Medium long run (Aerobic run)

Aerobic runs or Medium Long Runs form the backbone of all our training programmes.  They are high priority runs throughout the aerobic phase, where they play a key part in building the highest possible peak for later racing. In the strength, anaerobic, coordination and taper phases, they are lower priority workouts that serve to help maintain previous aerobic development and allow you to keep your peak performance level for longer.

The only dfiference between an aerobic run and a medium long run is that we use the term ‘medium long’ when the duration of the run is 3/4 of your longest run or longer.


Run at a comfortable pace (not jogging) for the duration of the run. You should be able to converse.

Important points:

  • These will be your recovery runs in later phases so always finish such runs knowing you could have run faster and further
  • If you need a recovery day afterwards you are running too hard.

Rate of Perceived Effort: 

3-5 (55-75% VO2Max)

Experienced competitors/elites: 

Initially time spent on your feet is more important than hitting paces, but experienced competitors should note that their aerobic runs are not “long slow distance” but rather at 70-100% of your maximum steady state.

“Lower aerobic effort, while it may be fine for joggers and fun runners, does not exert the desirable pressures on the cardiac and respiratory systems that an athlete needs.” – Arthur Lydiard, Running with Lydiard


  • Aerobic


  • Knowing your recovery pace

 Biggest mistakes:

  • Starting out too fast
  • Running too hard and tapping into anaerobic metabolism.
  • Clock-watching and pushing the pace to arrive at a pre-set idea of what it should be rather than allowing it to come naturally.


Any terrain is suitable for this workout but Arthur Lydiard’s mantra was “undulating, undulating, not hills,” by which he meant a course with smaller ups and downs is ideal for this run as longer and steeper hills can make you stale. Mixing up the underfoot (having sections of tarmac, trail and grass, for instance) will help prevent repetitive strain injuries.


Aerobic Hill Run: This run deviates somewhat from Lydiard’s normal advice that:

“The surfaces you choose to run on are important. The better traction from the surface, the better development of circulatory and respiratory systems. Good traction allows more economical running, which, in turn, allows greater speed for longer periods within the maximum steady state.” (Running the Lydiard Way, 1978)

But if you are a mountain runner or otherwise focus heavily on off-road running events, you will need to include runs that specifically mimic the hard mountain conditions you face and learn to run economically on surfaces with poor traction, obstacles and extreme gradients.

  • This run differs from the standard run in that climbs are much longer (perhaps up to a few kilometres at  a time) and your route will feature 200-600m of ascent or more
  • Technical terrain such as loose rocks, dirt-path and heather can be part of your route depending on the terrain of your target race.

While some mountain runners are known to run on open mountain almost daily, we generally recommend you keep your training more balanced.

“I have found that anything more than two days a week of hill running sees my  race performance drop. I too would get very stale and mentally and physically tired if I trained too much on the mountains, I needed variety such as fast road runs etc. to keep me sharp.”-John Lenihan, 1991 World mountain running champion

Parts of the workout descriptions are adapted from BreakThrough Running with permission.

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Director and coach at Borg Coaching Services
Rene Borg is the head coach of Glendalough AC and a passionate runner competing over all distances and terrains.

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