Control of the muscles of a human body is limited if one remains outside of the body. We do have some limited ability to do so using electric fields, such as those produced by TENS units. These can cause a muscle to contract.
However, such contractions yield very little control. Our muscles are organized into muscle units, which are small groups of fibers within a muscle that always contract together. Our bicep has about 53 of them, and we recruit them in various orders to have fine control over our motion. If one is using TENS style electrical fields, it's hard to affect them one at a time -- you tend to contract the whole muscle. An individual being controlled in this way would be jerky, like a zombie.
To get a sense of what it would be like, consider playing QWOP, a game which challenges you to run by controlling the leg muscles directly.