Shoulder injuries, while not as prevalent as low-back injuries, are the third most commonly reported injuries in rowing.
To prevent and/or treat a shoulder injury, you'll want to look for and do exercises that strengthen and stabilize the rotator cuff and the scapula, two key areas of the shoulder. A lot of shoulder strength and stability is needed to “hang” on the oar. And when you lack stability in the shoulder, particularly the scapula? That's when you may find yourself bending your elbows at the catch, shrugging your shoulder through the drive, or even injuring your neck. Talk about taking those issues from water to land!
If you incorporate exercises such as these into your strength routine, you'll be helping both to improve your form and to prevent injury. Already have an injury? These exercises (preferably under the care of a professional) can help alleviate the symptoms, and stabilize and strengthen those weaker areas against further injury.
There are many, many variations of these basic exercises. For more good scapular stabilization exercises, check out the warmup poster in the boathouse. Look at the “scapular stabilizers” portion of the “activate” section.

Shoulder external rotation: 3–4 sets of 8–12 reps

Shoulder scaption: 3–4 sets of 8–12 reps

Scapular retraction: 3–4 sets of 8–12 reps