ISAK Body Composition
4 site Isak Skinfold Assessment - $45
8 Site ISAK Skinfold Assessment - $75
What is it?
Body composition is one of the most important — and most misunderstood — markers in sport and health.
Your weight on a scale tells you almost nothing useful. What matters is what that weight is made of, and how it's distributed.
ISAK skinfold testing is the internationally standardised method for assessing body composition — using calibrated calipers to measure subcutaneous fat at specific anatomical sites. It is the gold standard for body composition tracking in elite sport, trusted by professional teams, national academies, and high performance programmes worldwide for one simple reason: it is reliable, repeatable, and directly comparable over time.
At Tristar, we offer both the 4-site and 8-site ISAK restricted profile, delivered by a certified Level 1 ISAK practitioner.
What the results tell you
Sum of skinfolds (mm) — the primary tracking metric
Body fat percentage — estimated from the skinfold data
Lean mass estimate
Regional fat distribution (8-site only)
Comparison against population and sport-specific normative ranges
Practical interpretation of what the results mean for your training, nutrition, or health goals
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Athletes monitoring body composition through training cycles and competition seasons. People working on body composition goals who want a reliable, trackable measure rather than an estimate. Those whose GP or dietitian has recommended body composition assessment. Anyone who wants a meaningful baseline and a method that will show genuine change over time when retested.
ISAK testing pairs naturally with RMR testing — together they give a complete picture of how your body is composed and how it uses energy. It also integrates directly into the C-Suite health packages as a clinical-grade body composition component.
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Allow 30–40 minutes for the 4-site protocol and 40–50 minutes for the 8-site protocol, including set-up, measurement, and results review.
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No exercise, swimming, sauna, or hot shower for at least 2 hours before testing — these increase blood flow to the skin and can temporarily inflate skinfold measurements
Maintain normal hydration — don't over-drink or arrive dehydrated
Wear minimal, close-fitting clothing (sports bra and shorts, or equivalent) for ease of access to measurement sites
For tracking purposes, test at the same time of day, under the same conditions, each time
All prices NZD inclusive of GST.
How we test
Skinfold calipers are used to take precise measurements at standardised anatomical sites, marked and measured in a consistent, repeatable sequence. Each site is measured twice, with a third measurement taken if the first two fall outside the accepted margin of error. This protocol is what makes ISAK results reliable across time and across practitioners — reducing the variability that makes non-standardised skinfold testing so unreliable.
4-site protocol measures the tricep, bicep, subscapular, and iliac crest — a focused assessment giving a reliable sum of skinfolds and body fat percentage estimate. Faster and sufficient for most general health and fitness tracking purposes.
8-site protocol adds the supraspinale, abdominal, front thigh, and medial calf — a more comprehensive profile that tracks regional fat distribution in more detail. Preferred for athlete monitoring, performance tracking, and more nuanced body composition assessment.
Results are reported as a sum of skinfolds in millimetres — the most accurate and reproducible way to track change over time — alongside body fat percentage and lean mass estimates. Regional comparisons and sport-specific normative ranges are included where relevant.