Cutdown blocks
Long blocks that shorten and speed up through the session.
Also called: descending blocks.
Cutdown blocks bridge marathon-pace work and threshold work in a single run: the early blocks build volume at a manageable effort, the later ones sharpen. A good session for the transition from base to build, when you want quality but not yet the specificity of race-pace work.
The session
Shown at a 4:00 marathon reference — 52 min total, about 8.3 km, including 24 min of quality work.
Warm-up
- 12 min easy (6:43–7:24/km)
Main set
- 12 min @ 5:41/km (M)
- 3 min jog
- 8 min @ 5:14/km (T)
- 3 min jog
- 4 min @ 4:48/km (5K)
Cool-down
- 10 min easy (6:43–7:24/km)
Why this session works
Three shrinking blocks, each faster: marathon → threshold → 5K. One session that walks the whole aerobic curve top to bottom.
Source: Daniels 2014; Casado et al. 2022. Training phase: build.
Run it at your own paces
Open the workout generator and enter a recent race time — every rep length, recovery and target pace is recalculated for your fitness, and the session exports to .fit for a Garmin watch.
Frequently asked questions
What is a cutdown blocks?
Long blocks that shorten and speed up through the session. Cutdown blocks bridge marathon-pace work and threshold work in a single run: the early blocks build volume at a manageable effort, the later ones sharpen.
How long is this session?
At a 4:00 marathon reference it comes to 52 min and about 8.3 km, of which 24 min is prescribed quality work. The generator scales both to your own paces, so a faster runner covers more ground in the same time.
Who is this workout for?
It is written for the build phase of a marathon build. The distances shown suit a 4:00 marathoner; enter your own recent race time in the generator and every rep length and target pace is recalculated for you.
More fartlek and combination sessions
- Fartlek — Varied faster efforts inside a continuous run, with no track and no fixed structure.
- Mona fartlek — A fixed 20-minute sequence of hard efforts with equal float recoveries, descending in length.
- 10-20-30 workout — Repeated cycles of 30 seconds easy, 20 seconds moderate and 10 seconds near-sprint.
- Combination workout — Threshold, then interval, then repetition work in a single session — three gears in one run.