Do you wanna develop 5 sec sprints or 1 minute pulling power? They're different energy systems. The 5 second spurts require recruiting of the anarobic phosphate system in which case you can do 55-5's, which is real easy cruising for 55 seconds, and then sprint for five. Weight room max strength training after a coupla-three months of general strength conditioning and hypertrophy training benefits plenty in this case.

Anything else takes intervals, but that you probably already do. The simplest of course is to go all out until you feel like puking. Rest as long as you need to get your HR down to 50% or below, do it again.