Twist trainers are effective tools for developing core strength and muscle endurance. They primarily target the obliques (sides of your abdomen), abdominals (belly muscles), and lower back muscles while also engaging muscles in your hips to some extent.

Dip bars are effective tools for developing upper body strength and muscle endurance. They primarily target the triceps (back of the arms), pectorals (chest muscles), and deltoids (shoulder muscles) while also engaging muscles in your core to some extent.