This is one of the sessions actually moving the needle on my swim right now.
It's VO2 max work, but the interval length's been creeping up. Started at 50s a month ago, now I'm holding this pace for 75s, aiming for 100s.
Why the short rest is the point
Rest between reps is only 10 to 15 seconds, so I'm never fully recovering. That's deliberate. It trains your body to clear lactate while still swimming at pace, which is closer to what an actual race demands than the longer-rest version of this set, which just builds raw top-end speed.
This week's set was 75s at VO2 max, 3,000m total in 49:16, average pace 1:39 per 100m. Came out at 99 TSS and 1.07 intensity factor against a planned 77 TSS and 0.88, so I pushed harder than prescribed, which the numbers don't let you hide from.
Once I can hold that pace for 100s instead of 75s, I'll know I'm ready to swim the full Ironman distance at CSS pace, which should put me around 1:05 for the swim leg in Japan.
The actual change after a month of this though, my stroke rate's finally climbing without losing form. That's the bit I actually needed to fix.
