From my first few columns, you already know that improving stroke efficiency is a matter of decreasing resistance or increasing propulsion or both.

But there is an additional fundamental understanding that can help clarify what swimming strokes are all about and can greatly improve your swimming.

It’s a matter of perspective, how you consider or define “stroking.” It can help a swimmer to realize and understand that stroking is not a process of moving the hand past the body, but instead moving the body past the hand.

Top swimmers’ hands move up and down and in and out in order to keep the hand (and high-elbow arm) anchored against non-moving water and thus to lever the body past it.

Placing the hand in a fixed position and pushing backward in a straight line is not helpful for stroking because once water starts moving, it can’t provide traction or leverage.

The swimmer has to feel constant pressure on the anchored hand that adjusts up-down-in-out for the body to pass.

In addition to this force maintaining pressure backward toward the feet (action-reaction), the swimmer can also use help from a lifting force by adjusting the pitch of the hand, similar to what happens to a hand held outside a moving car.

The greater pressure on the underside of the hand moves it toward the area of lesser pressure above the hand. The result of these two forces enables the body to make forward progress.

For all arm strokes, there are two phases in this process: first, getting the shoulders past the hand, and then levering the hips to the hand.

The first phase requires the hands to scull out far enough to permit the shoulders to move past, while the second phase involves pressure closer to the midline of the body to maintain balance. There is also a greater force generated when the hand is closer to the midline.

An added bonus is that holding a force against the water takes much less effort than pulling-pushing the hands past the body, which enables a swimmer to make more efficient and relaxed progress through the water.

Regardless of the strokes you use, considering them from a different perspective might help you toward greater efficiency.

Dr. Bob Colyer of Bluffton is an actively retired college professor and coach who has recently published “Swim Better, A Guide to Greater Efficiency for Swimmers & Instructors.” bobcolyer@yahoo.com.