Overview, Bryan

Chronic Training Load — a rolling 42-day (six-week) average of your daily TSS. TrainingPeaks calls this your "Fitness" score. Because it's smoothed over six weeks, one big or one missed session barely moves it — it only rises when higher training load is sustained, which is what makes it a decent stand-in for real, durable fitness rather than a lucky one-off day.

Each day updates the number a little toward that day's TSS (0 on a rest day) and a little away from yesterday's value — a 1/42 nudge every day adds up to the full 42-day average over time.

• New to the app / recently reconnected Strava? Your CTL starts from 0 and climbs as your synced history fills in — expect it to read low for the first few weeks even if you're already fit, exactly like TrainingPeaks' own guidance to treat a freshly-seeded Fitness score cautiously until ~4–6 weeks of real data has accumulated.
• Rising CTL — you're building fitness through consistent training.
• Falling CTL — training volume has dropped (planned rest, a break, injury) and fitness is slowly fading.

Acute Training Load — the same idea as CTL, but averaged over just 7 days instead of 42. TrainingPeaks calls this your "Fatigue" score. Because the window is so short, it reacts fast: a few hard or long sessions in a row push it up within days, and a few easy or rest days bring it back down just as quickly.

Same walk-forward math as CTL, just with a 1/7 nudge each day instead of 1/42 — so it tracks your last week, not your last six.

• ATL above CTL — you've loaded more this past week than your six-week average: normal after a hard block, and exactly what pushes Form (TSB) negative.
• ATL below CTL — this past week was lighter than your average: normal during a rest/taper week, and what pushes Form positive.

Training Stress Balance — simply Fitness minus Fatigue. It's the headline number on the gauge, and the fastest read on whether you're rested or carrying load right now.

• Above +10 — fresh, tapered, primed for a big effort. Great right before a key session or event; held too long and fitness (CTL) starts to slide.
• −10 to +10 — the sustainable middle ground. Neither strongly fresh nor fatigued — most day-to-day training happens here.
• −10 to −30 — carrying real, productive overload. This is where fitness gets built, as long as easy days stay genuinely easy so the load gets absorbed rather than piling up.
• Below −30 — heavy fatigue. Coaches generally treat this as a signal to prioritise recovery — the risk of injury, illness or burnout rises the longer it stays this deep.

These bands are a general guide, not a hard rule — they vary a bit by athlete, and this app's own coach commentary uses them (not a wearable's "readiness" score) to describe your Form each day.