Should you incorporate speedwork into your long run?

The Sunday morning long run is a sacred ritual among distance runners. Traditionally, this run has been done at a slow, even pace, but in recent years an increasing number of runners have been experimenting with adding some faster-paced running into the mix. This has ignited a debate in the running world–is adding some speedwork to your run making you better, or are you missing out on the benefits of long, slow mileage? Canadian Running asked Stephen Anderson and Donna Mader, coaches at New Brunswick’s Fredericton Stride, to find the answer.

The purpose of the long run

Both Mader and Anderson agree that the long run is the most important run of the week–particularly if you’re training for a marathon. And while running slow to run fast sounds a bit contradictory, long, slow mileage has many physiological benefits. Most important, it helps to increase aerobic capacity and endurance.

“Without getting too scientific, it forces your body to produce more mitochondria in the muscle cells, which are necessary to produce energy from food,” says Mader.

Should you add speedwork to your long run?

The answer, as is often the case, is it depends. “The purpose of the long run is time on your feet,” says Anderson. “This is important. So doing your long run at an easy pace is fine with me. But it is also important to recognize that a long run is a tool to really improve.”

With that in mind, Anderson says that once you’ve gradually built yourself up to running for about 2.5 hours, you can, if you wish, start incorporating some marathon-paced speedwork into your long run. 3 x 10K or 5 x 5K with a one-kilometre jog in between are some examples of long run workouts he provides his athletes.

The benefit to training this way is that you adapt to your marathon pace within your long run, which can be an important training tool when you’re training to sustain your goal pace for 42.2 km. “It also builds confidence for the runner to know that in the later stages of a long run, they are capable of running at race pace,” says Mader.

Should everyone start doing workouts within their long runs?

The answer to that is a little clearer: no. As Anderson pointed out, speedwork should only be added to a long run once you’ve built up your (long, slow) mileage really well, and can handle the time on your feet at a slow pace. This, he emphasizes, needs to be done slowly and carefully, to avoid injury.

Mader agrees, adding that it’s important to consider your starting point. “First-time marathoners may want to be a bit more cautious, because the long-run distance is so new to them,” she says.

The bottom line

The main purpose of the long run is to increase aerobic capacity and get the time on your feet to ensure you can complete the distance on race day. While adding speedwork to your long run can improve your performance, you should only do so when you’re ready. 

If you’re tackling your first marathon build, focus on increasing the length of your long run each week with long, slow miles to allow your body to adapt to this new training load. If this is your second or third marathon build, consider talking to a coach, who can help you incorporate speedwork into your long run safely and effectively.