The depths I have shrunk to when a can only manage 4 min k pace for a 400m rep.
Ok it was on grass but seriously it felt very slow.
Ran on the grass from Robertson Rd gates in centennial park back to Anzac Pde.
Reps were 82, 79, 81, 84, 78, 80, 81, 83, 79, 82. All done with a 60 sec walk recovery.