WHY WE USE DIFFERENT SET/REP RANGES, WEIGHTS AND REST PERIODS FOR DIFFERENT FITNESS GOALS
The human body produces energy using three metabolically different energy systems. All three are complex chemical processes that I’m not even going to attempt to explain in detail. Go take a course in biochemistry if you really want to know.
The purpose in describing the three systems is to better understand when and what they are used for, how to maximize the benefits of your time in the gym and reach your fitness goals faster with the least amount of effort.
Each system burns a specific kind of fuel and at a particular rate depending on the demands you place on your body.
The three energy systems are:
- The adenosine triphosphate–creatine phosphate (ATP-CP) system, or phosphagen system, supports very brief, high-intensity activities like a single-effort vertical jump.
- The glycolytic system provides energy for activities of slightly longer duration and lower intensity like body building.
- The oxidative system supports long-duration, lower-intensity activities like walking or distance running.
(Now wasn’t that exciting?)
ATP is the fuel your muscles run on. It’s either converted from glycogen (carbs) or fat.
All three systems run on ATP. The glycolic system and the oxidative system make the ATP you need on demand (as needed). But a small amount of ATP is stored in muscle cells for immediate short bursts of energy. Think in terms of single Olympic lifts or power lifting.
The cells only contain enough ATP for about five seconds of serious effort. Recovery time to replace the ATP is three to five minutes. It will not burn a lot of fat or build a lot of muscle. (See where we are headed with this?)
ATP-CP athletes are fast, strong and explosive, specializing in brief, single-effort activities like swinging a golf club or baseball bat, Olympic weightlifting, high-jumping, and shot-putting. Athletes in field and team sports like soccer, lacrosse, tennis, martial arts, basketball and other activities also rely heavily on the ATP-CP system during the highest-effort moments of sprinting, serving, kicking or driving to the hoop.
THE GLYCOLYTIC SYSTEM
As your ATP-CP system sputters out the glycolytic system takes up the slack but only for another minute or two. At near maximum effort only 20 to 40 seconds. The glycolytic relies on ATP that it must covert from glycogen (carbohydrates).
A side note; The “burn” you feel in this type of exercise is not caused by lactic acid ( another source of fuel) build up but from the buildup of hydrogen ions from the chemical conversion of glucose to ATP.
At near maximum effort this energy system’s time to recover enough ATP to repeat the effort is only one to two minutes.
Glycolytic athletes specialize in activities lasting 10 seconds to 75 seconds or so. They’re fast and seemingly tireless — though perhaps not quite as strong as the ATP-CP athlete, nor as enduring as the oxidative athlete — and they tend to be muscular and lean. This type of training is ideal for burning fat (in recovery) and building muscle mass. Weight training using sets of eight to 12 reps and sprinting 400 meters or less typify glycolytic training.
Note that neither the Glycolytic nor the ATP-CP system require any oxygen. They are anaerobic chemical processes.
THE OXIDATIVE ENERGY SYSTEM (Requires oxygen-aerobic)
The oxidative system is always idling in the background. Its first priority is keeping your bodily functions running-digestion, brain function, heartbeat, body temperature and on and on. But in terms of exercise, the oxidative system is the last to kick in.
In fact, all three systems are always idling in the background. Supporting each other. But they each have different priorities as the demand for energy increases during exercise.
The fuel for the oxidative system is oxygen and fat. Although the oxidative system is continuously active and produces loads of energy, the process of converting fat into usable energy can take a while. Once it gets started, though, it’s your body’s most reliable engine over long periods of time but produces the least amount of immediate power.
Oxidative athletes are typically leaner and lighter than the other two athletic types. Jogging, slow swimming, cycling, walking, hiking, martial arts, continuous-action team sports (basketball, ultimate Frisbee, soccer)
So the three systems:
1. Burn different sources of fuel to produce energy
2. Each produce energy for different lengths of time
3. Each requires a different length of time to recover
4. They produce energy in a specific order
5. Each produces a different adaptive response in the body
That is why your workouts need to be planned a certain way depending on your goals.
How do we use that information to plan our workouts? Check back this week and we’ll cover them one by one.
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