Diurnal and sequential grip functions in normal subjects and effects of temperature change and exercise of the forearm on grip function in patients with rheumatoid arthritis and in normal controls.

Rate of grip development (power), time to reach maximum grip strength and fatigue were not affected by the diurnal variation known to influence maximum grip strength and work during grip formation in normal subjects. Rheumatoid hands were less affected by exercise or temperature change of the forearm than were normal hands. Cold more consistently produced change in hand function than did warmth or exercise. Environmental changes affected the dynamic (rates of grip development and release and power) more than the static parameters (maximum grip strength and work) of grip. Measurement of power, fatigue and rate of grip release provide additional parameters useful in the assessment of hand function in patients with arthritis.