Performance Analysis of Surfing: Rodeo Clown Flip

Anyone who has seen a surfer or skateboarder pull off a flying aerial move is amazed that a human can do such an incredible trick. Although we are all completely dumbstruck by the performance of these maneuvers, these sports often have an unfair reputation of not being truly professional. We often consider these athletes to simply be kids who have spent too much time playing around on the beach.

Surfing and Skateboarding are no longer sports dominated by athletes with talent only. These professional athletes spend many hours training. Professional surfers now spend almost as much time out of the surf, working out (often with trainers) on balance balls, with weights, and in the gym and swimming pool. They do thorough warm up sessions before going out to compete and often also have cool down routines for after a surf.

The use of scientific analysis in surfing has been long in coming. There are a number of reasons for this and I won't give you a history of soul surfing, but the main reason is the difficulty of doing any physiological or biomechanics testing on a surfer. Because surfers do their sport in water and shifting, changing waves (size, direction, steepness...), it is very difficult to test them in the same conditions and obtain relevant scientific results.

Recently, for the first time a team of scientists joined some professional surfers in the Mentawais and recorded their paddle speed, surfing speed and heart-rate during surfing sessions. They also took blood samples to monitor lactic acid build-up and hydration data. These scientists were able to provide the surfers with some physiological and performance data which will surely help them to train better for competition.

Using video to analyze surfing is another way in which these athletes and other non-professional surfers could improve their performance. The professional surfers get lots of video of their performances from all different angles and we hope they use this information to make improvements. Of course, because of the changing waves and the 3 dimensional nature of surfing (moving up and down, forward and sideways), it is difficult to make comparisons with video.

As we looked through some of the video from the surfing trip to the Mentawais, we found one of Jordy Smith of South Africa, performing a Rodeo Clown Flip. We won't try to describe the move here. At about the same time at a competition in the Maldives, an American surfer, Patrick Gudauskus was completeing the first ever rodeo clown in competition. We have decided to look at both these videos and compare their performances. Jordy's wave is the first video and then Pat's wave is the first part of the second video.





Once you get over being completely amazed that surfers can do such things on a wave, take a closer look.

The first thing you will notice is that Jordy is on a much bigger wave than Pat and this can make comparison difficult. We can still look at the technique though and we will do this in stages.

1. The Setup: Jordy launches into his rodeo clown with his board facing almost vertically up at the sky, while Pat's board is about 30 degrees from the vertical when he launches. This may be because of the size of the wave. However, what is obvious is how this affects the height of the flip. Jordy's vertical entry helps project him higher into the air.
2. The Take Off: Here both Jordy and Pat transfer their weight onto their back foot. This helps them launch the board out of the water, bring the board up to their hands for the grab and creates the rotation by pushing on the back of the board.
3. The Grab and Spin: Once again they both use a similar technique here. They both grab the board quickly once they are in the air and begin their rotation. Some of their rotation has come from the back foot pushing on the board but once they are in the air they both use their heads to complete the spin. Watch how they both turn their heads to their left (the direction of spin) . If they did not use their heads to turn they would not be able to complete the spin.
4. The Top of the Flip: As they spin around both surfers actually travel upward to their high point. The high point of the flip is determined by the surfers maximum height above the wave. It is obvious here that Jordy is much higher than Pat throughout the flip. At the top, Jordy's body and board are well above the wave (we can see sky and clouds between him and the wave). Pat's board and body are at just about the height of the wave. Although in this case it does look like Jordy is much higher we need to clarify this by pointing out that Jordy is on a bigger wave (this is not controlled by the surfer) and the camera angle filming these two flips is not the same and therefore the camera angle used to film Jordy's flip may be making it look much higher than it was.
5. The Landing: The landing of course is dependent on all the other factors that occurred before, including the take off, spin and height. Jordy has rotated further and is still above the wave as he prepares to land. He therefore needs to stretch out his legs to find his landing and ride out of it. Pat, on the other hand has not been able to rotate as far, because he did not get the same height above the wave. He is forced to land low down, but by landing with knees bent and hands still on the board he too is able to ride out.
   

So both of these flips were spectacular and although they looked different they were actually performed with similar techniques and there is a lot to learn by analyzing the videos.

