The 4-2-1 Workout Is Everywhere on TikTok. Here’s How to Do It Right

There are 5.5 million posts on FitTok. That’s a lot of noise to sift through if you’re looking for science-backed, trustworthy training advice. Some of this advice is overcomplicated (like the 30/30/30 method). Some of this advice is downright dangerous (remember dry-scooping?). But you can find legitimately sound training principles through social media, and one that’s been making the rounds as of late 2024 is the 4-2-1 workout.

We’ll break down this worthy training trend with the help of Noah Tenenbaum, a REP Fitness Product Analyst, and certified strength and conditioning specialist with a master’s degree in applied physiology and kinesiology. You’ll learn if it’s worth your time (spoiler: it is), how to do it, and who may want to consider skipping or modifying it. 

What is The 4-2-1 Workout Method?

Despite its name, the 4-2-1 workout isn’t a one-off gym session; it’s a system for structuring your weekly workouts (known as a training split). It consists of four strength training days, two cardio workouts, and one mobility session. The goal of the program is the same as 99.9 percent of workouts that exist: to help you gain (or maintain) muscle while leaning out. 

And despite the recent TikTok glow-up, the 4-2-1 workout is far from new. How old is it? Well, it’s tough to say, but splitting up your week between lifting, running, and stretching isn’t a ground-breaking concept. In fact, there’s already a name for it: concurrent training, which combines strength and endurance exercise in a single program. 

“Some fresh out of a textbook people might raise some red flags about Concurrent training, saying, ‘It’s not optimal to try and improve competing adaptations,’” says Tenenbaum. “However, for 99.9999 percent of people, this is probably how we should be training for health and longevity.” 

Is the 4-2-1 Workout Plan Legit?

Yes. Training splits are a well-established method that trainers use to manage their clients' training volume and recovery. So, the 4-2-1 workout is an effective and proven aspect of exercise science. The question isn’t “is this workout legit?”, it’s “is it right for me”? Let’s break it down:

The 4-2-1 workout is a solid foundational training split that’ll have you looking fitter, feeling stronger, and achieving overall better health. It balances strength training, which you need to build muscle and gain strength, and cardio, which improves your heart health and cardiovascular capacity. 

In short, it’s effective as a catch-all training plan that'll work for pretty much anybody. The 4-2-1 workout falls short for folks needing a hyper-specific training protocol. Triathletes, for example, will need more sport-specific conditioning and, probably, less weight training. And bodybuilders may need up to five or six lifting days with less intense cardio like walking. 

If you are looking for a general routine that will cover your bases, you still need to be diligent about structuring the 4-2-1 workout.

How to Follow the 4-2-1 Workout

First: seven days of training is a lot; beginners should steer clear and work their way up to this amount of training. If you’re just starting, try two weight training days and one cardio day. You can do two full-body dumbbell workouts and one running or cycling day. Build your base over a few months and add more sessions as you progress. 

Choose Your Strength Training Split

Before starting this program, you need to decide how to structure your training. Tenenbaum says to do two days of strength training followed by a cardio day, repeating that, and then finishing the week with the mobility day. Evidence supports strength before endurance: a systematic review showed strength-first sessions boost lower-body performance, especially important for balancing the 4-2-1 workout. 

For your strength training, Tenebaum suggests you follow a full-body lifting split or an upper-lower split is best. As for what equipment to use, it’s all fair game—dumbbells, barbells, kettlebells. As long as you’re managing your volume and recovery, train in a way that’s fun for you.

Full-Body Split Explained

You’ll train every major muscle (or close to it) four times a week on a full-body split. The primary benefit, as Tenebaum explains, is [The full-body split] helps me have a higher overall intensity trained on each muscle group.” Basically, you can push every exercise really hard. 

You must be precise with your exercise selection, or you risk burning out your muscles before the week ends. If you do an intense compound exercise like the squat on Monday, make that your only leg exercise for the day, and then follow up that workout with less fatiguing machine movements like that seated hamstring curl and leg extension. 

