How fast should you run your interval sessions?

As a coach, creating a session for a big group is tricky. The ability range can be vast. You may have 16-minute 5k runners and 30-minute parkrun runners.

If they are doing the same session together, asking them to do the same pace for the structured reps, is not going to suit them both.

For example, 5 x 4 minutes at your 5k race pace is great for the quicker runners — they are overloading their current ability by doing more time at their race pace. However, for someone whose current parkrun time is 30 minutes or more, 20 minutes at 5k pace is actually a regression on that.

If we are looking to improve, we need "progressive overload". Do more than what we have been doing previously.

Let's take a simple example. Dave. He's been running for a few years, but his current 5k time is 30 minutes on the nose. He does a track session every Monday with his club, a 60-minute run during the week, and then a fast parkrun on Saturday.

But his parkrun times are not improving, despite always giving his best at the track session and following the advice of the coach.

Recent sessions at track have all been to 5k pace. He did 6 x 4 minutes at his 5k pace and 5 x 1km at his 5k pace. So why haven't those parkrun times improved?

Well, let's take the 5 x 1km as a good example. If Dave ran that in 30 minutes, then what time can he expect at parkrun on Saturday? 30 minutes, of course.

Perhaps even a small regression as the 5 x 1km included some rest and recovery between reps. So what does Dave need to do differently to improve his parkrun time?

Dave has no control over the sessions the coach sets at track. What he does have control over is the pace he runs them at. If the session is 30 minutes of running, or 5k of running, the only way Dave can make improvements is if he runs it slightly faster than his current 5k pace.

If a session is shorter, let's say 20-24 minutes, then Dave is really going to have to push the pace to make gains, running the reps significantly quicker than his current 5k pace.

What if Dave rocks up to track and the coach says 10 x 3 mins at 10k pace today? Well for Dave, that's a regression again. He needs to do those reps quicker than his 5k pace to see the benefits.

Let's introduce Daisy. Dave's daughter. She's really fast. An 18-minute 5k runner. So to see improvements she only needs to run 20 minutes at her 5k pace or just under. Much less time than her dad.

But Daisy faces another possible dilemma. She rocks up at track, and the coach says 6 x 5 mins at your 5k pace or under. Perfect for Dave. A potential disaster for Daisy. If she runs 30 mins at her 5k pace, she's almost certainly going to get injured.

Now you might assume no coach is going to make that mistake and push their runners that hard. You'll be surprised. It actually happened this summer to one of the runners I coach. A 17-minute 5k runner was asked to do 9 x 3 mins (27 minutes total) at 5k pace. 10 minutes more than they normally do. The outcome? They got injured, of course.

So the point of this blog is to have that awareness of what you need to do to improve and potentially avoid injury. The coach always has a tough task if working with a mixed-ability group. So don't be afraid to alter the pace to best suit you.