Kaley Cuoco Pulled Off a Stability Ball Balance Challenge

Kaley Cuoco has been a longtime source of prime fitness content, from showing off her jump roping skills to sharing post-yoga selfies. In one of her latest posts, the actress shared footage of a tricky balance challenge that she pulled off during a recent workout.

In a video that Cuoco posted to her Instagram Story, she balances on an exercise ball on her knees, holding on to two Stick Mobility Sticks (Buy It, $169, stickmobility.com) propped on either side of her to remain stabilized. Cuoco explains in the video that the exercise is deceptively challenging. "This is way harder than it looks — way harder," she says. (

To amp up the intensity, Cuoco's trainer Ryan Sorensen directs her to drop the mobility sticks so that she's completely balancing on the ball. "No way," Cuoco responds, before relenting and dropping one stick. Eventually, she even drops the second stick and stays balanced on the exercise ball for a few seconds before rolling off.

The workout is more than just an opp for Cuoco to show off her impressive balance skills. The move, referred to as a stability ball kneeling hold, requires core and posture activation and stability through the trunk, Sorensen tells Shape. "For Kaley, this is a great exercise specifically for her with riding horses," he says. (Yep, ICYDK, Cuoco also has a longstanding passion for horseback riding.) "It takes a lot of coordination, posture, adductor [inner thigh muscle] strength, and core strength, not to mention the focus to make sure everything is clicking to maintain balance and posture."

Jen Widerstrom, trainer and Shape consulting fitness director (who hasn't trained with Cuoco before), says the stability ball kneeling hold is a great way to uniquely challenge your core muscles. "What's wonderful about any kind of stability ball exercise, is that it creates an unstable foundation," she says. "When you're operating from an unstable foundation, you naturally stimulate your core in a different way that creates what I call 'higher muscle recruitment.' With a normal sit-up, you hit your abs in front, which are called your rectus abdominis. But by doing balance ball training like Kaley's doing, now you're having a 360-degree, unpredictable inclusion of your core." Translation: You're going to find that you're working muscles that you probably didn't know you had, says Widerstrom.

This type of training specifically leverages the transverse abdominis, a section of muscle that runs along the front and side of your abdomen to wrap around your core (similar to a corset), notes Widerstrom. It can also pay off when you're doing other exercises in your routine, adds the trainer. "This kind of exercise will translate into lunging, squatting, upper body work — it will translate into every other exercise because you're creating deeper core inclusion which creates stability in those other exercises," she explains. (See: Why Core Strength Is So Important)

Keep in mind, though, that Cuoco's workout requires significant skill, says Widerstrom. "That is a very advanced exercise," she explains. "What's great is that there are progressions, but to even get on the ball is going to be a bit of a circus act." The trainer says she'd classify Cuoco's workout as an intermediate to advanced move. "I would look at it as a fun challenge, brain training, and a nice warm-up or finisher at the beginning or end of your workout." (

The advanced progression of the exercise is to eventually balance on the ball without the help of the mobility sticks, says Sorensen. "The reason we used the sticks was to add stability so she could get the feel of what it takes to hold herself in an unstable environment," he explains. Though they went with mobility sticks for different sizing options and added grip, you could also use PVC pipes for this move, notes Sorensen. If you don't have access to a PVC pipe, you could even use brooms or hold onto someone's hand for added stability, says Widerstrom. (