He has not started his kick. His left leg is straight and extended well above his hip, as if in a Superman position, with his heel just touching the surface. This requires great hip flexibility and strength. His same-side arm is fully extended, and he is breathing. Most amateurs let their legs drop below hip level when breathing and this creates drag.
He begins his kick with a slight push down of the knee (driven
by the hips). His foot is still high but is getting ready to power down as his
knee extends. In this shot you can see that his quad is a bit lower than his
hip for a split-second. All this begins as he is making his catch. It is the
timing of a tall swimmer who fully extends out front every stroke.
He snaps his knee right, extending it, as the catch is completed.
This provides some force to help him rotate his hips and gives leverage for his
pull. After that movement however, the leg needs to be out of the way, and it
is – perfectly straight behind him, in line with the left arm that’s about to
pull. His knee has actually moved UP as his kick finishes DOWN, so there is
little net movement of the entire leg downward. With good ankle flexibility
most of the force will be backward. There will be no drag caused by his leg
during the pull.
His left leg is still straight as he pulls, and creates no drag. His hips are at the surface (you can see them just breaking the water line) which is critical to reduce drag. You can see his right leg fully recovered (and straight) above his hips and breaking the surface. He’s as streamlined as you can get, so the power of his left arm pull is all going toward moving him forward vs. overcoming lower body drag.
Left leg is still straight… You can see the right knee begin to drive down to start that kick.
This is where many amateurs create drag. Instead of maintaining a
straight leg after they kick, their hamstring overreacts and pulls the foot up
toward the surface. This creates a ton of drag against the calf and the back of
the foot, and leaves the knee bent and below the bodyline. This is especially
important for a 2-beat kick since it is mostly arm driven and any leg drag is
highly detrimental.
