Originally Posted by Zenturtle
I know the unassisted rotation clip and agree with your explanation.
In my view body bending can be used to improve propulsive power, but as far as I know Ti swimming, TI is more about always holding a straight line.
you're talking about a degree of undulation which will always be present of the kick is to provide forward motion.
I was told by a mech engineer triathlete that a straight legged alternating kick withotu any knee or torso bend will also provide forward movement but I dont' think it's the most efficient way for thehuman body to move forward.