Half-Marathon Float Session

Workout - Half-Marathon Float Session

• 17min 30s @ 6'00''/km
• 6 lots of:
  • 2.0km @ 5'45''/km
  • 1.0km @ 5'45''/km
  • 53s rest
• 12min 30s @ 6'30''/km

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Intro: Check out “I Ran A 66 Minute Half Marathon After THIS WORKOUT” from Ben Is Running — if you haven’t watched it yet, it’s worth your time. Here’s a breakdown you can use to run this session yourself. Watch the full video for the complete breakdown.

Key Points:

• The workout is structured as 7 × 2 km intervals at half‑marathon intensity, with 1 km easy recovery segments between them (adds up to roughly 22 km total including a 3 km warm‑up).
• Training at altitude requires pacing adjustments of about 10‑12 seconds per km slower than your sea‑level pace.
• Aim for ~3:25 min/km on the 2 km efforts (equivalent to half‑marathon effort) and ~3:50‑3:55 min/km on the 1 km float (around 4 minutes each).
• Heart‑rate climbs to roughly 160 bpm during the float portions at altitude — this signals how hard your body is working, so pay attention to your effort level.
• The runner finished 6 intervals instead of the full 7, a smart call before a race to protect freshness and prevent fatigue.

Workout Example:

Warm‑up: 3 km easy (out‑and‑back)

Repeat 6‑7 times:
  • 2 km at ~3:25 min/km (half‑marathon intensity)
  • 1 km easy float at ~3:50‑3:55 min/km (≈4 min) – keep HR around 160 bpm

Total volume: ~22 km (including warm‑up)

Running this at sea level? Shift your 2 km interval pace to ~3:10 min/km — that’s roughly equivalent to the altitude paces above.

Practical Tips:

1. Account for altitude — expect to run about 10‑12 seconds per km slower than your normal training paces.
2. Watch your heart rate on the float sections; if it climbs higher than expected, back off the intensity slightly or cut the float shorter.
3. Know when to stop — finishing 6 reps instead of 7 kept the runner fresh heading into race week, a lesson in respecting your recovery needs.

Closing Note: Test this altitude‑adjusted 2K‑1K float session on your own, and match the paces to what feels right based on your recent work in the Pacing app. See what kind of boost you get on race day. 🚀

References

• I Ran A 66 Minute Half Marathon After THIS WORKOUT - YouTube (YouTube Video)