobic threshold by running steadily at or just below that threshold. For those of you who are heart rate runners, your anaerobic threshold is between 85-88% of your maximum heart rate. For those that aren’t it is typically the pace you could hold for about an hour-long race.
While the traditional tempo run is a great way to stimulate the anaerobic threshold, it isn’t the only way to train this system, nor should it be. Below I have 3 different ways to improve your anaerobic threshold, including the classic tempo run, while adding variety to your tempo routine. The change of stimulus allows for greater gains while still focusing on training the aerobic system.
Tempo Run
The traditional tempo run is a staple in many runners’ training arsenal. However, it can still be a difficult workout to execute properly. The goal of a tempo run is not to run as hard as you can for the specified time or distance; that should be left for race day. We’ve all executed tempo runs that way, but the idea is to keep the effort where you finish feeling like there is more in the tank.
A tempo run should generally be somewhere between 15-40 minutes, depending on your experience level and event focus. For a tempo run under 30 minutes you should target a pace you could hold for roughly an hour race. For a tempo run approaching 40 minutes you should run 5-10 sec/mile slower than that to keep it at the same effort level.
Tempo Run: Mile Repeats
Everyone is familiar with traditional mile repeats, but this is a great twist that makes the workout a little more moderate with great aerobic benefits. These type of aerobic intervals are often referred to as cruise intervals. The workout is simple: 3-6 x 1 mile repeats with 60-120 seconds easy jog or walk between each repeat. Start at or even 5-10sec/mile quicker than half marathon pace and work down to 10k race pace for the last 1-2 repeats. Aim to move a little quicker each repeat. When you’re feeling more fit try shortening the rest by 30 seconds instead of speeding up.
A runner new to this type of work or running less than 35 miles per week should aim for 3-4 repeats with a touch more recovery. A more experienced runner training over 40-50 miles per week should aim for 5-6 repeats with a little less recovery. As your fitness improves try to reduce the recovery time before you increase the speed.
Tempo Run 400’s
This is on of my favorite icing on the cake workouts. This session should be done in the final 4-6 weeks of preparation. It is intended to work on economy and put a little bit of snap in your legs. As alluded to in the name, it’s an aerobically based workout disguised as a more traditional hard interval session. Once again, many people refer to these as cruise intervals. The beauty is you get a lot of the same benefits as a tempo run, but at a faster pace.
The key is in the controlled pacing of the repeats. The number of repeats should vary, depending on your training level and experience, from 2-4 sets of (3-4x400m). The recovery should be 45-50 seconds between repeats and 2:00-2:30 between sets. Start the first set at or 5-10sec/mile quicker than 10k pace and finish the final set at 5k pace or even a few ticks quicker. You should finish feeling in control and comfortable. This is a great confidence booster in the final few weeks before a race as you will be surprised how good you will feel running relatively fast.
Aerobic Above All Else
There are a number of other ways to target this energy system and improve your aerobic ability, these are just a few examples to spice up your routine and make the most out of your workouts. Anytime I give a training talk, whether it’s about 5k or the marathon I always finish by saying, “when in doubt err on the side of being more aerobic”. Remember, the vast majority of distance races are dependent on aerobic ability; even a 5k is 88-90% aerobic in nature while the marathon is close to 99%. Your training should reflect the demands of the race. I know running fast is fun, but remember tempo work is the key to running fast come race day.