"Remember: FORM over speed": A pro trainer shares her favorite bodyweight exercise for building core strength and cardio fitness

The other day I heard someone call bodyweight training “boring”, and I couldn’t disagree more. Look beyond staples like squats, push-ups and sit-ups and you’ll find a huge variety of fun, effective moves to try.

To prove my point, top Sweat app trainer Kelsey Wells recently revealed one of her favorite bodyweight exercises: the cross-body mountain climber.

"As a compound exercise, all mountain climber variations work multiple muscle groups at once, targeting your core, back, hips, legs, glutes and shoulders," she writes.

Wells also loves how you can do them in one of two ways to hit different fitness goals; fast and dynamic for cardio perks or slow and controlled for extra core activation.

How to do cross-body mountain climbers

• Start in a high plank position, facing down with your weight spread between your hands and your toes. Your hands should be directly underneath your shoulders, and your body should form a straight line from your head to your heels.
• Bring your right knee as far towards your left elbow as you can while keeping your back flat and your body steady.
• Return it to the start position then repeat on the other side.

Four-minute cross-body mountain climber workout

If you want to turn this move into a quick core workout, use it in a traditional Tabata format. This means you’ll do 20 seconds of work followed by 10 seconds of rest, and repeat this sequence for eight total rounds.

If you’re a beginner, start by performing the exercise slowly. Focus on perfecting your form and feeling your core muscles working as you bring each knee forward.

If you’re a bodyweight training veteran, pick up the pace and see how many repetitions you can complete in each 20-second work window (while maintaining immaculate form, of course) to spike your heart rate.

Can you build muscle with bodyweight exercises?

The gym is the obvious place to go if you want to build strength and muscle, but you can achieve this through bodyweight exercises too. As long as you’re challenging the working muscles, you can make progress.

However, bodyweight training does have its limitations. Foremost among them is the fact that there aren’t as many variables to play with.

If you’re a beginner, you may find that 12 push-ups or lunges are enough to pose a challenge. But as your strength and fitness levels improve with continued training, you might need something harder to hit the stimulus needed for continued progress.

This is called progressive overload—tinkering with the variables of each exercise over time, ensuring your workouts stay challenging to prevent training plateaus.

With bodyweight training you can add more sets or repetitions into your workout, slow down the tempo of your lifts or choose a harder exercise variation (such as swapping squats for Bulgarian split squats) to make your training more difficult.

But it’s much easier to track your progress and tangibly upgrade your workouts by gradually adding more weight to each exercise. For example, if you were able to do three sets of 12 repetitions of a biceps curl using 10lb dumbbells one week, you might try using the 12lb dumbbells the next week.

This is where a gym membership or a set of adjustable dumbbells can be handy.