Wednesday, August 19, 2015

Comparing ِِAnalysis For The 50 m Butterfly Women Race At The World Championships In KAZAN 2015

Sarah Sjöström: she is the Sweden champion; she broke the Championship record in this race with time: 24.97 sec. she also the world record holder for this event by (24.43).
Farida Osman: she is the Egyptian champion; she broke the African record in this race with time: 25.78sec.
Note: regarding for many changes in shots of this video and the diagonal angle for the video this make it difficult to know the exact water entry distance and angle  

Reaction time (RT):
We will start with the Reaction time For This Race is Illustrated in the next picture:
The best (RT) is for Wallace Vanderpool from Bahamas with RT: 0.60 sec it illustrated with pink color Also the RT for Sarah Sjöström: 0.65 sec illustrated with red color and the RT for the Egyptian Swimmer Farida is 0.70 sec illustrated with green color.

Sarah did not appear in the streamline under the water during this video. But for Farida Osman she did 9 kicks to breakout and she open her arms in the last 3 kicks of the streamline and which leads to increased resistance and this shown in the following analytic video:

Breakout Distance:
There was a challenge in determining the accurate breakouts distances Because of the diagonal angle for this video but it had been reached to the result that outlined in the following image:
Both Sarah and Farida almost breakouts at the same distance with approximately 11.59 m but for the longest breakouts distance for this race goes for the Denmark swimmer Ottesen she breakout approximately at 14.20 m and it been clarified this in the following picture:
Analysis data for performance are shown in the following table:
what described in the previous table that Sarah`s time is 24.97 and Farida time is 25.78 where the difference between them about 0.82 sec. In addition, considering the average speed for both swimmers, the difference in the distance between them is almost around 1.58 meters. It is worth mentioning that what draw my attention when analyzing this race for both swimmers the Numbers of cycles for them is equal 23 cyc. and here we should ask this question why there is a difference in the speed for both swimmers Despite the length of each cycle and number of cycles is equal, but also the stroke time (ST) for Sarah is (1.08) sec. less than the stroke time for Farida (1.12) sec?

The answer for this question due to the estimated speed that Sarah moves her arms and it depend more on undulation curve for Sarah is shorter and more forward movement than Farida Osman as the undulation curve for Farida more wider than Sarah, leading to increase the ups and downs movement more than forward. As for Sarah, she go for 2.17 meters  as an average in 1.08 sec for each cycle while Farida takes a longer time in each cycle with average 1.12 sec to reach 2.17 meters in each cycle, and there is a an example picture for the undulation curves:
In the first illustration of the drawing shows a shorter wave, leading to more forward direction than up and down. For the second illustration of the drawing, it shows a wider wave this leading to increase more the up and down movement more than forward. In addition, this technique for Farida can help her more in longer races such as 100 m and 200 m butterfly with a different rate in (Race Pace). The following analytic video shows the difference between the undulation waves for both swimmers:

Breathing plan:
Breathing plan for Sarah is 23 cycle without breathing. And this gives her more advantage to go forward is the same plan she followed when she broke the world record in 2014, but the number of cycles was 21 cyc, you can see the world's 50m butterfly swimming Sarah Sjöström analysis
As for the Egyptian swimming Farida Osman, there was a significant difference in shooting. Which led to the difficulty of identifying a full breathing plan but shows that Farida take a breath at the  5th, 9th, 17th and 18th cycle during this race leading to increased waviness curve while the requirement  for this race is to shortening the undulation curve and the up and down movement as much as possible.

By: C.Moemen Arafa

*** Please note- Mr. Moemen Arafa’s first language is Arabic. English is his second language. We apologize in advance for any editorial errors. Thank you.


  1. Why the difference between line wave israces?

  2. Why the difference between line wave israces?

  3. for Sarah is short wave and it more forward movement than Farida she hae a wider body wave it mean more up and down movement more than Sarah.