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Jennifer Garner’s go-to lower-body exercise is great for building power

Jennifer garner box jumps
(Image credit: Getty)

Let me start with a confession — I’m not a big fan of the box jump. I know that it’s an excellent leg exercise for runners, as it builds strength, power, and speed in the lower body, but no matter how much I practice, I still feel like I’m going to fall face-first into the block. One woman who has mastered them, however, is actor Jennifer Garner, who recently posted a video of herself doing the move on her Instagram. 

Along with the caption “33 inches is very tall,” Garner can be seen mastering the impressive box jump on her second attempt. The 13 Going On 30 actress has tagged her trainer, Beth Nicely in the video. Nicely founded The Limit, a dance workout method, that mixes dance with HIIT training. 

In an interview with Shape (opens in new tab), Nicely said, “[Garner] likes to work really hard, she's very, very strong. I consider her a professional athlete in what she's capable of physically. We both love to dance, we both love to work hard, I think it's a good combination.” 

But how do you do a box jump, what are the benefits of the move, and how can you make box jumps easier, or harder? Read on to find out more. Looking for more workout inspiration? Check out what happened when this writer did 50 bird dogs every day for a week, or when I tried Chris Hemsworth’s 250-rep dumbbell workout.  

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How to do a box jump 

To do a box jump, start by standing with your feet shoulder-width apart in front of a box — don’t start with a 33-inch box like Garner did, start with something around 12-inches, and build up. If you are completely new to the move, it’s worth speaking to a personal trainer before attempting this move to ensure your form is correct. 

Bend your knees and push your hips back as you swing your arms behind you, then push from your feet and jump up onto the box. You should land in a partial squat position, with both feet landing on the box at the same time and your knees bent but not tracking over your toes to absorb some of the impact of the jump. 

Carefully step down, then repeat. Do not be tempted to jump down off the block — this can put a lot of strain on your joints, especially if you’re a beginner. If you’re not careful, this is an easy way to injure yourself. 

Make sure, when you land on the box, you’re not in too low a squat. Your back should not be hunched, and your knees should not be collapsing as you land. If your knees are collapsing, it might be that you need to work on your hip and glute strength before progressing with this exercise. 

It’s a good idea to check your form in the mirror as you practice the move. If you have poor form, you might be putting yourself at risk of injury, If in doubt, check in with a personal trainer. 

The best time to do box jumps is at the start of your workout, after a warm-up, when your legs are fresh. Keep repetitions fairly low at first, especially if you’re a beginner. 

a photo of a woman doing a box jump

(Image credit: Shutterstock)

What are the benefits of box jumps? 

Box jumps can help you build powerful legs, which are important for running faster, or lifting heavier weights. Building explosive power is especially important for sprinters, football or soccer players or any athletes who need to move quickly with force. A box jump is a plyometric exercise, that forces you to push your muscles to the max, raising your heart rate as you do so. 

To do a box jump correctly, you’ll need to engage all of the muscles in your lower body — your glutes, hamstrings, quads, and calves, while also engaging your core and your arms as you jump upwards. 

As box jumps also work on your vertical jumping height, you’ll also work on your hip mobility, as you’ll need full hip extension to master the move. 

Jennifer Garner doing box jumps

(Image credit: Jennifer Garner/Instagram)

How can you make box jumps easier, or harder? 

As mentioned above, box jumps are an advanced move, and Garner’s 33-inch jump is seriously impressive. If you’re not ready to do a box jump yet, start by doing step-ups, working on building your leg strength, without the explosive power. If you want to work on this, try stepping up onto the box, then doing a one-legged hop at the top of the movement. 

If you’re trying to make box jumps more challenging, simply add more height to the exercise. As you build strength in your legs and hips, move up to a higher box to keep the move challenging. 

If you're looking for more fitness guides, we have you covered. Check out how to connect your Apple Watch to Peloton, how to do a reverse plank and how to build a home gym for under $500.

Jane McGuire
Fitness editor

Jane McGuire is Tom's Guide's Fitness editor, which means she looks after everything fitness related - from running gear to yoga mats. An avid runner, Jane has tested and reviewed fitness products for the past five years, so knows what to look for when finding a good running watch or a pair of shorts with pockets big enough for your smartphone. When she's not pounding the pavements, you'll find Jane striding round the Surrey Hills, taking far too many photos of her puppy.