Hi again Pat!
Follow-up on the original first question…your feet are not supposed to pivot during a squat but should instead remain in one place.
And yes you are correct about the band stiffness and progression! Progressing with weights, not bands, is recommended.
For the single-leg leg press versus the squat:
You are correct in that they are working the same/very similar muscle groups. The benefit of the single-leg leg press is that it allows you to isolate each leg more than you normally would be able to during a squat. So even though you are working similar muscles, it is beneficial to add in single-leg exercises to help isolate each of the muscles in each leg on its own. Even though this is a benefit of the single-leg leg press, this does not mean you should “choose” it over squats. Squats are more functional for balance. This is why it’s so important to add variety in your workouts and how it’s important to do both exercises! The upper body portion of the single-leg leg press is just for stabilization, not as a benefit of the movement/not to work your upper body muscles.
I hope that makes sense! Please let me know if you have any feedback or exercise requests for tomorrow’s session!
Adeline