Metabolic conditioning workouts have become insanely popular. In fact, the term is sometimes used, rather loosely, to describe any workout that’s intense in nature. But, metabolic conditioning is training that can be adapted to meet a variety of sports and fitness goals. Let’s look at what a metabolic conditioning workout is and what the benefits are.
What is Metabolic Conditioning?
Metabolic conditioning workouts are designed to maximize the efficiency of a particular energy system in order to meet a particular fitness goal. You’re probably already familiar with the three main energy systems your body uses to meet the demands of exercise. If not, let’s review them and see how they relate to metabolic conditioning.
The Fast Energy System (ATP-Creatine Phosphate)
The quickest and more readily available form of energy your body can harvest is stored ATP and creatine phosphate. This is an energy pathway your muscles can use for ultra-short periods of exercise, less than 30 seconds in duration. Think of shot putters, sprinters, and powerlifters who need to generate short-term power quickly. You also tap into this energy system when you first break into a sprint or do a broad jump. Unfortunately, you only have limited supplies of pre-formed ATP and creatine phosphate. After about 30 seconds of exercise, these reserves are used up. Then, your muscles need another source of ATP to continue contracting.
The Glycolytic Pathway
Once your muscles use up ATP and creatine phosphate stored in the muscle, they look for an additional energy source for continued movement. That would be the glycolytic energy pathway, a pathway that doesn’t require oxygen and burns mostly carbohydrates.
The glycolytic pathway is optimal for periods of exercise that last between 30 seconds and 3 minutes. This pathway is limiting though as lactic acid and hydrogen ions build up eventually and your muscles fatigue to the point that you have to stop. It’s during the rest periods between high-intensity intervals that lactic acid is partially flushed from your system and your muscles recover to the point that they can again work at the same intensity.
The Oxidative Pathway
For longer periods of exercise, your muscles tap into the oxidative system, an energy pathway that requires oxygen and burns fat primarily as fuel. This pathway is most important during longer periods of sub-maximal exercise where the pace is slow enough that you can adequately deliver oxygen to your muscles. Think of brisk walking, jogging, or cycling at a steady intensity, as these activities mainly use oxidative pathways and burn fat as fuel.
In reality, you use more than one pathway at a given level of exercise intensity, but you predominantly use one of these pathways and the dominant one depends on exercise intensity and duration.
Understanding Metabolic Conditioning
Metabolic conditioning workouts are designed to target a particular energy system and make that system more efficient. This allows you to perform better at that exercise intensity. To maximize a particular energy system, you would select a work to rest ratio that forces that system to adapt. For example, you would use a different work to rest ratio to target your oxidative system than you would when you’re focusing on the creatine phosphate system. Let’s look at how you can use the work to rest ratio to target an energy system and make it, over time, more efficient.
Suppose you’re a sprinter or an Olympic lifter and you want to maximize the efficiency of your ultra-short-term energy system, the ATP-creatine phosphate component. This energy system comes into play mostly with speed and power movements that last less than 10 seconds. What’s more this energy system takes 2 to 5 minutes to fully recover once it’s spent. To target this ultra, short-term energy system and gradually maximize its efficiency, use short, active intervals and long rest periods. For example, a work to rest ratio of around 1 to 10 or even 1 to 15 is ideal. So, you might do 10 seconds of an intense exercise such as sprinting or squats or box jumps and rest for 2 minutes. You need the longer rest period for some degree of recovery to take place. During the recovery, your muscles regenerate some of the creatine phosphate they used up.
If you’re trying to improve your sports performance in a variety of sports, including weight training, you can do it by enhancing the efficiency of your intermediate, or glycolytic, pathway. You use this pathway primarily when you do short-term, vigorous activities, like weight training or running short distances of less than 800 meters. It takes between 1 and 4 minutes for this system to fully recover, so you need enough rest between work intervals for at least partial recovery to take place. During the rest period, your body clears lactic acid and the acidic pH of your blood normalizes to some degree.
A good work to rest ratio for targeting the intermediate system is 1 to 2. So, rest for twice as long as you work. An example would be 30 seconds of fast running, kettlebell swings, or box jumps followed by a minute of rest and then repeat.
What if you want to maximize the efficiency of your oxidative energy system so you have greater endurance and can run longer? In that case, use a work to rest ratio of 2:1 or 3:1. Since you’re exercising sub-maximally, recovery periods can be shorter. In this case, you might do a minute of work and recover for 20 to 30 seconds. If you choose a shorter work interval, for example, 30 seconds of work and 15 seconds of recovery, you’ll also target your glycolytic system since you can exercise more intensely during the active interval as its shorter.
Another benefit of metabolic conditioning, other than the fact you can make a particular energy system more efficient, is you get more of an after-burn effect when you use an interval structure. That means you burn more calories even after a workout is over.
The Bottom Line
Metabolic conditioning workouts are designed to make a particular energy system more efficient. Doing this increases the amount of physical work you can do, using that energy system, in a given period of time. By changing the ratio of work to rest, you can “fine tune” an energy system and make it more efficient. Take advantage of this targeted and time efficient way to train.
American Council on Exercise. “The Three Primary Energy Pathways Explained”
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