Fig. 3

Evaluation of wrist extensor strength. a. Digital hand-held dynamometer (microFET2TM System, Hoggan Health Industries Inc., Salt Lake City, UT, USA). b & c. Top and bottom views of custom-designed holder. Semi-circle shaped liner consists of rubber to tightly hold the dynamometer. The screw on the one end tightens the dynamometer into the liner. d. Screws at both sides (red circle) of the cradle function to lever and to tilt the holder (green arrows). e. Overall view of the custom-designed system that measures wrist extensor strength. f. The head of the dynamometer placed perpendicular to the long axis of the forearm over the long finger metacarpal at the level of the metacarpal neck. The wrist is stabilized onto the plate. The subject is asked to extend the wrist with maximal force for 5 s, and the maximal value is recorded as the muscle power. G. The subject’s forearm laid flat on the plate with the wrist in pronation and neutral flexion-extension position and the shoulder in slight abduction and neutral rotation. Wrist is stabilized firmly onto the plate using the wrist strap