Before diving into the specifics of the different energy systems, it’s important to define what the broad term “conditioning” means. Joel Jamieson defines conditioning as “a measure of how well an athlete is able to meet the energy production demands of their sport” (see author’s note below). This means that a basketball player who can jump, cut, and shoot efficiently while still making it back on defense for the entirety of the game is just as conditioned as a long jumper who can jump and recover three or more times during a meet.
Simply put—conditioning is specific to the sport at hand.
Oxford Languages defines aerobic exercise as any exercise intended to improve the efficiency of the body’s cardiovascular system in absorbing and transporting oxygen. The more efficient your body is at transporting oxygen to muscles, and the better your muscles are at absorbing oxygen, the better your aerobic fitness is. The aerobic system produces the vast majority of energy that we use during daily activities (walking, writing, standing up and sitting down, etc.) and can produce energy for hours on end. This energy is produced in the form of adenosine triphosphate (ATP), which is the fuel your muscles run on.
The aerobic system is often referred to as an athlete’s gas tank—the larger an athlete’s gas tank, the longer they can compete at or near maximal efficiency. It’s common to think that aerobic fitness is only important in endurance sports like cross country or swimming, but this is false.
It’s common to think that aerobic fitness is only important in endurance sports like cross country or swimming, but this is false. Share on XRegardless of what sport is being discussed, all three energy systems are working behind the scenes at different times. For an Olympic weightlifter, where success is primarily based on the abilities of the anaerobic alactic system, the aerobic system is responsible for recovery between attempts. This is crucial for success, as first attempts are often used as an extension of the warm-up. If an athlete can’t properly recover between each lift attempt, their results will be poor.
An important note about the aerobic system is that it is the only energy system that can use both fats and carbohydrates to produce ATP. This is important because fat as a fuel source can produce approximately nine calories per gram, more than twice the amount that carbs can produce, at around four calories per gram. While this means the aerobic system has a much larger capacity for energy production, the process of breaking down fat for fuel takes much longer than breaking down carbs. With this increased capacity comes a decreased rate of energy production—meaning the aerobic system cannot produce energy for high-intensity, explosive movements (sprinting, jumping, etc.).
There are various ways to measure aerobic fitness. While the gold standard is a lab-based VO2 Max test, this is often not the best option for sports teams for multiple reasons (cost, test length, necessity for proper equipment, etc.). In a team setting, there are a number of standardized tests that will work well.
One of the most common aerobic fitness tests is the beep test. This test is straightforward, can be done with large groups, and can easily be used to assess the effectiveness of a conditioning program. I personally use the 1200m shuttle test, also called the Bronco test, to test my athletes’ max aerobic speed. This allows me to specify personalized distances for various conditioning workouts.
My coaching staff and I recently tested 80+ athletes’ max aerobic speed in under 45 minutes. Quick and efficient is often the name of the game in my world as a high school strength coach, and the 1200-meter shuttle test definitely fits that description.
This article will look at the aerobic system: what it is, the physiology behind it, and various methods to improve it in different levels of athletes (techniques to build an aerobic base as a beginner, intermediate, and advanced athlete). It will provide practical examples and methods for coaches looking to increase their athletes’ aerobic conditioning.
Author’s note: Throughout these articles on conditioning, the main citation used will refer to Joel Jamieson’s Ultimate MMA Conditioning. While this book is specific to mixed martial arts, the methods discussed in it can be applied to any sport, from cross country to shot put. During my years as an athletic performance student, my mentors referred to Ultimate MMA Conditioning as the gold standard for energy system development (ESD). As I have ventured into running a year-round high school athletic performance program for various sports, I have found Jamieson’s methods to be second to none.
How Do You Improve Your Aerobic Fitness?
There are three main components of aerobic energy production:
- Oxygen supply (responsibility of the respiratory system and the heart).
- Oxygen utilization (efficiency of the muscles’ ability to utilize oxygen).
- Substrate availability (amount of fats and carbs readily available).
