(Note: Fit To Play columnist Jim Johnson will lend his voice on the 2024 Summer Olympics throughout the next month with special features pertaining to specific events and what goes into them for the athletes competing in Paris.)
If you are paddling your canoe and stop paddling, the boat will stop. This is because the water resists movement through it. This resistance is called drag and will resist swimmers, canoeists, cyclists, kayakers, and rowers in this year’s games.
Swimming was introduced in the 1896 games with four events and will dominate early television coverage as the games begin. This year there are 37 different swimming events. The U.S. is a dominating force in Olympic swimming because of numerous youth swimming programs and great coaching in high school and college.
To swim faster, athletes need to increase propulsion and decrease drag. One type of drag is called form drag, mostly related to the cross section of the object — the greater the cross section, the greater the drag. Swimmers reduce form drag by staying streamlined, turning their heads to breathe with as little motion as possible. For many sprints, they don’t even breathe.
Cyclists ride in a bent over position in order to reduce cross section. Watch the pursuit cycling events and you will observe some amazing techniques to reduce drag.
The shape of an object also affects form drag. For example, when swimmers enter the water, their arms are joined together in an upside down V in order for water to get displaced gradually. The shape of bikes and helmets is similarly designed to reduce form drag. Observe rowing shells and you will see very narrow, pointed boats, in fact, so narrow that most people turn over the first time they try. This is true for the stern as well. A single scull is 27 feet long and an eight is 62 feet. A square stern boat is slower.
Take a good look at the eight finalists in any swim race and they are very similar. These are the eight fastest swimmers in the world and have the natural body for swimming. You will notice that they are all muscular but not heavily so. Too much muscle increases drag. They have long arms and are also tall. The average height for the eight finalists in the Tokyo games was 6 foot, 2 inches for men and 5-9 for women. Katie Ledecky is 6 feet tall, and Michael Phelps is 6-4; many swimmers are taller. The taller swimmers can generate more propulsion but also have less drag.
Surface drag, the interaction between surfaces, is another form of drag. You will notice the skin tight swim suits and caps. Swimmers shave all of their body hair. Cyclists wear special suits to reduce surface drag. Boaters maintain their boats in pristine condition with special coating.
In early 2000 manufacturers developed swimwear that significantly reduced drag and possibly increased buoyancy (against the rules). Everyone wanted one. While the suits did reduce drag and reduce time, the cost was around $700 per suit and even kids in swim leagues insisted on having one. The whole thing got out of hand and finally swim authorities stepped in, pushing back against the technology, banning all “non-textile suits.” Today, suits must not go past a swimmer’s knee or above men’s waist, and women’s suits cannot go past the shoulders.
The surface of the water also resists movement. Waves inhibit swimmers but waves are somewhat mediated by the design of the pool as well as the baffles on the lane lines. Harvard swimmer David Berkoff had his own way of reducing surface drag. In the preliminary of the 1988 Seoul Olympics, Berkoff pushed off the blocks in the 100-meter backstroke. Spectators, unaware of Berkoff’s technique, were confused; there didn’t seem to be anybody in lane 5. But there was Berkoff, arms outstretched in a perfect V, using his aerodynamic dolphin kick to thrust him forward — underwater. Berkoff popped up about the 35-meter mark, far ahead, backstroked to the end and repeated. He set a world record.
The world soon became familiar with the “Berkoff Blastoff,” a model soon to be imitated by everyone. It wasn’t long before Berkoff’s technique was banned and all swimmers are now required to surface after the first 15 meters of every lap. Not good for spectators, the ‘Blastoff’ is also dangerous as swimming underwater can lead to unconsciousness. While the Blastoff is a thing of the past, Berkoff’s start using the dolphin, rather than the flutter kick, is now the accepted start for backstroke and freestyle. Look for Berkoff’s daughter, Katharine, in the backstroke at the Paris games.
Jim Johnson is a retired professor of exercise and sport science after teaching 52 years at Smith College and Washington University in St. Louis. He comments about sport, exercise, and sports medicine. He can be reached at [email protected]
Source link : https://www.recorder.com/The-Olympic-Report-with-Jim-Johnson-Drag-Slows-Swimmers-56129785
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Publish date : 2024-07-22 18:50:37
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