Abstract: Adapter devices that adapt hand exercise devices to permit the use thereof by persons of widely variable hand size, and permit the use thereof in exercises or tests other than the isometric exercises and tests for which they are known. The adapters provide replacement grips and couple force applied to those replacement grips to the handgrip surfaces of the hand exercise device. One version of the adapter includes a piston and cylinder connected to the replacement grips that move in a range of motion during a hand exercise or test, to allow for isotonic, isokinetic or isodynamic hand exercises. Other versions of the adapter use removable cams, screw cams, rotary cams, and sliding cams to adjust the distance between the grips for the size of the user's hand. A further adapter provides replacement grip surfaces sized for a user's finger and thumb for performing a pinch exercise or test.