Originally Posted by Abu3baid
Thank you, I have seen that thread before and I want to ask about something more specific especially on the way down.. Is the pressure on the ball of my foot or the outer half or the instep?
It starts on the ball of your front foot and progresses to the outer half and towards the heel as the knee straightens. I know some of this is discussed in the thread, but we're specifically looking at the feet, so you want to focus on the pressure image of the feet in the upper right hand corner.
The contours of Grant's left foot are pretty well defined, which says to me that the pressure is pretty evenly distributed throughout the whole foot. You can see that the pressure is pretty much the same on the ball and the heel of the foot. The right foot is a different story. There is more pressure on the ball of the right foot than the heel.
If I had to put a number on it, I'd say 50/50 ball/heel for the front foot, 60/40 for the back.
At the top of the backswing, you can notice that a lot of pressure has come off the left foot, namely from the heel. The pressure on the back foot looks like pretty much the same distribution as address, just with more of it. The net effect of this is the white dot (center of pressure) has moved more towards the toes than it was previously, at address.
I'd say the feel is that the pressure moves from the heel of the left foot to the ball of the left foot during the backswing. The back foot should feel increased pressure overall, with no movement or shift from the address position. Notice the pressure doesn't really move towards the heel or the outside of the right foot, it's a pretty uniform increase.
This is only a few milliseconds after the last screenshot. It's mentioned in the video that Grant's pressure actually increases slightly in his right foot, which you can clearly see. You can also see that there is less pressure on the left heel (it's almost disappeared from the image).
When you compare this moment with the top of the backswing, you can see that the lower body has started forward. The hips have opened slightly and there's a bit of a squatting motion happening. If I had to make a guess (which I do, because I don't know this for sure), I'd say the left knee has increased flex slightly, which explains the pressure shift.
Pressure is almost centered where it was at address already, and we only got to A5. The majority of the pressure is focused on the ball of the left foot. The pressure of the back foot is centered mostly on the balls, as well. If you look at the trace (the white arc the dot is following), you can see that this is pretty much as far towards the toes as Grant gets during his swing.
In terms of your question, the early part of the downswing has the pressure primarily on the ball of the left foot. I didn't see any part of the swing where the pressure is focused primarily on the left instep.
Pressure is starting to make it's way to the outside of the left foot, but if you look closely, you can still see a decent outline of the foot and the arch.
This does not mean that the weight shifts to the outside of the left foot. I still think the foot is pretty well planted, maybe slightly favoring the left side. I can replicate this feeling by standing straight up and then bending my right knee so that I'm standing on only my left leg. In order to maintain balance, the pressure in my left foot shifts slightly to the outside.
The pressure in the left foot is shifting towards the heel as the left knee straightens. Just as before, there is more pressure towards the outside of the foot, but it's still pretty well defined. Again, the foot is firmly planted. I'd almost say the pressure is distributed 50/50 in the front foot, there's just a whole lot of it, now.
There's a couple of things here that I think are pretty important:
First, the pressure of the right foot is primarily on the instep, but notice that the right heel is still exerting some pressure on the ground. No lifting, here.
The other thing I noticed is that Grant has his weight forward 91%, but the upper body is still at center and there is no excessive hip movement. Basically, I'm trying to say that he's not getting his weight forward by throwing his body towards the target, but rather by pushing his left leg down against the ground.
As a side note, I'd love to see the actual pressure numbers instead of just a ratio. I'd bet that at impact, not only does Grant have 91% of his weight forward, but he actually "weighs" more (is exerting more pressure against the ground) than he did at address.
You asked for it, so here it is. Pressure is on the left heel and the outside of the foot. The foot has rolled slightly and the left instep is off the ground. There's only one point of contact for the right foot. Even though it's 95% weight forward now, Grant is exerting a lot less pressure on the ground than he did at impact, making him "weigh" less.
So I hope this helps. This is what I meant when I said that everything you were looking for was in the video. Hopefully, I didn't mess up any of the analysis too badly, but I'm sure somebody will correct me if I did.