Lately, “metabolic conditioning” is everywhere — from Instagram and YouTube to CrossFit boxes and barre studios. But like other fitness jargon, we have to ask, what the heck is it?
Well, to be honest, a lot of trainers who push metabolic conditioning, or metcon workouts for short, don’t really know. Some think it’s high-intensity interval training. Others think it’s all about torching calories. Either way, it sure sounds cool! But what’s a lot cooler is actually understanding what it is. And how to harness it for the results you want.
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All About Metabolism: The Three Energy Systems
Contrary to popular belief, metabolism is more than the number of calories you burn each day. Rather, it refers to every single energy-producing and energy-using reaction that occurs in your body.
A little science lesson: A chemical called adenosine triphosphate (ATP) fuels every cell in your body with the energy that cell needs. To get ATP, your body relies on three energy systems: the phosphagen, glycolytic and oxidative systems, explains Pamela Geisel, CSCS, CPT, an exercise physiologist at the Hospital for Special Surgery’s Tisch Sports Performance Center in New York City.
“Metabolic conditioning is any form of exercise that increases the efficiency of any energy system.”
The phosphagen system is fast-acting and responsible for supplying the body with ATP for quick, high-intensity exercises, such as sprints and Olympic lifts. But it tuckers out fast. After that, it needs substantial rest time to spring back into action.
Once you push past the 10-second mark, your glycolytic system starts to take on the brunt of the work, supplying APT for activities such as heavy weightlifting and longer sprints that last up to a few minutes in duration. This system also then needs some time to recover.
So your oxidative (aka aerobic) system next picks up the slack, fueling you through longer duration activities, from 5Ks to triathlons. You can thank all three processes for keeping your body moving.
It’s important to remember that while the three energy systems work on a sort of continuum, no one system is ever doing all of the work. Rather, they’re all working at any given moment — some are just doing more of the work than are others.
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So What Does This Have to Do with Metabolic Conditioning?
When it comes down to it, metabolic conditioning is any form of exercise that increases the efficiency of any energy system. (We know, pretty general.) But it’s important for every fitness goal, whether you are trying to improve your mile time, get more out of your cycling classes, or build muscle and burn fat.
After all, as your body’s energy pathways become better at producing ATP, buffering out nasty metabolic byproducts (which your muscles don’t want) and recovering, the more your body can do. And in less time too, says Sam Simpson, CSCS, CPT, co-owner and vice president of B-Fit Training Studio in Miami. This is where a lot of people (trainers, included) fall into the trap of thinking that metabolic conditioning is all about pushing your body to the point that you’re reaching for the trashcan.
High-intensity interval workouts — alternating between periods of all-out effort and lower-intensity rest — are one way to improve metabolic efficiency over time. But other ways include circuit workouts and supersets, or mixing a couple of exercises that work different muscle groups and then resting, Simpson explains.
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The Benefits of Metabolic Conditioning
A bonus benefit of metcon worktous is that, by placing large demands on your body’s energy systems, they burn calories at a high rate, Geisel says. That can often mean altering body composition in a big way. Even after you leave the gym, metcon workouts burn calories through a process called excess post-exercise oxygen consumption or EPOC.
Basically, when you tap your body’s metabolic pathways (not to mention muscles and heart) at a high level, you force the body to do overtime as you recover and get everything back down to baseline. Research suggests that basal metabolic rate (the number of calories you burn before factoring in activity) may stay elevated for 16 to 24 hours following certain high-intensity and circuit workouts — both players in the metcon game. (Curious what you’re BMR is? You can calculate it here.)
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How to Boost Metabolic Conditioning in Your Own Workouts
The best metcon for you depends primarily on your goals and current fitness level. After all, different metabolic conditioning methods train different energy systems, and that depends on work-to-rest ratios. Don’t worry, we’ll explain.
If you sprint for 10 seconds, and then rest for two minutes (120 seconds) before repeating, that’s a 1:12 work-to-rest ratio. It’s going to primarily train your powerful, fast-acting (but quickly depleting) phosphagen system.
Consider if you cycle between performing squat thrusters for 30 seconds and medicine ball slams for 30 seconds. Then you rest for five minutes (300 seconds) — that’s a 1:5 work-to-rest ratio. This will hone in on your glycolytic energy system.
The Tabata protocol, one common HIIT method, alternates between 20 seconds of all-out effort and 10 seconds of rest for four minutes (or eight rounds), cuing up the oxidative system with a 2:1 work-to-rest ratio.
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Planning Out Your Perfect MetCon Workouts
Often, exercisers fall into the trap of thinking “less rest is harder, and therefore better,” but that’s not quite accurate. Before you decrease rest in an effort to make things “harder,” think about the energy systems. You can end up training a different pathway than you originally intended if you always go all in. Here are a few more factors to consider.
1. Work-to-Rest Ratio
As a general rule, lower work-to-rest ratios such as 1:12 to 1:20 are ideal for developing power. On the other hand, higher ratios such as 1:1 or 1:3 are best for improving endurance, Geisel says. (Note: Tabatas are unique in that they involve so little rest.) Middle-of-the-road ratios such as 1:3 or 1:5 are ideal for improving performance at high-intensity activities. More specifically, this approach helps develop areas of activity that involve some rest, such as powerlifting and sports like baseball, Geisel explains. For the greatest muscle-building, calorie-burning potential, those intermediate work-to-rest ratios of 1:3 to 1:5 are going to come in handy.
2. Fitness Level and Intensity
It’s important to also consider your current fitness level before taking on high-intensity metcon workouts, especially when it involves little rest. “Remember that metabolic conditioning exercises require proper form even with maximal effort,” Geisel says. “Beginners may find them too intense to perform with proper form, increasing their risk of injury.” (Also, those with existing health issues should always check with a doctor before jumping in.)
3. Exercise Selection
After choosing your intensity and rest duration, it’s time to pick your metcon exercises. One option is to tag-team two exercises such as pull-ups and push-ups or squats and shoulder presses, Simpson says. You could even perform four or five different exercises as a circuit, resting at the end of each round. Meanwhile, medicine ball slams and kettlebell swings are two high-intensity exercises that are famous as standalone metcon workouts.
4. Fitting Them In
In terms of scheduling, you can perform these exercises at any point in your workout, but they are best served as a five- to 10-minute finisher at the end of a strength training routine, Geisel says. You can also perform circuits or supersets for a quick, effective 10- to 20-minute workout. Just make sure to warm up with some light cardio or bodyweight moves to prime your body for those metcon workouts to come. Then grab a timer and get ready to sweat!
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