CSS 20 x 100 m in Blocks of Five
A 3800 m advanced threshold session with twenty 100 m repeats at CSS on 10 seconds rest, split into four blocks of five.
- Duration
- 1 h 20 minestimated
- Distance
- 3,800 m
- Effort
- 103
- Level
- Advanced
- Focus zone
- Threshold
Your values
Targets relative to your threshold values. Enter your values to see absolute numbers.
100% is your threshold pace. Higher values are faster, lower values are slower.
| # | Step | Length | Target |
|---|---|---|---|
| 1 | Warm-upEndurance Easy freestyle | 600 m | 85-92% CSS pace |
| 2 | Rest | 20 s | |
| 4 ×Repeat these steps | |||
| 3.1 | Warm-upRecovery Drill of choice | 50 m | 75-85% CSS pace |
| 3.2 | Warm-upEndurance Freestyle | 50 m | 85-92% CSS pace |
| 3.3 | Rest | 15 s | |
| 4 ×Repeat these steps | |||
| 4.1 | Warm-upTempo Build to CSS pace | 50 m | 92-96% CSS pace |
| 4.2 | Rest | 15 s | |
| 5 | Rest | 45 s | |
| 5 ×Repeat these steps | |||
| 6.1 | IntervalThreshold Block 1, freestyle at CSS pace | 100 m | 99-102% CSS pace |
| 6.2 | Rest | 10 s | |
| 7 | Rest | 30 s | |
| 5 ×Repeat these steps | |||
| 8.1 | IntervalThreshold Block 2, freestyle at CSS pace | 100 m | 99-102% CSS pace |
| 8.2 | Rest | 10 s | |
| 9 | Rest | 30 s | |
| 5 ×Repeat these steps | |||
| 10.1 | IntervalThreshold Block 3, freestyle at CSS pace | 100 m | 99-102% CSS pace |
| 10.2 | Rest | 10 s | |
| 11 | Rest | 30 s | |
| 5 ×Repeat these steps | |||
| 12.1 | IntervalThreshold Block 4, freestyle at CSS pace | 100 m | 99-102% CSS pace |
| 12.2 | Rest | 10 s | |
| 13 | RecoveryRecovery Easy backstroke and freestyle | 300 m | 75-85% CSS pace |
| 14 | Cool-downRecovery Easy choice of stroke | 300 m | 75-85% CSS pace |
About this workout
Twenty 100s at CSS give you 2000 m of threshold work, enough to make a real difference to the pace you can hold over 1500 m and beyond. The short rest of 10 seconds keeps the effort close to continuous, and the extra 30 seconds after each block of five lets you reset mentally before the next one.
Hold the same time on every 100, at CSS pace. The first block should feel controlled, the second steady, the third is where the work starts, and the fourth tests whether you paced the first three well. Use the block breaks for a sip of water and two or three slow breaths, not for longer rests.
The set is for experienced swimmers who already handle 10 to 15 x 100 at CSS with 10 to 15 seconds rest. In the week before an important race, cut it to two blocks.
Tips
- Swim the first block at CSS even if it feels easy, it decides the last block.
- Let the watch count the repeats so you can focus on the pace.
- Keep the streamline off each wall long, it saves energy over 80 push-offs.
Good forPoolMasters swimmingHalf-distance triathlonFull-distance triathlon
Season phaseBuildPeak