Weight training is perhaps the most systematic way of achieving muscular strength and endurance. However, you can also practice all types of calisthenics using your body as the resistance (weight).

Often, when people go on vacation, they think they must put their workouts on hold. Just because a weight room is not accessible, doesn't mean that you can't develop or maintain muscular strength. There are many ways to retain muscular strength and endurance which require no special exercise equipment. Using a chair or bench you can perform bench dips, incline push ups and crunches (shown in the movie above). You can also use empty milk jugs filled with water as weights. It takes very little room to pack a jump rope or piece of surgical tubing which can be used for a number of types of exercises and stretches. With a little imagination, you can organize many household items into a "road gym".