We all know that the backbone of a long distance runners training program is the old steady state state or long run. These big runs are an absolute must if you want to be able to get to marathon distance and beyond. If however you're aim is to do more than just finish a race then you are going to need to do a little more than just plodding along at the same pace and this is where tempo runs come in.
Simply a tempo run is a purposefully fast training run, typically at a pace roughly 25 to 30 seconds per mile slower than your current 5K speed. At this sort of speed your body is able to get rid of as much lactate—a result of burning carbohydrates—as it produces. All this really means is that this is about as fast as you can go before you're legs start feel like they are made up of battery acid. Your body’s lactate clearance is at the same level as its lactate production, meaning the dreaded dead-leg sensation doesn’t set in.
And that’s a really important difference between a flat out run (like a shorter race) and a tempo run. When you're going all-out, your body bypasses this limit, allowing for fatigue to develop rapidly. A tempo pace, on the other hand, can be held steadily (albeit not all that comfortably) for the duration of the session. Which should be somewhere between 20-30 minutes (not including warm, cool down etc) and at absolutely no point should it feel like a race or a sprint.
There are a tonne of reasons to add tempo work to your training but the big one is that tempo runs build up your lungs (and cardiovascular systems in general) and muscles. Meaning faster paces become easier even on longer races.
The other less talked about side of tempo training is the confidence it instils in you. Knowing that you can run fast and for a long time, this can really help you if you lack confidence in picking up the pace in the later stages of a race.
If you are already running somewhere between 1 and 3 times per week the simplest way to start incorporating tempo runs into your training is to just add in a short tempo run each week.
Starting at around 15 minutes and slowly building up to 20 minutes, all while keeping in that all important tempo zone.
If however you are really pushing your running training and running between 4 and 7 days a week already, try swapping out one of your traditional runs for a shorter tempo session. Try it for six weeks and see how you feel afterwards.