1. What is Critical Swim Speed?

Critical Swim Speed (CSS) is a measure of a swimmer's aerobic capacity and represents the theoretical swimming speed that can be maintained continuously without exhaustion. It's similar to the lactate threshold in running or cycling.

2. How Does the Calculator Work?

The calculator uses the CSS formula:

Where:

• \( D_{400} \) — 400 meters distance
• \( D_{200} \) — 200 meters distance
• \( T_{400} \) — Time to swim 400 meters (seconds)
• \( T_{200} \) — Time to swim 200 meters (seconds)

Explanation: The formula calculates the slope of the line connecting the 200m and 400m swim times, representing the swimmer's sustainable speed.

3. Importance of CSS in Swimming

Details: CSS is used to set training zones, monitor progress, and predict performance in longer distance events. It helps swimmers train at the right intensity for aerobic development.

4. Using the Calculator

Tips:

• Enter your best recent 200m and 400m times in seconds
• Times should be from maximal effort swims
• The 400m time must be longer than the 200m time
• For best results, swim these tests on separate days with full recovery

5. Frequently Asked Questions (FAQ)

Q1: How accurate is CSS for predicting performance?
A: CSS is a good predictor for distances between 400m-1500m. For sprints or ultra-distance, other factors become more important.

Q2: What's a good CSS value?
A: Competitive swimmers typically have CSS values between 1.2-1.8 m/s. Elite swimmers may exceed 1.8 m/s.

Q3: How often should I test my CSS?
A: Every 4-6 weeks during training cycles to monitor progress.

Q4: Can I use different distances?
A: The standard is 200m/400m, but some use 400m/800m for distance swimmers.

Q5: How should I use my CSS in training?
A: CSS pace is often used for threshold sets. Common workouts include 10-20 x 100m or 5-10 x 200m at CSS pace with short rest.