In reply to mountainbagger:
1600 is probably too long for vo2 max tbh, especially for slower runners. For vo2 max its generally between 2:30-5 minutes of effort, so even for me at 5:20 pace I'd only do vO2 max workouts at 800-1000m generally, maybe 1200's but never 1600. The rest is roughly matched or a bit less. I typically do 800's with 400 jog recovery which comes out about 90% of my effort time.
There's no real need to run much under 5k pace when training v02 max. Just more or longer at that pace. So if your 5k (race) pace is 6:30 run 5 x 1 k at that pace. there are gains from doing shorter sprint work, form, function etc, so I'm not saying dont do it but you don't need to be hammering 400's with long rests as a distance runner.
re tempo, that's 1 hour at race pace. Not general run pace. I race 10 milers around 56 minutes so 5:35-5:40 pace, but I'll never hit that pace in training apart from in tempo sessions. With tempo as a rough guide its 1 min rest / mile. with 25-30 minutes at that effort. So 5 x 1 mile at 5:30 pace for me is 27-28 mins of effort with 4 x 1 min of rest between the efforts. Or 3,2,1 miles with 3 minutes and 2 minutes slow jog rest.
LT work shouldnt be that hard its 'comfortably hard' because theoretically you can run that pace for an hour, so dont hammer your first rep, probably run that slightly slower and keep the pacing solid. Your breathing should be balanced and steady, during vo2 max sessions it will be hard. I can feel when the minute is up during mile reps, its almost at the perfect point when I feel fairly recovered.
Post edited at 15:48