ISCA Science Newsletter


May Science Newletter

Notes from Science Presentations
at the ISCA Hall of Fame Summit

Hydrodynamics Mechanisms
Underlying Human Swimming Propulsion
Dr. Ernie Maglischo

The purpose of this talk was to suggest an alternate explanation for human swimming propulsion; one that is not based on pushing water backward with the palm of the hand, as is popularly believed. Recent research, by H. Takagi, and colleagues (2018 personal correspondence) suggests that swimmers accelerate their bodies forward by forming counter-rotating vortices on the dorsal side of the hands that lower the pressure on that side by a considerable amount, thus creating a pressure differential between the palm side of the hand where the pressure is higher and the dorsal side of the hand where the pressure is reduced dramatically. Evidence for this theory was presented and some suggestions for effectively creating this pressure differential are described.
The Role of the Coach in Dry Land Exercise
to Prevent Injury and Increase Performance
Dr. Ted Becker

The shoulder external rotation exercise can assess a left vs right strength imbalance. The elbow is at the side and the forearm swings away from the abdomen. If the shoulder muscles are weak there will be a “racheting” i.e., the arm rotation will not be smooth.
Panel on Coaching Multi-Sport Athletes
Dr. John Heil

Based on comments from our expert panel, swim coaches who work with multi-sport athletes can be more effective by considering the full multi-sport training regimens and competition schedules. With this in mind, the multi-sport swim coach should be aware of periods of heavy training and competition in other sports and sensitive to overtraining, adjusting swim training schedules accordingly. Because of the non-weight bearing nature of swimming, training can often continue, possibly at increased levels and with potential therapeutic benefits following non-swimming injuries.
Polarized Swim Training:
The Science Behind Sound Decision Making
Dr. Daniel Carl

We are not there yet in terms of making a claim that polarized training would be a preferred approach to swim training. Collectively, across the programs that I have been able to witness and discuss with coaches, we are more closely aligned with a pyramidal training program which contains a larger base, some threshold in the middle, and more specialized training at the top. However, there is limited to no current research or work in swimming that addresses the middle ground of threshold training. This middle ground is what is eliminated in a polarized model as being unnecessary. Therefore, its necessity or its elimination has not been clarified. A polarized model, typical would be 80% base / 20% specialized, could in theory be a preferred, efficient swim training method.
The World (Record) Is Not Enough:
How to Swim 100 Meters in 40 Seconds
Dr. Rod Havriluk

(Seifert, Chollet, & Bardy, 2004)
Swimmers typically waste time on the arm entry, shorten the push phase, have gaps in propulsion, and lose hand force. Strategies to decrease the time of the arm entry phase, ensure an adequate push phase, increase the arm index of coordination, and minimize hand force losses can help every swimmer swim much faster.

ISCA Certification Program
The following courses are Powerpoint Slide Shows with the option to display subtitles in 68 different languages. The courses will soon be available on the ISCA website and are now available on the STR website.

Biomechanical Foundations of Swimming
Swimming Without Pain
ISCA Science Partners

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