Swim race analysis

Swim race analyzes

Swim race analysis

The purpose of a swim race analysis is to reveal strengths and weaknesses in your performance. Thus, allowing you to focus on abilities that will optimize your performance.
In this post, I will explain how to create a swim race analysis. To demonstrate, I will use Sara Sjøstrøm’s world record race in the 200-meter freestyle. However, you may apply the techniques and methods to other sports. I have used the metric system for my swim race analysis. Nevertheless, the calculations work just as well with other measurement units.

Determine your swim race analysis targets.

200-meters freestyle on short-course consists of one dive, seven turns at the wall with underwater swim where swimmers utilize dolphin kicks, and the freestyle swim. During the race, we document the time for each part of the race. Thus, giving us data for comparison.

Decide what data you want to collect.

When I create a swim races analysis for 50 to 200 meters, then I want to know the following:
  • Starting speed (0-15 meters).
  • Turns (5 meters into the wall and 10 meters out).
  • Dolphin kick and breakout speed (10 meters out from the wall).
  • Swim speed. (10 meters out from the wall until 5 meters before the wall).
  • Pacing strategies (Split times for each 25 meter).
  • Frequency and stroke length (10 meters out from the wall until 5 meters before the wall).

It might seem like a lot  to analyze, but it is a simple procedure.

Firstly, you need to collect the data.

The first challenge is to get precise data from the race. A easy way to collect this data is to film the race and analyze it. When I created a swim race  analysis for Sara Sjøstrøms race, I chose this youtube video.
By using kinovea, I was able to slow down the video and run it frame by frame. Thus, making it easy to get precise time measurement for the race.
Use the Kinova to pinpoint the exact moment for each time measurement. For example, as the picture below shows.
starting speed
I note at what time the head passes the 15- and 20-meters mark and when the legs hit the wall after 25 meters. Furthermore, I continue this process for each length at each measure mark. For my swim race analysis objectives, I have collected the following data:

Distance

Time

Time intervall

Distance

Time

Time intervall

15 m

6,1 s

 

110 m

Missing

 

20 m

9 s

2,9 s

120 m

65,2 s

 

25 m

12 s

3 s

125 m

68,3 s

3,1 s

35 m

16,9 s

4,9 s

135 m

73,4 s

5,1 s

45 m

23 s

6,1 s

145 m

79,6 s

25,15 s

50 m

25,99s

2,99 s

150 m

82,61 s

3,01 s

60 m

30,92s

4,93 s

160 m

86,84 s

4,23 s

70 m

37 s

6,08 s

170 m

94 s

7,16 s

75 m

40,1 s

3,1 s

175 m

97,6 s

3,6 s

85 m

45,2 s

5,1 s

185 m

101,6 s

4 s

95 m

51,4 s

6,2 s

195 m

107,9 s

6,3 s

100 m

54,45s

3,05 s

200 m

110,43 s

2,53 s

Secondly, this is how you may use the data.

Starting speed. (0-15 meters)

The starting speed is more important in shorter races than the long ones. For example, the athlete in a 1500-meter race may manage to compensate for lost time during the race that lasts for approximately 14 min. However, in a 50-meter race that lasts only for 20 to 24 sec, even a minor speed loss may cost you your victory. The importance of the starting speed for 200-meter is somewhere between these two examples. Therefore, the starting speed is not crucial for success, but you should not underestimate its importance. Every 0,1 sec might make the difference between first and second place.
Calculating the starting speed is simple. Divide distance with time
15 m/6,1 sec = 2,46 m/s

Turns (5 meters into the wall and 10 meters out).

The time intervals tell us the athlete’s ability to maintain speed into the wall, efficiently turn, and create velocity out from the wall. From the video analysis, I have deducted these time intervals:

Distance

Time

Time intervall

First turn

20 m

9 s

35 m

16,9 s

7,9 s

Second turn

45 m

23 s

60 m

30,92 s

7,92 s

Third turn

70 m

37 s

85 m

45,2 s

8,2 s

Fourth turn

95 m 

51,4 s

110 m

Missing

 

Fifth turn

120 m

65,2 s

135 m

73,4 s

8,2 s

Sixth turn

145 m

79,6 s

160 m

86,84s

7,24 s

Seventh turn

170 m

94 s

185 m

101,6s

7,6 s

Dolphin kick and breakout speed (10 meters out from the wall).

