While swimming backstroke, it is important
that the technique of your arm movements is correct. This avoids strain on the shoulders and allows you to swim more efficiently.
This article explains the correct motions during the different phases of the arm stroke: catch, pull, push and recovery.
Backstroke Swimming Video
Here's a nice video that illustrates those arm movements while swimming backstroke:
Initial position
To start the discussion, we imagine that the swimmer is lying on his back in the water, with one arm straight and extended to the front. The palm is rotated outwards. The other arm is extended to the side of the swimmer, with the palm turned inwards. The flutter kick is used for propulsion.
Underwater catch
The arm extended to the front starts the under water phase with the catch:
The elbow bends, and the arm starts to move towards the swimmer's feet.
The palm rotates in direction of the swimmer's feet.
This phase serves to correctly set up the arm for the propulsive pull phase.
Underwater pull and push
The underwater pull and push phase of the stroke starts once the elbow is bent about 90° and the palm is turned in the direction of the swimmer's feet. It's in this phase that the swimmer applies propulsive force to the arm:
The forearm and palm are aligned and parallel to the
end of the pool.
They move backwards as a unit.
The elbow is kept bent at 90°.
Once the elbow can no longer move further backwards,
it extends, the hand moves further backwards until the arm is
completely extended.
Finally the hand brushes past the hip and starts the recovery above the water.
Recovery above the water
While one arm moves backwards under water, the other one simultaneously recovers above the water:
The recovering arm stays extended, rises and executes a
semi-circular
motion above the water.
During
the recovering arm's semi-circular motion, the hand rotates so that
when the arm is
about to enter the water in front of the swimmer, the palm is now
turned outwards and the hand will enter the water with the pinky finger
first.
As the arm splashes into the water, the swimmer's
body rotates towards that arm. The
opposite shoulder clears the water.
At this point, the arms exchange their roles: the recovering
arm becomes the stroking arm and the stroking arm becomes the
recovering arm.
Some tips
In the past, swimming backstroke was taught with the
arm kept straight during the whole under water phase. However this puts more strain on the
shoulder and should be avoided, as it could lead to swimmer's shoulder.
As explained above, the body should rotate between 30 and
45° towards the stroking arm when it enters the water. This puts less
strain on the shoulder, allows to apply more force and lets the other shoulder clear the
water, effectively reducing drag.
Although the body rotates from side to side while swimming backstroke, the head should always stay perfectly still.