Wilks Coefficient for Google Sheets

README.md

Wilks coefficient function for Google Sheets

About the Wilks coefficient

The Wilks coefficient or Wilks formula is a mathematical coefficient that can be used to measure the relative strengths of powerlifters despite the different weight classes of the lifters.

(source)

Adding custom functions to Google Sheets

https://developers.google.com/apps-script/guides/sheets/functions

Usage

=WILKS_COEFFICIENT("F";51)*47,5

⬇️

60,11

wilks_coefficient.js

/**
 * Calculates the Wilks Coefficient based on gender and body weight. (https://en.wikipedia.org/wiki/Wilks_coefficient)
 *
 * @param {string} g Gender ('M' for male, 'F' for female)
 * @param {number} x Body weight (in kilkograms)
 * @return The calculated Wilks Coefficient.
 * @customfunction
 */
function WILKS_COEFFICIENT(g, x) {
  let a, b, c, d, e, f;

  switch(g) {
    case "F":
      a = -216.0475144;
      b = 16.2606339;
      c = -0.002388645;
      d = -0.00113732;
      e = 7.01863*Math.pow(10,-06);
      f = -1.291*Math.pow(10,-08);
      break;
    case "N":
      a = 594.31747775582;
      b = -27.23842536447;
      c = 0.82112226871;
      d = -0.00930733913;
      e = 4.731582*Math.pow(10,-05);
      f = -9.054*Math.pow(10,-08);
      break;
    default:
      return -1;
  }

  return 500.0 / (a + b*x + c*Math.pow(x,2) + d*Math.pow(x,3) + e*Math.pow(x,4) + f*Math.pow(x,5));
}