The Wilks Coefficient or Wilks Formula is a coefficient that can be used to measure the strength of a powerlifter against other powerlifters despite different weights. Robert Wilks is the author of the formula.

 

Equation

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

 

Example

The main function of the Wilks formula is in weightlifting involved in both Olympic and Powerlifting contests. It is used to identify the best lifters across the different bodyweight categories and can also be used to compare men and women lifters as there are formulas for both gender. First, second and third places on the winner’s podium within their own age, bodyweight and gender classes are awarded to the competitors who lift the most weight respectively. Where two lifters in a class achieve the same combined total lifted weight the lighter lifter is determined the winner.
The Wilks formula comes into play when comparing and determining overall champions across the different categories. The formula can also be used in team and handicap competitions where the team includes lifters of significantly varying bodyweights. The Wilks formula like its predecessors, the O'Carroll and Schwartz formulas, were set up to address the imbalances whereby lighter lifters tend to have a greater power to weight ratio ... lighter lifters tending to lift more weight according to their own bodyweight. This occurs for a number of reasons relating to simple physics, the nature of the makeup and limitations of the human skeletal and muscular system and, the shorter leverages of smaller people. This phenomena can be seen by looking at the current men's senior world powerlifting records. http://www.powerlifting-ipf.com/Records.44.0.html Note the totals section and that lighter lifters below 100 Kg bodyweight achieve totals in excess of ten times bodyweight whereas heavier lifters do not. The Wilks system is primarily a handicapping process that provides an adjusted statistical method to compare all lifters of varying classes and groups on an equal standing and makes allowances for the disparities. Wilks charts and a calculator are freely available on the website of the International Powerlifting Federation (IPF). http://www.powerlifting-ipf.com/Downloads.55.0.html
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. 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. The Wilks Coefficient credits heavier lifters with more points than lighter lifters, despite the lighter lifter totaling more for their bodyweight.

 

Коэффициент, рассчитанный по формуле Вилкса, служит для сравнения результатов атлетов разных весов. Коэффициент Вилкса отражает соотношение между собственной массой атлета (с точностью до 0.1 кг) и суммой набранной в трех упражнениях (приседания, жим лежа, становая тяга )
В первой левой колонке таблицы - вес с точностью до килограмма, в первой верхней строке - десятые части килограмма, на пересечении - коэффициент Вилкса.
Для определения абсолютного результата необходимо умножить сумму троеборья на коэффициент Вилкса.
Атлет, обладающий большим абсолютным коэффициентом, имеет предпочтение.

 

Формула Вилкса для мужчин.

