Regular, gentle exercises help you maintain shoulder flexibility and prevent injury recurrence. For your back shoulder muscles (above, left), use one arm to stretch the opposite arm across the front of your body. Hold it there for 10 seconds. Repeat three to five times, then switch arms and repeat three to five times on that side. For your front shoulder muscles (above, right), bend your arms forward at the elbows, then gently pull your elbows back to squeeze your shoulder blades closer together. Hold for 10 seconds. Repeat three to five times.