Ok I've made this as a new thread instead of just having it my training thread. There are a couple of other posts there that may interest people as well.
Basically the stance width for squats doesn't make any difference to your VL and VM recruitment. There are a number of studies that prove this. The pictures below are taken from the Target Bodybuilding book. This shows the areas of the leg as measured by MRI, probably the most reliable method of seeing what is happening in the muscle (medical imaging people correct me if I'm wrong). What they did was get some experienced lifters to perform the variations of the squat for a number of sets and reps and this makes the muscles involved appear lighter on the MRI. As you can see there is no difference between the two stance widths.
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