Bodybuilding is not all about bulking up; some bodybuilders do it for their other hobbies. A mixed martial arts fighter, for example, will go to the gym for the endurance training as well as the strength training. Fighters are interested in all forms of physical training, and all of that fits under the wider umbrella of “bodybuilding”. Because of that different people will have different training regimens in order to make sure that they get what they need out of the training, and thus they slant their training as needed in order to optimize the effects as per those individual regimens.
A person looking for additional endurance will tend towards higher reps during the workout in order to not only gain the advantages of some strength training but to also build his endurance. They are also likely to put in more laps on the track as well as work on other crunches rather than regular sit-ups. They are also more likely to eat starches over sugars as their carbohydrates of choice as starches are better for long-term endurance. They are also likely to spend more in the sauna in order to build up their endurance rather than to merely relax, and so they are more likely to enjoy higher temperatures in the sauna.
On the other hand someone more interested in agility training is more likely to engage in activities that feature movement over staying power. This means more sprints rather than long runs, and they are more likely to include sports as part of their training, especially those that emphasis constant movement such as handball and basketball. This also means that they are likely to enjoy spinning classes rather than treadmills as the spinning classes emphasize speed over endurance. They are also less likely to hang around and relax afterwards, possibly enjoying a quick run home over the sauna or even showers.
This is not to say that trainers do not work on areas outside of their focus, just that bodybuilding incorporates a number of different schools of study other than merely working on the straight ability to lift, and that bodybuilders often take advantage of that. A fighter that needs to do more damage is more likely to hit the weights, while one working on dodging is more likely to work on agility training. Endurance training is always an option for those who want more staying power. Bodybuilding is more than just lifting weights, and bodybuilders that embrace that find greater success regardless of their focus.