Resistance training and bodybuilding are two popular fitness terms, but they are often used incorrectly, leading to confusion or misunderstandings. Resistance training and bodybuilding are definitely not the same thing, even though the terms are frequently used interchangeably.
Resistance training is a very general term that covers a wide variety of activities including any type of exercise where your muscles have to overcome a resistance, regardless of the type of resistance used. Naturally, any activity that involves lifting weights is a form of resistance training, because the weights are the resistance, but weights are far from the only type of resistance.
Resistance can also come in the form of bands or cables, medicine balls, etc. Even bodyweight exercises such as push-ups and squats are forms of resistance training, because in those exercises muscles have to overcome the weight of your body, so your body is the resistance.
Technically, the term resistance training could be used to describe virtually every type of exercise, but most people do not classify sporting activities as resistance training, unless lifting weights is a primary component of the sport. To simplify things, other than traditional cardio exercises such as treadmill walking, virtually every exercise performed in a gym type setting is considered resistance training.
Bodybuilding is a term that people often use as another way of saying resistance training or lifting weights, but it actually refers to the competitive sport where contestants flex their muscles in a variety of poses and are judged on how their body looks. Bodybuilding has different weight classes and there are both amateur and professional events, with the Mr. Olympia Competition being the most prestigious event in the sport.
Bodybuilders are judged on factors like the size of their muscles, definition (how much their muscles stand out / having minimal fat), and symmetry (proportion) of their body. People who participate in bodybuilding exercise specifically to improve the way their body looks, so they can earn higher scores in competition. Consequently, bodybuilders are concerned more about how their body looks and less about how it functions.
This is one of the reasons bodybuilding training is very different than training to improve athletic performance or exercising for general health and fitness. By understanding the differences between resistance training, bodybuilding, and other fitness terms, people can better articulate their exercise goals and seek out the right training program to help them be successful.