Breaking down the aerobic system into these three parts makes it easy to understand what needs to be done to improve aerobic fitness. Simply put, you can improve your aerobic fitness in three ways: increasing the amount of oxygen supplied to the muscles, increasing the efficiency of these muscles’ ability to utilize oxygen, and increasing the amount of fats and/or carbs available for energy production.
To improve the heart and respiratory system’s ability to transport oxygen to the muscles, cardiac output needs to be improved. Cardiac output can be defined as the amount of oxygenated blood that your heart can distribute per pump. This can be improved by:
- Increasing the size of the left ventricle.
- Increasing how hard the heart can squeeze (contractility).
(This will be covered in more depth in the next section.)
Next is oxygen utilization. To improve the muscles’ efficiency in utilizing the oxygen that is transported from the heart, muscle fiber types need to be discussed. Muscle fibers can be split into two general categories: slow-twitch (type I) and fast-twitch (type II). For the aerobic system, an increase in the size and efficiency of slow-twitch muscle fibers is key.
Substrate availability is the third and final piece of building better aerobic fitness. The body stores fats and sugars, which are then used (along with oxygen) to produce energy during exercise. In the absence of these two fuel sources, the aerobic system basically runs dry. The more substrates the body can store, the better the aerobic system can perform.
If one of these aspects of the aerobic system is improved, aerobic fitness will increase. If two or all three of these aspects can be improved, aerobic fitness will be significantly better, and the athlete will be able to perform at a much higher level for a much longer period.
Improving the Aerobic System for a Beginner Athlete
For a new athlete with no aerobic base established, the focus should be primarily on the body’s ability to transport oxygen to the required muscles. If the heart and respiratory system can be made stronger and more efficient, the athlete will soon realize they have a lot of potential to increase the size of their gas tank.
For a new athlete with no aerobic base established, the focus should be primarily on the body’s ability to transport oxygen to the required muscles, says Alex Roberts & @Steve20Haggerty. Share on XAs mentioned above, cardiac output is the amount of oxygenated blood that your heart can distribute per pump. Training cardiac output is simple (not easy) and requires a high volume of low-intensity conditioning. Any exercise that can be done at a steady state for an extended amount of time (at least 30 minutes, preferably between 45 and 90 minutes) can be used for low-intensity conditioning. Think jogging, biking, swimming, jumping rope, etc.
Sport-specific drills can also be used here. The same exercise doesn’t have to be used for the entire session. An example would be: jog for 15 minutes, perform sport-specific drills for another 15 minutes, and finish with another 15-minute jog. This can break up the monotony of jogging for 45 minutes. Keep in mind what sport team is being trained: If the athletes play a field sport, jogging is ideal. Don’t have soccer players swim for 30 minutes and expect their on-field conditioning to improve.
Most beginner athletes with no aerobic base will likely be young athletes just getting into training. We run a summer strength and conditioning program for incoming freshmen every summer. If you’ve ever tried to have a freshly graduated eighth grader jog for 30 minutes in the Midwest heat and humidity, you know it doesn’t work very well. While we do perform long-duration, low-intensity conditioning with them, we also implement game-based cardio. We have various games and relay setups that will keep them working at a low intensity level, and they are much more content playing a game for conditioning than jogging for long periods.
An example of game-based cardio we use throughout the summer is “Ultimate Ball.” Fields that are 50 yards long and 30 yards wide work well, but dimensions can vary based on available space. Set up two end zones with cones, each 10 yards deep. An easy way of setting up fields quickly is to use the width of a football/soccer field as the field’s length. This way, three fields can be set up on one field.
The rules are as follows:
- Using a football or any other ball, teams pass the ball to each other with the ultimate goal of catching the ball in the end zone.
- When a player catches the ball, they can only take three steps forward. (They can move backward/laterally as much as they want.)
- The other team gains possession if a pass is incomplete and touches the ground.
- The crucial factor is that players are constantly moving—if players take too long to pass the ball, give them a “shot clock” of 3–5 seconds.
