How do I keep my implants from dropping?

Best to run this question by your plastic surgeon who knows your situation best. He/she may make recommendations such as use of a supportive bra and may also have recommendations in regards to avoidance of certain pectoralis major related exercises. Best wishes; hopefully, you will be pleased with the long-term outcome of the procedure performed.

The answer is there's not much you can do to support the implant beyond what the healing process by way of generating a capsule does. Wearing a broad particularly during athletic activity is a good idea.