Originally Posted by s.sciame
1) one session is threshold oriented: the main set is typically about 2km long, at threshold pace, split in repetitions from 100 to 400m with short recoveries (10 to 20s)
2) one session is endurance oriented: the main set is typically about 4km long, swum at 3s to 6s/100m below threshold pace, split in 400m reps with short recoveries (<= 20s)
3) one session is not quite speed oriented, it's more about getting used to change pace for a while and then settle down to cruising pace again: the main set is typically 1.6km long, swum slightly faster than threshold, split in 100m reps with little bursts of sprint on 1 or 2 lengths out of 4 and simulating open water starts and sighting (short recoveries again)
Thanks--this is helpful to check against my own plans. Thinking like a runner (not sure how productive that is, but it tends to be how I approach planning my training sessions), I've been doing something similar:
1) 1-2 sessions where endurance is targeted: long repeats (400m for me right now) on relatively short rests (30s now, but this will drop little by little). 4000m is my longest session right now. I think I may decrease pace and decrease rest a bit--I have probably been doing these a little too fast right now.
2) speed work (don't know what else to call it--it's definitely not all-out sprinting), each session concentrating on various times to swim at an effortful pace. This mimics my running, where I'd run repeats at various distances, much faster than race pace but by no means sprinting. So, something like:
400m running repeats (1:15-1:30 each) become 100m swimming repeats (about 1:20 now)
800m running (3:15-3:30) become 200m swimming repeats (about 2:57 now)
1600m running (6:30-7:00) become 400m swimming repeats (about 6:48 now)
Each of the above examples would be done in a different practice session, so I hit 1 or 2 different lengths of "speed work" each week.
All this on 1-2 minutes rest/easy recovery (good for drills/tightly focused slow repeats in the pool, probably), though I wasn't very strict--wanted to be fairly well rested for each repeat. In running, I started with 4 x 400 and added a repeat each week up to 10 x 400, descending times slightly (if not, it meant I started too fast).
I never did more than 3200m speed work no matter what the distance was for that week, and worked up to max reps gradually over several weeks. Then dropped down to periodize effort. I really saw my pace improve over the season by hitting a variety of distances with faster-than-race-pace efforts like this. Since I was racing long (50k to 50 mile) races, I didn't have to be very fast for this to be "speed" work.
3) The threshold/tempo pace repeats--I will experiment with adding this (steady but fairly fast effort for 10-15 minutes within a longer repeat or session). I'll probably work on longer (400m and up) repeats, bookended by easier-paced repeats for warm-up and cool down.
It'll be interesting watching how this approach works with swimming. Thanks again for the suggestions so far--I'd be very interested to hear other ideas, too. Especially from those who have already done a long swim event!