Does the person going backwards pull the heel of the moving foot to a position under the body. Yes?
Well try that with a bent front knee.
Where does the drive come from. It comes from a push of the heel against the floor with a straight knee, not rigid.

"{Does the person going backwards pull the heel of the moving foot to a position under the body. Yes? Well try that with a bent front knee."

Please explain how you intend to get the heel under a lowered body without bending the knee? This is pointless though - we were talking about the straightness of the legs when they are at the straightest, which is to say at mid-stride. You obviously aren't pulling your heel under your body at mid-stride.

"Where does the drive come from. It comes from a push of the heel against the floor with a straight knee, not rigid."

Please learn to recognize the difference between

1) straightening = becoming straighter than it was
2) being fully straight
3) being straight AND rigidly locked.

You won't have anything of value to say until you learn that these are THREE DIFFERENT SITUATIONS.

You never give up do you. The heel becomes a ball. You would have difficulty doing this trying to keep the knees straight..You are going to have to change some of your actions. The above we were taught in a Bronze Medal Class years ago. I would suggest you fork out the $300 for Barichi's the Bible ( four DVD's in the set ) Or you could look at the Melissa's action on the Three Step in Learn the Dances on this site..Or go and do a Bronze Medal. We might as well get onto the Forward Walk also. Your knee will not straighten unless you straighten it. It will not happen if you don't try.
As a practise stand with the feet together right heel off the floor. Straighten the right knee to a heel. Do the same at the extent of the stride. Then once you come over it with the push from the supporting foot start to soften the knee. Watch for this action also on the Change Steps in the Waltz.

Not sure why this suddenly popped to the top of the displayed message months later (is there some kind of random shuffler?) but it demands comment now that it's there:

"You never give up do you. The heel becomes a ball. You would have difficulty doing this trying to keep the knees straight."

Nobody said anything about keeping the leg completely straight! In fact, the message you are replying to was not advocating keeping the leg straight, in fact it was advocating flexing it at a time when YOU, QUICKSTEP, wanted to keep it straight! Given your response, it appears you can't even keep track of what argument you are making...

Anyway, on the subject of straight legs, take a look at that blackpool 2006 foxtrot video. You just won't see two straight legs on the lowered actions (step 1's) at mid-stride. These are the best dancers in the world, but when they lower that much, even they can't generate the rediculously large strides that would be geometrically required to get both legs straight, so they end up with at least one bent. I seem to recall you saying something to the effect that such a failure would be the end of one's chances in competition... well, I guess not!

(Wheras if they were to scale way back and not lower much, they could have both legs straight while taking fairly small social-sized steps)

Not quite sure what you are suggesting. But go to the first bar of music and also the intoductory step and watch Timothy in freeze frame. What do you see. Do you see two straight legs on the heel of the front foot and the ball of the back foot. You have two chances one behind the other to look at.. Would you say the weight goes to mid point.Into the Reverse Turn what do you see before the knees flex. Have a look at Jonathan on bar 40. Do the freeze frame thing on him .Have a good look as he prepares to go into the Fallaway, left foot forward on the first beat of the second bar of the 5th phrase. You must remember that before you can have a bent knee you must have a straight one. Come back and tell me .What do you see on Timothy Howson's first two steps. Also point out to me anyone of them who gets in front of there front foot when going forward. There is none so blind as thoughs that will not see. Happy viewing.

" But go to the first bar of music and also the intoductory step and watch Timothy in freeze frame. What do you see. Do you see two straight legs on the heel of the front foot and the ball of the back foot."

No, not on the step 3 to step 1 transition. There you will see that he always has at least one leg bent. And that goes for the others as well. The supposed "rule" of getting two straight legs in a lowered driving action is pure nonsense... the best in the world can't even manage to move enough as would be required to accomplish that when the body lowers as much as theirs does.

On the other hand, if you don't lower much, then it's easy to have both legs straight!

And of course this doesn't apply to the step 1 to step 2 transition, where the body is not so low.

"You must remember that before you can have a bent knee you must have a straight one."

Utter nonense. There is nothing that says a leg must be dead straight before it can start to bend; it merely must be straigher before it bent than after it bent. And that's what we see.

You will see one leg straight at times, but you won't see both straight in a lowered position, because when you lower that much it becomes impossible to get your feet as far apart as that would require!

