Sources and licenses
Every number on gymnical comes from a published formula or a public data set. This page lists each one, what we use it for and its license. Naming a source does not mean that project, journal or agency endorses this site.
| Data | Source | Used for | License |
|---|---|---|---|
| Competition results | OpenPowerlifting project, openpowerlifting.org (full results file, downloaded 2026-10-31) | Strength standards, masters tables, median lifts by bodyweight, total, DOTS and Wilks percentiles, lift ratios, milestones and attempt statistics | Public domain (the project waives all rights to its data). We use the data only, not the project's code. |
| Grip strength, height | CDC, National Center for Health Statistics, NHANES 2013-2014 (muscle strength, body measures and demographics files) and NHANES 2011-2012 (muscle strength and demographics files) | Grip strength by age and grip strength standards; typical heights | U.S. federal work, not protected by copyright (17 U.S.C. 105). Used only for group statistics, as the NCHS data rules require. |
| VO2 max reference values | Kaminsky and colleagues, the FRIEND registry treadmill percentiles, Mayo Clinic Proceedings (2015) | VO2 max chart by age and sex | Individual figures quoted as facts with the citation; the table layout is our own. |
| Formulas | Published papers: one rep max (Epley, Brzycki, Lombardi, Mayhew, O'Conner, Wathen, Lander), DOTS, Wilks, FFMI (Kouri), Riegel, Cooper, Léger and Gadoury, Uth, ACSM metabolic equations, Tanaka, Gellish, Nes, Karvonen, Sayers, Jones and Doust (treadmill grade), Schoenfeld and colleagues (training volume and repetition duration), Gulati (women's max heart rate), Kline (one-mile walk test), McArdle (Queens College step test), Bosco (jump flight time), Naismith and Tobler (hiking time), Sinclair (weightlifting totals), the rowing monitor watts formula, Buist and Nielsen (weekly mileage studies) | All calculators (see the method page) | Formulas and methods are facts, not protected by copyright (17 U.S.C. 102(b)). Our code is our own. |
| Training guidance | American College of Sports Medicine position stand on resistance training (2009); U.S. Physical Activity Guidelines for Americans, 2nd edition (HHS); CDC and American Heart Association target heart rate ranges | Rest, sets and reps, progression pages | Figures quoted with the citation, in our own words. HHS guidelines are a U.S. federal work. |
| Bar and plate specifications | International competition rules for weightlifting and powerlifting, plus equipment specifications from at least two sources per figure | Bar weights, plate colors, plate calculator | Facts, written in our own words. No maker names are used. |
| Fonts | Big Shoulders Display, Inter Tight, Fragment Mono, served from our own server | All pages | SIL Open Font License 1.1 |
| Site code | Astro (static site generator) | Building the pages | MIT |
Attribution
This site uses data from the OpenPowerlifting project, https://www.openpowerlifting.org. You may download a copy of the data at https://gitlab.com/openpowerlifting/opl-data.
Notes
- Lifters' names never appear on this site. We publish only percentiles for groups with at least 200 lifters.
- We do not use logos, seals or insignia of any federation, journal or agency.
- All results are estimates for general information. They are not medical advice.