Science of Performance: Two Styles of Fly

By Swimming World correspondent G. John Mullen of Swimming Sciencet and Center of Optimal Restoration , Creator of Swimmer's Shoulder System
SANTA CLARA, California, May 22. THE techsuits left a void in the sport of swimming. I'm not talking about modest Masters swimmers, but in butterfly.

Look at the 2009 World Championship results and note the vast difference in times. I'd argue fly is the stroke most deteriorated by the restrictions on swim suits.

Techsuits allowed swimmers to swim extraordinary speeds underwater and keep their hips high in the water despite fatigue. This aid resulted in superhuman results in many butterfly races. A lot of the current world records are unfathomable, but the sub 50 second 100 fly is still unbelievable!

Who could forget the 100 meter fly showdown between Phelps and Cavic? Some of you wonder which showdown I'm talking about, the Olympics or World Championships, but it simply doesn't matter. The result was the same and I'm not even talking about times.

Phelps and Cavic are two different animals. Phelps is lanky, tall, and the ideal body type in the eyes of many in the swimming community. Cavic was a bulkier fast-twitch beast out of a storied sprint program. These different characteristics brought a few of the greatest races of all time.

NO TWO STROKES ALIKE
One can break butterfly into two styles, the body driven or shoulder driven stroke. Coach Mike Bottom has characterized the shoulder driven fly and has used it with great success in sprint fly. However, the body driven fly is the fly commonly utilized by Olympic medalists for the past 30 years.

PHELPS V. CAVIC
Out of the water differences weren't the only things differentiating these two swimmers. In the water, Phelps uses a body driven, high-amplitude butterfly. He uses his elongated torso, to send force from his chest, through his hips, down to his ankles.

This type of fly is ideal for distance as it creates a longer distance per stroke, uses more core musculature, and is more efficient in transferring energy.

The Cavic style or shoulder driven stroke is for sprints. This uses the shoulder-blade stabilizing muscles to lock the shoulders into place, providing a stable base for propulsion via the arms. This allows a higher tempo and force production due to the power of the arms. This stroke appears less graceful, but is a powerful beast, resulting in greater levels of hydrogen ions and lactic acid.

SUIT NO MORE
Without the suits, the shoulder driven fly is at a disadvantage. They do not receive the buoyancy or compression aide to hold this powerful stroke for a whole 100 meters long course. This is one reason Cavic is invisible since since 2009 and great short course yard sprinters have difficulties translating success to long course meters (Staab, Shields).

In yards, the shoulder driven fly will still succeed for a few reasons:
1. Walls: the more frequent walls allow the swimmers to rest their arms and use their legs for nearly 2/3 of the lap.
2. Length: a five-second difference between yards and meters provides a huge physiological difference. This is why there are so many flag swimmers in long course, they don't have the physiological means to finish a full 100 meter race due to failure of their anaerobic system.

The body driven fly will remain successful in long course for these reasons:
1. Distance per Stroke: the athlete with the fastest second 50 typically wins 100 LCM events. The body driven stroke increase the distance per stroke, decreases stroke rate and holds off fatigue.
2. Efficiency: the ability to transmit force through the core is essential for efficiency. The body driven stroke allows a swimmer to use the stronger core muscles opposed to the shoulder muscles which are unable to withstand high levels of stress.

FUTURE
The future of fly depends on the techsuits. As long as the buoyancy and area restrictions exist, then the body driven fly or a hybrid style will succeed in the 100 meters. In fact, if swimmers use a body driven fly for the first 75 meters, then transitions to a shoulder driven fly to finish a race, then a hybrid might succeed, but unlike freestyle, changing a fly stroke disrupts rhythm and likely impedes efficiency. In free, transitioning between a body and shoulder driven stroke is feasible due to the axis of rotation remaining the same, in fly this difference leads to slowing.

CONCLUSION
If you're a young swimmer figuring out fly, learning the body driven stroke is essential. This competency will maximize overall fly success. However, the ability to perform a shoulder driven stroke is a must in sprint fly and short course yards.

Therefore, if you're a known body driven flyer, learn the shoulder driven stroke and how to unleash this beast in sprints and times in the race requiring speed (turns and finish). For example, if one is able to transition to a shoulder driven stroke at the end of a race or into each wall, they will able to transition speed in and out of the turns, maximizing yards success.

Learn both styles and find which works for your body and physiology, remember no two strokes are alike, individualization is key!

G. John Mullen is the owner of of the Center of Optimal Restoration and creator of Swimming Science. He received his doctorate in Physical Therapy at the University of Southern California. G. John has been featured in Swimming World Magazine, Swimmer Magazine, and the International Society of Swim Coaches Journal.

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