Breaking the Surface: How Block Positioning Can Make or Break Your Dive

Courtesy: Hussein Elzaafarany

Caeleb Dressel, Ranomi Kromowidjojo and Ben Proud. What do they have in common? Yes, they are swimmers, but more than that they’re some of the best sprinters in the world. Their main races range between 18 and 52 seconds; quicker than you can say Kromowidjojo.

Looking at such short sprints, it’s safe to say that everything counts; starts, underwaters, breakout, turns, stroke. All of it. What if you found out that you could make your first 15m 0.15 secs quicker just by changing the position of the wedge on your block: something that Milorad Cavic wishes he would have had in the 2008 Olympics 100 fly final where he lost to Michael Phelps by 0.01 coming 2nd and missing out on the Olympic gold.

Due to the sport’s competitive nature and its high skill cap, improvement has shifted away from new techniques or technologies and has gone back to the small changes that accumulate to make a big impact; dives being one of them. Through the analysis of a study carried out by Loughborough University, it was found that when full-grown males moved the wedges back to position 5 and allowed the angle of their back knee to increase to between 90 and 100 degrees, their horizontal speed off the block was up to 0.1m/s quicker, and their peak force was up to 11.6% higher. Another study showed that swimmers crossed the 15m mark 0.15 secs quicker when they placed the wedge in their preferred position, even though their reaction times were about 6% slower. This went back to muscle memory, which is the brain’s adaptation to make movements more efficient when they are repeated over time.

Photo: Mine Kasapoglu.

This goes to show that there is a statistical relationship between the position of the wedge and the distance traveled off the block. Despite this being an under-researched topic, these findings allow swimmers to benefit from marginal gains and improve their performance. Diving blocks have progressed immensely over the years, starting with flat blocks in the early 1900s to the high-tech Omega OSB-11s we have now, as it’s a crucial component of swimming. It’s no coincidence that top athletes still train to master their dives, as this enables them to assert an advantage over their competition. Unfortunately for some, having everything but a good dive could still mean missing out on one of the sport’s most prestigious medals, the World Championship gold, as it did for Sarah Sjostrom. At the 2019 Gwangju World Championships, the Swede was expected to come home with the gold in the women’s 100 butterfly final, but due to a mistake in her dive, she entered the water at a bad angle and lost some of her momentum, consequently losing out on the gold medal to Maggie MacNeil, and finishing second.

To read the full research paper from Hussein, click here.


An Egyptian swimmer, student and well-rounded athlete living in Dubai, Hussein dedicates his time to digging deeper into the topics that interest him. Research has always been a fascinating area for Hussein as it helps him embody the phrase we’ve all heard many times: work smart, not hard. Hussein is currently in year 12 and aspires to study mechanical engineering in the future, applying physics to areas, like swimming, that has had a great impact on his life.

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25 days ago

Nice article Hussein! Very interesting findings that are super relevant to our sport, which like you said is so heavily dependent on the minor details and minute differences. I’ve used the same starting position on the block (2/5) for 7 years, even though I’ve likely outgrown it and would benefit from putting wedge farther back. However, since I’m so used to putting the wedge on 2/5, it still allows me to get the best start which is why I’ve stuck with it since the age of 10. Well done on the writing and research, really enjoyed reading!

26 days ago

Have recently found that not only positioning the blokes correctly, I also place my back foot between the base and block. Thus removing the flex of the foot on the top of the block (only for sprints). At 64 getting reaction times of .50-.55. Give it a go at your next practise and let me now! Every part of a second counts in racing sprints!🥇🏊‍♂️😁

Ob man
Reply to  ROPES
26 days ago

Flex is good for power when combined with flex of the wedge. Elites should have ball of foot on wedge imb. But good on u for experimenting. No offence but at your age your tactic may be more useful as less power means you get less flex from wedge anyway. So u might be onto something for masters swimmers

Ob man
26 days ago

Great report!! Very useful thought stoker

Swim Alchemist
26 days ago

Cielo had a wedge during his 50 Free WR swim. Bousquet didn’t when he went 20.94.

The Original Tim
27 days ago

I got to play around with some hand-timed time to 15m experiments last summer at a local 50m pool with blocks with wedges. This was all wearing a practice speedo + drag suit, so not quite the same as racing.

If memory serves, I was consistently about .3 faster to 15m for free and fly, and anywhere from .2-.5 faster to 15m for breast with the wedge (and with the wedge and my back leg appropriately situated) than when doing a track start sans wedge. After I did a few warmup starts to dial in the positioning and get used to the angle of the block, I did a total of 6 starts for each stroke, 4 with the wedge… Read more »

Reply to  The Original Tim
27 days ago

I’d be curious to see how times shape up in relay starts.

1) Starting and leaving with both feet on the edge of the block,
2) Starting in a track position and then stepping up as the swimmer touches, and
3) Starting with both feet in the back then following #2.

And then when you include the wedge there are more variations. Could be interesting..

27 days ago

At 52 I don’t have the leg power to fly off these new blocks. Furthermore, you never get a chance to train with them. So, at masters competitions, I curl both feet at the front edge of the block, old fashion style. I get more power and am more familiar with my trajectory. Works for me.

Reply to  Alain
27 days ago

First time I’ve ever got to use the wedge was at a Masters meet. Haven’t gone back to the old way since.

Reply to  Alain
27 days ago

I think most times you are able to take the wedge off. If they are sprinting through the heats, then there may not be much time for you to take it off and the following swimmer to put in back on…can be a little stressful.

The unoriginal Tim
27 days ago

I can only assume thay if the wedges had existed in 2008 Phelps wouldn’t have got such an awful start on the 100 Fly so the winning distance is likely to have been more. He really bombed on that start.

Otherwise interesting article. The wedge must provide advantage and consistency. People used to track start without the wedge.

Last edited 27 days ago by The unoriginal Tim
Reply to  The unoriginal Tim
27 days ago

Everyone else’s start would have also benefited from the wedge too.

Reply to  The unoriginal Tim
27 days ago

Phelps was never the fastest off the blocks. But that start was really bad even for him. His turn wasn’t that good either. His closing speed saved the day

27 days ago

We need a swimswam case study on Brad Tandy’s start

His start itself just edges out Dressel imo (although once in the water, Dressel’s UWs overpower Tandy)