Vertical Bar path for squats putting me off balance?

[Man in the Box]

Hi all. I'm 6'2", 94.5kg and 35 (if any of this makes any difference).

After doing several months of strict SS last year and then a 7 month layoff (injury break that then turned into laziness and The Fear) I'm now a few weeks back into SS and progressing strongly again.

Last time round I noticed an issue with my squat form where my hips were driving up well but my chest angle was dropping slightly, taking the weight towards my toes and forcing me to handle it. This affected my force production as it breaks my drive upwards and feels like I'm having to lever it up with my back to a certain degree (is this what you call a good morning?).

Squat weights have started to get heavy again (115kg/254lb x 5 x 3) and I've noticed this becoming pronounced again. In an attempt to learn a strict vertical bar path I tried something to keep the bar exactly over my midfoot.

I stood in a doorway in squat stance with a broomstick across both my feet and touching the doorframe so I could be sure that my midfoot was in line. I then racked the broomstick in a low-bar position and tried to squat to get a feel for exactly where the mid line is.

What I discovered is that I can't. About a third to half of the way down my balance is too far back and I would fall over backwards if I kept going. The only way I can get all the way down is to shift my toes about an inch clear of my side of the door frame. This means that the bar is just in front of my toes when touching the door frame.

Can anyone shed any light on what might be happening or what I might be doing wrong? I'm quite tall so are there possible issues with my anthropometry? I'm pretty confident that my rack position is correct. I can't find any way of altering my decent that doesn't put me off balance. If I sit right up like a high bar squat then I can almost do it but I'm teetering back on my heels.

Is this just an issue where an unweighted squat simply cannot replicate a weighted one, even using a guide to keep the bar path straight?

I'm not sure a form video would help to answer this question as you can't see the mid foot line exactly. However I do need to take some updated form check vids anyway so will address that later.

Thanks in advance.

[Mark Rippetoe]

This is explained on pages 11-12 of BBT3. It has to do with the COM of the system, which approaches the position of the bar as the load goes up.

[tallison]

So, will the path of the lighter bar still be perfectly vertical, but not in line with the mid-foot - or does a light bar mess everything up and produce something other than a vertical path?

[Man in the Box]

Aah, thank you. Looks like one for the birthday list then!

[Man in the Box]

Clearly I need to go back and re-read the book then (bad n00b). Thanks for setting me straight.

[Mark Rippetoe]

So, will the path of the lighter bar still be perfectly vertical, but not in line with the mid-foot - or does a light bar mess everything up and produce something other than a vertical path?

The bar path will become more vertical as the weight goes up, because it has to. As moment forces against the Center of Balance have the potential to increase, they must be better controlled.

[Man in the Box]

Just so I don't look mental: I left the first reply before I realised that BBT3 was "Basic Barbell Training", which I own, and not "Better Barbell Training", which is a non-existent follow-up book that I totally made up in my head. Because I'm new, both replies had to be approved and appeared at the same time.

I'm sure everyone was worried about that one, huh! Huh?...
...move along, nothing to see here.
*shuffles away*