... although of course anyone can do the session on the grass, too.
3-4 sets of (4 x 400) on the track at 5k pace or faster, depending on how many sets you're doing. (3 sets = faster than 4 sets). 2 mins walking between sets.
For sets one and three - 200m jog recoveries between 400s. For sets two and four, 60 sec walking recoveries.
Bring lungs :-)