Training the Body's 3 Energy Systems

I would like to thank Ray Brown (Director of EASI Academy, Houston, TX; contributor to MidAtlantic Match Point, TennisONE, Procompare tennis and Tennis World USA) for piquing our interest in this topic. On an unrelated forum, Mr. Brown challenged contributors to (1) identify the three energy systems of the human body; (2) determine how each system is best suited for a particular tennis strategy; and (3) outline how to efficiently develop each system.

From our research - and bearing in mind that we discarded our lab coats, protractors and test tubes exactly 0.34 seconds after receiving our respective college diplomas - it appears that the three types of energy systems are as follows: ATP-PC; Glycolytic; and Oxidative.

1. ATP-PC: anaerobic energy system that utilizes ATP (as in Adenosine Triphosphate - a nucleotide that performs many essential roles in the cell including providing energy for cellular activities) to create energy. When this process takes place, ATP is broken down into ADP (Adenosine Diphosphate). The body then has to add phosphocreatine (PC) to the ADP in order to form ATP. This chemical energy source is used by living things almost like a battery - for short bursts of high-intensity work lasting approximately 10 seconds or less; think "maxing" in the weight room. In terms of tennis, this is the system that would support your body's energy needs in high intensity points of short duration: e.g., serve and volleys.

2. Glycolytic (Lactic Acid System): this system utilizes glucose (or carbohydrates stored in the muscle) to create ATP for energy. In this system, six-carbon sugars are split to three-carbon compounds with subsequent release of energy. Glycolysis can happen under anaerobic and aerobic conditions. However, because of the duration needed to break down glucose to form lactic or pyruvic acid (10 separate reactions), it is the system used for relatively short periods of high-intensity work lasting only a few minutes - think a set of circuit training. After a few minutes of work, the body accumulates lactic acid to the point where pain and fatigue (accumulation of acid breaks down the muscle) will begin to affect performance. For tennis players, this is the main source of eneregy. Most points are won and lost in bursts lasting anywhere between 30 seconds to 1 minute (more than ATP-PC but less than Oxidative). With a short rest break, the work will have to be repeated.

3. Oxidative (Aerobic System): this is an aerobic energy system where the body utilizes carbohydrates, fats and proteins to generate ATP for energy. This a complex system which relies on the circulatory system to supply oxygen. Although slow to kick in, it is the primary system used for long-term, low-to-moderate-intensity work lasting more than just a few minutes - think marathon runners. Although it's unlikely that tennis players will be called to rely on this system as a primary source of energy, it is foreseeable that under some circumstances - extremely long matches which rely mostly on endurance (extremely long points) rather than power - it may be a factor. However, we are "endurance animals" and, therefore, we should focus more on things at which we do not excel than building up the support system that we already master, The limits of endurance exercise, Basic Res. Cardiol. 2006 Sep. ("A skeletal design which favours running and walking, including the greatest ratio of leg length to body weight of any mammal; the ability to sweat and so to exercise vigorously in the heat; and greater endurance than all land mammals other than the Alaskan Husky, indicates that humans evolved as endurance animals").

A good training system will focus on developing each energy system. The first system is trained by including lots of short but high intensity drills into the practice. Think, for example, serving at 95%-100% of your speed and bolting towards the net in a quick sprint. Or, alternatively, perform 2-3 shot combos at maximum power and intensity. The player performs a lot of these sets but is given adequate time to recover. Some nutritionists would advise the post-workout ingestion of creatine (natural or supplement) along with simple sugars to rebuild the body's PC storages. The second system would be trained by performing repetitive, medium-intensity drills, lasting anywhere from 1 minute to 3 minutes. Utilize figure-8s, corners or side-to-sides (now you know why pros favor this drill). Again, adequate rest is given between sets in order to allow the body to recover. You rebuild this system by ingesting protein (amino acid leucine), glutamine, Vitamin C and water. To train the third system, you want to include drills that last anywhere from 20-40 minutes (depending on the level of the player). Although these drills would be of relatively low physical intensity (e.g. cross-courts, down-the-lines), the players should "suck in" sufficient oxygen in order for the oxidative process to commence. Players should look for slightly elevated but rhythmic breathing to ensure that enough oxygen is being ingested. If possible, coaches should develop training regimens where the boundaries of all three systems are being pushed beyond the player's comfort zones.

