Knickerbocker's theory does not explain why the first firm in an oligopoly decides to undertake FDI rather than to export or license. (Hills, 2008) also suggested that the imitative theory does not address the issue of whether FDI is more efficient than exporting or licensing for expanding abroad.
Isometrically, the lower back, the upper back, the abdominals, the trunk muscles, the costal muscles, and the shoulders and arms are all essential to the exercise and thus are trained when squatting with the proper form.
Your upper-body muscles must also work very hard to hold and support the barbell on the front or back of your shoulders -- depending on whether you perform front or back squats. While squats are normally classed as a leg exercise, so many muscles are involved in a secondary capacity that squats are almost a whole-body exercise.