Unfortunately, those of us who surf for fun and do not have sponsors, do not have too many opportunities to see ourselves in action. You can however set up a camera on a beach or get someone to film you from the beach. Try to get video looking straight out at the wave from the beach. It is difficult to analyze your performance when studying video that was filmed at an angle to the wave. It is also useful to have some sort of calibration scale that can be used to measure height (as we did in a previous post on Measuring Jump Height). Of course if you can get more than one camera setup you can really take a look at your technique from multiple views, which makes sense for a sport such as surfing.

We love to hear your comments or suggestions. Let us know what you think or what you want to see posted.

Andy Murray's Tennis Serve

Last week, Rafael Nadal won the 2009 BNP Paribas Tennis Tournament at Indian Wells, California, defeating Andy Murray easily in the final.

As we watched the tournament, we heard frequent discussions of Murray's second serve, and that if he could develop a better second serve he would be almost unstoppable. Of course, he was almost unstoppable at Indian Wells, but did lose badly in the final, mostly because of poor serving. In that final match against Nadal, he lost his service games four times and won only 6 of 16 (38%) of his 2nd serve points. Let's take nothing away from Nadal though; he has the best return game in tennis, possibly the best ever.

All tennis players, including beginners, know the importance of the serve. A good serve can result in easy points and puts pressure on an opponent. The first and second serves in tennis usually have different goals. With your first serve, you want to win the point with an ace, service winner, or at least put your opponent in a defensive position for the next shot. The first serve is generally flat and fast, and you can take more risk, knowing you have an attempt at a 2nd serve if you need it. The second serve is your backup safety. Your priority is to get the second serve in and start the point. If you miss the second serve, you will double fault and give your opponent a free point. Most tennis players put a lot more spin on the second serve, but this tends to reduce the speed of the serve.

Because of the slower pace, the second serve often gives the receiver plenty of time to get into position to hit an aggressive return. However, if you can make your second serve look similar to your first serve, at least in terms of the service motion, you can make it difficult for the receiver to predict the speed (and type of spin) of the serve, and you may retain a significant advantage, even as you serve slower and with more control.


We found some video of Andy Murray's first serve and decided to look at it from a biomechanics point of view. This video is set up very well for video analysis. The camera is set up along the baseline, which allows us to get a side-on view of Andy during his serve. We can also see the complete service motion in the video, including the racquet head, and can see the racquet make contact with the ball. It would have been great if we could've seen the complete ball toss (the ball goes out of the top of the screen) and if the camera had been stable and mounted on a tripod; but in general, this is good video sports analysis footage.



The power in the tennis serve, like many throwing or hitting sports (baseball hitting and pitching, football throw, and golf) is created by a chain of events. Each part of the body loads up with energy and transfers its energy to the next link in the chain. The timing of this energy transfer is critical to creating racquet head speed and therefore a good, fast serve.

In Andy's serve, we see how he starts with his knee bend as he throws the ball up. You may also notice that as he bends his knees his hips turn away from the court. He then transfers this energy now stored in his hips by bringing his back foot up to his front foot and rotating his hips into the court. Once again notice that as he rotates his hips back into the court, his shoulders now rotate away. This counter rotation in both hips and then shoulders creates the potential for racket head speed; Andy is coiled up and ready to explode his racket toward the ball.

As he does this, he releases the potential energy, rotates his shoulders back into the court, and throws his racket at the ball. All these energy transfers add up to create the speed with which he will hit his serve. If his timing is off, his speed will not be as high.

The ball toss is, of course, just as important. If you do not throw the ball consistently, it will be very diffcult to perfect the timing of your kinetic chain (described above). Andy's ball toss is high and a falls about a foot inside the court. If you want to hit a good hard serve, the ball needs to be in front of you, so that your body and racquet are moving forward when the ball is struck. If the ball toss is directly above your head, it is much more difficult to get theball moving forward with as much pace.

Ok, so Andy has a great first serve, and we can see that here. It is his second serve that the commentators were discussing. Unfortunately, we were unable to find any good footage of his second serve to compare it to his first serve. We are sure his coach is working hard on improving his kinetic chain sequence and timing to make it more difficult for his opponents to read his second serve.

Please post comments and let us know what you think, or whether you have any questions or suggestions. We would be delighted to hear from you.