TSS and Taper Planner
A taper works by letting fatigue fall faster than fitness, so your form rises into a peak. This planner runs the Banister and Coggan model on your training load, projects fitness (CTL), fatigue (ATL), and form (TSB) day by day to race day, and tells you whether you will actually peak.
Enter your current numbers or connect Strava to fill them from your last 6 weeks. We call the output your Taper Plan.
Gear up
Measure your training load
The planner is only as good as the load data you feed it. A chest strap or power meter gives the cleanest TSS. Always test a new taper on a B race first.
- Chest-strap heart rate monitorRelative Effort and TSS are most accurate from a chest strap, not a wrist sensor.View on Amazon →
- Training and Racing with a Power Meter (book)The Coggan and Allen book that defines CTL, ATL, TSB, and the Performance Management Chart.View on Amazon →
- Cycling power meterA power meter gives the cleanest TSS for cyclists and triathletes.View on Amazon →
- GPS multisport watchLogs the duration and intensity that feed your training load every day.View on Amazon →
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Set your zones
FTP Calculator
Turn one FTP number into your full set of cycling power-training zones.
Train by feel and data
Heart Rate Zone Calculator
Find all five training heart-rate zones, with Zone 2 front and center.
How a taper raises your form
Fatigue (ATL) fades on a 7-day time constant while fitness (CTL) holds on a 42-day one, so cutting training load lets fatigue fall roughly six times faster than fitness, and the gap between them, your form, climbs into a peak. The art of the taper is cutting enough volume to shed fatigue without cutting so much that fitness slides. This planner shows exactly where that balance lands for your numbers.
| Form (TSB) on race day | What it means |
|---|---|
| Below 0 | Still fatigued, under-tapered |
| 0 to +5 | Fresh but slightly under-peaked |
| +5 to +25 | Peaked, the target window |
| Above +25 | Over-tapered, losing sharpness |
TSS and taper planner FAQ
What are CTL, ATL, and TSB?
CTL (Chronic Training Load) is your fitness: a 42-day exponentially weighted average of daily training stress. ATL (Acute Training Load) is your fatigue: the same average over 7 days, so it rises and falls much faster. TSB (Training Stress Balance) is your form, equal to CTL minus ATL. Positive TSB means you are fresher than your recent training; negative means you are carrying fatigue. The goal of a taper is to let ATL fall while CTL stays high, pushing TSB up into a peaked window.
What TSB should I have on race day?
Aim for a TSB between +5 and +25 on race day. That range means fatigue has cleared but you have not lost so much training that fitness fades. Below zero you are still tired; above +25 you risk feeling flat and detrained. The exact sweet spot is individual, but +5 to +25 is the widely used target for a peak. This planner color-codes every day so you can see exactly when you cross into the peaked band.
How long should my taper be?
Most endurance athletes peak with a 7 to 14 day taper. A larger, more fatigued athlete or a longer goal event (marathon, Ironman) usually needs the full two weeks to shed fatigue, while a shorter event or a fresher athlete can peak in about a week. Longer is not always better: taper too long and CTL drops, taking fitness with it. Try 14, 10, and 7 days in this tool and watch where race-day TSB lands for each.
How does the Strava sync work?
If you connect Strava, the planner pulls your last 6 weeks of activities and uses each one's Relative Effort (Strava's suffer score) as a training-stress proxy to compute your current CTL, ATL, and recent daily load. When an activity has no Relative Effort, it estimates stress from the duration instead. This fills in the starting numbers so you do not have to know your fitness and fatigue figures, then you choose the taper length and race priority.
Is suffer score the same as TSS?
Not exactly, but it is a close enough proxy for taper planning. TSS is normally derived from power or heart rate against a threshold, while Strava's Relative Effort (suffer score) is built from time spent in heart-rate zones. They track each other well in magnitude for most athletes, so using Relative Effort to seed CTL and ATL gives a realistic Performance Management Chart without a paid platform. If you have true TSS values, enter your CTL and ATL manually instead.
Do I need a TrainingPeaks subscription for this?
No. This planner computes the same Performance Management Chart math (the Banister impulse-response model that TrainingPeaks popularized) for free, and can seed it from your Strava data. You get fitness, fatigue, and form projected day by day to race day, plus a peak verdict, without a subscription. Use it to time a taper; use a paid platform if you want full season-long tracking and workout libraries.
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