Thirty seconds on, thirty seconds off
The 30/30 is the most balanced interval format: as much rest as work. With 10 rounds, the block lasts 9 minutes and 30 seconds after the 10-second countdown. The equal ratio makes it a great first step into interval training, and also a classic session for runners.
A favorite of runners
In the late 1990s, the French physiologist Véronique Billat studied runners doing 30 seconds fast and 30 seconds slower. In her tests, the fast part was run at the speed that reaches maximal oxygen uptake (vVO2max), and the slow part at about half of it. The runners stayed longer at their VO2max, with less lactate, than in a hard continuous run. The “Billat 30-30” has been a staple of running clubs ever since, especially in France.
How fast is fast? The target speed is roughly the one you could hold flat out for about six minutes. The slow part is a jog, not a stop.
Sample 30/30 sessions
| Session | Work (30 s) | Rest (30 s) |
|---|---|---|
| Track run | Fast run at about your 6-minute pace | Easy jog |
| Bodyweight circuit | Jumping jacks, mountain climbers, squats, in turn | Walk around, breathe |
| Rower or bike | Strong effort | Very easy pace |
| Jump rope | Fast skipping | Rest, rope in hand |
Runners often do two sets of 10 rounds, with 3 to 5 minutes of easy jogging in between. Press Start again for the second set.
Getting the pace right
- Even pace: the last round should be as fast as the first one. If you slow down a lot, start a bit easier next time.
- Keep moving during the rest when you run: a slow jog keeps the session effective.
- Progress by adding rounds before adding speed, then move on to 40/20 for less rest.
Warm up for 10 minutes of easy jogging before the first round, and cool down the same way after the last one.