In your free body diagram, you are missing two forces....thrust/propulsion and drag. Here is the interesting thing about the relationship between drag and lift. In some fluid dynamics situations, what seems like higher drag can result in better lift. You could have a higher drag contribution from one part of your body resulting in more lift overall, reducing the drag of the rest of the your body. That's the complex part of fluid dynamics, which is why you can't just isolate one drag contributor and assume everything else stays the same or also increases because of that. Furthermore, a higher drag contribution from one part of the body, MAY allow certain swimmers to apply more thrust/propulsion.

But for sure, if you can reduce overall drag while and increase propulsion it's a win. If you can keep the drag the same and increase propulsion its a win. I am with you on keeping the head down and hips up for most of us. Without seeing Ken, we can't know what is going on, but based on what he has posted about swimming on here, his results in races, and his swim speed vs what he can do in the other sports, it seems like he is getting the speed out of his body in swimming that his engine can deliver. Most of us on this forum aside from a few fish, have swim results that are inferior to what our engines give us on the bike and run.

I would not under estimate biomechanical limitations in athletes though. They are real and no amount of work for some will get them in the right theoretical body position. In my case with several neck and shoulder/upper body injuries, my swim speed really took a nose dive in my early 30's and was never able to get things back to where they were. Adding another head/neck injury in my mid 40's just made all that worse. Still working on it. I'm not about to give up though, but all this hurts me the most in freestyle. Fly, breast, back are less affected by my neck+shoulder limitations.

his FBD is assuming you are just floating, no force or propulsion. He's missing the rotational forces.

been struggling w this thread and hoping to add some clarification here. Dev you have had some great responses and this discussion is interesting. you and beached are both coming at this from different view points ie one is static (beached) and one is active (you). Certainly with your perspective there are many more "forces" being encountered.
However beached is struggling with his descriptions too.
Im no unicorn and will work hard to not offer soundbites bc i agree... too many of them.
The construction of ones "aquatic posture" is a critical to enhanced performance in the water (whatever that metric happens to be spl, velocity, effeciency etc). Our aquatic posture is quite different than our land based posture that we have been using for quite a while to hunt and gather and run like hell at times.
The (main) 4 components of our posture (land and water) are our hips, chest, head and what connects them, our spine. Just as we learned on land to manage these components from birth until we are upright and moving, we have to re-learn them in the aquatic environment.
On land you can "play" with these segments to become more athletic with them. Articulate them more. Connect/"feel" them more. IE sliding the head on jaw line or tilting, extending sternum forward and back, pelvic tilts to name a few. This will help when you lose solid land and are horizontal in the water.
The impact of gravity changes dramatically as well as we go from vertical on land to horizontal in the water and essentially add two more gravity lines. So an increased awareness and athleticism with these parts will help you to know your making changes.
But i felt this discussion could use some clarification on the key components we are discussing and taking a step back.

Thankfully, there is no ONE WAY to be in the water with posture. We ALL bring a different set of factors that impact this and a good coach will work with you to help you find the alignment and energy in the components based on your personal factors.

To use me as an example... im a sinker with virtually no real kick to speak of. So for me to think about DPS (a paradigm that supports physios more than it does swimmers) is not only a waste of time but actually is negative to my performance.

To continue to watch videos of the best in the world is such a useless exercise. Its fun! Dont get me wrong! I stared, jaw on the floor watching mr thorpe kick 100 meter repeats at the otc back in the day (without fins) on a 1:20 base doing like 1:08s. If we all had that kick...(and his high COM and low Den and ability to coordinate his kick w his rotation etc etc) then spl can def be an impressive metric to track!
daved

Next time, draw a complete force diagram. If you are just floating there, in that position with head down, then by definition your centre of mass must be at the same position as your centre of buoyancy.
lifting your head will shift your centre of buoyancy rearward, c of mass is unchanged, which will cause your legs to actually raise up, not lower, assuming that your muscles are making your body rigid and that you have positive overall buoyancy.
Try it, float facedown, arms by your side with a small pullbuoy to compensate for the rearward shift in centre of mass caused by the arms by your side (arms by your side to ensure you aren't sculling) and from that position raise your head out of the water as if to sight and see what happens.
This should demonstrate that the only way that you can raise your head and keep it up is by exerting a downward force on the water with your arms. It is that downward force that causes legs to sink, and/or a failure to get the centre of mass forward enough, not simply lifting the head.
If that doesn't convince you, imagine you are standing in the middle of a floating dock. It's level. Now walk to one edge. What happens to the edge you walked to and the opposite edge?
Btw, Ian Thorpe swam "eyes forward", just like we all did back in the 70's 80's and '90's. His times still stand up today.
This is Palteirini demonstrating why the lower head is actually beneficial (imo). Although he's looking down, the head isn't actually riding low in the water. But look how high his shoulders get.

ericmulk wrote:

It's just amazing to me how fricking incredibly fast Palt is turning over during that entire 1500 meters; he's turning over like i would in an all-out 50 or 100 but sustaining it for 1500. I guess that's why he's the WR holder and I'm just a no-name masters swimmer. Also, it would be interesting to see him and Clark Smith swim side by side, since Clark has a much slower turnover rate but swims roughly same speed. Clark is 6'9" vs Palt at 6'3" but I *think* their diff in stroke rate is greater than their relative diff in height.