To many people, elbows are the ugliest body parts. Nevertheless, elbows are the reason for my career as a swim instructor and coach.

As a youngster, I was a struggling, weak, inefficient swimmer. To this day, I wonder how I managed to pass my Boy Scout swimming requirements.

Then, in my 17th summer – not coincidentally the summer after high school physics class – came my “Aha!” moment. I realized that successful swimmers kept their elbows above their hands, not only during the recovery over the water, but during the stroking phase underwater.

My desire to spread that discovery to others was the seed for my eventual aquatics career.

The high-elbow recovery for the Crawl stroke is initiated after the extended stroking hand presses past the hip to the thigh. The elbow lifts the upper arm (my mentor would say, anatomically, “medially rotates your humerus”), which turns inward while dangling the relaxed lower arm like a puppet on a string.

The upper arm continues to rotate forward past the face. Then the fingers lead the wrist and elbow, angled downward, through a sleeve-like hole.

What this does is create a “catch” position that utilizes the hand and entire arm as a stroking lever to propel the body past the hand. The key is to keep the elbow above the hand, pointed ahead.

The Butterfly stroke, being essentially a double-arm Crawl, recovers and strokes the same way, controlled by the swimmer’s elbows above the hands.

For the Breaststroke, as in the Butterfly, the arms stroke simultaneously, rotating the lower arms below the elbows to create forward momentum.

Finally, the Back Crawl stroke, with the body inverted, is made effective by inverting the upper arm so that the elbow stays below the lower arm.

In each stroke, then, the elbow is the key to leveraging the whole arm to propel the body past the hand, anchored against non-moving water. It enables the swimmer to use the inside of both the upper and lower arm, as well as the open hand for maximum surface area to press against the water.

I often say that I do not teach swimming so much as efficiency of aquatic locomotion. The best use of the swimmer’s elbows is the key to achieving aquatic effectiveness and efficiency.

Dr. Bob Colyer of Bluffton is an actively retired college professor, coach and author of “Swim Better: A Guide to Greater Efficiency for Swimmers & Instructors,” directed primarily to non-competitors.