Laying on your back, place your hands under your lower back/top of your bottom
Keeping your feet in the air move your legs slowly as if you were cycling in the air
If needed, adjust your hands so that your back feels a little more comfortable
Tips
If you feel any pain in your back please stop this exercise and notify your trainer, no need to panic, it just means your core muscles aren't ready for this exercise
Alternatives
Equipment
No equipment Is required for the Horizontal cycling