Getting In Shape By Training The Energy Systems

Have you ever noticed the ultra-lean, heavily muscled physiques of sprint type athletes (100m runners, running backs, speed skaters) and wondered why your training hasn't produced such a result? After all, you train with weights 3-5x per week to build muscle. And you do a couple of moderate intensity cardio workouts to burn fat. So why don't you look better than these athletes? All they do is spend the bulk of their time running around a track. So why are their pecs, arms, and abs better defined than yours?

Well, there are a few answers to these questions. The first answer is, as you might have suspected, genetics. While many athletes would have you believe that their hours of hard training have made them into the athlete that they are today, the truth is that they did get a kick start from their chromosomes. You see, successful athletes are born with great potential for their sport. Then, while playing, as a kid, they began to self-select certain sports that they are good at. Add in a solid training regimen and their inherent potential shines.

But there's another side to the question. Although these athletes are born with an advantage, one that allows them to develop muscle and burn fat more easily than most, we can't underestimate the importance of their hard training. By targeting the muscle fibers that contribute to e power as well as training the anaerobic energy systems (ATP-PC system and glycolytic system), these athletes can't help but get bigger, stronger, and leaner. And if you apply the tricks I'm going to teach you in parts 1 and 2 of this article, you'll get bigger, stronger, and leaner too.

The Anaerobic Energy Systems
First, let's define our terms. If you're familiar with the term "aerobic", you'll know that it means "with oxygen". Therefore, aerobic energy systems are systems in the body in which energy (ATP) is generated from the consumption of oxygen. Simple enough.

Now, the opposite of "aerobic" is "anaerobic" which, by definition, means "without oxygen". Therefore, anaerobic energy systems are systems in the body in which energy (ATP) is generated from non-oxidative sources. Now this is where it gets hairy.
From the aforementioned definitions it would appear that these two energy systems were mutually exclusive; only one is active at a time. And in fact, once upon a time, in a land far, far away, researchers believed that no oxygen was used to make ATP during anaerobic exercise. Thus the name. However, current research shows that even during the most "anaerobic" of events, the aerobic system (with oxygen) is also activated (to a small extent).

With that said, it's important to realize what determines the ability of the body to go "with" or "without" oxygen. Well, the main two determinants are intensity and duration. Here's an illustration of these variables in action.

As I'm sure that you all know, if you're on the track and you start to run really fast, for the first few seconds you'll feel quite explosive. But after just 3-10 seconds, some of that explosiveness will subside and you'll slow down a bit. Still pushing hard though, yet getting progressively slower, about 15-20 seconds into the run, your muscles will begin to burn and you'll have to slow down even more. Finally, due to the burning and fatigue, you'll either have to work your way down to a slow paced jog or you'll have to stop altogether. Why does this occur, you might ask? Well, check out the following chart:


Time To: ATP-PC Glycolytic Aerobic System
Peak Power/System <1sec. 20sec. 2-3min.
Maintenance of Peak 10sec. 20sec. 3min.
Total Capacity 10-30sec. 1-2min. hours
Full Time For Recovery 3min. 1-2hr. 24hr.-48hr.
½ Time For Recovery 30sec. 15-20min. 5-6hr.



The ATP-PC system is so-called because the provision of energy at very high intensities is dependent only on stored ATP already in the muscles and on the ability of the muscle's very limited amount of phosphocreatine (PC) to regenerate the ATP as it gets used up. Since these stores are limited, as you might imagine, as the ATP and the PC become depleted, the body has to slow down. Therefore, as you can see in the chart, this system has only a limited ability to generate ATP as the peak power of the system occurs at the 1-second mark and the system only has a capacity of 30 seconds. However, the rate of ATP generation is the fastest of the three and that's why this system is so important for high intensity exercise. When using the ATP-PC anaerobic energy system, you can generate a lot of power for a very short period of time. A 100m sprint is run within the ATP-PC domain.

The Glycolytic anaerobic energy system is so-called because the provision of energy from this system is dependent on muscle glycogen (carbohydrate stores). As you can see in the chart, the glycolytic system provides ATP generating power for longer than the ATP-PC system but it's ability to sustain high intensity exercise is also limited in that the total capacity of this system is 2 minutes.

So the bottom line is that in order to generate power during high intensity exercise, the anaerobic energy system first utilizes stored ATP, then PC, and then muscle glycogen. Well, hold on though! In looking at the substrates used during anaerobic work (ATP, PC, glycogen) you'll notice that fat is mysteriously missing from the list. Does that mean that I'm spending all this time writing about a form of exercise that burns no fat? No way! Listen up.

