Although there are many factors to consider before getting to the pull phase in freestyle, the correct arm angle in the pull phase is critical to maximise power and stroke efficiency and thus propulsion through the water.
Here we analyse stroke techniques of two swimmers.
The swimmer above has a reach that is quite far from his body on the pull phase, which adds to resistance and can also throw him off balance.
It is important to use the elbow in the pull. Bend the arm as soon as you start the catch phase. Try to attain an elbow angle of 110-120 degrees.
Although not 'wrong' and still widely seen as a 'classic' stroke technique, it is advisable to avoid the old 'S' -shaped pull method, pulling under the body, which loses power; but instead continue the pull past the body towards the rear, with the thumb brushing past the hip to begin the arm recovery phase.
Here we see another swimmer, note the elbow angle.
Also see how the swimmer above has already started the next (right) arm entry into the water, together with long glide, which is preparing for the catch phase resulting in faster propulsion through the water.
This brings us onto a whole new topic... timing! Watch this space.