Hi! We don't use gerund (as you do in English) to express the noun of an action. Some actions have their own noun, and in other case we say the infinitive.
For example, for swimming, "nadar", the noun is "nado". I don't fullt understand the meaning of "I limit my swimming", but here are some examples with "nadar", and "nado".
- Me encanta nadar. (I love swimming)
- Estoy mejorando mi nado. (I'm improving my swimming)
- Nadar es beneficioso para la salud (Swimming is good for your health)
"manejar" (drive) doesn't have a proper noun, and don't use to talk about the driving itself but the way I drive ("la forma en que manejo" / "mi forma de manejar").
- Estoy mejorando mi forma de manejar.
You can use the same with "nadar". Here in Argentina, is more common "mi forma de nadar" / "la manera en que nado" than "mi nado", so instead of "Estoy mejorando mi nado", we tend to say "Estoy mejorando mi forma de nadar".