Calculate your TRIMP training load using Banister's model. Track session intensity with heart rate data and monitor acute vs chronic training load ratio.
Training load quantification is essential for preventing overtraining and optimizing performance. TRIMP (TRaining IMPulse), developed by Dr. Eric Banister in 1991, is one of the most widely validated methods for measuring the physiological stress of a workout using heart rate data.
This calculator computes your TRIMP score for a session based on duration, average heart rate, resting heart rate, and max heart rate. It also provides session RPE-based training load as an alternative when heart rate data isn't available.
By tracking TRIMP over time, you can monitor your acute (7-day) and chronic (28-day) training loads and keep the ACWR (Acute:Chronic Workload Ratio) in the optimal zone to maximize fitness while minimizing injury risk. Whether you are a beginner or experienced professional, this free online tool provides instant, reliable results without manual computation. By automating the calculation, you save time and reduce the risk of costly errors in your planning and decision-making process.
Training by feel alone leads to inconsistency. TRIMP provides an objective number for each session that accounts for both duration and intensity. By tracking your weekly TRIMP, you can ensure you're progressively overloading, recovering adequately, and staying in the optimal training zone. Having a precise figure at your fingertips empowers better planning and more confident decisions.
Banister TRIMP = Duration(min) × ΔHRratio × e^(b × ΔHRratio) Where: • ΔHRratio = (HRavg − HRrest) / (HRmax − HRrest) • b = 1.92 for males, 1.67 for females Alternative: Session RPE Load = Duration(min) × RPE (1-10 scale) ACWR = Acute Load (7-day) / Chronic Load (28-day average)
Result: TRIMP = 98.7 (Moderate-High)
With a 45-minute session at 155 bpm average HR, the ΔHR ratio is (155−60)/(190−60) = 0.731. Using the male weighting factor (b=1.92), TRIMP = 45 × 0.731 × e^(1.92×0.731) = 45 × 0.731 × 4.08 ≈ 134.2. This represents a moderate-to-hard session.
Banister's impulse-response model proposes that every training session produces both fitness and fatigue. Fitness accumulates slowly and dissipates slowly; fatigue accumulates quickly and dissipates quickly. Performance = Fitness − Fatigue. TRIMP quantifies the input to this model, allowing coaches to predict when an athlete will be in peak form.
The Acute:Chronic Workload Ratio has become the gold standard for injury prevention in team sports. Research across football, rugby, cricket, and athletics consistently shows that ACWR between 0.8 and 1.3 represents the lowest injury risk. Spikes above 1.5 increase injury probability by 2-4×.
Track your TRIMP for every session in a spreadsheet or training app. Sum weekly totals and calculate rolling 4-week averages. When planning training blocks, aim to increase weekly TRIMP by no more than 10-15% per week. Include recovery weeks where you reduce TRIMP by 30-50% every 3-4 weeks.
TRIMP stands for TRaining IMPulse, developed by Dr. Eric Banister. It quantifies the physiological stress of a training session by combining duration with heart rate intensity. Higher TRIMP means more training stress. It's widely used in endurance sports for load monitoring.
The exponential weighting factor (b) differs because blood lactate response to exercise intensity differs between sexes. Males use b=1.92 and females use b=1.67, reflecting the different physiological responses to higher-intensity exercise.
It depends on the session purpose. Recovery/easy sessions: 30-80 TRIMP. Moderate endurance: 80-150. Tempo/threshold: 150-250. High-intensity intervals: 200-350+. Long endurance (2+ hours easy): 200-400. Context matters more than the absolute number.
ACWR compares your recent load (last 7 days) to your average load (last 28 days). An ACWR of 1.0 means your recent training matches your average. Below 0.8 means you're undertraining; above 1.3-1.5 means you're spiking load dangerously. The sweet spot is 0.8-1.3.
TRIMP uses heart rate; TSS (from TrainingPeaks) uses power data. Both quantify session stress but from different physiological markers. TSS is preferred in cycling (where power meters are common); TRIMP works for any sport where you can measure heart rate.
Yes. Session RPE Load = Duration × RPE (1-10 scale) is a validated alternative. It correlates well with heart rate-based TRIMP (r ≈ 0.75-0.90) and is simpler. Rate the overall session difficulty on a 1-10 scale about 30 minutes after finishing.