Swimming is unlike other sports in the aspect that the athletes achieve the top-speed at the start of the race. Not after a period of acceleration like in running events, etc. Whereas athletes achieve their top-speed during the dive. However, after the athlete hits the water, this speed decreases rapidly. To move through a substance that has 1000 times higher density than air causes more resistance than in land-based sports. Furthermore, an athlete that swims twice as fast will also have four times higher water resistance. Also, there is no steady surface to generate speed. When the swimmer pushes the water to generate speed, the water also gets pushed back. If you have ever tried to jump from a floating device. Then you would know what I am talking about. Meanwhile, the runner can push against the solid ground to create speed.
Therefore, swimmers achieve top velocity after the dive and after the turn where the athlete can push out from the wall. Swimmers that manage to preserve this momentum further out from the wall have gained a great advantage. 

Sara´s kick and breakout. 

First breakout after the turn

25 m

12 s

 

35 m

16,9 s

4,9 s

Second breakout after the turn

50 m

25,99 s

 

60 m

30,92 s

4,93 s

Third breakout after the turn

75 m

40,1 s

 

85 m

45,2 s

5,1 s

Fourth breakout after the turn

100 m

54,45 s

 

110 m

Missing

 

Fifth breakout after the turn

125 m

68,3 s

 

135 m

73,4 s

5,1 s

Sixth breakout after the turn

150 m

82,61 s

 

160 m

86,84 s

4,23 s

Seventh breakout after the turn

175 m

97,6 s

 

185 m

101,6 s

4 s

Swim speed (10 meters out from the wall until 5 meters before the wall).

The swim speed is the focus of most workouts. For long course competitions, swim speed has the highest impact on performance. However, it is crucial to recognize that the swim speed is not the only aspect that impacts performance. For instance, in short course competitions, there are more turns. Thus, your ability to take advantage of these turns will have a higher impact on your performance.

Distance

Time

Time intervall

Speed

First length

 

15 m

6,1 sec

 

 

20 m

9 sec

2,9 sec

1,72 m/s

Second length

 

35 m

16,9 sec

 

 

45 m

23 sec

6,1 sec

1,64 m/s

Third length

 

60 m

30,92 sec

 

 

70 m

37 sec

6,08 sec

1,65 m/s

Fourth length

 

85 m

45,2 sec

 

 

95 m

51,4 sec

6,2 sec

1,61 m/s

Fifth length

 

110 m

Missing

 

 

120 m

65,2 sec

 

 

Sixth length

 

135 m

73,4 sec

 

 

145 m

79,6 sec

6,2 sec

1,61 m/s

Seventh length

 

160 m

86,84 sec

 

 

170 m

94 sec

7,16 sec

1,40 m/s

Eight length

 

185 m

101,6 sec

 

 

195 m

107,9 sec

6,3 sec

1,59 m/s

Pacing strategies (Split times for each 25 meter).

It is not necessarily the athletes with the highest top speed that wins the races, but the athlete with the highest average speed. The split times from each length may reveal weaknesses in your pacing strategies.

Distance

Time

0-25 m

12 s

25-50 m

13,99 s

50-75 m

14,11 s

75-100 m

14,35 s

100-125 m

13,85 s

125-150 m

14,31 s

150-175 m

14,99 s

175-200 m

12,83 s

Frequency and distance per stroke cycle (10 meters out from the wall until 5 meters before the wall).

Stroke frequency tells us how many stroke cycles you perform per minute. Your stroke frequency combined with stroke length determines how fast you swim. However, at one point, these two components will restrict each other. The longer stroke length you have, the longer time it takes to perform the stroke cycle. Thus, reducing your stroke frequency. Therefore, calculating stroke frequency and comparing it with stroke length is useful to determine your swimming efficiency.
There are different ways to determine the stroke frequency. I have chosen a straightforward strategy by timing three-stroke cycles and divided them by three.
Frequency start
Frequency end

How to calculate stroke frequency

From this, it is easy to calculate the stroke frequency:
Stroke frequency
However, many stopwatches for coaches have an inbuild frequency measurement as a function. This function calculates the average stroke frequency after three cycles. It automatically calculates how many stroke cycles an athlete will perform with this speed. Some stopwatches also provide the possibility to calculate stroke frequency from only one stroke cycle. Therefore, an average stroke cycle time gives a better estimation of the overall stroke efficiency with swimmers that use longer stroke time while breathing.

Sara Sjøstrøms stroke time and frequency from the 200-freestyle race.

