In the back extension, you want to be thinking “squeeze your glutes” rather than “arch your back."
There are so many great and effective ways to use a stability ball. These balls are incredibly versatile, partially because they throw you off balance while you work out, providing a full-body challenge.
The big thing you want to focus on is keeping your movements slow and controlled. How? Actively focus on what each exercise is supposed to be working.
In the back extension, you want to be thinking “squeeze your glutes” rather than “arch your back." During the leg curl, visualize your hamstrings doing the majority of the work to pull the ball toward you and away from you.
With the pike, imagine your lower abs are pulling your hips up into the air (you can also make this move easier by bending your knees and bringing them toward your chest, rather than keeping them straight).
Finally, with the stability ball arm circles, you want to be focusing on keeping everything completely still except your forearms, which are making small circles. Ready to go balls to the walls?