How to Work Out Your Arm Muscles

Use free weights that are comfortable for you to lift. If you start off with weights that are too heavy, you will have trouble keeping your form. The right weights will be heavy enough for you to perform two to three sets of 12 to 15 repetitions. By the end of each set, your arms should feel the results of your exercise.

Work your biceps by holding a free weight in each hand, palms facing outward and resting against your thighs. In a slow, steady motion, lift the weights, bending your arms at the elbow. Slowly lower the weights to your starting position. You can also perform this move with a barbell.

Work your triceps with free weights by holding a free weight in your right hand. Rest your left knee and hand on a flat bench. Start with your right elbow bent at a 90-degree angle. Keep your back straight and slowly raise your right arm behind you until your elbow is almost locked. Return to starting position.

Use a resistance band in place of weights. Stand on a band with your feet hip-width apart, your knees loose. Hold the band with two hands, palms facing outward and bend your arms at the elbows until your hands are in front of your shoulders. Return to starting position.

Do standard or modified pushups. For the standard version, lie prone with your hands and toes touching the floor. Raise your body, keeping your back straight, until your elbows are almost locked. Lower yourself back down. That counts as one pushup. If that's too hard for you, perform a modified version by touching the floor with your bent knees instead of your toes.