I had been looking around for an explanation of the swim drills in the triathlon plans. Nothing to be found on the TR forum, but the details below were posted on the Slow Twitch forum several years ago.
Re-posting here for other clueless swimmers…
Your lead arm will remain fully extended in front of you until your working arm completes a full stroke. The working arm now becomes the lead arm and remains fully extended in front of you until your working arm completes its full stroke and �catches up�.
Half Catch-Up (HCU)
This abbreviated catch-up will bring the full catch-up drill closer to your actual freestyle stroke. Instead of waiting until your working arm reaches your lead arm, start pulling with your lead hand a little earlier, when your working hand is even with your lead arm�s elbow.
Fingertips & Thumbs (F&T)
During your normal freestyle stroke, keep your elbows high and lightly drag your fingertips across the water as your working arm recovers. Then, as your working hand exits the water on the release, lightly scrape your thumb against your thigh. These two actions can be done individually or combined.
Swim with clenched fists and focus on rotating your shoulders and bending your working elbow during the catch such that you create a pull that’s nearly as powerful as one done with an open hand.
Restrict yourself to one arm�s use for an entire pool length by keeping the opposite arm extended in front of you or at your side (advanced). If necessary, perform this drills using fins until you improve to the point that you can eliminate them. Try to use a moderate kick and normal body positioning, rolling into your working arm.
Front Sculling (FS)
Stretch your arms out in front of you, fingertips pointed forward, arms no more than shoulder width apart and use both hands to propel yourself forward by �sculling� in a figure-eight pattern as you simulate the catch over & over. Use a minimal kick and do this with your head up or down.
Chest Sculling (CS)
With your chest facing down, bend your elbows and point your fingertips down while keeping your elbows high. Make the same figure-eight patterns with both hands in order to propel yourself forward, effectively repeating the center of the stroke.
Back Sculling (BS)
This time, keep your arms at your sides and point your fingertips back toward your toes as you propel yourself with those familiar figure-eight movements without moving your hands any wider than shoulder width.
Instead of turning your head to the side to breathe, raise your head to look forward and �sight� a landmark toward which you�ll swim. Breathe just as you would when turning to the side by inhaling before lowering your head, exhaling underwater, and learn to disrupt your stroke as minimally as possible in the process - eventually not at all.
Swim facedown using only your feet to propel you as you breathe just as you would during a freestyle stroke by rolling to the side and turning your head to catch some air. Focus on �pushing� your chest down while keeping your legs & hips up toward the surface as you practice balance & kicking technique.
Side Kicking (SK)
Swim on your side with your lower arm extended ahead of you and the upper arm resting against your side. Rest your head against your shoulder and look down keeping your head completely submerged while using only your kick to propel yourself. Rotate your head slightly when inhaling and try to keep your hips & legs high throughout as you swim a full pool length before switching sides.
Kick & Rotate (K&R)
Begin kicking on your side for 3-5 seconds then rotate onto your belly and �catch up� to your leading arm with the other arm bringing both arms out in front of you. Pull with the arm that was leading as you roll onto your opposite side. Kick for 3-5 seconds on this side, catch up with the other arm and immediately pull the previously leading arm and rotate to the opposite side. Over time, try to spend only 2 seconds at a time kicking on each side.
Stroke Counting (SC)
Target your stroke efficiency by trying to reduce the number of strokes you use to reach the opposite side of the pool. Count your strokes on your first trip across, then try to reduce the number of strokes during the next 2-3 trips across the pool by taking longer, more powerful pulls, rotating more & gliding a bit longer.
Bilateral Breathing (BB)
Swim your regular freestyle stroke while breathing during every third stroke forcing yourself to discover and improve your weaker side. If this is challenging & uncoordinated at first, hang in there - your clumsy side will improve with practice.
Extensive Endurance AE (Endurance)
Subthreshold ME/Intensive Endurance (Sustained Power)
Suprathreshold ME (Threshold)
Aerobic Capacity/Speed Endurance VO (VO2max)
All-Out/Anaerobic AC (High Power)
Sprint NM (Burst Power)