The hardest part of treadmill training is translating coach-speak (“4 × 8 min at threshold”) into actual treadmill settings (km/h and incline). The trick is to anchor every zone to your current race times and let the math fall out.
Below is a reference table for a runner whose current bests sit roughly at:
- 5K: 19–20 minutes (~15.5–15.8 km/h)
- 10K: ~42 minutes (~14.3 km/h)
- Half marathon: ~1:34 (~13.4 km/h)
- Full marathon: ~3:19 (~12.7 km/h)
That is a runner whose limiter is lactate threshold durability rather than raw speed. The zones shift down or up proportionally for slower or faster runners — the relationships between the zones are what matters.
Treadmill speed zones
| Zone | Purpose | Speed (km/h) | Incline |
|---|---|---|---|
| Recovery | Very easy, post-hard-day | 9.5–10.5 | 0–1% |
| Easy / Zone 2 | Aerobic base | 10.5–12.0 | 1% |
| Steady | Moderate aerobic | 12.0–13.0 | 1% |
| Marathon Pace (MP) | Goal race effort | 12.5–13.0 | 1% |
| Threshold / Tempo | ~1-hour race effort | 13.8–14.3 | 1% |
| 10K effort | Hard but controlled | 14.3–14.7 | 1% |
| 5K effort (VO2) | Top end aerobic | 15.2–15.8 | 1% |
| Speed work | Neuromuscular | 16+ | 0–1% |
The 1% incline approximates the wind resistance and uneven push-off you would face outdoors. Skip the incline only for short fast intervals where leg turnover matters more than equivalent effort.
Calibrating your own zones
If you don’t know your current race times, two field tests give a good first estimate:
- 30-minute time trial. Average speed over the last 20 minutes is roughly threshold pace.
- 5K time trial. Subtract 4–5% from average 5K speed to get threshold. Add roughly 8–10% to 5K speed for stride/sprint work.
A simpler heuristic: your easy pace should let you hold a conversation. Your threshold pace should let you speak in short phrases. Your VO2 pace should not.
How each distance responds to which zone
| Race distance | Highest-leverage workouts |
|---|---|
| 10K | Threshold + VO2 max |
| Half | Threshold + long tempo + progression runs |
| Full | Long runs + marathon-pace blocks inside long runs |
Threshold is the common denominator. A runner who only had time for one quality session per week and wanted improvement across all three race distances should make it a threshold workout.
The 80/20 distribution
Most well-coached endurance runners follow a ratio close to:
- ~80% easy / aerobic running
- ~15% threshold
- ~5% VO2 max and speed
Going harder than 20% of the time leads to plateau and injury, not faster races. The temptation to run every easy day a bit too fast is the most common self-inflicted limiter at the intermediate level.