Teams of 5–8 are ideal, but we’ve run teams of 12 with large groups. The game lasts 10 minutes, and at the end of the game, we switch which teams play.
An important note: the easiest way to ensure that cardiac output is, in fact, being trained is to base the work off of heart rate, says Alex Roberts & @Steve20Haggerty. Share on XAn important note: the easiest way to ensure that cardiac output is, in fact, being trained is to base the work off of heart rate. To revisit the physiology of cardiac output: the main objective is to increase the size of the left ventricle and to increase the heart’s contractility. If the heart is beating at too high of a rate, the heart won’t fully expand and fill with blood, leading to a different training stimulus.
An easy heart rate guideline for cardiac output training is as follows: the athlete’s heart rate should be 130–150 beats per minute for high school- and collegiate-aged athletes. Teach athletes how to check their heart rate themselves. Have everybody count their beats for 10 seconds (using the carotid artery) and multiply that number by six to find their heart rate. To make it even simpler, give them an adjusted rate that can be used for a 10-second count. For example, they’re spot on if their 10-second heart rate is between 22 and 25. If any higher or lower, adjust as needed.
An easier but less accurate method is the conversation check. If an athlete can hold a conversation with a partner while conditioning, chances are their heart rate is in the appropriate range for cardiac output. Obviously, using heart monitors or a wearable device that gives heart rate readouts is ideal, but that’s not realistic for my setting at the high school level.
An example progression of cardiac output sessions can be found below.
Improving the Aerobic System for Intermediate Athletes
An athlete who has completed at least 12 weeks of consistent cardiac output training can be considered “intermediate” in the sense that their aerobic system has a good foundation that can be built upon. These athletes might be getting bored with jogging for 30+ minutes with their heart rate at 145 bpm. Increasing the time of these cardiac output training sessions every three to four weeks would be sufficient to continue to build up the athlete’s gas tank, and they can be easily progressed in this way for months on end.
Another option would be to add a second priority and focus on increasing the size and efficiency of the athletes’ slow-twitch muscle fibers. Rather than replacing the cardiac output session with a slow-twitch session, complete at least 30 minutes of cardiac output, then add a slow-twitch session afterward.
What does this look like?
A great way to increase the oxidative abilities of slow-twitch muscle fibers is via Jamieson’s ‘tempo method.’ An example of an aerobic tempo would be to assign a 2020 tempo during the squat. Share on XA great way to increase the oxidative abilities of slow-twitch muscle fibers is via what Jamieson calls the “tempo method.” Most coaches are probably familiar with weight room tempos. They involve working under specific tempos during movements in the weight room. General tempos bring much value outside the desired conditioning stimulus (hypertrophy, coordination, fine-tuning technique) relevant to this discussion.
An example of an aerobic tempo would be to assign a 2020 tempo during the squat. This means the lift’s eccentric and concentric portions last two seconds, with no pause at the top or bottom. This is different from “normal” (strength or hypertrophy) weight room tempos; an important detail is that pauses at the top or bottom give the muscles a quick chance to recover, which will take away from the oxidative demands of these muscles.
Another detail Jamieson mentions is to use continuous breathing. Again, different than traditional tempos, but max strength is not the desired stimulus. To increase the oxidative abilities of an athlete’s muscles, the oxygen supply needs to be as continuous as possible.
To better understand why an athlete would want larger slow-twitch fibers when they’re not nearly as powerful as fast-twitch fibers, it’s essential to dive a bit deeper into the physiology of what slow-twitch fibers bring to the table. Apart from being responsible for long-endurance activities, slow-twitch fibers also assist in improving the endurance capabilities of fast-twitch fibers. Lactate is a byproduct of anaerobic exercise (which fast-twitch fibers are responsible for) and can be oxidized and converted into ATP with the help of—you guessed it—slow-twitch muscle fibers. So, the larger the slow-twitch fibers, the better the endurance of the fast-twitch fibers. A true win-win.
