What cruise intervals are
Threshold running in blocks of 5 to 15 minutes, with a minute's easy jog for every 5 minutes of running. The same benefit as a tempo run, easier to hold.
The name and the idea come from Jack Daniels' Running Formula. The pace is your threshold (T) pace, the same as a tempo run. Only the shape is different: the jog breaks the run into blocks, so you can hold good form and an even pace for longer in total.
The rest rule: a minute for every 5 minutes
Daniels' rule is a short jog of about a fifth of the rep's length. Run-R rounds it to the nearest 30 seconds and never goes under a minute, so a watch can count it.
| Rep | Jog after it |
|---|---|
| 5 min | 1 min |
| 6 min | 1 min |
| 8 min | 1:30 |
| 10 min | 2 min |
| 12 min | 2:30 |
| 15 min | 3 min |
The rest is short on purpose. It lets your breathing settle, not recover fully. If you need longer than this, the pace is too fast.
Cruise intervals or a tempo run?
| Tempo run | Cruise intervals | |
|---|---|---|
| Pace | Threshold | Threshold |
| Shape | About 20 minutes without a break | Blocks of 5 to 15 minutes with a short jog |
| Total at threshold | About 20 minutes | 15 to 40 minutes in Run-R plans |
| Good for | Holding a hard pace without a break, mentally and physically | More time at threshold for the same effort, and a gentler start |
Both do the same job. Run-R plans use both: they start with short blocks, add the 20 minute tempo along the way, and build to longer sets. See the full order on the tempo run page.
Cruise intervals and track intervals are not the same
Interval (I) sessions such as 5 × 1000 m are quicker, at about the pace you could race for 10 to 12 minutes, with a jog about as long as the rep. Cruise intervals are slower and the jog is much shorter. Mixing the two up is the usual way they go wrong: run cruise intervals at interval pace and the short rest stops being enough.
Sources
- Jack Daniels, Daniels' Running Formula (Human Kinetics, 3rd and 4th editions): cruise intervals, the 5 to 1 work to rest rule, threshold pace.
- Run-R's engine for the sessions and paces: how Run-R builds plans.