Our answer: Generally speaking, slightly lower weights, higher repetitions and pushing to muscle exhaustion will, over time, increase your muscular endurance. A good specific way to increase your muscular endurance is to superset or triset different muscle groups. For example, you may be focusing your workout on your chest and triceps, but also include within your exercise superset one set of an exercise for a different muscle group, so you can rest the primary group but continue working. So you could start out with a flat bench press set and then go straight into a set of pushups to the point of muscle exhaustion. The key then is to take as short of a break as possible and go right to a high intensity leg exercise like polymeric squat jumps. Then when you finish your superset, you will be able to go back to the chest/tri exercises more quickly as you would already have given those muscles some time to recover. Training this way, you accomplish many things all at once; you strengthen your heart, improve your lung capacity, and increase muscular endurance.