In 2021, I acted as an expert witness for USA Powerlifting (USAPL) in JayCee Cooper v USA Powerlifting (62-CV-21-211, State of Minnesota District Court). As part of my testimony, I performed an analysis of performance in male and female weightlifting competitions. The text of that statement is presented below, edited for ease of reading and a different audience. It’s still pretty dry though.
I have conducted an analysis of sex-based performance differences in weightlifting disciplines. In Olympic weightlifting and powerlifting, competitions are divided by sex, then body weight (BW) categories within sex.
Weight categories can be divided into: 1. “closed weight categories” (those BW categories with an upper body weight limit), and; 2. the “open weight category” (the top BW category with no upper body weight limit).
Importantly, competitor characteristics differ between these two types of BW category. Those within closed weight categories tend to be competitors at “fighting weight”. Data from closed weight categories is predicted to be a robust measurement of strength relative to BW and my analyses will focus on these weight categories to make assessments of performance gaps.
In contrast, competitors within the open weight category have no competitive pressure to limit acquisition of body fat to meet an upper weight threshold, often confounding strength outputs when compared to body weight. Data from open weight categories permits examination of maximum lift capacity.
Olympic weightlifting.
To assess the performance gap between males and females in Olympic weightlifting, I first compared world records (WRs) by sex and weight class, recorded by the International Weightlifting Federation (IWF) and available on their public database (accessed on 28th December 2021).
Olympic weightlifting is a sport composed of two different lifts: the snatch and the clean and jerk. Competitors are scored for the best combined total across both lifts.
A note: Weight categories in Olympic weightlifting were adjusted in 2019 (typically by a few kg at each threshold), and I have collated data from the 1998-2018 competitive block and the 2019-present competitive block into a single dataset.
Modelling of Olympic weightlifting WR total lifts by BW in closed weight categories reveals an average 32% advantage for males across the combined range of BW.
To examine the hypothesis that male performance advantage may be largely (or even wholly) mediated by increased height and lever-derived advantages, I compared Olympic weightlifting data between equivalent weight categories which, to some extent, limit athlete height.
Between 1998 and 2018, a 69 kg category was common to both males and females; since 2019, males and females both have a 55 kg category. Comparison of records in the shared 69 kg (1998-2018) and 55 kg (2019-present) BW categories reveal that male WR holders are 30% stronger than the female WR holders at the same BW. Furthermore, the male WR holders are similar (69 kg; 4 cm taller) or the same (55 kg) heights as their female WR peers, demonstrating that the 30% male strength advantage is not a function of superior height.
Trend line analysis of male and female BW at the same total lift capacity reveals parity of strength when females weigh approximately 35 kg heavier than males.
Only the two female WR holders in the open weight category (super heavyweight females at 106 kg BW in 1998-2018 and 151 kg BW in 2019-present) have posted WRs higher than any male WR within their competition block. The male WRs they respectively beat are those for the very lightest of male lifters.
Male WRs in the 69 kg category (1998-2018) and the 67 kg category (2019-present) are higher than these female WRs, despite male BW deficits of 37 kg and 84 kg, respectively.
Comparison of Olympic weightlifting WRs in the open weight category reveals a 37% and 46% advantage for males (1998-2018 and 2019-present, respectively).
Note: The above data was presented in Hilton and Lundberg, 2021.
International powerlifting.
Following the same methodology as above, I compared classic/raw powerlifting WRs recorded by the International Powerlifting Federation (IPF) and available on their public database (accessed on 30th December 2021).
Powerlifting is a sport composed of three different lifts: the squat, the deadlift and the bench press. Competitors can compete for individual lifts and for the best combined total across all three lifts.
Analysis of classic/raw international powerlifting WR total lifts by BW in closed weight categories reveals an average 35% advantage for males across the combined range of BWs.
There is no shared BW category in powerlifting. However, there is an 83 kg male and an 84 kg female closed weight category. Comparison of WRs in these categories reveals the male WR holder is 32% stronger than the female WR holder at similar BW.
Trend line analysis of male and female BW at the same total lift capacity reveals parity of strength when females weigh around 40 kg heavier than males.
As for Olympic weightlifting, only Bonica Brown (pictured above; the female WR holder in the open weight category) has posted a WR higher than any male WR. The male WR in the 66 kg category surpasses that of Bonica Brown, despite a body weight deficit of 67 kg.
Comparison of international powerlifting WRs in the open weight category shows a 65% advantage for males.
USAPL powerlifting federation.
Moving to elite domestic competition, I compared records for classic/raw powerlifting held by USAPL and available on their public database (accessed on 4th January 2022).
Analysis of classic/raw USAPL record total lifts by BW in closed weight categories reveals a 36% advantage for males across the combined range of BWs.
Comparison of records in the 83 kg male and 84 kg female categories reveals the male record holder is 30% stronger than the female record holder at similar BW.
Trend line analysis of male and female BW at the same total lift capacity reveals parity of strength when females weigh around 35 kg heavier than males.
Only the female record holders in the 84 kg and open weight category have posted records higher than any male record. The male record in the 66 kg category surpasses those of the female records in the 84 kg and open weight category, despite a BW deficit of 18 kg and 67 kg, respectively.
