Revising the Wilks Scoring System for pro RAW Powerlifting

TL;DR

This paper updates the Wilks scoring system for pro RAW powerlifting by fitting new polynomial models to recent top results, aiming for fairer, bodyweight-independent scoring across weight classes.

Contribution

The study introduces a revised polynomial-based scoring system for pro RAW powerlifting, replacing outdated formulas to improve fairness across bodyweights.

Findings

4th order polynomials best fit the data

Scores normalized to ensure fairness across weight classes

Revised scores show more consistent performance evaluation

Abstract

Purpose: In powerlifting the total result is highly dependent on the athletes bodyweight. Powerlifting is divided to equipped and RAW types. Pro RAW powerlifting competitions use the Wilks scoring system to compare and rank powerlifting results across bodyweights, to choose the winners. The Wilks formulas are 5th order polynomials fitted to equipped powerlifting results from the years 1987 - 1994. The Wilks formulas were meant to be updated every 2 to 5 years, but have never been revised. This study aims to update the Wilks scoring system for use in pro RAW powerlifting. Methods: The 10 highest RAW powerlifting totals per weight class for bodyweights 60 - 175 kg for men, and 44 kg and up for women, were collected from the openpowerlifting.org database. Polynomials were fitted to these data separately for men and women, using polynomial regression. The scores for men and women were calculated using these fits, and the results are assessed. Results: 4th order polynomials were chosen for best describing the dependence of powerlifting total result on bodyweight. The mens scores were normalized to 500 points, and womens to 455 points, on those fitted curves, to bring the top scores to the same level across weight classes of each sex. These scores appeared similar across the different weight classes for both men and women. This even scoring across body weights is here considered the single most important characteristic of a scoring system for pro competitions. Key words: Wilks score, revised prediction curve, polynomial regression, powerlifting