Glossary: Fitness, fatigue, and form

The numbers

• Fitness (long-term training load): 42-day rolling average of daily Load. A proxy for how much work you can absorb.
• Fatigue (short-term training load): 7-day rolling average of daily Load. A proxy for accumulated tiredness.
• Form: Fitness minus Fatigue. A proxy for freshness.

See Glossary: Load, IF, Fitness, Fatigue, Form for the underlying Load computation.

Reading Form

• Form above +25: very fresh, but you have lost training load. Common in long off-season or post-race recovery.
• Form +5 to +25: fresh and ready. Race-day target for most athletes is around +10 to +20.
• Form -5 to +5: balanced. Training and recovery roughly matched.
• Form -5 to -20: productive training stress. Most build-block work happens here.
• Form below -20: heavy overload. Sustainable for short windows; injury / illness risk rises if held too long.
• Form below -30: unsustainable.

What Form does not capture

• Wellness state. Form can be positive while the athlete is exhausted from life stress. Always pair Form with wellness trends.
• Specificity. Two athletes with the same Form can be vastly different in race readiness because the underlying Fitness was built from different work.
• Acute spikes. A single huge day can push Fatigue up briefly even if the week as a whole was reasonable.

How to use Form across a season

• Base phase: build Fitness slowly. Form hovers around 0 or slightly negative.
• Build phase: push Form negative (-10 to -20). Recovery weeks bring it back toward 0.
• Peak phase: maintain Fitness, manage Fatigue down. Form rises toward race readiness.
• Taper: Fatigue drops faster than Fitness. Form climbs to race-day target.
• Race day: Form around +10 to +20 for most A-race contexts.

Where Form lives in Grepiac

Grepiac computes Fitness, Fatigue, and Form from Activity.tss (or tss_override if set). These values surface on the athlete dashboard and on the coach view.

When Form lies

• Bad Load data: if many recent activities have wrong Load (broken power, wrong threshold), Form will be off. Use Load override to correct.
• Long gap with no activities: Form climbs sharply during gaps. The "fresh" reading is mostly detraining, not real freshness.

See also: Glossary: Load, IF, Fitness, Fatigue, Form, Load computation and override.