I haven't been shy about my love of Orangetheory Fitness: I joined three years ago to help me get in shape for my wedding [1] and all the floor work made fall in love with weightlifting again [2]. And when I'm not in studio, I like doing this 27-minute treadmill workout [3] from an Orangetheory coach. But one of the best things I love about Orangetheory is that I learn something new every time I go; I regularly steal moves from my OTF workout and incorporate it into my own fitness routine.

Last week, there was one move in particular that challenged my core strength, balance, arm strength: hollow hold with close-grip chest press. I will admit that I have a pretty weak core overall, so hollow holds in general are a challenge for me. Add in a single-arm chest press with a 15-pound dumbbell, and my entire core was shaking. But in a good way!

Strength Benefits of Hollow Hold With Close Grip Chest Press

This was no accident; Orangetheory coach Tim Brown, ACE-certified personal trainer and regional fitness director of Orangetheory Fitness Missouri, told POPSUGAR, "This is a very controlled and patient movement, which I love because most people think fast and chaotic when they think Orangetheory Fitness, and this is anything but." He said it challenges your core because with the hollow hold and a dumbbell in just one hand, you are imbalanced which forces you to steady your core. "Each rep is a concentrated effort to maintain the hold and balance your body in a straight line," he said. "The core is challenged the entire time."

This move forced me to slow down and engage my core [4], focus on my stability, and work on my form to get quality reps in. As part of the workout block, we did sets of eight reps on each arm in between other exercises, then sets of 10 on each arm, then sets of 12 on each arm until the block was finished.

For this move, grab a medium-weight dumbbell (10-20 pounds). If you're not sure how heavy your weight should be, use this guide [5]. Tim said to choose a dumbbell weight that can be controlled and maintained through the rep count without pulling your neck or putting too much pressure on your lumbar spine. "If discomfort arises, simply bend your knees and place your feet on the floor to stabilise and focus on the press," he said. "When you feel that you're ready to resume the hollow hold, remember to consciously tighten your abdominal muscles to protect and pressure that may creep to your spine."

I recommend incorporating this move into any ab workout to fire up your core and work on your stability. It also doubles as an arm workout, so is a good exercise to work into your upper-body day. Either way, you will definitely feel the burn!

How to Do Hollow Hold With Close Grip Chest Press

• Grab a 10- to 20-pound dumbbell (or 5- to 10- kilograms) and then lie on your back with your legs fully extended. Pick up the dumbbell with your right hand and hold it with your arm bent at a 90-degree angle.
• Actively press your lower back into the floor and draw your belly button into your spine. Inhale as you slowly lift your shoulders, arms, and legs off the floor keeping your body in a "banana" shape. Keep your heels as low to the ground as possible while still pressing your lower back into the floor. Don't let your chin touch your chest.
• Exhale as you extend your right arm up into a close grip chest press with the dumbbell parallel to your body and your palms faced in. Lock out your elbow and hold for one second.
• Inhale as you bend your elbow and bring the dumbbell back down to your side, keeping your arm close to your abs.
• This counts as one rep. Continue for seven more reps on your right arm before completing eight reps on your left arm.