Check Out Mollie O’Callaghan’s Wild Splitting en Route to 100 Free Top Seed


In the semifinals of the women’s 100 free, 18-year old Australian swimmer Mollie O’Callaghan took the top seed in a time of 52.85. She nearly even split her race, flipping at the 50 mark in 26.42 and closing just 0.01 seconds slower in 26.43. O’Callaghan’s last 50 is now the fastest back half ever swum by a woman in the 100 free.

O’Callaghan previously set the 100 free back-half record at the 2022 Australian National Championships, where she split 25.92/26.57 to record an overall time of 52.49. That time still stands as the fastest in the world this year.

In her semis race, O’Callaghan was 8th at the 50 mark but then charged home to win. The Aussie’s back half split was the only sub-27 final 50 out of the entire semifinals field, with the next fastest being Penny Oleksiak‘s 27.43 which is a whole second slower. This is especially notable considering that Oleksiak is also known for her back half speed, as she flipped in 7th in the 100 free finals at the Rio Olympics and ended up closing in 26.93 to win the race. However, Oleksiak’s final 50 in that race is still a whole 0.6 seconds slower than what O’Callaghan can go.

O’Callaghan was basically floating to a 26.42 on the first 50, not needing to take the race out fast since it’s only the semifinals. However, she has has proven she can close in a similar speed when going out faster like in Trials, when she opened half a second than she did today but still managed to close only 0.14 seconds slower.

Check out our analysis of O’Callaghan’s closing speed following her swim at Australian trials here.


Data courtesy of Daniel Takata. Follow his Swimming Stats page on Instagram here

Mollie O’Callaghan 26.43 52.85 2022 World Championships
Mollie O’Callaghan 26.57 52.49 2022 AUS Nationals
Britta Steffen 26.61 52.07 2009 World Championships
Britta Steffen 26.62 52.22 2009 World Championships
Mollie O’Callaghan 26.73 52.83 2022 AUS Nationals
Amanda Weir 26.76 53.02 2009 World Championships
Bronte Campbell 26.80 52.27 2018 Commonwealth Games
Ranomi Kromowidjojo 26.83 52.75 2012 Eindhoven Swim Cup
Sarah Sjostrom 26.84 52.78 2015 World Championships
Sarah Sjostrom 26.86 52.73 2014 Stockholm Open
Sarah Sjostrom 26.88 51.71 2017 World Championships
Emma McKeon 26.88 51.96 2021 Olympics
Sarah Sjostrom 26.92 53.05 2011 NED Open
Simone Manuel 26.92 52.54 2018 USA Nationals
Sarah Sjostrom 26.93 52.93 2014 Stockholm Swim Cup
Penny Oleksiak 26.93 52.72 2016 Olympics

Notably, in the 200 free, O’Callaghan had similar closing power en route to taking silver in a time of 1:55.22. However, it stand out as much as it did in her 100. Her final 50 in that race was a 28.56, which was the second-fastest in the field but still slower than Yang Junxuan‘s 28.49 that helped her win gold. O’Callaghan oepend her 200 free in 56.88 and closed in 58.40.

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11 days ago

Great stuff. Thanks for the historical data.

11 days ago

She can certainly win the 100free but:

  • she’s certainly given her competition a clear roadmap on how to beat her. The question is whether anyone else is in sufficiently strong form to be able to take it out sufficiently hard and then hold her off.
  • she’s going to give everyone watching heart tremors.

At this point, its unclear that anyone else’s form is anything better than 52 high but is she running out of gas and still capable of putting it out of reach ? I’m not sure

11 days ago

Wtf. Her 200 should be way faster then

11 days ago

What is her 200 free time?

Nic swimmer
Reply to  swimmer
11 days ago

1.54.9 pb

11 days ago

She wasn’t actually racing a 100 free, she was doing pace 50’s on 0 seconds rest. 🙂

11 days ago

What if she’s not a good sprinter, just has A LOT of endurance /j

Reply to  DCSwim
11 days ago

no way u just used a tone indicator on swimswam comments

About Yanyan Li

Yanyan Li

Yanyan is from Madison, New Jersey and spent the majority of her life there. Although she wasn't the greatest competitive swimmer, she learned more about the sport of swimming through scoring countless dual meets, being a timer, and keeping track of her teammates' best times for three years as a …

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