What Exactly Is ‘Metabolic Conditioning’?

Workouts touted as ‘metabolic conditioning,’ or ‘met-con,’ are popping up in gyms and studios everywhere. The science-y term definitely sounds cool (and maybe even makes us want to sign up for that new class), but what does it actually mean?

In non-scientist speak, ‘metabolic conditioning’ is a type of workout specifically designed to boost our body’s ability to make and use energy. These workouts help our bodies work more efficiently, so we can exercise at higher intensities, burn fat for fuel, and see better muscle gains and fat loss over time.

Here’s everything you need to know about the increasingly trendy training style, how it works, and how to tell if you’re already doing it (you might be!).

How Met-Con Training Works

Basically, there are three ways your body can produce and use energy: the phosphagen system (which covers quick, max-intensity work), the, glycolytic system (which covers moderate-intensity work), and the aerobic system (which covers long-duration, lower-intensity work). The point of met-con training is to challenge these systems so they become more efficient, helping you develop different aspects of your fitness, like power, muscular endurance, and cardiovascular ability, says Todd Nief, CF-L3, head coach and founder of South Loop Strength and Conditioning, a CrossFit studio in Chicago.

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Your body relies on the phosphagen system when you perform super quick, powerful exercises like all-out sprints or Olympic lifts. These rigorous exercises may last just 10 seconds or so, but require at least a few minutes of rest afterward because they’re so intense.

Your body relies on the glycolytic system when you perform more moderate exercise, like running intervals or lifting weights. You can perform these moves for about a minute or so and will need to rest for about twice that time.

And lastly, your body relies on the aerobic system when you perform lower-intensity exercises like running or biking at a pretty comfortable pace. You can perform at this level for at least a few minutes at a time and may only need a few seconds of recovery between sets.

What Met-Con Workouts Actually Look Like

Tons of workouts fall into the met-con category, including anything that’s labeled as HIIT, bootcamp-style class, and (probably the most iconic) CrossFit® classes, says David A. Greuner, M.D., F.A.C.S., F.I.C.S., of NYC Surgical Associates, who specializes in fitness and sports medicine.

Related: 9 CrossFit® Workouts You Can Do Pretty Much Anywhere

Typically you’ll rotate through a bunch of different exercises (like burpees, box jumps, and squats) and use different types of equipment (like kettlebells and rowing machines) for set periods of work and recovery. Which exercises you perform, how long you perform them for, how long you rest, and how long you work for overall determine which of your energy systems you’re really challenging, Nief explains.

Often, met-con workouts involve a variety of different work and rest intervals to challenge all of your energy systems, explains Greuner. (Cardio and strength training in one!) But the beauty of met-con is that every workout is a little different, and if you want to focus on a specific goal, you can! For example, a workout that emphasizes quick all-out sprints or lifts will develop power, while one that emphasizes longer intervals of rowing or lifting will develop endurance.

Because met-con workouts are designed to push your energy systems to the max, as long as you give work intervals your all you can see results without spending hours in the gym, Greuner says.

That said, met-con training demands a lot of your body, so start out slow when adding it to your routine. If you’re not used to high-intensity workouts, jumping right into met-con can leave you incredibly sore, burnt out, and increase your risk for injury, he says. Start with one or two sessions per week and add a third after you can crush and recover from those two weekly workouts.

Related: Add a recovery supplement to your routine to maximize the benefits of your workouts.