Something you’ll be encouraged to hear is that actors sometimes procure motion capture work through voice over auditions! Agents are also tapped into motion capture for their clients for video games, film, animation and more.
Remember, many actors are interested in motion capture. It pays to be competitive, dedicated and vigorous in your studies. Motion capture is its own area of expertise. Find workshops and classes specific to learning how to perform for motion capture, as well as online resources. Go to YouTube and watch veteran motion capture artists, like Andy Serkis, demonstrating how the work is done.