Try this exercise with the TheraBand FlexBar to improve grip strength as well as the strength of both wrist flexors and extensors. This tool can be used as an aid to assist in decreasing pain of forearm and elbow.
The FlexBar is great for rehab and has easy to grip texture for a variety of finger and hand movements and positions. If you'd like to purchase one for yourself, head over here. As an Amazon Associate, Rehabilitation Health earns from qualifying Amazon purchases.