Big arm muscles can make a huge difference to your physique. Your arms are an important muscle group if you compete in bodybuilding, and even if you don't, big arms can still turn heads in the gym and help you become stronger. While you won't be able to build huge arms in just two weeks, you can certainly increase their size, provided you perform an intense workout twice per week, focusing on both the biceps and triceps.
Begin each workout with chinups. While often considered a back exercise, chinups are great for biceps and forearm growth. Use a narrow grip with your hands facing toward each other and perform five sets of eight repetitions. If you're able to, perform your sets with weight added either with a dipping belt or a weight vest. For an added challenge, wrap a towel around the bar, which will test your arm muscles and grip strength even more.
Move on to dips as your second exercise. Charles Poliquin, owner of the Poliquin Performance Center for elite athletes, recommends using V-shaped dip bars and executing each repetition with a full range of motion to really hammer your triceps. In the bottom position, you should be able to pinch a sheet of paper between your biceps and forearms, and in the top position your elbows should be locked out. As with chinups, add weight to your dips if you can, and do five sets of five reps.
Perform preacher curls using dumbbells or a barbell as your third exercise. These hit the long head of your biceps muscle, which helps to develop your biceps "peak." Bodybuilder and strength coach John Meadows also recommends taking three seconds to lower the weight on each rep when doing biceps exercises to boost muscle growth.
Finish your workout with skullcrushers. Meadows says these are a great triceps exercise, but they can be quite stressful on your elbows, so he recommends doing them at the end of your workout when your joints are already warm. Use dumbbells or an EZ bar and lie on a bench or the floor. Aim for three sets of 20 reps, getting a good stretch in the bottom position and exploding up on each repetition.