Dumbbells and barbells are popular types of free weights. Each type of weight has particular strengths and weaknesses, and so many athletes use both types for a well-rounded training routine. If your primary goal is to build muscle mass, you don't have to limit yourself to one type or the other. However, if your resources are limited to investing in either dumbbells or barbells, you may find one type of weight is more suitable for your particular fitness goals.
Differences in Equipment
The dumbbell is a small free weight, consisting of a grip bar and two disc-shaped weights, spaced just far enough apart to comfortably accommodate your hand. Dumbbells are typically used in sets, one in each hand. By contrast, the barbell has a far longer grip bar, with weights spaced several feet apart. You grip a single barbell with both hands.
Advantages of Barbells
If you must choose between barbells and dumbbells, barbells may serve as the ideal foundation for free weight training, according to Loren Chiu's comparative study of barbells, dumbbells and kettlebells, for the National Strength and Conditioning Association. Barbell training offers more opportunity for gradual progression than a training regimen using dumbbells -- as most gyms have plates of just a few pounds, which you can add to the end of each barbell. When you're pressing a lot of weight, barbells often prove more practical, as they are already set in an overhead, bench-press position. By contrast, you have to lift dumbbells from the floor, a difficult maneuver if you're pressing heavy weights.
Advantages of Dumbbells
When training your legs, dumbbells are generally the easier and safer means of maintaining balance and building muscle mass. While it's possible to achieve the same results using either type of weight, using dumbbells can foster good form, resulting in a more effective workout. If you're a beginner or are training without a spotter, dumbbells offer the safer option, enabling you to let go of the weights if need be without endangering yourself. To build well-distributed muscle mass, dumbbells also ensure that you use each side of the body evenly. By contrast, it's easy to inadvertently favor one side or the other when you're gripping a single barbell. Dumbbells also permit a greater range of motion, letting you perform exercises that work more of your muscles. As an added benefit, dumbbells require greater coordination and stabilization of your core and limbs.
Whichever type of weight you use, you can make the greatest strides in building muscle mass by adopting good form and following a regular, varied workout routine. The American College of Sports Medicine recommends 30 minutes of moderate exercise, using both sides of the body, five times per week. Alternately, you can train more vigorously for at least 20 minutes, three times a week. For optimal strength training, move your joints in a controlled way, without relying on momentum. Keep your spine straight and use your leg muscles instead of your back muscles when lifting a weight from the ground.