One must-do exercise: The crossover lunge.
"It's a great move for changing direction and improving your ability to stay with an opponent when playing defense," says Cameron McGarr, C.S.C.S., a performance-enhancement coach in Santa Clarita, CA.
"By adding this gem to your routine, you'll be able to run circles around the competition—literally." Stand with your feet shoulder-width apart. Step with your left foot—passing it in front of your right leg and planting it in front of you and to the right at a 45-degree angle. (You should look as though you're walking sideways.) Lower your body as in a normal lunge, and then reverse the motion back to the starting position. That's one rep. Perform 3 sets of 12 reps, resting 60 seconds between sets.
Your biggest weakness is: your glutes. Most people have severe imbalances between the strength of the muscles on the front and the rear of the body, bringing new meaning to the phrase "weak-ass game." When you jump and run, your glutes should be the prime movers, but if your quads are taking over the movement, you'll never perform at your peak, and you'll increase your risk of injury. To bring up weak glutes, try the single-leg hip bridge. Simply lie on your back, bend one knee 90 degrees, and place that leg's foot on the floor. Keeping your body in a straight line, drive your foot down and bridge up off the floor . That's one rep. Perform 3 sets of 12 reps, resting 60 seconds between sets.
Remember this when you train: "If you're playing or practicing several times a week," says McGarr, "your legs are getting plenty of work and you should train them less in the gym." Heavy leg workouts will only hinder your ability to recover and slow your progress. Try training upper body twice a week (one heavy, low-rep day and one moderate, higher-rep day works well) and lower body just once—make sure to do both heavy strength and higher-rep work in this one workout.