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Research Credits & Acknowledgements

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Everything useful on this site stands on other people’s work. We credit it here, and in the references at the end of every guide.

Research databases

  • PubMed, provided by the U.S. National Library of Medicine (NLM) at the National Center for Biotechnology Information (NCBI). Study citations on this site link to PubMed records. PubMed abstracts remain the property of their publishers; we summarise and link to them, and do not reproduce full texts.

Health and nutrition bodies we rely on

  • World Health Organization (WHO). Physical activity guidelines and body-mass-index classifications
  • Indian Council of Medical Research: National Institute of Nutrition (ICMR-NIN): Dietary Guidelines for Indians and Indian food composition data
  • U.S. National Institutes of Health, Office of Dietary Supplements (NIH ODS). Supplement fact sheets
  • Mayo Clinic, the NHS and the U.S. Centers for Disease Control and Prevention (CDC). Patient-facing medical references
  • International Society of Sports Nutrition (ISSN) and American College of Sports Medicine (ACSM). Position stands

Calculator formulas

Our calculators use published equations, credited on each tool page. Including Mifflin-St Jeor (1990), Harris-Benedict as revised by Roza and Shizgal (1984), Katch-McArdle, the U.S. Navy circumference method (Hodgdon and Beckett), Epley, Brzycki and Lombardi 1RM estimates, the Tanaka maximum heart rate equation (2001), the Karvonen heart-rate reserve method, and the DOTS coefficient as implemented by the OpenPowerlifting project.

Software

This site is built with Astro, Tailwind CSS and React, with icons from Lucide. We thank their open-source maintainers.

Photography

Client transformation photos are of real Simplified Fitness clients. Other photography is our own or licensed for use.

Medical disclaimer

All content is educational and is not a substitute for advice from a qualified medical professional. Read the full disclaimer.

Anatomy renders

The skeleton, muscle and “muscles worked” images on this site are our own renders of BodyParts3D, © The Database Center for Life Science, licensed under CC BY 4.0. Source: BodyParts3D database (Mitsuhashi et al., 2009, doi:10.1093/nar/gkn613), via the open-source Human Atlas packaging. We changed the colours and highlighted muscle groups. BodyParts3D is an adult male reference model and does not include every structure; for example, it has no latissimus dorsi or rectus abdominis, so our back and core figures show the muscles that are modelled.

Photography

Article and calculator photos come from Pixabay and are used under the Pixabay Content License. They show stock models, not Simplified Fitness clients. Client transformation photos are the only images of real clients on this site.