I am in the exact same boat
41 years of swimming and last Sept my shoulder gave out. Went to a PT they said that all I need to do is to start strength training. Cut all swimming out from Sept18 to Mar19 5 days a week of ST and PT.

Started swimming again late March (currently my CSS is 9s faster per 100m than my best effort last 2 years)
My ROM is now what it was at 30ish.



PT 3 to 5/week (10 to 45 mins depending on schedule)
ST 2/week 1.5 hr each

PT 1
Door way stretch
- wall wrist foam roller
- wall angles with foam roller
- band hand cuffs
- body blade external\internal rotation
- body blade Flexion
- band no moneys
- high plank unstable left\right
- Swimmer prone 1
- Swimmer prone 2
- Swimmer prone 3
- Foam roller pec stretch


Strength Training 1
- Suspension Trainer jump squat
- Cable Row with rotation
- Stability Ball Pike
- Wall Slide
- Rainbow Medicine Ball Slam
- Split Stance Landmine Press
- Sled Reverse Fly
- Stability Ball Iron Cross
- Pull ups
- Kinetic Training Bandbell

ST (the fun one)
- Battle Ropes
- Tire Flips
- Pull-ups
- Weighted Sled Push - 50 ft Rope Pull Back
- Sledgehammer
- Wall Ball
- Push-ups
- Cable Pushdown (tricepts)
- Russian Twist with weights
- Kinetic Training Bandbell