Here’s a cool graphic from the NY Times article — a computer-generated fluid dynamics study showing the flow of air around the jet  car’s fuselage. The orange areas indicate where resistance is highest. The blue areas represent the lowest resistance.  If you mentally replace the fuselage with a human body, you can see there’s minimal water resistance around your outstretched arm. The potential for drag will be greatest around your head and shoulders, decrease a bit on your lower torso, then increase around your hips, decrease as the water passes over your legs, then increase again at your feet. 

And that’s assuming you do Active Streamlining as well as the pictures I showed in the "Best Body Shape" blog.  If the head lifts, or wags, there’ll be a much more intense – perhaps even red – shade there. If the legs are splayed or thrashing, lots of red there as well. 

 

 These next two shots — screen shots from Lesson Four of Easy Freestyle DVD — illustrate how I use the propulsive phase of the Zipper/ZenSwitch drill to spear myself into projectile-like position. In the first pic, I’m just at the beginning of the propulsive phase of the Switch.

 

At this moment my velocity is fairly low because: (1) Much of the momentum of the previous Switch has already dissipated, and (2) I’m not very well streamlined — which is a natural condition of setting up to propel. Even so, I’m still mindfully doing all I can to minimize drag — as reflected by my head position and my legs, which are "drafting behind" my upper body, . 

In the next moment, I’ll drive my"high" side, moving me past my right arm. As I do my velocity will increase considerably, making it critical that I be superstreamlined as I reach peak velocity in the stroke cycle.

Here, a millisecond later, I’m traveling at the highest velocity I will attain during the stroke cycle and as you can see I’ve consciously squeezed my bodyline into the lowest-drag position and come as close as humanly possible to the "projectile" shape illustrated in the pictures on my previous post.