Have We Taken "Exercise Stacking" Too Far?

Just when I thought I'd seen it all on TikTok, I stopped dead in my tracks when I saw a video of someone running on a treadmill with a loaded 135-pound barbell on their back. "That's a recipe for disaster," I thought to myself.

A few minutes later, this video popped up on my FYP of a person doing backward walking squats holding a heavy dumbbell, then transitioning into walking lunges holding two dumbbells.

I decided to search "lifting weights on the treadmill" to see if this was a trend or just a couple of one-off videos. Sure enough, videos like this one populated in the TikTok results page, showing someone doing jump squats on a moving treadmill.

My only thought was "why?" Not only did these "exercise stacking" videos seem dangerous, but they seemed counterproductive as well. Wouldn't you get a better strength workout if you just focused on lifting, or a better cardio workout if you just focused on running? I asked a few personal trainers to find out.

Experts in This Article

Caroline Juster, CPT, is a certified personal trainer based in Chicago.

Brittany Hammond, CPT, is a certified personal trainer and group fitness instructor based in Los Angeles.

What Is Exercise Stacking?

Exercise stacking is exactly what it sounds like: Doing multiple types of exercises at one time. The (presumed) goal? To get more bang for your buck. If you have a packed schedule, you may want to combine cardio and strength into one workout to save time. This is a good idea when you do it right (read: safely).

Take compound exercises, for example. These types of moves work multiple large muscle groups at once, and can be intensified to get your heart rate up as well. For instance, doing burpees targets your arms, core, and legs, and if you do them at a fast pace, you're building cardio fitness, too. Jump squats are another exercise you can do to achieve this. However, doing strength-building exercises while on a moving treadmill isn't exactly the best way to go about working multiple muscles and systems at once. More on that below.

Is Exercise Stacking Beneficial?

It can be, for the reasons highlighted above. But when it comes to lifting weights on a treadmill, it's a hard no. "Combining strength training and cardio in this manner doesn't provide any additional benefits," says certified personal trainer Caroline Juster, CPT. "If you want to get stronger or build muscle, it's best to lift weights on stable surfaces like solid ground or an exercise bench. This is where you're most efficient and can safely exert the most force. Introducing an unstable surface like a moving treadmill means you won't be able to move as well or go as heavy, and your gains will suffer as a result."

Certified personal trainer Brittany Hammond, CPT, agrees. "Besides being physically dangerous with a risk of a fall, this doesn't actually train your muscles any better," she says. "In fact, I would say that if you're doing something like a lunge on a treadmill, there would be no way you could get full range of motion on the exercise, rendering it fairly useless."

Juster goes on to say that to become a better runner, you need a well-thought-out combination of volume (doing more,) intensity (pushing faster paces,) and technique work. "Adding extra load to your body doesn't necessarily make your workouts more effective and can put unnecessary wear and tear on your joints. After all, running already places massive forces on your body," she says.

Both Juster and Hammond agree that if you want to get a little more bang for your buck, walking with a weighted vest or backpack on — called rucking — is a safer version of … whatever it is these TikTokers are doing.

"Some people are training for events that require them to carry weights, such as a backpacking trip," Juster says. "If that's you, it's best to use a rucksack or weighted vest specifically designed for this purpose. Walk outside on solid ground, or if you must use a treadmill, keep it to a walking pace."

The Bottom Line

Sure, exercise stacking may seem like you're getting a two-for-one deal, but stick to either separating your strength and cardio workouts or adding tried-and-true compound exercises to your routine for your safety. "While you may be tempted to try TikTok trends like this one, the dangers of them significantly outweigh any benefits," Hammond says. And I couldn't agree more.

Danielle Zickl is a freelance writer who has 10 years of experience covering fitness, health, and nutrition.You can find her work here on PS, and in many other publications including Self, Well+Good, Runner's World, Outside Run, Peloton, Women's Health, and Men's Fitness.