Visualization For Improved Swimming Efficiency & Increased Bottom Time
by
Larry "Harris" Taylor, Ph.D.
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This article is based on material presented in the author’s basic class
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As a scuba diving instructor, one of my pet peeves is seeing divers (either in real life or on scuba training videos) swimming in a most inefficient manner. This is not only aesthetically displeasing to me, but is indicative of a number of problems for the underwater swimmer and their buddy. In general, when swimming underwater with fins, almost all arm movements are wasted: they add very little to propulsion, but working the arm muscles can consume enormous amounts of energy (as indicated by increased air consumption). Simply getting divers to swim with hands relaxed at their sides will dramatically increase bottom time since air is not wasted in this needless muscular activity. Long, sweeping arm movements, as if doing the breaststroke, pose a hazard, especially in limited visibility water, to the buddy since this movement can easily displace another diver's mask. (Based on personal experience, I can assure you that having a buddy hit you in the face with flailing arms with the subsequent flooding of the dislodged mask is not a particularly endearing trait.).
The combination of thrashing arms and a kick that looks like the diver is riding a bicycle is not only forcing the diver to do far too much physical labor for minimal amounts of forward motion, but the extraneous movements, especially circling motions of the hands, create convection currents that can, when swimming near a soft bottom (common in fresh-water lakes) rapidly reduce the visibility to near zero (or worse) as the disturbed bottom material moves into suspension around the diver. In a reef community, the disturbed sand and sediment often settles on coral, clogging vital passages and smothering the small critters. Thus, sloppy swimming not only wastes a diver's energy, but also poses a life-threat to the reef ecosystem.
Finally, massive un-coordinated movements in the water send out pressure waves that lets every creature in the reef community know that an in-water trespasser is present in their community. More efficiently swimming divers move smoothly through the water column and thus, do not spook so many reef inhabitants. So, efficiently swimming divers not only have more time to visit underwater splendor, but they often interact with reef inhabitants that would flee from the offending pressure waves generated by divers broadcasting their presence with unnecessary arm and leg movements.
As a scuba instructor, I emphasize efficient swimming technique. At the first pool session, I ask each student to feel their biceps, then their calf, and then their thigh. I ask them, "Which muscle is largest?" Then I suggest that it makes the most sense to let the biggest muscle bear the burden of in-water propulsion. I also point out that using the smaller muscles, especially the calf, is a common source of muscle fatigue and cramping. The more they let the big muscles do the work, the less likely they are to experience in-water discomfort. This is also a time when I point out that swimming on the surface without fins is primarily an upper body skill, whereas swimming underwater with fins is primarily a lower body activity.
I next suggest a visualization technique will help them develop the use of their larger muscles for more efficient in-water swimming. The exercise is done as follows.
I ask all of the students to sit on a bench near the pool. I tell them that I want them all to close their eyes and listen to my voice. I do NOT want them to open their eyes until I ask them to do so. Then, using a soft voice and paraphrasing, with a slight twist, the Man of La Mancha, I slowly say (pausing a few seconds between each of the statements below to allow students to picture my suggestions),
"Come, enter with me into YOUR imagination"
"You are surrounded by blue-green ... the color of serenity."
"You are warm, weightless, floating, as if on a cloud."
"You are content"
"You are at peace ... one with the surrounding blue environment"
"You sense something ... far away ... too far away to see the details."
"It is coming closer"
"You are still floating ... in absolute tranquility ... in this world of all blue, the spot comes closer ... it is pink, but still too far away to see."
"The pink spot glides slowly and effortlessly towards you."
"There is something familiar and friendly here, but the pink object is still too small to discern."
"The pinkness, in the blue calm around you, becomes larger."
"You identify the pink spot ... you smile, still one with the environment, at this recognition"
"The pink spot is
"Barbie!"
At this point, everyone smiles. (An indication to me that they see a Barbie in their imagination.)
"Now, look at Barbie."
"Focus on her."
"She is 90% leg ... The legs are loooooooooooooooooooooooooooong and straight."
"Her toes are pointed ... this makes her fins a natural extension of her loooooooooooooooooooong legs."
"Her hands are at her side."
"Remember this image."
"Open your eyes."
I then tell our students that whenever an instructor or assistant says, "Be Barbie" (and they will hear it a great deal, especially during early phases of training) that what we are asking them to do is to not use their hands for swimming and to extend their legs to move more efficiently through the water. I also point out to those more inclined to physics that the longer and straighter the legs (without locking the knees), the longer the lever arm and thus, the more efficient the conversion of muscular energy to forward momentum.
The natural movement of a land-dwelling person with land dwelling survival instincts (see Primitive Brain ) when first learning scuba is to use the arms as a means of propulsion or stabilization. It takes time to overcome this very human tendency. Even with arms/hands at their sides, novice students will unconsciously move hands at the wrist in a paddling motion, especially when turning. Those in our classes with consistent wrist-paddling motions are encouraged to swim holding their hands at the waist to limit this paddling behavior. The important factor in all phases of training is that the hands are NOT used to swim or to change direction. The exact position of the arms/hands is a matter of personal comfort. Some students swim with hands behind their backs holding their tank; others with hands held at their waist. In a wet suit, the tailoring of the suit often makes arms/hands at the side more comfortable. It is NOT important to me which technique an individual chooses; what is important to me is that the student adapt to the underwater world by learning to swim and change direction without using the hands.
Conclusion
Visualization is a well-known technique for improving physical performance. It allows students to form a mental image of the desired goal (allowing the legs to do the work with little extraneous movements). It is particularly useful in scuba training because many habits of land-dwelling people are inappropriate while using scuba in an underwater environment. So, one can think of visualization as a training aid to assist land-dwellers in adapting behavior to their new underwater world. Although I am certain that some in the diving community will smirk at the use of the technique (and especially at the image I have chosen), the bottom line is that this technique works. I very strongly believe that this visualization, coupled with continual reminders to "Be Barbie" throughout training, is the primary reason for our students having shallow water (10-35 ffw) bottom times in excess of 50 minutes per dive their first weekend of diving. Our students consistently have first dive weekend (5 dives) accumulated bottom times of between 258-302 minutes. (In many cases it would be longer, but because the second day of diving is a three-dive day, we limit dives 3 and 4 to no longer than 60 minutes.)
So, if you want to spend more time under the surface of the water, then reducing your arm movements and extending the legs will significantly reduce your air consumption and thus, increase your bottom time
AND
One successful method of adapting to this form of underwater swimming is to imagine "being Barbie."
Bottom line:
Divers who imagine "being Barbie" during training develop efficient swimming techniques.
This swimming efficiency leads to decreased air consumption and increased bottom time.
Acknowledgement
The Barbie doll photographed by the author belongs to his personal collection of dive toys.
Barbie is a product of the Mattel Corporation.
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Larry "Harris" Taylor, Ph.D. is a biochemist and Diving Safety Coordinator at the University of Michigan. He has authored more than 200 scuba related articles. His personal dive library (See Alert Diver, Mar/Apr, 1997, p. 54) is considered one of the best recreational sources of information In North America.
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