Contrary to what some people might think, when you’re trying to gain muscle mass, you shouldn’t waste your time doing isolated movements. Instead, you should be doing compound exercises (movements that involve the use of two or more joints). The reasons are, compound exercises work multiple muscle groups at the same time, and more importantly, work your large muscle groups – quads, triceps, pecs, back, etc…
Dumbbells, in my opinion, are better than barbells because they give you a greater range of motion and require more stabilization. There are a lot of great compound exercises you can do with just a pair of dumbbells that will help you put on some serious mass.
Renegade Rows
Renegade rows take ordinary push-ups and turn them into the kind of exercise you begin to dread. They are a great exercise for your pecs, triceps, biceps, back and shoulders, as well as your core. To do them, set a pair of dumbbells on the ground. Get into a pushup position with your hands gripping the dumbbells like a pushup bar. Do a pushup and then pull one dumbbell off of the ground and up to your shoulder. Then do another push-up and repeat the same movement on the other side.
Thrusters
Thrusters combine an overhead squat with a dumbbell shoulder press. This is a killer move for building up your legs, back, shoulders and arms. Thrusters are also good for developing core strength (a common theme among compound movements) and a tough cardio workout. Trust me, your heart starts pumping fast after just a few of these.
Now, it’s important to note that you don’t want to use a weight as heavy as you could normally squat or shoulder press; you’ll tire out before you even get started. I suggest using about half the amount of weight you would normally shoulder press until you get comfortable with this exercise.
Performing a thruster is simple. Like I said, it’s just a squat and a shoulder press combined into one movement. Stand in a starting squat position with a dumbbell in each hand. Bring the dumbbells over your shoulders and squat down. On your way back up, push the dumbbells over your head into a shoulder press. Repeat.
Dumbbell Bench Press on a Stability Ball
This exercise takes an ordinary bench press and makes it more challenging by increasing the range of motion and incorporating core muscles for stabilization. Sit down on a stability ball (exercise ball, Swiss ball, whatever you prefer to call it) and pick up a heavy pair of dumbbells and set them on your knees. Lift the dumbbells up to your shoulders and begin to roll your butt out forward so the ball rolls under your back. The ball should support your shoulders. Use your core to support your lower back. Don’t let your hips sag. Now, simply bench press the dumbbells.
Sources:
http://www.builtfit.com/exercises/compound-exercises-for-mass.htm
http://www.t-nation.com/free_online_article/sports_body_training_performance/the_one_dumbbell_workout
http://www.weighttraining.com/exercises/thrusters
http://www.bodybuilding.com/fun/kettlebells.php?Name=Alternating+Renegade+Row