My longest and hardest training is usually in the middle of the week. I am approaching 4,000 meters in a swim workout gradually.

Warm up:

• 400 freestyle
• 3 x (200 pull buoy & 200 flutter kicks)

Drills:

• 4 x 100 1-arm swim

Main sets:

• 3 x ( 3 x 100 descending*)
• 1 x 200
• 1 x 300
• 1 x 400

Total Distance (in meters): 3800

* In the descending sets, I started with 20 seconds of rest between the first and second 100-meter, then I rested for 10 seconds between the second and third 100-meter. I repeated the whole set 3 times.