Sliders are what's called an "instability surface," which "forces you to engage your muscles the entire time" to do the move correctly. Slider workouts build strength, endurance, and stability and also promote flexibility. ... But gliding discs work by sliding your hands and feet across the floor while also supporting your own body weight, which makes the muscles in the weight-bearing limbs work even harder as the core stabilizes to control the movements. Available in a variety of colors.