Home / How do you calculate Pound For Pound Strength? Wilks Score, Sinclair Coefficient, and Allometric Scaling
How do you calculate Pound For Pound Strength? Wilks Score, Sinclair Coefficient, and Allometric Scaling

Have you ever wondered whether, relatively speaking, a 160 lb lifter with a 1300 lb total is stronger than a 300 lb lifter with an 1800 lb total. Those are completely normal thoughts that any powerlifter may have. The entire goal of the sport is to measure levels of strength among lifters in both the same and different weight classes. Powerlifters like to use the Wilks Score to find out how they weigh against lifters in different federations.

*If you're interested in finding out more about federations, check out this article on the dos and don'ts of powerlifting federations.

However, there are other methods that overall weightlifters use to calculate pound for pound strength.

Methods for calculating pound for pound strength:

What is the Wilk’s Score?

MegSquats going over the Wilks Score

The Wilks score is used to calculate the pound for pound strength of powerlifters. The creator of the Wilks Score was Robert Wilks and it is calculated by multiplying a lifter’s total by the Wilks coefficient and is used to offer a sort of index to compare totals lifted by individuals in different weight classes.

Here's an app to calculate your Wilk's score online if you don't want to do the calculations by hand:

https://wilkscalculator.com/

Wilks Coefficient = 500/ a + bx +cx^2 + dx^3 + ex^4 + fx^5

x = lifters body weight in kg

When it comes to the Wilk’s Score, lifters are given different values based on whether they’re a man or a woman.

Men’s values are:

A:-216.0475144

B:16.2606339

C: -0.002388645

D: -0.00113732

E: 7.01863E-06

F: -1.291E-08

Women’s Values are:

A: 594.31747775582

B: -27.23842536447

C: 0.82112226871

D: -0.00930733913

E: 4.731582E-05

F: -9.054E-08

Now, if you’re truly interested in using the Wilks Score and you don’t want to calculate it using the above formula, the people at symmetricstrength.com have created a very useful tool that basically allows you to enter your body weight and exact max lifts for the Big 3 (squat, deadlift, bench press) lifts. On that same note, you can also enter your max number of reps with a given weight for each of the different lifts so they can give you an estimated Wilks score (they also give you estimated max lifts, which is pretty cool).

The purpose of the Wilks score is to give all lifters an equal playing field and tell lifters which lifter is the undisputed champion among all of the lifters at a powerlifting meet.

Advantages

Disadvantages

Estimations? Okay

What is the Sinclair Coefficient (for weightlifters)?

Sinclair Coefficient

The Sinclair coefficient is used by Olympic weightlifters to compare strength relative to body weight. While weightlifting is a bit different than powerlifting the idea behind the coefficient is very much like that of Wilk's coefficient. Since this site is more geared towards powerlifters however, we will only briefly touch on the Sinclair coefficient and what it offers to lifters. The Sinclair Coefficient is used by the IWF as a way to compare the weight lifted by the lightest person at a competition to that of the heaviest person at that same meet.

The formula for the Sinclair Coefficient is:

10^A(log base 10 (x/b))^2

x: the lifter’s bodyweight

b: the current world record holders bodyweight

a: the coefficient for the current Olympic cycle or 1 if x weighs less than b’

The best calculator found on the web for this is the calculator the IWF uses

What is Allometric Scaling?

Allometric Scaling

While the Wilks score is what’s been used by powerlifters to figure out who has more relative strength for several decades, an up and coming winner in the powerlifting universe is Allometric Scaling which basically notices the changes in a certain species as they change in size. While Allometric Scaling has been used for quite some time to find the relationship between several regular bodily functions. For years, scientists have been using it to find out how the metabolic rate of an animal changes as the animal grows in size and what scientists have found is that the metabolic rate has a linear relationship with the size of the animal.

What does this mean for powerlifting? Well, it can be used to find the way that strength grows with the size of a human being. The reason why allometric scaling works is because of the Kleiber's law, which states that for most animals, their metabolic heart rate rises by ¾ as the animal’s mass grows.

Advantages

Disadvantages

*If you want to have a full breakdown of what powerlifting is and how it works, check out this article.

Which one is better?

Well, it appears that they each have their own ups and downs. Some of the information I’ve found on the Wilk’s score shows that it doesn’t really have the most reliable information (such as the estimations and older data used) but, it also has it’ bonuses. There is no real bias in any of the individual lifts, which makes it helpful to use for finding pound for pound strength on each of the different lifts. We have the Sinclair coefficient as well but, because of it being so tied to weight lifting we can’t really consider that to be of too much importance. Last, we have to take a fair look at Allometric measuring. It uses natural phenomena to measure strength relative to size which makes it a great equation to use to make estimations.

However, we also have to take into account the fact that it doesn’t really help super heavyweight powerlifters. According to Allometric Scaling the totals of world record holding lifters like Hafthor Bjornsson and Ray Williams fall way below those of past title holders which shows that something is probably off with the way it’s being calculated (because of the body-fat percentage of these super heavyweights.

Conclusion

To be honest, none of these calculation methods are perfect. They each have some type of issue, whether it’s body fat percentage with super heavy weights or the bias towards heavier individuals with the Wilks coefficient there is always something. However, there is one thing that can be said about Allometric Scaling, and that’s that the majority of lifters aren’t super heavyweights and thus don’t have to worry about the body fat percentage issue. Or a better way of saying this is that if you have an average 10-15% bf then you should be good to go. Meaning that using Allometric Scaling wouldn't hurt at all.

Resources:

https://europepmc.org/abstract/med/10613442

https://journals.lww.com/nsca-jscr/pages/articleviewer.aspx?year=2000&issue=08000&article=00015&type=Abstract&Ppt=Article%7Cnsca-jscr:2000:08000:00015%7C%7C

https://science.sciencemag.org/content/276/5309/122

https://en.wikipedia.org/wiki/Kleiber%27s_law