Training sets suggestion

credit:  http://www.fionafordcoaching.com/

Goldilocks set-an example of 'CSS' swim training

Main Set For Lane 2 (for those swimming 1:35 to 1:50 for a fast 100m)
Repeat this set three times through, taking 50 sec rest between each set:
100m + 25 sec rest
200m + 25 sec rest
200m 

Main Set For Lane 3 (for those swimming sub 1:35 for a fast 100m)
Repeat this set three times through, taking 40 sec rest between each set:
100m + 20 sec rest
200m + 20 sec rest
300m

swimming three times a week 

1x Technique orientated session

1x Endurance biased session with longer steady paced swim sets

1x Quality session working on your threshold speed

"Spike Set"

WARMUP: 400m easy freestyle focusing on relaxed breathing technique, followed by 200m steady pull buoy focusing on good rotation through the hips and shoulders.

DRILLS: 4x 50m as Scull #1 (see here) for 15m followed by 35m freestyle. Take 10 sec rest between each 50m and preferably use a pull buoy to isolate the focus on the catch.

MAIN: 

1. 12x or 16x 50m with every 4th 50m as a sprint. On the other 50m intervals all you have to do is swim fast enough to make the turn-around time. The selected turn-around time here should be your half of your 100m threshold pace + 5 seconds. i.e. if you can do 100m intervals in 1:50, half of this would be 55 sec + 5 sec = 60 sec. A swimmer doing 1:30 for their intervals would make their turn-around time 50 sec, etc. You don't need to be overly pedantic about this, just choose a time to start off which you think will give you about 3 to 5 seconds rest between each 50m when swimming at a good pace.

2. 9x or 12x 50m with every 3rd 50m as a sprint. This time add another 5s to your turn-around time from the previous set. This extra rest will be very welcome and will allow you to swim the sprints faster than the previous set.

3. 6x or 8x 50m with every 2nd 50m as a sprint. Again, add another 5s from Set #2.

4 Finally 3x or 4x 50m, sprint every one (!) with another 5s rest added onto Set #3.

Cool down with a few easy drills to bring your heart rate back down