Which workout do you think would be harder?
Option 1:
1600m in 3:56, 1200m in 2:55, 800m in 1:54, 400m in 54 w/ 2:30 rest between each interval
Option 2:
1600m in 3:57, 800m in 1:51, 600m in 1:22, 400m in 55, 400m in 55 w/ 5 - 7 min. rest between each interval
I think Option 1 would be harder, because you're getting less rest and still running about the same pace.