I read an article which cited a study that gave the strength ratios for a healthy shoulder.
I am currently on a shoulder routine for posture so this is very relevant to me, but I find the ratios hard to believe, for instance 2:1 for Adduction and Abduction, with extension high on the strength list.
Although I cant directly see the text, the study can be found here with the info below: http://www.ncbi.nlm.nih.gov/pubmed/10736387
In general, adduction (toward the body) is higher than abduction torque (2:1), internal rotation is higher than external rotation torque (3:2), and extension is higher than flexion torque (5:4). Overall, according to Halder et al., "Adduction strength is highest, followed by extension, flexion, abduction, internal rotation, and external rotation." (8) If you want to promote balance around the shoulder joint, consider the above-mentioned ratios.
I can externally rotate about 4KG on a cable pulley which is really about 2KG once you factor in the pulley is taking some of the resistance. So working up from what should be my weakest exercise I calculated that I should be adducting 7KG and extending 5KG, this sounds a bit much to me.
Can any1 actually adduct 3.5x the amount and extend 2.5x the amount that they can externally rotate?
Adduction 7KG (iron cross http://www.exrx.net/WeightExercises/Lat ... Cross.html
Extension 5KG (reverse front raise, so pulling down)
Flexion 4KG (front raise http://www.exrx.net/WeightExercises/Del ... Raise.html
Abduction 3.5KG (side lateral raise)
Internal Rotation 3KG
External Rotation 2KG