Don’t be afraid of weights. After all, muscle burns more calories than fat. Do you want to know how to lose arm fat? Start with dumbbells, says Dede Lagree, who has worked with Angel Elsa Hosk and is the owner and head trainer at Lagree Fitness Studio. For Lagree’s arm-toning workout, choose a pair of dumbbells that you can safely lift at least 20 times. But pick a weight that challenges you: Your arms should feel that 20th rep! Don’t have dumbbells? Substitute soup cans or water bottles, Lagree says. Check out all the great body changes you get from lifting.
Begin standing with feet together. Step the right foot forward and bend the knees into a forward lunge, keeping the right knee in line with the second toe of the right foot; extend the arms forward and drive the fingertips toward the right foot. Push off the right foot and briefly balance on the left leg, keeping the right knee bent 90 degrees and bending both elbows; the palms should be facing one another. With control, step the right foot back into a reverse lunge position, bending both knees while simultaneously reaching both arms overhead. Reverse the movement and return to the starting position. Complete a total of eight to 10 reps on the right side before switching to the left.
You'll also build muscle to fill out your arms and firm them up. “Generally, when people are complaining about underarm jiggle, they’re usually referring to the area that is governed by the tricep,” says Williams. “If the jiggle or looseness in that part of your arm is due to a lack of muscle, then strengthening and building muscle in your tricep will also create some change in the aesthetic of that area.” She recommends performing triceps push-ups, extensions, and dips to hone in on that area and add some muscular definition to your arms.
If you're ready to move on from classic Bulgarian split squats, Swan's amped-up variation gets your upper body in on the action for a true total-body exercise. "This combination move works your legs, butt, chest, back, arms, and core," she says. "And it not only hits all the major muscle groups—it also lets you work on balance." Give it a shot and you'll see why.