A lot of people get very worried about the amount which they move their limbs while speaking publicly and for some reason get bothered by it to the extent that they seek out the answer to a seemingly very worrying and valid question: will my hand movements distract the audience. The answer is flat and simple: NO!
The thought that you need to stop moving your hands so you do not distract the audience is based on a completely faulty ad baseless premise. Hand movements are used to emphasize and put weight in certain points. People around the world who are confident and comfortable in their abilities and their ideas move their hands when they speak.
Hence, it is better for you to not focus on restraining your hands from moving when speaking or even keeping a serious look on your face. A good speaker lets his or her words and body flow. Instead of limiting it you should be looking for more movement and motion. Instead of distracting the audience, they will bring them in and make it easier for them to listen to you. Purposeful movements come naturally when you speak and they will come to you as well. You do not need any rehearsal in this regard, but make sure to not make a conscious effort of freezing your arms when speaking.