Lisa suggests doing the ladder backward if you're feeling really conditioned.
"When I'm in really good shape, I think I would actually prefer to do it the other way, starting at the 100's and going up. In that case I would put a lot more thought into how to do each segment:
"8 x 100: Keep a steady pace to get warmed up. None of them fast or with tons of effort.
"4 x 200: Picking up the pace, remember the times for each 200 and then figure out the average at the end.
"2 x 400: Your time must be a little better than twice the average for the 200's. Make the second 400 slightly faster than the first one—just by a second or two.
"1 x 800: Give it all you've got. Faster than the sum of the two 400's. Try to negative split. Basically, this is what the set works up to for a good end-of-the-set time."
Lisa explains that for this method, "I would only want to do it when I am in good shape, so that even though I had done 2,400 already, I could still crank on that last 800."
She adds that this set is not something she gets to do very often, as most Masters swimmers don't want to do that much. But for the distance folks, this is a really good one.
When training for two-mile or longer ocean swims, people attempting this workout may want to do it once down the ladder and then repeat it back up—swimming for a total of 6,400 meters, or about 4.5 miles.
Although this is way more yardage than one needs to cover to complete a two-mile ocean swim, it is a nice confidence booster and challenging set to try if you have the time and motivation. By completing it, a two-mile race will seem like a piece of cake.
Determining Your Interval
As far as intervals are concerned, I've tried this set and I prefer completing the entire distance on a 1:15 (one minute, 15 second) base per 100 meters. This forces me to maintain the same speed throughout the set, and I am challenged to get more rest by swimming faster on the longer distances.
Pick an interval per 100 that you are comfortable repeating and try it for the 800 (for instance, if you can swim a 100 at 2:00 comfortably, try the 800 on 16 minutes).
Another approach is to take a specific amount of rest between each set—perhaps 15 seconds. Although that may not seem like a lot after an 800, by the time you reach the 8 x 100 you will have 15 seconds between each one; enough rest to compose yourself and really try to maintain the same pace on each repeat.
For the ultimate endurance workout, your intervals can decrease as your distance decreases. Start with a 30-second break after the 800, then allow yourself 20 seconds between the 400's, 10 seconds between the 200's and only five seconds between the 100's.
If you can complete this set, then you are probably ready to hold the pace you maintained on your 100's for any ocean race!