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Acute Training Load (ATL) Calculator

Calculate your Acute Training Load (ATL) to track recent training stress and fatigue levels over the past week.

Acute Training Load (ATL) Calculator

Assess short-term training stress by updating ATL with today’s TSS and decay constants.

Understanding the Inputs

Accurate ATL depends on reliable training data

  • Current ATL (optional): Existing acute training load value representing short-term fatigue. Leave blank to calculate from zero.
  • Daily TSS: Training Stress Score for today’s session or daily total. Higher TSS generates greater acute fatigue.
  • Time Constant (days): Decay constant used for acute load. Seven days is standard; shorter values emphasize recent workouts even more.

Related Calculators

Track training load holistically

Chronic Training Load (CTL)

Pair ATL with CTL to compute Training Stress Balance.

Training Stress Score (TSS)

Daily TSS updates drive ATL changes—plan workouts accordingly.

Training Impulse (TRIMP)

Use heart-rate-based loading when power data are unavailable.

Power-to-HR Efficiency

See how fatigue alters efficiency as ATL fluctuates.

Complete Guide: Managing Acute Fatigue

Use ATL to steer daily training decisions

Acute Training Load reflects how taxing recent workouts are. Tracking ATL helps you recognize when to push harder and when to schedule recovery. Combine ATL with CTL to calculate Training Stress Balance, a quick indicator of freshness. Remember that physiological signals—resting heart rate, mood, appetite, soreness—should corroborate load metrics before major decisions.

Sustainable progression hinges on balancing load and recovery. Use ATL to ensure hard sessions are followed by easy ones, monitor taper effectiveness, and prevent overreaching before competitions. Adjust the time constant for your sport and individual response to capture fatigue accurately.

Frequently Asked Questions

Short-term load management essentials

What is Acute Training Load (ATL)?

ATL is the exponentially weighted average of recent TSS (typically last 7 days) and indicates short-term fatigue or training stress.

How is ATL different from CTL?

ATL captures short-term stress while CTL describes long-term fitness. Comparing them helps determine fatigue via Training Stress Balance (TSB = CTL − ATL).

Why use a time constant of seven days?

Seven days approximates one week of training microcycles. You can adjust between 5–9 days depending on sport and personal recovery dynamics.

What ATL range should I target?

The absolute value depends on discipline and fitness. Focus on how ATL compares to CTL and how it trends week to week rather than chasing a fixed number.

How fast can ATL change?

Because ATL weights recent workouts heavily, it responds quickly to high-TSS days. Expect noticeable jumps after intense sessions, followed by declines during rest days.

What happens if ATL stays higher than CTL?

Persistently high ATL indicates accumulating fatigue. Training Stress Balance becomes negative, signaling the need for recovery or reduced load.

How does ATL inform tapering?

Reducing ATL while keeping CTL stable helps shed fatigue before A-races. Track ATL drops to ensure you arrive fresh but still fit.

Should strength workouts contribute to ATL?

If quantified with TSS or a reliable load metric, yes. Many athletes approximate strength sessions using session RPE × duration to capture their contribution.

Can I run separate ATL calculations for different sports?

Yes. Triathletes often maintain sport-specific ATL/CTL to tailor fatigue management per discipline.

How often should I update ATL?

Update daily with new TSS data. Monitoring trends every few days helps adjust training before fatigue becomes unmanageable.

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Acute Training Load (ATL) Calculator

Calculate your Acute Training Load (ATL) to track recent training stress and fatigue levels over the past week.

How to use Acute Training Load (ATL) Calculator

Step-by-step guide to using the Acute Training Load (ATL) Calculator:

  1. Enter your values. Input the required values in the calculator form
  2. Calculate. The calculator will automatically compute and display your results
  3. Review results. Review the calculated results and any additional information provided

Frequently asked questions

How do I use the Acute Training Load (ATL) Calculator?

Simply enter your values in the input fields and the calculator will automatically compute the results. The Acute Training Load (ATL) Calculator is designed to be user-friendly and provide instant calculations.

Is the Acute Training Load (ATL) Calculator free to use?

Yes, the Acute Training Load (ATL) Calculator is completely free to use. No registration or payment is required.

Can I use this calculator on mobile devices?

Yes, the Acute Training Load (ATL) Calculator is fully responsive and works perfectly on mobile phones, tablets, and desktop computers.

Are the results from Acute Training Load (ATL) Calculator accurate?

Yes, our calculators use standard formulas and are regularly tested for accuracy. However, results should be used for informational purposes and not as a substitute for professional advice.