1. What is the 4-Site Skinfold Method?

The 4-site skinfold method (Jackson-Pollock) estimates body fat percentage by measuring subcutaneous fat at four anatomical sites. It's a practical, non-invasive method commonly used in fitness and clinical settings.

2. How Does the Calculator Work?

The calculator uses the following equation:

Where:

• \( a \) — Constant (20.1 for men, 22.2 for women)
• \( b \) — Multiplier (19.2 for men, 18.6 for women)
• \( c \) — Adjustment factor (0 for both genders in this equation)
• Sum of Skinfolds — Sum of triceps, biceps, subscapular, and suprailiac measurements (mm)

Explanation: The logarithmic relationship accounts for the fact that as body fat increases, the relationship between skinfold thickness and total body fat becomes non-linear.

3. Importance of Body Fat Measurement

Details: Body fat percentage provides a more accurate assessment of health and fitness than body weight alone. It helps in tracking fat loss, muscle gain, and assessing health risks associated with obesity.

4. Using the Calculator

Tips:

• Measure skinfolds on the right side of the body
• Take measurements with proper skinfold calipers
• Ensure consistent pressure and technique
• Take multiple measurements at each site and average them

5. Frequently Asked Questions (FAQ)

Q1: How accurate is the 4-site method?
A: When performed correctly, it has about ±3-5% accuracy compared to more advanced methods like DEXA.

Q2: What are normal body fat percentages?
A: For men: 6-24% (athletes 6-13%, fitness 14-17%, average 18-24%). For women: 16-30% (athletes 14-20%, fitness 21-24%, average 25-30%).

Q3: How often should I measure?
A: Every 4-8 weeks to track changes, as daily fluctuations can be misleading.

Q4: What affects skinfold measurement accuracy?
A: Hydration status, time of day, technician skill, caliper quality, and measurement site location.

Q5: Can I use this if I'm very overweight?
A: The equation becomes less accurate at very high body fat percentages (>30% for men, >40% for women).