Upper-Lower Split Explained

The upper-lower split breaks up your training into two upper-body and two lower-body days. Tenenbaum likes this option the most for people “whose total volume is the goal for maximum muscle gain,” since you can focus more on specific body parts instead of hammering your entire body four times per week. You’ll have to soften the intensity a touch to make it through the entire workout.

To structure this split, you could do one push-day workout and one pull-day workout for your upper and lower body. Or, you could spread the volume over all your upper- and lower-body muscles across two training days. 

Whichever split you choose, you won’t see gains unless you’re training with enough total volume. Researchers suggest about 10 weekly sets per muscle to build or maintain muscle. The good news is that you can easily accumulate this volume with four training days—hitting every body part two to four times per week (an idea that research supports) with enough time to recover between workouts—and have headroom to add more sets as you progress over the months. 

How to Manage Cardio Training

On the 4-2-1 workout, you don’t have to worry about whether to do cardio before or after weights. You’ll do conditioning work on two separate days. 

As for how to program your cardio: Aim for two moderate-intensity sessions per week, which the National Academy of Sports Science defines as Zone 2 cardio. You should be able to maintain a steady pace for 30 minutes to an hour at an intensity that allows you to speak with some difficulty. Program intense cardio workouts—like long or fast runs or cardio circuit training—after an upper-body strength workout (so your legs aren’t sore) and make your other cardio day a long walk or very light jog. 

Don’t Skip Mobility Work

Look, you will be tired by the end of the week, especially if you’re new to concurrent training or this number of training days. It is a lot. Do not, however, skip your mobility workout. This is a low-intensity day to keep your joints mobile and muscles pliable so you can complete your workouts effectively and without pain. 

Start by using a foam roller on your major muscles for a minute each. Pick a handful of static stretches for the muscles that feel tightest. Do two sets of 30 second holds on each side for each stretch. Then, select one or two dynamic stretches for your neck, shoulders, thoracic spine, hips, knees, and ankles. Do two sets of eight to 10 reps for each exercise. You could also perform a simple yoga flow (just pick a free one from YouTube) if you don’t want to build your own routine. (If you go that route, consider using yoga blocks if you’re a beginner.) 

It’s smart to warm-up before your lifts and cardio days. You can perform an abbreviated version of your full-fledged mobility day, focusing on the areas you’re training for that specific session.

Program Progressive Overload

You won’t make gains unless you do a little more each week—whether you increase the reps, weight, or distance, speed. But because this program is a bit of a balancing act between lifting and cardio, you have to be judicious about how aggressively you progress your training.

“Making very small weekly weight increases on exercises would likely be doable for most,” explains Tenebaum. “Depending on the modality of cardio, increasing the total time of the cardio is usually doable, assuming the effort isn’t too high. Or. Increasing the effort of the cardio can be done in small amounts weekly, if not increasing the cardio volume.”

You may also need to fluctuate your intensity based on your goals. For example, if you plan to max out your squat or deadlift, you shouldn’t program intense sprints or a long run that same week. Or, if you want to push your cardio training to new heights, reduce the intensity of your lifting sessions by lightening up on the load a bit. 

Takeaways

• The 4-2-1 workout method structures your week into four strength days, two cardio sessions, and one mobility day for balanced fitness.

• It’s based on concurrent training, combining strength and endurance work without sacrificing progress in either.

• Beginners should scale the workout down to start. Try two strength workouts and one cardio session, then build volume gradually.

• Choose a strength training split: full-body for intensity, or upper-lower for more muscle-specific volume.

• Prioritize Zone 2 cardio for steady-state conditioning and slot intense cardio sessions after upper-body days.

• Mobility and recovery are non-negotiable. A dedicated day of stretching and foam rolling improves performance and reduces injury risk.

• Progress slowly using progressive overload by adding small increases in weight, reps, or cardio duration each week.

Andrew Gutman is a NASM-CPT and health and fitness journalist with bylines in Men’s Health, Gear Patrol, Men’s Journal, and Insider Health. He’s the former Training Editor of Muscle & Fitness and FLEX, and the former Editor-in-Chief of BarBend.com. When he’s not writing, he’s lifting, rolling on the mats (he’s a BJJ purple belt), or reading to his son.

This article was reviewed by Ashley Boyer, ACE-CPT, for accuracy.