Isokinetic testing of shoulder strength: normal values.

In isokinetic muscle testing of the shoulders of 31 normal volunteers, no statistical difference was found between dominant and nondominant shoulders, even though there was a consistent pattern of greater strength in the dominant shoulder. Internal rotation strength was greater than external rotation (p less than 0.01) by the ratio of 3:2 for both the fast and slow torque arm speed. Extension strength was greater than flexion (p less than 0.01) by a ratio of 5:4 at both speeds. Adduction strength was greater than abduction (p less than 0.01) by a ratio of 2:1 for both speeds. Overall, adduction strength was greatest, followed by extension, flexion, abduction, internal rotation, and external rotation. Male strength was greater than female, but the advantage decreased when normalized for lean body mass and exercise habit.