Underarm fat is unsightly, especially as it folds over your bra or tank top. Lifting weights tones the latissimus dorsi, pectorals and supraspinatus muscles which border and make up the area under your arm. Additionally, since you cannot spot reduce your arms with lifting alone, you should incorporate an aerobic exercise program to shed fat covering your toned muscles. Cutting back on your calories will augment your weightlifting efforts. Lift a heavy enough weight so you can only do six to 12 repetitions for four to six sets of an exercise.
Dumbbell Chest Presses
Grab a pair of dumbbells, holding one in each hand, then sit at the edge of a flat exercise bench. Lie back on the exercise bench and straighten your arms upward over your chest.
Keep your feet flat on the floor.
Bend your elbows to slowly lower the dumbbells until they touches your shoulders, then contract your pectoral muscles to push the dumbbells back up over your chest. Repeat to complete one set.
Rest for one minute, then grab a heavier pair of dumbbells. Repeat the exercise for one more set. Increase the weight you use again for your remaining sets as long as you can complete at least six reps.
Lateral Pull Downs
Connect a straight bar to the pull down machine, ensuring the bar curves down to form a handle. Wrap your fingers around the corner if you have short arms or around the straight part of the handle bar if your arms are longer.
Sit down on the chair as you pull the bar down with you. Lean back slightly.
Contract your latissimus dorsi to pull the bar down to the top of your chest, squeezing your shoulder blades together and drawing your elbows behind you. Slowly straighten your arms to return to the start position and repeat for one set.
Rest for one minute then increase the weight by 10 pounds and repeat the exercise for another set. Continue to increase the weight you are using for your remaining sets as long as you can do six reps.
Hold the bar of a dumbbell with both hands and sit at the edge of a flat exercise bench. Position the dumbbell so that it is in a vertical position, resting on your thighs.
Slowly lie back on the exercise bench with your feet flat on the bench, lifting the dumbbell directly above your chest.
Contract your abdominal muscles by sucking your navel toward the bench to stabilize your body throughout the exercise.
Slowly lower the dumbbell behind your head, keeping a slight bend in your elbows and moving only at your shoulders. Lower the dumbbell until your upper arms are close to your ears.
Contract your pectorals, lats and serratus anterior muscles to bring the dumbbell back over your chest -- the serratus anterior lies between your pectorals and your lats, under your arms. Repeat the exercise for multiple sets, using progressively heavier weights to complete six to 12 reps.