The tempo run is probably the most difficult session here. Tempo pace is where you stop feeling comfortable and is the boundary area between aerobic and anaerobic exercise. One way to think about it is the point at which your sense of humour begins to fade.
Fartlek runs are a decent substitute.
Long tempo (7+ miles) – 10k pace plus 30/35 seconds per mile
Medium tempo (5-7 miles) – 10k pace plus 15/20 seconds per mile
Short tempo (3-4 miles) – 10k pace Intervals – ideally done on a running track or on a grassy field.
1600m 10k pace -35/40 secs/mile 3/4 min recovery
1200m 10k pace –40/45 secs/mile 2/3 min recovery
800m 10k pace -45/50 secs/mile 2 min recovery
400m 10k pace -55/60 secs/mile 1 ½ min recovery