We say this often, but dumbells – and especially adjustable dumbbells – are the most versatile pieces of home gym equipment you can buy. So versatile, it's possible to have a full-body workout in six exercises using one dumbbell only, as the below workout exemplifies.What's the benefit of doing full-body workouts? This type of exercise burns the most fat as you use many muscles simultaneously. But unlike cardio workouts such as running and cycling, strength training such as this workout will build muscle as well as burn fat. Better still, by accumulating muscle mass, you'll also elevate your basal metabolic rate (BMR), which will help your body burn more calories even when you aren't exercising.Want arms and chest muscles as big as Sylvester Stallone or Arnold Schwarzenegger? Try this 3-exercise, 1-dumbbell triceps and pecs workout and see how easy it is to pack on muscle. But before you do that, let's see how fitness i