Measurements of grip and pinch strength are controversial methods for rating impairment, primarily because they “are functional tests influenced by subjective factors that are difficult to control” (4th ed., 64–65). Subjective factors might include effort, pain, time of day, and fatigue. Other factors influencing grip may include gender, age, sensation, comorbidities, age, nutritional status, and perhaps handedness. Since grip and pinch strength are highly correlated, and most of the available literature deals with the former, this update will focus on assessment of grip.
Grip strength is one isolated measure of the performance of a group of muscles and joints. The force generated upon grasp is determined by the neuromusculoskeletal (anatomical and physiological) capacity of the digits, hand, wrist, forearm, and elbow, as well as psychological factors.
Limitations of thumb and finger joint flexion or wrist motions are associated...