Nevertheless, since most points are played within the ATP-PC and Glycolytic range, a competitive player who has mastered the basics of the various strokes should spend the majority of his practices trying to improve those 2 systems. Unfortunately, a lot of players spend an inordinate amount of time working on stationary drills (which may kickstart the aerobic energy system) that have no effect on increasing the threshold of the two main energy systems for this type of an activity.

Steal This Drill: Third Set Training

Have you ever made it to a third set against a tough opponent, come close to winning but, due to fatigue, managed to only snatch defeat from the jaws of victory?! If so, you understand the role of proper physical conditioning when it comes to tennis. Unfortunately, too many players don't play enough sets (particularly THREE SETS IN A ROW) or train hard enough to get themselves in the best possiible position to win. Often times, this a result of lack of time or inexperience. However, assuming that you are motivated to learn and improve, here is one way to train for the third set if you only have one hour available:

Grab an equally motivated partner and play serving games up to 10 (or 11, 15, 21). One player serves the whole game and then the partners switch roles. Here's the kicker: each player should do 10 kangaroo jumps before each point. If you're tough, you will do 10 before the second serves as well. This will get your heart racing real quick and teach you how to think when you're physically and mentally fatigued. Another alternative would be to have only the person who lost the point do the jumps.

Here's the deal, "muscle fatigue leads to changes in interaction between structures of abrain's neural network", Fatigue-induced increase in intracortical communication between mid/anterior insular and motor cortex during cycling exercise (Eur. J. Neurosci. 2011 Dec;34(12):2035-42. doi: 10.1111/j.1460-9568.2011.07909.x. Epub 2011 Nov 20.; Hilty, L; Langer, N.; Pascual-Marqui, R., Boutellier, U.; Lutz; K.). As you may know, the cortex (see "intracortical" in the title of the article) plays a key role in memory, attention, perceptual awareness, thought, language, and consciousness. In the study (involving cyclists), there was a "lag" in the communication time between the various functions of the brain. See also Reduced muscle activation during exercise related to brain oxygenation and metabolism in humans (2010 Jun 1;588(Pt 11):1985-95. Epub 2010 Apr 19; Rasmussen, P., Nielsen, J; Overgaard, M., Krogh-Madsen R., Gjedde, A; Secher, NH; Peterse, NC): "Exhaustive exercise provoked cerebral deoxygenation, metabolic changes and indices of fatigue similar to those observed during exercise in hypoxia indicating that reduced cerebral oxygenation may play a role in the development of central fatigue and may be an exercise capacity limiting factor." Deoxygenation...hypoxia = being deprived of oxygen (suffocating). 

In a sport as complex as tennis, where time is measure is fractions of a second, you cannot afford to have any kind of a lag - lapse in judgment - or central fatigue as that's exactly how the errors pile on. This is particularly true in a long three-setters where you are more prone for "taking the coward's way out" by hitting silly drop-shots, going for aces (including second serves), return winner or any other quick way for finishing the point. If you train yourself, your body will be more efficient at maintaining good energy for the duration of the match. Furthermore, your body will be better prepared to return the appropriate amount of oxygen and energy to the brain in order to stabilize its functions enabling you to make better decisions. Therefore, it is advisable that you incorporate some mentally stressful exercises into your routine so that you can understand the effects on your body and decision-making; know what you need to do (almost automatically) when you are in fact fatigued; and slowly push your tolerance levels beyond your comfort level thereby allowing you to play longer and higher quality matches. 

