HOW: Get set-up sitting upright. With your elbow bent to 90 degrees, position your wrist in a neutral position with your palm facing up or in. While maintaining your forearm and wrist position with the side you want to target, hold a flexbar in both hands, rotate the flexbar down towards the ground with your opposite hand. While keeping the tension, slowly let your target wrist move into extension, let go of the tension, go back to starting position, and repeat. See video for tips.
FEEL: You should feel the muscles on the inside of your forearm working as well as other muscles in your forearm and hand to help with gripping the flexbar. You may feel tension on the inside of your elbow as well.
COMPENSATION: Perform slowly, do not lose elbow position.