Вес    0        0.1        0.2         0.3        0.4        0.5        0.6        0.7        0.8        0.9
40    1.3354  1.3311  1.3268  1.3225  1.3182  1.3140  1.3098  1.3057  1.3016  1.2975
411.29341.28941.28541.28141.27751.27361.26971.26581.26201.2582
421.25451.25071.24701.24331.23971.23601.23241.22891.22531.2218
431.21831.21481.21131.20791.20451.20111.19781.19441.19111.1878
441.18461.18131.17811.17491.17171.16861.16541.16231.15921.1562
451.15311.15011.14711.14411.14111.13821.13521.13231.12941.1266
461.12371.12091.11811.11531.11251.10971.10701.10421.10151.0988
471.09621.09351.09091.08821.08561.08301.08051.07791.07541.0728
481.07031.06781.06531.06291.06041.05801.05561.05321.05081.0484
491.04601.04371.04131.03901.03671.03441.03211.02991.02761.0254
00.10.20.30.40.50.60.70.80.9
501.02321.02101.01881.01661.01441.01221.01011.00791.00581.0037
511.00160.99950.99750.99540.99330.99130.98930.98730.98530.9833
520.98130.97930.97730.97540.97350.97150.96960.96770.96580.9639
530.96210.96020.95830.95650.95470.95280.95100.94920.94740.9457
540.94390.94210.94040.93860.93690.93520.93340.93170.93000.9283
550.92670.92500.92330.92170.92000.91840.91680.91520.91350.9119
560.91030.90880.90720.90560.90410.90250.90100.89940.89790.8964
570.89490.89340.89190.89040.88890.88740.88590.88450.88300.8816
580.88020.87870.87730.87590.87450.87310.87170.87030.86890.8675
590.86620.86480.86350.86210.86080.85940.85810.85680.85550.8542
00.10.20.30.40.50.60.70.80.9
600.85290.85160.85030.84900.84770.84650.84520.84390.84270.8415
610.84020.83900.83780.83650.83530.83410.83290.83170.83050.8293
620.82810.82700.82580.82460.82350.82230.82120.82000.81890.8178
630.81660.81550.81440.81330.81220.81110.81000.80890.80780.8067
640.80570.80460.80350.80250.80140.80040.79930.79830.79730.7962
650.79520.79420.79320.79220.79110.79010.78910.78810.78720.7862
660.78520.78420.78320.78230.78130.78040.77940.77850.77750.7766
670.77560.77470.77380.77290.77190.77100.77010.76920.76830.7674
680.76650.76560.76470.76380.76300.76210.76120.76030.75950.7586
690.75780.75690.75610.75520.75440.75350.75270.75190.75100.7502
00.10.20.30.40.50.60.70.80.9
700.74940.74860.74780.74690.74610.74530.74450.74370.74300.7422
710.74140.74060.73980.73900.73830.73750.73670.73600.73520.7345
720.73370.73300.73220.73150.73070.73000.72930.72850.72780.7271
730.72640.72560.72490.72420.72350.72280.72210.72140.72070.7200
740.71930.71860.71790.71730.71660.71590.71520.71460.71390.7132
750.71260.71190.71120.71060.70990.70930.70860.70800.70740.7067
760.70610.70550.70480.70420.70360.70290.70230.70170.70110.7005
770.69990.69930.69870.69810.69750.69690.69630.69570.69510.6945
780.69390.69330.69270.69220.69160.69100.69050.68990.68930.6888
790.68820.68760.68710.68650.68600.68540.68490.68430.68380.6832
00.10.20.30.40.50.60.70.80.9
800.68270.68220.68160.68110.68060.68000.67950.67900.67850.6779
810.67740.67690.67640.67590.67540.67490.67440.67390.67340.6729
820.67240.67190.67140.67090.67040.66990.66940.66890.66850.6680
830.66750.66700.66650.66610.66560.66510.66470.66420.66370.6633
840.66280.66240.66190.66150.66100.66060.66010.65970.65920.6588
850.65830.65790.65750.65700.65660.65620.65570.65530.65490.6545
860.65400.65360.65320.65280.65230.65190.65150.65110.65070.6503
870.64990.64950.64910.64870.64830.64790.64750.64710.64670.6463
880.64590.64550.64510.64470.64440.64400.64360.64320.64280.6424
890.64210.64170.64130.64100.64060.64020.63980.63950.63910.6388
00.10.20.30.40.50.60.70.80.9
900.63840.63800.63770.63730.63700.63660.63630.63590.63560.6352
910.63490.63450.63420.63380.63350.63310.63280.63250.63210.6318
920.63150.63110.63080.63050.63010.62980.62950.62920.62880.6285
930.62820.62790.62760.62720.62690.62660.62630.62600.62570.6254
