I did this practice in a 20-yard pool, but you could easily adapt it to 25 yards.
Alternate 40 SA drill and 40 LA drill for 480 yards, then finish with 120 freestyle.
MAIN SET: 2180 (equivalent)
1 X 400 IM with no equipment.
10 X 40 breast kick with 10 Rocket Launchers before each 40. Take as few kicks as possible on the 1st 20; take as many kick as possible on the 2nd 20 of each interval. To vary the stress on my knees, I did each 40 in a different way:
#1: with a kickboard
#2: Head-Lead on Back with Pull Buoy (PB)
#3: Head-Lead on Back
#4: Head-Lead on Stomach
#5: Hand-Lead on Back with PB
#6: Hand-Lead on Back
#7: Hand-Lead on stomach
#8: Underwater on stomach
#9: On Back with Arms Out of the Water
#10: Kickboard again
1 X 400 “IM” with pull buoy. For each stroke, I did 20 scull/20 kick/20 scull/20 kick/20 whole stroke. This 400 uses two recent GoSwim.tv drills: BUTTERFLY – Pull-Buoy Kick and BREASTSTROKE – Pull-Buoy Kicking.
With swim tether:
Push off and do a pulldown, then 30 Head-Lead Breast Kicks, then 30 Hand-Lead Breast Kicks, then turn and swim assisted whole-stroke breast back to the starting point. Repeat.
2 X 40 breaststroke with swim tether.
1 X 400 IM with fins
80 EZ swim
WARMDOWN KICK SET: 400
Swim 4 times through the following, nonstop:
20 Underwater breast kick
20 Hand-Lead breast kick on your back
20 Hand-Lead breast kick on your stomach
20 Head-Lead breast kick on your back
20 Head-Lead breast kick on your stomach
80 EZ free/back
Total Yardage: 3260