Part XI · Swim workouts
Threshold Swim: Hold a Hard Effort Lap After Lap
Warm up 12 minutes, swim four to eight 5-minute blocks at about 7 out of 10 with an easy minute between, then cool down 10. It raises the effort you can hold before you tire.
Workout at a glance
Threshold · Lactate clearance, sustainable race pace
45–69 min
- 01
Warmup
You could keep this up for hours
12 min
RPE 3/10
- 02
Threshold
You could hold this for about 20 minutes
1 min recovery · easy swim
4–8 × 5 min
RPE 7/10
- 03
Cooldown
You could keep this up for hours
10 min
RPE 3/10
The lesson
- 01
Warm up for 12 minutes
Easy swimming, building a little over the last few minutes. No drills today. The blocks need you fresh.
- 02
How long could you keep it up?
About twenty minutes. If you could hold it for an hour, you are going too slow; if only five minutes, too fast. That test finds the effort; swim every block at it. About 7 out of 10, your breathing quicker than in the warm-up but even, stroke after stroke.
- 03
Swim 5-minute blocks
Four to eight of them, with 1 minute of easy swimming between. Your app sets how many. Freestyle, body long, every block at the same effort. Swim the clock, not the wall, so it is the same session in open water.
- 04
Why blocks
Hold it much past twenty minutes and the effort creeps up too hard. The easy minute lets you swim more minutes at the right effort.
- 05
Keep the stroke long
If your reach shortens and your arms start to hurry, you are going too hard. Ease off until the stroke lengthens again.
- 06
Never grit your teeth
If your breathing turns ragged and you are clinging on, you have slipped into VO2max work, which takes much longer to recover from. Back off until your breathing is even again.
- 07
Cool down for 10 minutes
Easy swimming, any stroke. You finish tired but in control, as if you could have held it a little longer.
Watch for
- Starting too fast. The first ten minutes feel strong, then the later blocks fall apart and you finish slower than you began.
- Turning it into a race. You swim the last minutes all-out and need days to recover instead of one.
- Hanging on the wall in the easy minute. Keep swimming easy, so the next block starts warm.
- Letting the stroke go short and choppy. You work harder for less and train the stroke you do not want.
How hard is a threshold swim? Hard but steady: an effort you feel you could keep up for about twenty minutes, about 7 out of 10, with your breathing quick but even. If you could hold it for an hour, go a little harder; if only five minutes, or your breathing turns ragged, ease off. That finds the effort, and you hold it for every block.
Can I use heart rate or pace for a threshold swim? Not well. Heart rate usually runs lower in the water than on land, and MONS sets swims in minutes, not metres, so there is no pace to chase. Your breathing rhythm and the feel of the effort work the same in any water.
How often should I do a threshold swim? Your plan spaces them for you: at most two a fortnight, counting threshold runs, rides and swims together, added one at a time as your body handles them.
Next
VO2max Swim: Hard Repeats That Make Fast Laps Feel Easier→One step harder. Two-minute repeats at an effort you could only keep up for a few minutes.
From the book
31Learn to feel the right effort by heart rate→