Pronation
and Supination
There are currently no standard examination positions for pronation and supination. During these movements the shoulder is difficult to fully stabilize without using 90 degrees of shoulder abduction and even then the subject can move the shoulder somewhat the elbow is usually flexed to 90 degrees during these tests (as described by Gallager et al 1997).
The movements are best performed in a seated position (see below). The instantaneous axis of rotation is directly down the shaft of the ulna as can be seen by the red line. The shoulder must be closely monitored for movement as must the elbow, however, if the elbow is overly stabilized then the range of motion will be restricted (remember not to increase the intra-muscular pressure in the forearm too much by over stabilizing the elbow).
Pronation and supination can also be performed in the lying position where stabilization can be more easily applied (see below).
As velocities in some sports (any involving throwing an object) are known to reach thousands of degrees/second (Pappas et al., 1985) testing using a dynamometer will never be considered to be fully functional. Generally it is accepted that speeds of 30 degrees/second is slow with 90 degrees a standard test speed. Any speed up to 190 degrees/second is achievable but speeds over this are hard to maintain.
Range of Motion
Gallagher et al (1997) suggest a -50 to +50 degree range of motion, however, I find this hard to achieve and a -30 to +30 degree range seems more sensible particularly as the peak angle for pronation is aproximatly-8 degrees and peak supination occurs at +12 degrees (Gallagher et al 1997).
Normal Strength Values Are Here
