! To strengthen the internal and external rotators of the left shoulder requires similar but mirror-image manoeuvres.
Supraspinatus conditioning requires abduction work and initially should be performed below shoulder level. The starting position is quite different from the previous two exercises. To strengthen your right supraspinatus, place one end of the cliniband under your left foot and extend (keep straight) your right elbow. Hold the other end of the band in your right hand and then internally rotate your right arm so that your right thumb points towards the floor and the back of your right hand faces forwards. Then, keeping your elbow extended, move your right arm away from your body (keeping the elbow straight) against resistance to just below shoulder level, and then let it return to the starting position in a controlled fashion. An easy refinement is to combine pure abduction with a little flexion so that you bring the arm forward as you move it away from your side.
Pinch your scapulae together
Pain should not be felt during any of the three exercises. Three-to-five minute sets over the course of a day will produce a conditioning effect. By shortening the length of the band you will be able to progressively increase resistance. There are a huge number of variations on the exercises described which achieve similar conditioning gains, and I make no claims for the superiority of the chosen three. However, they have worked well in my clinical practice and rarely cause unanticipated problems. Similar exercises can be carried out using the pulley systems found in most gyms and with further adaptations can be done with free weights. Maintaining scapular retraction (the scapulae are 'pinched together' towards the middle of your back and 'pushed down') while carrying out these exercises enables you to develop your scapular stabilising muscles at the same time.
Strengthening the scapular stabilisers without expert supervision is more difficult, but there is benefit in integrating wall leans (standing push ups against a wall), knee push ups and regular push ups in any conditioning programme. Seated rowing will strengthen the latissimus dorsi and should be undertaken while attempting to maintain scapular retraction.
A recent clinical supplement to Medicine & Science in Sports & Exercise, vol. 30 (4), April 1998, provides an excellent overview of the diagnosis, investigation and treatment of sporting shoulder injuries.