You’ve probably heard the term metabolic conditioning or metabolic training and wondered what the term means. Metabolic conditioning is a way of structuring a workout for maximal calorie burn and fat-burning potential and one that elicits a greater anabolic response as well as more sustained after-burn afterward.
For example, when you lift weights, you typically rest for variable periods of time between each set to give your body time to recover. The rest period between sets helps your muscles bounce back enough to maximize your lift on the next set. However, it also reduces calorie and fat-burning benefits. With metabolic conditioning, you reduce or eliminate the rest periods so that your body is placed under more stress.
Another feature of metabolic conditioning is it taps into anaerobic pathways. As you’re probably aware, there are three main energy systems. Let’s look at each and how it relates to metabolic conditioning.
The Phosphagen Pathway (anaerobic)
This pathway is also known as the creatine phosphate pathway and is optimized for short bursts of exercise that last for 30 seconds or less. During brief periods of exercise, creatine phosphate donates a high-energy phosphate bond to make ATP, the body’s energy currency. Since creatine phosphate is in limited supply, it can only make energy available for brief periods of time. It’s called into play during quick explosive movements, like a sprint or a near-maximum lift. If you depended solely on the phosphagen pathway, you could only sustain movement for a brief period of time
Glycolytic Pathway (anaerobic)
The glycolytic pathway predominates during exercise that lasts from 1 to 4 minutes. Like the phosphagen pathway, the glycolytic pathway doesn’t require oxygen and primarily uses carbohydrates as a fuel source. The downside is lactate builds up along with hydrogen ions, your muscles burn, and you’re forced to stop. So, like the phosphagen system, this is a short-term energy system, although it sustains movement for longer than the phosphagen pathway.
Oxidative Pathway (aerobic)
This is the energy system your body mainly uses during sustained periods of exercise and, as the name suggests, it requires oxygen. For example, when you run or cycle at a moderate pace for 20 or 30 minutes, this is the energy system working hardest. The oxidative pathway uses predominantly fat as a fuel source.
Keep in mind, that each energy system operates to some degree with all forms of exercise. This just shows the predominant energy system that comes into play with various intensities and duration of exercise.
As mentioned, metabolic conditioning taps into anaerobic pathways, creating what is known as an after-burn. The after-burn is where your body continues to burn additional calories and fat after a workout is over. Not only do you burn calories at a higher rate for hours afterward, but metabolic conditioning also creates a more robust hormonal response. This hormonal impact of metabolic conditioning gives rise to a more favorable environment for shedding body fat and building muscle.
There are several approaches you can take to reap the benefits of metabolic conditioning. Here are some of the most common.
Metabolic Conditioning: Circuit Training
With circuit training, you move quickly from one resistance exercise to the next with little or no rest. It’s the lack of recovery between exercises that create the metabolic conditioning effects and the resulting after-burn. The key is to train with intensity on each exercise and rest only long enough to push hard on the next one. Circuit training with light weights or with longer rest periods doesn’t place enough stress on your body to elicit a metabolic response. The exercises you do during a circuit workout run the gamut from movements using weights, bodyweight exercises or explosive movements like kettlebell swings or medicine ball throws. For maximum metabolic conditioning, the circuits should be challenging and the rest periods minimized.
Metabolic Conditioning: High-Intensity Interval Training
Not all interval-style workouts are true metabolic workouts. An interval-style metabolic conditioning workout is one where the active intervals are intense enough to leave you breathless. During these intervals, your body releases catecholamines, your body temperatures rises, you breathe hard, and lactate builds up in your muscles. The benefit of lactate is it stimulates the release of growth hormone and testosterone. In other words, during a metabolic HIIT workout, your body is under metabolic stress and it responds with greater hormone release.
Tabata-style workouts are an example of an interval-type workout that taps into anaerobic energy pathways. They’re structured so that you do 20 seconds of intense activity followed by 10 seconds of recovery. You repeat this sequence for 8 rounds total. Most people do 2 to 3 rounds in total. During the short intervals, you work at near maximum intensity. As you might expect, this places stress on your body and leads to greater fat burning and release of anabolic hormones.
Metabolic Conditioning: High-Intensity Resistance Training
A standard strength-training workout doesn’t qualify as metabolic conditioning but you can turn it into one. To supercharge the metabolic benefits of strength training, choose compound exercises that work multiple muscle groups, especially lower body muscles, lift heavy, and minimize the rest between sets. Think heavy barbell squats and deadlifts, as opposed to isolation exercises that work a single, small muscle group, like biceps curls or triceps extensions. Add bodyweight exercises too, like dips, push-ups, and pull-ups. A metabolic strength-training session should get your heart rate up more than a standard session and should feel exhausting.
The Bottom Line
The drawback of metabolic conditioning is it’s challenging and stressful on your body – but with stress and challenge come change. Such workouts are ideal for getting leaner and the greater anabolic response helps with muscle building as well. Metabolic conditioning workouts are also a plateau buster when you’re trying to get leaner. With the metabolic-conditioning after-burn, you boost fat burning for hours after a workout. Plus, this type of training can help you reach a higher level of conditioning. So, if you’re looking for a way to kick your workout up a notch, give it a try.
ACE Fitness. “The Three Primary Energy Pathways Explained”
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Br J Sports Med. 2009 Jul;43(7):521-5. doi: 10.1136/bjsm.2007.041970. Epub 2008 Jan 9.
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