Anterior impingement:
During the mid range of abduction and
adduction a sharp and significant drop is often seen. See below.
This is because the anterior structures
are most vulnerable to impingement in this position (in isokinetic terms
that is).
In flexion a drop appears at the start
of range. See below.
This is because the anterior deltoid
locates the gleno humoral joint before lifting it.
This can impinge anterior structures.
However, internal/external rotation will
not necessarily show any change. The drops seen are usually as impingement
occurs causing reflex inhibition.
Frozen shoulder (non specific capsulitus):
The curves seen will be erratic with a
low coefficient of variance. These results are entirely due to pain.
Sub acromial bursitis:
The curves are similar to that seen in shoulder
impingement but the peak torque is usually much lower.
Subscapularis tendonitis:
The torque curve is similar to that seen in shoulder
impingement, however, a normal curve is usually seen in early repetitions
with changes only evident in later repetitions.
This is probably due to a gradual build up of pain
during the test.
Chronic Supraspinatus tendonitis:
The torque curve is usually flattened during the concentric phase of
either internal or external rotation (dependent on the position of the
humorous), if the test is performed in 90 degrees of abduction then the
curve will be flattened in the latter half of internal rotation see next
figure.
If the test is performed in any other position
the curve will be flattened in the external rotation component see next
figure.
