Increase reps and attack with supers and giants to solve that one.
Also, I don't fully agree with this advice. Telling somebody who was previously injured to increase volume to avoid injury doesn't sit too well with me.
I would say:
1. Identify what caused the injury. Yes it's important to rehabilitate the injury but it might just happen again if the actual cause was a weakness of a certain muscle group or imbalance.
2. Warm up correctly - especially when training upper body it's so important to warm up the rotator cuffs.
3. Always practice good form.
4. Do not train the injured muscle group until it is fully healed.
