HOW: Start on your back with a slider/towel under each heel. From this position, straighten your arms and bring them directly in front of you, bend your knees, and engage your core. Slowly and with control, slide one foot out while reaching the opposite arm overhead. Extend as far as you feel that you can control then return to the starting position and switch arm/leg.
FEEL: You will feel your core muscles working as you extend your leg and reach overhead.
COMPENSATION: Be sure to keep your core engaged as your reach overhead and extend your leg! The farther away you reach, the more your back is going to want to arch! Avoid this, keep your core engaged and strong!