Measurement of the flexing force of the fingers by a dynamic splint with a dynamometer.

Purpose and Methods: In order to determine forces acting upon an articular joint during hand rehabilitation, a dynamic splint was built and connected to a dynamometer (capable of measuring forces in the range 0 - 600 gf). Through trigonometric calculation, the authors measured the flexing force in the proximal interphalangeal joint of the middle finger at 30 degrees, 45 degrees, 60 degrees, and 90 degrees of flexion. Measurements were obtained in a population of 40 voluntary adults, 20 females and 20 males, This flexing force was correlated with age, sex, and anthropometric measures.
Results: Force in the flexing tendon is maximal at the start of flexion, and decreases as the angle of joint flexion increases. A relationship was observed between finger length and the magnitude of the force exerted on the tendon: the longer the finger, the greater the force exherted upon the tendon. Force is greater at all the measured angles, (except 30 degrees) in males and in individuals of higher stature, and bigger arm span.
Conclusions: The flexing force can be effectively measured at all flexing angles, that it correlates with a number of different anthropometric parameters, and that such data are likely to open the way for future studies.