The Fatigue Resistance Session for 5k

What do we need to be able to PB over 5k? We need to hit a hard pace and hold it. Many athletes turn up on race day, having done their 5k pace interval work, and head out at their goal pace. All good. It is often around the 3k mark that the wheels start coming off and the athlete is unable to hold the pace. Almost certainly, for any athlete running 5k/10k, their weakness isn’t hitting goal pace, it i sustaining it for more than a few k. We need to train our bodies to be able to sustain race pace in a highly fatigued state.

Typically runners do lots of short and fast intervals at 5k pace and below, with long recoveries; and then, on another day, they will do a tempo run at around HM pace to train the famous ‘lactate threshold’ so that one can sustain high intensity work. What does this approach miss? The law of specificity – nowhere are we sustaining (or replicating the physiological stresses of sustaining) 5k pace for any meaningful amount of time. If we want to sustain 5k pace for 5k, we need to replicate the physiological stresses that this causes. The difficulty of course is that in replicating these stresses we will fatigue the body very quickly, and simply doing a 5k time trail at or near goal pace will, in all likelihood, overly fatigue the body and adversely impact the rest of our training. It is a difficult balance to achieve.

One classic way to address this is by progressive 1k reps. E.g. 5 x 1km at goal pace with 90 sec recoveries. The progression for this is to bring down the recoveries to 60 sec and then 45 secs. See previous #projectPB 5k Specific Intervals

This #projectPB session uses another approach: injecting a disproportionately high level of fatigue into the body before running at 5k pace – teaching the body to manage high blood lactate levels, as if in the second half of the race.

Fatigue Resistance Session for 5k

Warm up inc drills and strides

3 Sets of:

  • 400m close to flat out (you should be hurting after this)
    [1 min standing recovery]
  • 1600m at 5k pace
    [4min jog recovery]

Warm down

The 400s give the ‘fatigue injection’ and high blood lactate levels we are after. The 1 min recovery gives enough time for us to compose ourselves but not let fatigue levels drop too much. And then you need to sustain a mile at goal pace. It should feel like the second half of a 5k race (not that pleasant), whilst not causing too much muscular damage in getting there. We then get a long 4 min jog recovery in order to reset our fatigue levels for the next set and not overly fatigue over the entire session.

This session should be done in the second half of your training period, as you look to focus on more specific sessions. Ensure easy days are scheduled before and after the above session – it will hurt!

Feeling brave? Try extending the 1600m to 2000m.

Let us know how you get on! #projectPB


This is an advanced session, for those looking to push their 5k time, and not suitable for beginner runners. Always consult a medical professional before embarking on any exercise program. See our Terms & Conditions for more information.