Methodology
How this calculator works
Swim TSS Methodology
Swim TSS follows the same conceptual model as bike TSS (Coggan): Duration × IF² × 100. The Intensity Factor uses CSS pace as the threshold reference, making it directly comparable to bike TSS in structure.
- Use CSS (Critical Swim Speed) as the threshold pace reference for IF calculation.
- Present IF as the ratio of CSS pace to actual pace, so faster swimming produces higher IF.
- Frame load classification with triathlon-specific recovery guidance.
FAQ
Frequently asked questions
What is Swim TSS?
Swim TSS quantifies the training stress of a swim session using the same conceptual model as bike TSS: duration multiplied by intensity squared. It uses CSS (Critical Swim Speed) as the threshold reference.
How is Swim TSS calculated?
Swim TSS = Duration (hours) × Intensity Factor² × 100. The Intensity Factor is your CSS pace divided by your actual swim pace. Faster swimming relative to CSS means higher IF and higher TSS.
What is a good Swim TSS for a training session?
A typical age-group triathlete swim session produces 30-80 TSS. Sessions above 100 TSS are hard and require planned recovery. Weekly swim TSS of 100-200 across 3-4 sessions is common.
How does Swim TSS compare to Bike TSS?
Swim TSS per hour tends to be lower than bike TSS because water limits how long athletes can sustain high intensity. A 60-minute moderate swim might produce 40-60 TSS, while a similar bike effort produces 50-70 TSS.
Evidence
References
This calculator provides estimates based on published exercise science research. Individual responses vary. These outputs are not a substitute for coaching, medical clearance, or your own experience. Always listen to your body and consult a qualified professional before making significant changes to your training.
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