It's not about Forehands and Backhands, Stupid! [Redux]

Yes, Karsten Braasch was ridiculously good given his unorthodox shots. It doesn't mean that you shouldn't pursue "clean" strokes; just don't become consumed by this quest. At some point, "it is what it is" and you're just going to have to figure out the best way to win. 

Or how about Monica Niculescu? Not bad for WTA top 30. Before you judge, please check out her preparation, intensity and movement. If it helps to avoid the distraction, cover the top of the video and just focus on her feet. How many of you who would like to play D-1 can move like that?!

Returning Against a Serve and Volleyer

Not many players favor the serve-and-volley game style in the modern game of tennis. Accordingly, facing such a player can be very frustrating sometimes unless you have a great deal of experience under your belt. Here are some things to keep in mind when facing a net rusher:

1. Make him volley. This may seem like routine advice, but that's not quite the case. A S-V player provokes the following unconscious thoughts in your mind: A) he's coming in; B) he's coming in because he likes it; C) if he likes it, he must be good at it; and D) if he's good at it, I better keep the ball away from him. This is exactly the way the net rusher wants you to think; he wants to tempt you to go for the low percentage passing shot off his major weapon. It's hard enough to pass someone who is coming in off a ground stroke! Why would you try to do this off a serve?! Therefore, a better tactic would be to make the player volley and see what tools he has on his belt. Maybe it's all just a bluff! You will never know unless you test him. 

2. Your point of recovery following the return should be inside the baseline. The good serve a volleyers will attempt to combine good serves with sharp angles. For them, this guarantees that the returner has the most ground to cover. Therefore, returning and then recovering deep behind the baseline's center-T plays right into their hand. You want to recover in an aggressive position in order to ensure that you are as close to the next shot as possible. Force them to aim their volleys deep - not only may this draw errors but it will also reduce the angles that they can create. 

3. Don't forget about the chip return (NOT a slice). Depending on how solid your chip return is (if it's not, try to improve it), a chip return may give you a better option if you're unsure of your opponent's tendencies. For one, the chip requires little or no back-swing (you're utilizing the opponent's pace and only redirecting the shot) so you can make the decision on where to hit and how deep much later (in terms of tennis-time). Also, the chip requires a continental grip so if you have a one-handed backhand, it's easier to transition from the forehand grip (Western or Semi-Western) to the chip (since you only have to go half-way). In addition, a chip has a completely different spin - something that the volleyer may have difficulty handling. A topspin ball dips into the volleyer's string-bed. A well-struck chip will "pop up" of his strings - thereby forcing the volleyer to make adjustments. Volleyers are more accustomed to volleying against a topsin than against a ball that spins the "other way". 

4. Stay close in. Similar to playing a big-bomber, it's important to stay closer to the court when returning and thereby position yourself so as to cut off the server's angles. Most likely, the serve and volleyer will attempt to come in off a spin serve (kick, topspin, or slice) in order to give himself more time to close in. If you stay back, you will allow him to take an extra couple of steps - at which point, it will be difficult to make him volley below the net (your goal is to make him pop up the volley as opposed to sticking it downwards). Stay close in, use the pace of his serve (even a kick-serve has sufficient pace for you to use and redirect) and seek to make the rusher volley behind the center-T or half-volley around the center-T.

The center-T should be your target in these instances. Pound it incessantly and force the volleyer to generate angles from the middle of the court; don't give him an opening (i.e. too far away from the middle but within reach) from which he can generate an angle. Unless he's very, very good, chances are that he will have difficulty handling these shots. The best return is, actually, slightly cross-court from your return position - this force the opponent to adjust the face the face of the racket and to generate a slight "inside-out" angle. For example, if you're returning from the deuce side down-the-line, the opponent can stick a cross-court backhand volley without much difficulty. Return cross-court, and he will have problems generating the same angle with his forehand volley down-the-line. 