The interesting thing with anaerobic training is that although very little fat is burned during the short, high intensity efforts, quite a bit of fat is burned in the recovery time between efforts. Therefore by effectively training the anaerobic system (via interval workouts), you'll be dropping large amounts of fat as well.

The Benefits of Training The Anaerobic Energy Systems
While training the anaerobic energy systems is clearly be of benefit for enhancing athletic performance, there are many other non-athletic benefits as well:

1) This type of training is very calorie expensive. Short, 30-minute workouts can burn in excess of 400kcal during the exercise. While carbohydrates provide much of the fuel used during the high intensity interval, fat is also burned preferentially during the low intensity aerobic recovery period between the high intensity intervals.

2) The post exercise calorie expenditure is huge with this type of exercise. In some studies the resting metabolic rate remains elevated (by 15% or more) up to 24 hours after the workout. Interestingly, after exercise the body preferentially burns fat so this elevated metabolism is burning predominantly fat.

3) This exercise leads to an up regulation of aerobic, anaerobic, and ATP-PC enzyme activity. This means that all the energy systems of the body will operate at higher levels and become efficient at burning calories and generating energy.

4) The muscles used during this type of exercise will change their composition, shifting toward an increased percentage of fast twitch fibers. This increase in power-producing fast fibers comes at the expense of the weaker slow twitch ones. The shift is desired as the fast fibers grow more easily than the slow fibers.

5) There is an increase in specific muscle cell organelles (i.e. the sarcoplasmic reticulum). This leads to a better calcium balance and contractile ability.

6) There are short-lived increases in testosterone (38%) and growth hormone concentrations immediately after exercise. While this is debatable, these changes may contribute to an anabolic state in the body.

So What Are We Waiting For?
For the optimal application of anaerobic training in order to improve body composition, here is a that I've found particularly successful. I have also used this program for off-season conditioning in my athletes.

Day 1 - 1.5 hours of Resistance Training (Upper Body - Pushing Type Exercises)
Day 2 - *30 minutes of Anaerobic Interval Training (Rowing)
Day 3 - 1.5 hours of Resistance Training (Lower Body)
Day 4 - *30 minutes of Anaerobic Interval Training (Cycling)
Day 5 - 1.5 hours of Resistance Training (Upper Body - Pulling Type Execises)
Day 6 - *30 minutes of Anaerobic Interval Training (Running)
Day 7 - Rest
*The anaerobic training activities are varied in order to activate different muscles from one workout to the next.

In structuring your interval days, here are some suggestions.

1) Before beginning such a program, be sure to experiment with high intensity exercise. If you have never tried such exercise before, you are in for a surprise - it's difficult.

2) Use a 1:3 ratio of exercise to recovery (i.e. for every 1 second you sprint, rest for 3 seconds).

3) To maximally activate your anaerobic glycolytic system, your exercise duration should be 30s to 60s. As a result your recovery will be between 90s and 180s.

4) Intensity is key to the success of this program. If your intensity is too low during the exercise, you will not realize the full training adaptation. If intensity is too high, you won't be able to complete the workout. You'll have to play around with the intensity until you get it right.

5) Your exercise intensity should be more than double that of your recovery intensity for 60s bouts and more than triple for 30s bouts. For example, if running at 11mph for 60s during your exercise interval, you should be running at approximately 5.5 mph for 180s during your recovery interval. Likewise if you're cycling at 350 watts for 30s during your exercise interval, your recovery should be at about 100 watts for 90s during your recovery interval.

6) When increasing the intensity from one workout to the next, be sure to increase the work. Do not increase the exercise duration or decrease the duration of the recovery. If the exercise to recovery ratio drops below 1:3, you'll lose power during your exercise interval and the activity becomes more aerobic.

Here is an example of these rules in action from one of my client records.
Day 2 - Rowing 5-minute warm-up followed by 7 sets of the following:60 seconds at 250 watts*180 seconds at 125 watts
Day 4 - Cycling5-minute warm-up followed by 15 sets of the following:30 seconds at 300 watts (level 12)*90 seconds at 100 watts (level 2)
Day 6 - Running5-minute warm-up followed by 7 sets of the following:60 seconds at 11mph*180 seconds at 5.5 mph
*If it's easy to maintain the same workout output for the full 30 minutes, increase the work (watts or speed) for the next workout. Increase the intensity to the point that it becomes difficult to complete all the sets at the prescribed intensity. Just like with resistance training, use progressive overload to continually improve.So there you have it. A new for improving body composition that's very effective and doesn't involve boring hours of your life spent on the cardio equipment. Give this program a try and the next time you're admiring the physique of a well-trained anaerobic athlete, it may be your own.