What is Training Load?

A runner lying on a running track - the impact of training load

What is training load?

When you train, you don’t go for a run then wait until you’ve fully recovered before going for another.

Instead, you run three or more times each week (at the highest levels, perhaps running up to ten times a week). And while there will be recovery days included, mostly you’ll be running while still tired from the previous runs.

You’ll be accumulating load.

Your Training Load is the cumulative load from your training workouts.

It’s easy to overdo it, leading to injury and time spent recovering (rather than training).

But if you’re training for an event, regular (and repeated) workouts are a necessity.

It’s a balance. Load your body too little, and it will not adapt; load it too much or too quickly, and it will break down instead of adapting; load your body correctly, and sustained long-term improvements are possible.

Training Load Scores

How can you monitor your Training Load?

Using a Training Load Score calculated for each workout.

Training Load Scores combine ‘how hard?’ and ‘how long?’

They represent each workout’s metabolic stress – its impact on your body from the workout intensities and durations.

Training Load Scores are also known as Training Stress Scores (TSS) or Running Stress Scores (RSS) but the word ‘Stress’ may be confusing, implying mental stress rather than physical or metabolic stress.

Load (rather than Stress) helps remove potential confusion, and is the term used by Steve Palladino in his article library.

Training Load Scores are relative to your Threshold Power

A one-hour run at Threshold Power produces a Training Load Score of 100.

Why?

Scoring relative to your Threshold Power means Training Load Scores:

match improvements in your fitness. As you become fitter, you can run the same workouts with less additional load; or you can handle harder workouts for the same additional load.
match individual capabilities. If our thresholds are different and we run a workout together, your training load score for the workout will differ from my training load score for the same workout, reflecting our individual capabilities.

Counter-intuitively, if your fitness improves, and you run the same workout as one you ran earlier in your training, you’ll run it at a higher intensity, but end up with the same Training Load Score.

In numbers, if your Threshold power has improved from 250 Watts to 270 Watts, and you run a workout with 16-minute intervals at 94-96% of Threshold power, you’ll run the intervals at 235-240 Watts initially, repeating the workout at 258-264 Watts later in your training (higher intensity) but end up with a Training Load Score of 80 for both runs – your fitness has improved, you can handle the harder workout, and the relative impact of your workout is the same.

Training Load Scores are the foundation for metrics you can use to monitor your training load.