You certainly can get back to exercise after breast augmentation. We encourage all our patients to start gentle exercise almost straight away after the surgery. Although anything that involves exertion such as running, skipping, and jumping is to be avoided within the first six weeks. After this, you can get back to full exercise.
If your implant has been placed in a dual plain pocket, that is under the muscle, I would recommend avoid doing any heavy chest weights that involve pull-ups, flies, or bench press. The reason for this is due to the extra compression the muscle causes on the implant, that may then have an effect on the shape of the breast. All other activities are fine. Dual plane, in the most part, gives a better result and has a lot of rates of capsular contracture, so you need to decide what is more important to you, chest weights, or the best possible result.