"Come back and tell me .What do you see on Timothy Howson's first two steps."

Bent knees that don't fully straighten. That's obvious, for all to see, so we don't have to take your obviously incorrect word for it!

I would suggest you freeze frame ( and anybody else) Jonathan Crossley as he takes, and has taken his first step into the Fallaway. Look at that rear leg is it straight .It is worth taking notice of how and when he turns his shoulders and side into CBM. If one was to see a still Photo at that point one could be fogiven if it was thought it was nearly a Contra Check.
Look again at Timothy Howson can't you see two straight legs. He is for a moment suspended between the heel of the front foot and the ball of the back foot. When the ball becomes a toe the knee is flexing. I am on my screen now looking at Timothy Howsen on the introductory step right at the start. He is in freeze frame on the heel of the front foot and the ball of the rear foot his knees are straight. (we will call it ballroom straight 'cos as we know the knees are never locked. His partner still has a flat front foot and the very tip of the toe on her back foot. Her front knee is obviously bent towards her partner. It would be impossible to get any more to the tip of the toe of the moving leg even if she tried.
Now I am looking at Christopher After the Swivels. I never noticed before how high he is as the feet are level and onto the second quick Two straight legs, and straight legs as he lowers. I'm on freeze frame again with Timothy. If you want to see and you will see if you open your eyes on all these top dancers . Feet and leg action just as it is written. Back to Timothy. Can you at any point see his body in front of his front feet leg or knees. You are able to freeze the frames I hope. Even then you need to know exactly where to stop.
To recap Have a look at Christopher into the Reverse Turn. Are the legs straight. Take a look at Jonathan on the same step into a Reverse movement. And the rear foot.What. Straight again and to the very tip of the toes. Considering you infered that Chris is one of your teachers. Why didn't you pay more attention to what was being said. It was a lecture wasn't it.
If anybody wishes to see 2006 Foxtrot Final go to www.thedancingchannel.tv It costs nothing just follow the instructions and join the club. To freeze frame simply touch your space bar. With mine I can freeze first off. Then when I watch the whole thing again next time I can't. So I log out completely and start again. Keep an eye on that blue bar below. If you can hear the music on your second go around, but the view is blocked. Click on the dancing channel. Also use to clear the still picture at the end, and to start again. Take note you will at some time have to click on Samples. That's what you are watching.

Quickstep, you just aren't looking carefully enough!

If you really look with care, you will see that they don't have both legs straight at the same time when IN A LOWERED POSITION, such as when going into step 1. They simply can't manage it - their bodies are so low, that geometry means their feet would be impossibly far apart if both legs where straight at once.

Later, in the risen actions they may get both legs straight. But not in a full lowered action. It would be impractical, and a very silly thing to attempt!

You wrote If you really look with care , you will see that they don't have both legs straight at the same time WHEN IN A LOWERED POSITION
Which means they do have both legs straight when not in a lowered position. "It's taken a Blackpool video and a lot of writting to finally make you come to your senses ". With the weight equally divided between the two. On the heel of the front foot and the ball of the rear foot. The ball on the rear foot will become a toe on the rear foot as the body weight is moving forward onto a flexed knee onto which is now the supporting foot. This is according to the manuals and exactly what I have been quoting since the beginning. So this the discussion is finshed with the conclusion that we can all see for ourselves exactly how a Foxtrot should be danced and where to get two straight legs. Which incidental has been on this site also from the beginning.
Dosvidania

"You wrote If you really look with care , you will see that they don't have both legs straight at the same time WHEN IN A LOWERED POSITION
Which means they do have both legs straight when not in a lowered position."

Of course! There's never been any dispute on my part that the legs can be straight when the body is at a higher altitude. In fact, most of my posts have explicitly mentioned that. If you were following the 'championship lowering means the feet would be impractically far apart if the legs were straight' argument, it clearly only applies in a lowered position! In a risen position, or even a moderatly lowered position as a social dancer might use, it's not problem at all to get the legs straight when appropriate. The issue only comes up when the center gets close enough to the ground that the hypoteneuse of the quasi-triangle would be inhumanly huge, thus the legs cannot both be straight in that situation.

"With the weight equally divided between the two."

Nope...