MOTION
A swimmer swims into the wall, flipturns, and then pushes off into the top water still moving into the wall. This decelerates the swimmer. Drag is proportional to velocity. Thus, the water on top which the swimmer pushes into has more drag pushing them to the wall where the force Normal pushes opposite that. There is thus a smaller net force forward and thus smaller acceleration as opposed to the swimmer pushing under that water on top.
However, the swimmer's velocity is higher when the force of drag does not limit him. He swims under him.
Forces
Pushing off of a wall
energy
The chemical energy of human energy is converted into kinetic energy to forward. To rotate my shoulder, as shown in the video, rotation happens according to Krot= .5(I)(sigma)^2. This comes from chemical energy.
momentum
Assuming these two swimmers push off with the same velocity, the more massive swimmer (me, obviously) travels farther because he has more momentum pushing him forward according to the equation P = MV where P is momentum and M is mass and V is velocity.
Rotation
Rotator cuff: my shoulder moves into the computer to rotate my arm around. If I increase the length of my arm by not bending it, then I increase the radius of the swimmer system, requiring a large torque to move my arm around because torque = rFsin(theta). Angular acceleration is (net torque/rotational inertia). Rotational Kinetic energy is .5(rotational inertia)(angular velocity)^2. Thus, increasing the length of my arm increases the torque required for it to move and thus requires more energy. This will come in the form of chemical energy from food.