Glossary
Training load
A single number for how much work one run cost you, from its intensity and its duration. A 60-minute easy run scores roughly a third of a 60-minute hard one.
What it is
Training load turns a run into one number. It multiplies how hard you went by how long you went for. Every system does this slightly differently, but they all rest on the same idea, first written down by Banister in 1980.
The unit is arbitrary. What matters is that the numbers are comparable to each other. A load of 90 is twice the work of a load of 45, in that system.
| What you ran | Rough load | Why |
|---|---|---|
| 60 min easy | 40–60 | low intensity, moderate time |
| 60 min at threshold | 110–140 | high intensity for a long time |
| 30 min of intervals | 70–90 | very high intensity, short |
| 3 hours easy | 130–170 | low intensity, a lot of time |
What it is not
It is not how hard the run felt. Two runners can post the same load and have had completely different days. It is also not fitness. Load is what you spent, not what you gained — which is why a fitness score can fall in your best block.
And it is not comparable across apps. A load of 120 in one app is not a load of 120 in another, because the intensity term differs.
What moves it
- Duration. The strongest lever. Doubling a run roughly doubles its load.
- Intensity. Load rises faster than linearly with effort, so hard running scores heavily for the time spent.
- Heart rate accuracy. If your zones are set from a wrong maximum, every load figure built on heart rate inherits that error.
- Heat. Heart rate rises in heat at the same pace, so the same run scores higher on a hot day.
When to ignore it
Ignore a single run's load. It is noisy, and one number does not mean much.
Ignore it entirely for the first two weeks with a new watch or app. The baselines have not settled yet.
Ignore it when it disagrees with how you feel over several days. Load knows nothing about your sleep, your job, or whether you are getting ill.
Sources
- Banister EW, Calvert TW. Planning for future performance: implications for long term training. Can J Appl Sport Sci 5(3):170-176, 1980 primary
- Foster C et al. A new approach to monitoring exercise training. J Strength Cond Res 15(1):109-115, 2001 primary
- Bourdon PC et al. Monitoring athlete training loads: consensus statement. Int J Sports Physiol Perform 12(s2):S2-161, 2017 reference