Engine Category · 11 Reference Guides
Understand the mechanisms that drive adaptation: how RPE and Reps in Reserve regulate daily load, why every body composition method (DEXA, InBody, smart scale, and AI photo scan) carries an error range, and how Zone 2 and concurrent training work under the hood.
Learn Fundamentals at a Glance
18–23%
Midpoint ~20% (±2.5% band)
60.4–64.3 kg
Fat mass: 13.7–17.6 kg
0.46
Below 0.50 (Ashwell adult guideline)
Sits inside the broad athletic performance window (roughly 8% to 20% for men, varying widely by sport and position).
Adjust waist, shoulders, or hips above to see how your proportions map across the 6 Pelaris 3D Blueprint builds.
A streamlined endurance build that carries speed and distance with ease.
Runners, distance swimmers, triathletes
Broad shoulders over a narrow waist, the classic athletic taper.
Swimmers, gymnasts, rugby backs
A powerful, solid frame built for moving heavy loads.
Powerlifters, strongmen, rugby forwards
A strong lower-body engine with power through the hips and legs.
Track cyclists, sprinters, rowers
Balanced shoulders and hips around a defined waist, ready for any training style.
Functional fitness, hybrid athletes
A sturdy frame with strength through the core, ready for any training style.
Heavyweight lifters, athletes in a rebuilding phase
For adults aged 18 and over. Shown as a range because every field estimate has error tolerance. Not a medical assessment.
The link carries the numbers you entered in the part of the address after the #, which is never sent to a server. Share it only with people you are happy to show those numbers to.
RFM (Male) = 64 − 20 × (Height ÷ Waist) · RFM (Female) = 76 − 20 × (Height ÷ Waist) · Range = ±2.5% to ±3.5%
Woolcott and Bergman (2018) validated Relative Fat Mass against DXA across 3,456 US adults in NHANES, finding lower total error than BMI. Even so, any field method (tape, bioimpedance scale, or AI photo scan) carries an individual error tolerance of roughly 3 to 4 percentage points. Use the same tape site and time of day, and watch how the range moves over 4 to 8 weeks rather than chasing a single number.
General fitness and training estimates only, labelled EST. Not medical advice or a clinical diagnosis.
Complete Learn Shelf
Every guide below includes its paired interactive calculator mid-article plus FAQ answers and peer-reviewed citations.
Bring your watch history into Pelaris. Export FIT files from Garmin, COROS, Suunto, Wahoo or Polar, drop them in, and every session lands on its real date.
Why power matters in netball and how to build it: a strength base, jump and landing work, contrast training in-season, and how to train around game day.
Why dryland work adds speed, what to do in the gym, the honest answer on overhead pressing, and how to lift through a season and a taper.
Export your Hevy or Strong history as CSV, bring it into Pelaris, and keep every set, PR, and progression baseline. Step by step, with no lock-in.
The best split is the one that fits your week. How full body, upper/lower, and push/pull/legs compare, and how to choose by days available.
Training for strength and training for size overlap but are not the same thing. Rep ranges, weekly volume, and how to choose your emphasis.
What Zone 2 actually is, why easy training builds your engine, and three ways to find your zone with nothing more than a watch and honesty.
What RPE means, how it maps to reps in reserve, why lifters misrate it, and how honest effort scores make a program smarter than percentages.
A practical guide to programming strength and endurance together without losing adaptation in either. Interference effect, scheduling, volume management.
A practical 12-week guide for strength athletes adding running. Progressive base building, interference management, and when to escalate intensity.
Progressive overload is more than adding weight. The six levers, when to pull each, and how to keep getting stronger without burning out.
More Learn Calculators
Evidence & Primary Literature
Woolcott & Bergman (2018) DXA-validated Relative Fat Mass, Ashwell (2012) Waist-to-Height ratio, Epley 1RM, Helms RIR, and Daniels VDOT.