Three to five sets of 8–10 reps, with the 2020 tempo discussed above, are sufficient to improve the oxidative abilities of slow-twitch fibers. Any compound movement already included in the strength program can be used. As any coach who has used tempos in the weight room will support, that two-second eccentric/concentric tempo will quickly turn into a one-second tempo and might be half a second by the time the third set is reached. With this in mind, it would be smart to prescribe a 4040 tempo, knowing that four will probably be a two.
A notable advantage of the tempo method is that it takes place during strength training sessions, so it’s not another running workout. If the athletes are already familiar with the compound movements in which the aerobic tempos will be prescribed, this method can be trained at the same time as cardiac output. Simply add the tempo method to weight room movements during the accumulation phase of the program. This should fit well with everything else taking place at this point in the program and doesn’t require adding a session after the cardiac output session.
Improving the Aerobic System for Advanced Athletes
For those athletes who have built a legit aerobic base after training the two above-mentioned methods for at least 12 weeks each (either concurrently or separately), it’s time to intensify their aerobic training. As the competitive season approaches, cardiac output and the oxidative abilities of slow-twitch fibers should be solidified.
Explosive Repeat
As sports practices become more and more frequent and intense, athletes might even be getting cardiac output training during practice, depending on the sport. With the residual effects of aerobic endurance being around 30 days, the focus of aerobic training can be shifted to the aerobic endurance of fast-twitch muscle fibers. This can be done using the “explosive repeat” method, which Jamieson attributes to Yuri Verkhoshansky.
The explosive repeat method can drastically improve the recovery capabilities of fast-twitch fibers between explosive sport-specific movement, which is crucial in many sports. Share on XA straightforward training method that can easily be progressed and intensified week after week, the explosive repeat method involves athletes performing explosive exercises repeatedly—hence the name. This method can drastically improve the recovery capabilities of fast-twitch fibers between explosive sport-specific movements, which is crucial in many sports.
The movement used should be as explosive as possible, with the goal being to get the heart rate as high as possible. The athlete is then given time to recover before repeating this exercise.
Optimal exercises for lower-body sessions are weighted squat jumps (can use a bar, goblet variations, or one dumbbell/kettlebell in each hand) or jumping weighted lunge switches (best using a weighted vest or a goblet variation). The best upper-body exercises are either plyometric push-ups or power-focused bench presses. Creativity helps here, as these are not the only exercises you can use. As long as the exercise is an explosive movement that athletes can perform for continuous reps, it should work.
Athletes should perform at least two series of 1–3 exercises, performing 6–10 sets per exercise. It’s extremely important to have athletes actively recover for 8–10 minutes between series. Work-to-rest ratios are as follows:
-
Week 1: 10 seconds of work, 60 seconds of rest
Week 2: 12 seconds of work, 45 seconds of rest
Week 3: 14 seconds of work, 30 seconds of rest
Again, it’s very simple to progress. Each week doesn’t have to have longer work and shorter rest periods. This can be done every two or three weeks, but at this point, the athlete should be well-conditioned aerobically and can likely handle this quick intensification schedule. An important note: it’s possible to use the explosive repeat method to improve anaerobic abilities as well, but with different work:rest ratios. Anaerobic explosive repeat work involves longer periods of work with shorter periods of rest.
Conditioning Is the Best Ability
A car with a one-gallon gas tank is not very effective or impressive. How frustrating would it be to have to fill a gas tank up after every 20–30 miles? This is the same as any athlete who cannot recover between bouts of exercise, whether between plays on the field, rotations on the court, or attempts on the platform.
The saying ‘availability is the best ability’ is often used when speaking of injuries, but the same can be said when speaking of conditioning, says Alex Roberts & @Steve20Haggerty. Share on XThe saying “availability is the best ability” is often used when speaking of injuries, but the same can be said when speaking of conditioning. An athlete can be the strongest, most explosive athlete in the game, but if they can’t compete at their potential for the duration of the competition due to a small gas tank, their stock decreases significantly. Increase your athletes’ aerobic capabilities and watch the team’s success increase with it.
References
Jamieson, J. (2009). Ultimate MMA Conditioning. Performance Sports Inc.
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