5. Attack. Another oft-forgotten play is to come in yourself (chip-and-charge). This may work as a great surprise-tactic since the server expects to face an opponent who is staying deep. You have a slight advantage in these situations because out of the two players, you're the only one who knows what to expect. Depending on the serve, you may in fact "beat the player" to the net since, the ball would have reached your position a split second after the server's contact with the ball. Chip down the T (low), rush in and pounce on the opponent's next shot (particularly any pop-up floaters). Stun him once or twice and you will either force him to do more with his serves (resulting in more double faults or second serves; [DING-DING] BONUS) or his volleys (errors). If you're lucky, you might actually force him to stay back ([DING-DING] DOUBLE BONUS) and that's when you know that you have really rocked his boat. 

Steal This Drill: Peel the Orange for a Nasty Slice Serve

The slice serve is an often underutilized serve but one of the most effective. When juniors (and other developing players) see Isner, Roddick and Karlovic bombing aces at 145mph+ down the middle, it is easy to become mesmerized and forget about all the other serving possibilities. If, however, we put testosterone aside and analyze Roger Federer's serving pattern, we see that he is one of the best at exploting the slice serve.

As a matter of fact, Federer routinely starts his service games with the out-wide serve and uses it up to 2/3 of the time (on first serves) thoroughout the match (more on a faster surface than on a slower surface). The slice serve is effective because (a) it gets the opponent's momentum moving to the right (red arrow) and (b) even a well struck return doesn't compensate for an open court (sharp cross-court backhand or down the line forehand - both difficult to track down). On the ad-side of the court, the slice serve is a great way to start a wrong-foot play (i.e., hit behind the returner) as well as to "keep an opponent" honest (especially when she runs around your normal serves and pounds winners).

When practicing the slice serve, it is often tempting to just put a target out-wide in the service box (deuce side) and aim for it. A better way may, in fact, be to insert a broomstick or PVC pipe right through the center strap (red line) and aim for serves down-the-center. Try to get your slice serves to curve outwards (orange line) around the right side of the pipe. This may be a better way to practice than aiming straight for the wide serve because you will work on actually seeing the ball breaking around the pipe as opposed to merely hitting flat serves out-wide (i.e., "side-winder's" v. "throwing darts"). That is, you're working on the slide; the skid; the curve. As you get better, move the pipe 1 inch to your right (i.e., the opponent's ad-side - purple line above) and continue curving your serves around it down-the-T. Keep moving it inch-by-inch until the pipe is about 10 inches or a foot off-center (your right side). When you master 10 sliders around the pipe in this position, start shifting the pipe more and more to your left (i.e., towards the opponent's deuce side) until it reaches about half-way into the service box (opponent's deuce side). This is the point where the ball should to "break" left and slide out-wide.

One of the concepts to keep in mind when practicing the slice serve is to vizualize "peeling the orange". I first learned this from Guy Fritz when I was practicing at his and Kathy May's home in Rancho Santa Fe which was surrounded by orange groves. At first, I thought that he actually wanted me to quit my day job and start peeling oranges for a living but what he meant was that the string bed simulate an orange peel moving up and around the ball. Here's the interesting part: the red part of the arrow outlines the path of the string-bed BEFORE it makes contact with the ball. The blue part of the arrow outlines the general contact point. The RED zone is, however, the contact zone for a good kick or top-spin serve. This means that, from the opponent's point of view, it looks as if you're "kicking him" out wide.

Do this correctly, and you will bamboozle him into switching his grip to backhand and shifting his weight onto his left foot thereby making it more difficult to cover the slider. At the last second, you actually make contact with the ball ("up and around") curving the ball towards your left (his right). Sometimes, this may require two grip changes from the opponent (from forehand to backhand and back to forehand again). If this happens, your opponent - even one with a monster forehand - may be tripped up by a serve that looks as if it's going to the backhand and then breaks to his forehand. This may just enough of an edge to create a huge opening in you opponent's side of the court which you can exploit with your groundstrokes. So peel the orange for juicier points.