Which training principle states hat exercising a certain body part or practicing a particular skill primarily develops that park or skill

The training principle of Specificity states that

exercising a certain body part or practicing a particular skill primary

develops that part or skill. Ensuring that exercise programs have specific

goals would make training a lot easier and improvements more noticeable. If you

want to be a good runner, you have to incorporate running into your training

program. If you want to beat that time in swimming, you have to incorporate

sprints in your swim training. You are not only training your muscles for the

activity, you also need your brain to be trained enough for the exact activity

or skill that you are going to perform. Specificity principle reminds and

ensures an individual to assign activities that would help meet specific goals.