Structural Output
1RM, relative power, heart-rate zones, kinetic expenditure.
Four instruments for training load and output: estimated one-rep maximum, Wilks relative-strength coefficient, Karvonen heart-rate zones, and MET-based calorie burn.
Start here
- Max Load Capacity — Brzycki 1RM plus training zones.
- Heart Rate Zones — Karvonen zones anchored to your resting HR.
Featured tools
Max Load Capacity · Brzycki 1RM
Estimate one-rep maximum from a sub-max set using the Brzycki formula. Recovery / Hypertrophy / Strength zones.
Strength-to-Weight Efficiency · Wilks
Wilks coefficient — the powerlifting gold-standard for comparing lifters across bodyweight classes.
Operational Heart Rate Zones · Karvonen
Calculate the five training zones using Karvonen (heart-rate reserve) method. More accurate than %HRmax alone.
Kinetic Expenditure · MET
Calories burned per activity using the MET (Metabolic Equivalent of Task) method from the Compendium of Physical Activities.
Guides & explainers
- Training Load and Structural Output GuideEstimate output, compare sessions, and choose training ranges without pretending formulas replace coaching.
- Brzycki 1RM GuideTurn a clean 3-10 rep set into a 1RM estimate accurate to within 3%.
- Wilks Coefficient GuideHow lifters compare across bodyweight classes using a single relative-strength number.
- Karvonen Heart Rate ZonesWhy HR reserve beats flat %HRmax for setting training zones.
- MET Calorie Burn GuideThe academic method underneath every fitness tracker's calorie number.
Related clusters
Frequently asked questions
› Why Brzycki and not Epley? Troubleshooting
Brzycki is most accurate in the 1–10 rep range; Epley holds up better at 10+. For 3–5 rep sets — the ergonomic sweet spot — Brzycki wins.
› Why Karvonen over %HRmax? Troubleshooting
Karvonen incorporates resting HR — a fit person's reserve is higher, so zones shift up. Better personalisation than flat %HRmax.