Under/overs
Feel the turn. Under/overs will push you beyond your threshold pace, causing lactate to build up in your blood. As you slow down again your job is to keep the legs turning as your body tries to deal with the lactate. Over time, your body will get better at this and your ability to run at this pace will increase.
60 minutes.
Summary
Steps
Warm-up
6 minutes
3 minutes @ Zone 4
1 minute @ Zone 5
3 minutes @ Zone 4
1 minute @ Zone 5
5 minutes rest
3 minutes @ Zone 4
1 minute @ Zone 5
3 minutes @ Zone 4
1 minute @ Zone 5
5 minutes rest
3 minutes @ Zone 4
1 minute @ Zone 5
3 minutes @ Zone 4
1 minute @ Zone 5
5 minutes rest
3 minutes @ Zone 4
1 minute @ Zone 5
3 minutes @ Zone 4
1 minute @ Zone 5
5 minutes rest