Length

1. stroke

2. stroke

3. stroke

Average stroke cycle

Stroke frequency

0-25 meter

1,3 s

1,3 s

1,3 s

1,3 s

46,2

25-50 meter

1,4 s

1,4 s

1,5 s

1,4 s

41,9

50-75 meter

1,6 s

1,5 s

1,5 s

1,5 s

39,1

75-100 meter

1,5 s

1,4 s

1,4 s

1,4 s

41,9

100-125 meter

1,4 s

1,4 s

1,4 s

1,4 s

42,9

125-150 meter

1,3 s

Missing

Missing

1,3 s

46,2

150-175 meter

1,4 s

Missing

Missing

1,4 s

42,9

175-200 meter

1,3 s

1,3 s

1,4 s

1,3 s

45,0

Although, if you have not used a stopwatch with an inbuild stroke frequency calculator. Then you need to convert the stroke frequency into average stroke cycle time first. You may use the formula below:
Frequency
Distance per stroke:

Length

Swim speed

Average cycle

Distance per stroke cycle

0-25 meter

1,72 m/s

1,3 sec

2,24 m

25-50 meter

1,64 m/s

1,4 sec

2,30 m

50-75 meter

1,65 m/s

1,5 sec

2,48 m

75-100 meter

1,61 m/s

1,4 sec

2,25 m

100-125 meter

Missing

1,4 sec

Missing

125-150 meter

1,61 m/s

1,3 sec

2,10 m

150-175 meter

1,40 m/s

1,3 sec

1,82 m

175-200 meter

1,59 m/s

1,3 sec

2,07 m

How to use your swim race analysis.

Single swim race analysis.

A good swim race analysis allows you to discover strengths, weaknesses, and changes in your race performance. As an illustration, Sara´s 200-freestyle is a good blueprint for how to perform this race. After all, it was a world-record. Nevertheless, it is possible to find weaknesses in this race also. Take a look at Sara´s seventh length. She kept an incredibly even pace through the whole race. Except for this length. Even though her turn and breakout time shows more efficiency on the seventh length than the fifth (100-125 m) and sixth length (125-150 m). The seventh length went up 0,7 sec. By using this data, it is possible to deduce that her swim speed was the main reason for her time loss on the seventh length.
Her stroke frequency increased during the sixth length. It seems to have dropped on the seventh length. However, the stroke frequency does not seem to have changed much compared to the fourth (75-100 m) and fifth length (100-125 m). Furthermore, the distance per stroke cycle declines from 2,10 m on the sixth length (125-150 m) to 1,82 m on the seventh length (150-175 m).
It is normal to experience a decrease in distance per stroke cycle during a race. The muscles will not be able to withhold strokes with that power for a longer period. One way of compensating for this loss is to increase stroke frequency. As we can observe that Sara did during her sixth length (125-150 m), where she progressed from 42 to 46 strokes per min.

Do not make to hasty conclusjons

Out of this swim race analysis alone, it might have been reasonable to claim that Sara might benefit from better muscular power endurance to keep her distance per stroke cycle better. However, one swim race analysis are not enough to make such a claim. Only Sara and her coach will be able to get an accurate interpretation of how this swim race analysis reflect her race. Her seventh length (150-175 m) might have been an abnormality caused by a technique failure restricted to this length. It could also have been a tactical maneuver to save more speed for the final length. Although, that would have been a risk. Her opponent Pellegrini is well known for finishing strong.
To clarify, one swim race analysis is not enough to make decisive claims. It is necessary to have a 360⁰ overview of the race. In other words, you should not make conclusions without the athlete´s race recollection and the coach’s knowledge of the race strategy and workout history. However, a swim race analysis is a mighty useful tool.

Compare to previous races.

To compare with previous races is one of the best ways to utilize the use of race analyzes. By comparing them to previous races, you can deduce how your racing abilities have changed. Moreover, by comparing this to your workouts diary, you will be able to deduce how your training has affected your race. Above all, give you useful tools for how to recreate or change part of your workout to achieve even better results.

Compare to other athletes.

By comparing your races to other athletes, you will be able to discover where you have an advantage and vice versa. As an illustration, you discover that your swim speed is better than your opponent. However, your opponent has a turn and break out the speed that you are unable to match. Hence, your turn and breakout speed needs to improve if you want to leave the next race as the victor. In short-course races, the turn and breakout take up over 50% of the race. Therefore it is especially important to improve your ability in this part of the race.

For other sports.

You may perform race analyzes as shown above in other sports also. Depending on what data you want to acquire. 100-meters sprinters may divide their race in three.
  • Reaction time
  • Acceleration time
  • Top speed
Or you may go into more detail by analyzing contact time per step.
Longer races like cross-country or marathon running, you can compare different parts of the race against other opponents. For example, by adding the accumulative time used in uphill slopes, downhill, or straight levels, it is possible to deduce how you are performing on these parts compared to other athletes. As an illustration, a cross-country skier realizes that one of her opponents goes faster than her in every downhill. Something that might indicate that her skies need a better glide. However, if the same opponent also performs poorer in uphill, then you need to evaluate how to balance the cons and pros.
If you have questions about how to analyze races or performance in your sports, then send me an email on [email protected]. I will help you to find an analyzing method that fits your needs.
person swimming in body of water

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