This World Class Workout is a complex "ladder" swim set that comes from four-time Olympic gold-medalist and former world record holder (in the 400m, 800m and 1,500m freestyle) Janet Evans.
Owning several of the top fastest performances of all time in her respective events (400m freestyle, 400m IM, 800m freestyle, 1,500m freestyle), Janet achieved her accomplishments due in no small part to years of dedication and the completion of monstrous sets requiring superhuman physical conditioning.
Her contribution is important because it is an endurance-building workout that's also designed to help a swimmer develop the "back-half" of their race.
Too often, training long distance develops endurance, but at the expense of speed and pacing consistency. Triathletes especially may focus their swim training solely on completing a mile-long swim without being fatigued for the bike and run legs that follow. However, if these swimmers want to be competitive, it is important for them to be able to finish the last half of their swim strongly and not succumb to a slower pace and fading energy.
Warm up as you see fit, anywhere from 800 to 2,500 yards/meters of easy swimming, kicking, and pulling with a buoy and paddles. A short warm-up set of 8x50 @ 10 seconds rest can elevate your heart rate and prepare you for the sustained activity soon to follow.
Janet Evans' World Class Workout
1 x 500 @ 6:15
2 x 400 @ 5:00
3 x 300 @ 3:45
4 x 200 @ 2:30
5 x 100 @ 1:15
TOTAL: 3,500 meters
The basic ladder structure of 500, 400, 300, 200, 100 is reconfigured by the amount of repeats within each set—so while you are decreasing the distance swum within each set, you are increasing the amount of times you swim that particular "repeat" distance. As a result, while each set allows you a slightly shorter repeat between each break, you are forced to swim that distance an extra time.
Janet's example is meant for seasoned swimmers who can maintain a base interval of 1:15 per 100m freestyle. Not many people can do this for the 3,500m duration of this set, so modifications are recommended.
If you only have access to a yards pool (rather than meters), you can attempt this interval in yards, though it may still be challenging. A 1:30-base will look like this:
1 x 500 @ 7:30
2 x 400 @ 6:00
3 x 300 @ 4:30
4 x 200 @ 3:00
5 x 100 @ 1:30
Throughout the set, it is most important to make the interval and force yourself to stay on pace. The first 500 should be comfortable but challenging, at approximately 85 percent effort. You should not have more than 10 to 15 seconds rest before launching into the next set of 2x400.