Try tennis or another racket sport. Racket sports like tennis or squash are great for building arm muscles and for a total body workout. Join a recreational tennis league in your area or take tennis lessons from the tennis pro at your gym. If a family member enjoys playing squash or racquetball, ask them to give you lessons and practice your skills. You should notice marked improvements in your arm strength and better arm muscle definition the more you play racket sports.
Start the clock, and immediately do 10 reverse lunges in perfect form. When you’re done with the reverse lunges, go straight into jumping jacks until the clock reads 1:00 minute. Then move on to the next move. Do each move 10 times perfectly starting at the top of the minute, and finish out the minute with jumping jacks until it’s time for the next move. For the single-leg deadlift, do 10 on only one side (don't change your standing leg during any set of 10 reps).
In a high plank position—palms flat on the floor beneath your shoulders, arms straight. Ease down on to your left forearm. Then, ease down your right arm until you’re in a forearm plank. Now push up with your right hand and then your left to return to a high plank. Repeat, alternating which side you lower first with each rep.” Lagree recommends doing two sets of ten reps. Another workout worth trying: these 9 resistance band exercises that will work your entire body.