like flexing muscle
The more you use a muscle at a certain task, like weightlifting or climbing, the more it will grow. Depending on the activity the muscle will form in a certain and best suitable way. It does so within it's own capabilities & limits. A muscle can be come bulky and powerful for heavy short lifts. Or a muscle has the capability to form in a way that it is more lean. A muscle can develop in many different ways. The growth lays within the capabilities and limits of the muscle, but more so in the activity given.