940.62500.62470.62440.62410.62380.62350.62320.62290.62260.6223
950.62200.62170.62140.62110.62090.62060.62030.62000.61970.6194
960.61910.61880.61860.61830.61800.61770.61740.61720.61690.6166
970.61630.61610.61580.61550.61520.61500.61470.61440.61420.6139
980.61360.61340.61310.61290.61260.61230.61210.61180.61160.6113
990.61110.61080.61060.61030.61010.60980.60960.60930.60910.6088
00.10.20.30.40.50.60.70.80.9
1000.60860.60830.60810.60790.60760.60740.60710.60690.60670.6064
1010.60620.60600.60570.60550.60530.60500.60480.60460.60440.6041
1020.60390.60370.60350.60320.60300.60280.60260.60240.60210.6019
1030.60170.60150.60130.60110.60090.60060.60040.60020.60000.5998
1040.59960.59940.59920.59900.59880.59860.59840.59820.59800.5978
1050.59760.59740.59720.59700.59680.59660.59640.59620.59600.5958
1060.59560.59540.59520.59500.59480.59460.59450.59430.59410.5939
1070.59370.59350.59330.59320.59300.59280.59260.59240.59230.5921
1080.59190.59170.59160.59140.59120.59100.59090.59070.59050.5903
1090.59020.59000.58980.58970.58950.58930.58920.58900.58880.5887
00.10.20.30.40.50.60.70.80.9
1100.58850.58830.58820.58800.58780.58770.58750.58740.58720.5870
1110.58690.58670.58660.58640.58630.58610.58600.58580.58560.5855
1120.58530.58520.58500.58490.58470.58460.58440.58430.58410.5840
1130.58390.58370.58360.58340.58330.58310.58300.58280.58270.5826
1140.58240.58230.58210.58200.58190.58170.58160.58150.58130.5812
1150.58110.58090.58080.58060.58050.58040.58030.58010.58000.5799
1160.57970.57960.57950.57930.57920.57910.57900.57880.57870.5786
1170.57850.57830.57820.57810.57800.57780.57770.57760.57750.5774
1180.57720.57710.57700.57690.57680.57660.57650.57640.57630.5762
1190.57610.57590.57580.57570.57560.57550.57540.57530.57510.5750
00.10.20.30.40.50.60.70.80.9
1200.57490.57480.57470.57460.57450.57440.57430.57420.57400.5739
1210.57380.57370.57360.57350.57340.57330.57320.57310.57300.5729
1220.57280.57270.57260.57250.57240.57230.57220.57210.57200.5719
1230.57180.57170.57160.57150.57140.57130.57120.57110.57100.5709
1240.57080.57070.57060.57050.57040.57030.57020.57010.57000.5699
1250.56980.56980.56970.56960.56950.56940.56930.56920.56910.5690
1260.56890.56880.56880.56870.56860.56850.56840.56830.56820.5681
1270.56810.56800.56790.56780.56770.56760.56750.56750.56740.5673
1280.56720.56710.56700.56700.56690.56680.56670.56660.56650.5665
1290.56640.56630.56620.56610.56610.56600.56590.56580.56580.5657
00.10.20.30.40.50.60.70.80.9
1300.56560.56550.56540.56540.56530.56520.56510.56510.56500.5649
1310.56480.56470.56470.56460.56450.56440.56440.56430.56420.5642
1320.56410.56400.56390.56390.56380.56370.56360.56360.56350.5634
1330.56340.56330.56320.56310.56310.56300.56290.56290.56280.5627
1340.56270.56260.56250.56240.56240.56230.56220.56220.56210.5620
1350.56200.56190.56180.56180.56170.56160.56160.56150.56140.5614
1360.56130.56120.56120.56110.56100.56100.56090.56090.56080.5607
1370.56070.56060.56050.56050.56040.56030.56030.56020.56020.5601
1380.56000.56000.55990.55980.55980.55970.55970.55960.55950.5595
1390.55940.55930.55930.55920.55920.55910.55900.55900.55890.5589
00.10.20.30.40.50.60.70.80.9
1400.55880.55870.55870.55860.55860.55850.55840.55840.55830.5583
1410.55820.55820.55810.55800.55800.55790.55790.55780.55780.5577
1420.55760.55760.55750.55750.55740.55730.55730.55720.55720.5571
1430.55710.55700.55700.55690.55680.55680.55670.55670.55660.5566
1440.55650.55640.55640.55630.55630.55620.55620.55610.55610.5560
1450.55600.55590.55580.55580.55570.55570.55560.55560.55550.5555
1460.55540.55540.55530.55520.55520.55510.55510.55500.55500.5549
1470.55490.55480.55480.55470.55470.55460.55460.55450.55440.5544
1480.55430.55430.55420.55420.55410.55410.55400.55400.55390.5539
1490.55380.55380.55370.55370.55360.55360.55350.55350.55340.5533