Training load explained: Effort, Power, Fitness, Fatigue and Form

• General

TrainerPlan turns every workout into a single number — how hard it was — and then tracks what those numbers do to you over weeks and months. Five words on the screen carry the whole system: Effort, Power, Fitness, Fatigue and Form.

If you have used another platform

The concepts are the industry-standard ones; only the labels differ. This table is worth keeping in mind while you read the rest:

In TrainerPlan Elsewhere you may know it as Effort TRIMP (heart-rate training load) Power TSS® — Training Stress Score® Fitness CTL (Chronic Training Load) Fatigue ATL (Acute Training Load) Form TSB (Training Stress Balance)

Effort and Power: two ways to score one workout

Effort scores a workout from heart rate. It weighs time spent in each zone, so an hour easy scores far less than an hour hard. It works for any sport where you wear a heart-rate strap or watch — running, swimming, rowing, cross-country skiing, the gym.

Power scores a workout from power output instead, which is more precise because it measures work done rather than the body’s response to it. It needs a power meter, so in practice it means cycling and, increasingly, running with a power pod.

You choose which one drives your charts with the Source selector on the athlete’s dashboard: Effort, Power, or Power & Effort combined. Most coaches leave it on the combined option, which uses power where it exists and falls back to heart rate everywhere else — so a cyclist’s turbo session and their weekend run both count.

Set your thresholds first, or the numbers mean nothing

Both scores are relative to your athlete. Effort needs a threshold heart rate; Power needs an FTP. Without them TrainerPlan has no scale to measure against, and the charts stay flat no matter how much training goes in. If your Fitness line is a flat zero, an unset threshold is almost always why.

TrainerPlan can also detect threshold changes for you from synced workouts and offer a one-click update, so the scale keeps up as the athlete gets fitter.

Fitness, Fatigue and Form: what the training does to you

Once every workout has a score, the chart tracks three running averages of those scores.

• Fitness is a 42-day weighted average. It moves slowly, because fitness is built slowly. It is the honest measure of the work an athlete is actually carrying.
• Fatigue is a 7-day weighted average of the same scores. It reacts fast — one big weekend sends it up, a rest week drops it.
• Form is simply Fitness minus Fatigue. It is the one to watch before a race.

Both averages are exponentially weighted, which is a formal way of saying yesterday counts more than a month ago, and a session fades in influence rather than dropping off a cliff.

Reading Form

Form is the gap between what an athlete has built and what they are currently carrying.

• Form is negative — Fatigue is above Fitness. They are absorbing a hard block. Expected during heavy training; a bad place to race from.
• Form is around zero — training and recovery are balanced. Where most of a season sits.
• Form is positive — Fatigue has dropped below Fitness. They are fresh. This is what a taper is engineering, and why Form usually climbs in the last ten days before an event.

Form staying strongly positive for weeks is not a good sign: it usually means Fitness is falling, not that the athlete is peaking. The point of a taper is to lift Form while Fitness stays high.

Where to find it

Open an athlete and go to their dashboard. The Fitness / Fatigue / Form chart is there, with the Source selector above it. You can also add it to a custom analysis dashboard alongside your other charts.

Planned workouts count too: TrainerPlan projects the chart forward using the sessions still on the calendar, so you can see what a training block will do to an athlete’s Form before you commit to it.

Training Stress Score® and TSS® are registered trademarks of Peaksware, LLC. CTL, ATL and TSB are terminology used by TrainingPeaks.