Rip, could you please talk about which muscles are engaged w/wide, normal and narrow stances while doing Free Squats and Hack Squats.
Unless you are a powerlifter, "normal" stance for a free squat is generally shoulder width apart, with the feet facing forwards or pointed just slightly outwards. I find that this engages the most muscles in the lower body, but slight variations on this stance can make different muscles work a little more.
---A closer stance will lessen the workload for the hips and butt, and will put more emphasis on the quads and thighs. A closer stance will also put more pressure on your back and abs, which is OK as long as you remember that there is not a need to go too heavy.
---A wider stance does the opposite - decreases the work for the thighs and puts more emphasis on the hips and butt.
Stance selection depends, in part, on what is most comfortable for you. Shorter people have an easier time with a closer stance, I think, than taller people. A wider stance gives you better ability to balance and engages the abs, back, and core muscles less. I would start shoulder width apart and adjust your stance according to what is comfortable for you to go deep enough and maintain balance.
Re: adjusting foot positioning, are you talking about "flat-foot" to "pointed toes?" If so, do you suggest adjusting w/the lying hamstring curls also?
Thanks Rip
More so than pointing/flexing the feet, I was referring to the toe position/angling or which way the feet are directed, which can be modified during squats, leg presses, and leg extensions, among other exercises.
You can position your feet straight ahead (maybe slightly outward), or you can turn them outward (like a plie in ballet), or you can turn them inward so that the toes on your feet are pointing towards each other.
---Positioning your toes outward (like a ballet plie) in squats and leg presses will emphasize inner thigh work.
I found this cute little picture (below) to illustrate what I am talking about.
EDIT: the pic shows the correct foot position to focus on the inner thighs, but for squats, your stance should be wider and your knees should remain behind your heels. Not quite the same as a plie. If you turn your feet outward about 45 degrees and squat in this position, you will definitely put more focus on your inner thighs, as well as your butt. I use this as a variation for my squats once in a while, or I sometimes add a couple of sets of these in after I do my squats with a straighter foot position.
---Positioning your toes inward will emphasize outer thigh work. However, I do NOT recommend this position for free squats or even Smith machine squats, as I think that it is very difficult to maintain balance and is a recipe for knee trouble, even with light weight. I would only position the toes inwards to focus more on the outer thigh when doing leg extensions, and maybe leg presses with relatively light weight.
---For leg extensions in particular, having the toes rotated slightly outward will target the inner sweep of the quads more. Working with the toes rotated slightly inward will target the outer teardrop of the quads more.
Pointed toes versus going flat-footed on hammy curls is another interesting question, and not one that I am too sure about in terms of the benefits of one versus the other.
I have had people recommend both ways to me for hammy curls, as well as leg extensions.
I'm not too sure what the effects of pointing the toes versus flexing them is when doing hammy curls...I usually try to keep my feet flexed, as I feel more of a stretch through the hamstring this way.
For leg extensions, I have found that foot flexion when the foot is pointed (downward), the lower quads work more, and when the foot is flexed upward, the upper part of the quads work more.
In general, I see all of these modifications as good ways to put some variety into your exercises from time to time, but with the exception of the inner thigh focus from plies, I'm not so sure that there is REALLY a great benefit or impact to doing much more than the standard or "normal" stances and foot positions.