In looking at the animation on www.swimsmooth.com I see that the hand follows a straight path front to back. This is probably better seen when looking up at the swimmer from under water. If you put a ruler to the path it is pretty much a straight line.
Now, I've seen and I've read posts that talk about a non-linear path. I guess the idea is to always try to accelerate new water rather than applying force to water that you've already accelerated.
So...why do they show a straight path.
And, if curved is better, what is the best path?
It seems to me that in order to keep the hand anchored in the same place there has to be forearm pitch and angle changes. If you get to a catch position and simply rotate holding that EXACT position your rotation will send the hand laterally. For me to anchor my hand my elbow gets a little wider and the angle between upper and lower arm gets smaller. I also adjust my hand and forearm pitch. I think if anyone simulates that pulling him or herself past a solid object you see the same thing. So I think the curve one sees in some swimmers is an attempt to keep the pressure straight back.
It seems to me that in order to keep the hand anchored in the same place there has to be forearm pitch and angle changes. If you get to a catch position and simply rotate holding that EXACT position your rotation will send the hand laterally. For me to anchor my hand my elbow gets a little wider and the angle between upper and lower arm gets smaller. I also adjust my hand and forearm pitch. I think if anyone simulates that pulling him or herself past a solid object you see the same thing. So I think the curve one sees in some swimmers is an attempt to keep the pressure straight back.
