Wilks Coefficient

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The Wilks Coefficient or Wilks Formula is a method by which the strength of a powerlifter is measured against other powerlifters of a different weight category.

[edit] Formula

The following equation is used to calculate Wilks Coefficient. The total weight lifted is multiplied by the Coefficient to find the standard amount lifted normalized across all body weights.

$Coeff = \frac{500}{a + b*x + c*x^2 + d*x^3 + e*x^4 + f*x^5}$

x is the body weight of the lifter in kilograms

Coefficients for men are:
a=-216.0475144 b=16.2606339 c=-0.002388645 d=-0.00113732 e=7.01863E-06 f=-1.291E-08

Coefficients for women are:
a=594.31747775582 b=-27.23842536447 c=0.82112226871 d=-0.00930733913 e=0.00004731582 f=-0.00000009054

According to this setup, a male athlete weighing 320 pounds and lifting a total of 1400 pounds would have a normalized lift weight of 778.26, and a lifter weighing 200 pounds and lifting a total of 1000 pounds would have a normalized lift weight of 635.8. Thus the 320 pound lifter would win this competition.

[edit] Uses

The Wilks Coefficient credits heavier lifters with more points than lighter lifters, despite the lighter lifter totaling more for their bodyweight. As you might have noticed the lighter lifter is actually stronger for his bodyweight, with a total of 5 times his own weight, while the heavier lifter could only manage 4.375 times his own bodyweight.