If you are going to do squats, especially against a wall, then use a medium sized exercise ball. It ensures that the spine is kept in the correct position. The ball should be in the small of the back and always below the neck line.

Also for the calf, allow the same ball to fall to the ground. Stand with your legs against the ball and slowly walk the ball backwards into the wall. Just enough to create pressure between you and the ball, to a point where it feels like the ball wants to ping you across the room.. Now stand up on your tip toes, and repeat (10x-20x). You need to maintain an upright posture and do the tip-toes stuff at the same time.

And for the upper thighs, ball against the wall and on the floor, just lean back, lean back as far as your confidence will let you.. The upper thighs will start to tingle the further you lean back and support yourself. Hold for about 10s - 20s.