Comparison of USAPL records in the open weight category reveals a 66% advantage for males in the open weight category.
USAPL single competition results.
International and domestic federation records may not be representative of performance gaps in any given year, where athletes are unlikely to be record-breakers. To capture a snapshot of performance gaps in a given competition, I analysed all lifts from the USAPL Raw Nationals competition in 2019, the year the Plaintiff applied to compete with USAPL in the female category. Data is available from the USAPL public database (accessed on 10th January 2022).
Analysis of USAPL Raw National 2019 lifts by BW in closed weight categories (256 male athletes, 236 female athletes) reveals a 50% field advantage for males across the combined range of BWs.
Comparison of lifts in the 83 kg male (53 athletes) and 84 kg female (48 athletes) categories reveals the male field performance advantage is 55% over the female field at similar BW.
Trend line analysis male and female BW at the same total lift capacity reveals parity of strength when females weigh approximately 50-60 kg heavier than males.
Analysis of USAPL Raw Nationals 2019 lifts in the open weight category (31 male athletes, 49 female athletes) reveals an average 70% advantage for males in the open weight category.
Locus of male advantage.
To understand more specifically where male advantage in powerlifting might differently manifest, I disaggregated data for individual lifts in records and results in the 83 kg male and 84 kg female weight categories, across the above IPF records and USAPL records and 2019 competition, and calculated male performance advantage for each lift.
Unsurprisingly, given known strength differences between males and females in the upper and lower body, male performance advantage is highest in the bench press and averages 64%. Moving away from the upper body focus, the average male advantage in squat and deadlift is 35% and 39%, respectively.
The maximum performance differences for individual lifts were found in the USAPL Raw Nationals 2019 dataset. In this typical competitive USAPL event, the male performance advantage in bench press was 76%, while advantages in squat and deadlift were 47% and 52%, respectively.
Summary.
When compared to other sporting disciplines, the male performance advantage in powerlifting is very large, and constitutes the largest male performance advantage in any individual (as opposed to team-based) discipline that I have analysed. Breaking down male advantage to individual lift level, male advantage is particularly high in bench press.
The consistent increase in male advantage in open weight categories compared with that in closed weight categories is explained by the more extreme stature achievable by males not limited by BW and - broadly correlated to weight - height. As one moves from international records to a single domestic competition, the male advantage in the open weight category reaches 70%.
The male performance advantage is higher in powerlifting than in Olympic weightlifting. The more complex nature of the lifts involved means Olympic weightlifting is a sport where strength, technical competence and biomechanical ability are necessary for success. In contrast, lifts in powerlifting are relatively simple moves, with fewer technical limits on raw strength.
The analysis of the USAPL Raw National 2019 competition reveals that the performance gaps between males and females are larger than evident in international and domestic federation records. This provides a snapshot for what happens “on the day” within a single typical competition.
Kudos for your efforts. Seems to have had some quite positive effects -- probably instrumental in banning transwomen from women's cycling at least:
"Female transgender athletes banned from women’s events by world cycling’s governing body"
https://globalnews.ca/news/9833371/transgender-athletes-world-cycling-womens-races/
Though I do wish news magazines and the like would deprecate if not anathematize phrases like "female transgender athletes" as they're nothing of the sort. They're no more than male transvestites, at least if they still have their nuts, and sexless eunuchs if not.
But in some related news, you might also be interested in a story out of Oklahoma where the State has more or less fully endorsed the definitions for the sexes that you, along with Heather Heying and Colin Wright, had had published in the letter section of the UK Times:
KJRH: "For example, the Order defines 'female' as a person whose biological reproductive system is designed to produce ova. 'Male' is defined as a person whose biological reproductive system is designed to fertilize the ova of a female."
https://www.kjrh.com/news/local-news/gov-stitt-signs-womens-bill-of-rights-through-executive-order
UK Times: "Individuals that have developed anatomies [gonads?] for producing either small or large gametes, regardless of their past, present or future functionality, are referred to as 'males' and 'females', respectively."
https://twitter.com/FondOfBeetles/status/1207663359589527554
Both, of course, making it unnecessary to actually be able to reproduce, to actually produce gametes, to qualify as members of the male and female sex categories. Those definitions may well have some social utility -- even they may be a rather problematic if not a "poisoned chalice" -- but they ain't biology. They do not at all comport with the standard biological definitions "promulgated" in more reputable sources -- the UK Times certainly qualifies as a decent newspaper, but it hardly qualifies as any sort of a peer-reviewed biological journal. But, for some specifics, see these sources, including the tweet of the definitions in the Oxford Dictionary of Biology:
https://web.archive.org/web/20170902010637/https://en.oxforddictionaries.com/definition/female
https://web.archive.org/web/20190608135422/https://en.oxforddictionaries.com/definition/male
https://academic.oup.com/molehr/article/20/12/1161/1062990 (see their Glossary)
https://twitter.com/pwkilleen/status/1039879009407037441 (Oxford Dictionary of Biology)
If one assumes that DSDs such as 5-ARD, which confers significant advantage in athletics, are equally dispersed through the sports population, do you think
- someone with that sort of T advantage should have shown up by now
- or other factors are at work? It seems surprising that someone with such an advantage hasn’t shown up.