Jessica Jones, NASM certified personal trainer and fitness expert at FitRated.com emphasized that having a good form is key to being able to do a one-arm push-up. “One of the most common form mistakes in push-ups in general is trying to feel the work in the arms,” Jones told POPSUGAR. “It’s your chest and shoulders that should be doing the work, so be mindful of the feeling of your shoulder blades squeezing together with each descent.”
Jones recommends perfecting your push-up form on a wall before you hit the floor. Begin by placing both hands shoulder-width apart on the wall and start pushing up from the wall. Once you’ve got a feel for the technique, you can go to the floor and mimic the same movements in plank position.”Now that you’ve internalized the form for the shoulders and pecs, you can place focus on keeping your body from sagging and ensuring your arms aren’t flaring out to the sides,” Jones said.
When you’re feeling ready to try one arm, Jones suggests that you work towards this step on the ground at your own pace. The best way to do this is to keep one arm close to the body and slowly move the other one away from your side with each push-up. Remember, you aren’t removing your arm entirely out of the way yet.
But when you feel like you’re ready to try a true one-arm push-up, Jones recommends that you try performing it on a wall first. “Move one arm out to the side until you eventually remove it from the wall entirely,” said Jones. “Once you feel comfortable with this, perform the same routine on the floor in plank-position.”