1600m @ Threshold pace; 1:30 min. recovery (200m recov)
1200m @ 5k pace; 2 min. recovery (400m recovery)
800m @ 5k pace 2 min. recovery (400m recov)
2x 400m @ faster than 5k pace; 2 min. recovery (400m recov).

Reverse 800m at your MARATHON pace. if you haven’t run a marathon recently then add about 1.5 min. to your 5kpace

Note: I gave a little longer recovery; depending on the heat…you decide what is good for yourself.  Jog the recoveries or walk around. I think you’ll find the Reverse 800m @ M pace to be challenging.  🙂