Glycolysis In Tennis

Every physical action we take requires some sort of energy that our body produces. The most important energy molecule in the cell that our body uses is adenosine triphosphate (ATP). ATP is “a high-energy molecule that stores a considerable amount of energy within the chemical bonds that hold the molecule together” (Exercise Physiology: Tennis Physiology). ATP results from energy being produced from either an aerobic system or anaerobic system. The production of ATP can come from systems such as ATP-PC and glycolysis, which is what tennis players use predominantly during a match.
Tennis uses different types of intensities for different lengths of time. Tennis requires constant movement, running side to side, back and forth. The muscle force
put into hitting the ball depends on the placement and force put behind the hit. Serving the ball requires strength and force and when the serve is returned, a quick reaction is needed in order to continue the rally. Different energy types are needed in order to perform the actions needed for this sport.
The metabolic systems required to play tennis are ATP-PC and glycolysis. ATP-PC is used for movements that require a great amount of energy per second and can only be used for a short amount of time. ATP-PC starts by the breakdown of ATP, which is broken down into ADP and an inorganic phosphate (Pi) and Hydrogen (H+). This releases energy for the muscle contraction, but only for a few seconds. The second part of this system takes phosphocreatine (PC) and breaks that down into creatine, an inorganic phosphate (Pi), and energy. We then take the energy and inorganic phosphate to rebuild the ATP. To make ATP aerobically, we take the energy and rebuild phosphocreatine by decreasing intensity during a recovery phase. The enzymes that help with this process are ATPase and creatin kinase. (Kraemer, Fleck, & Deschenes, 2016)
After the first 30 seconds of high intensity, we begin to rely on glycolysis. Glycolysis is anaerobic and last anywhere between 30 seconds to three minutes. This process starts with a carbohydrate, either glucose or glycogen, which is a 6 carbon molecule. This is then broken down into two, three carbon molecules. These three carbon molecules are further broken down into two pyruvates. The ATP that is produced depends on the carbohydrate that is used. Glucose produces 2 ATPs and glycogen produces 3 ATPs. (Kraemer, Fleck, & Deschenes, 2016)
Glycolysis is the most predominant metabolic system used because of the duration of the entire match.
Each set point can last anywhere from 15 seconds to 2 to 3 minutes, depending on the players. During a set, there is normally not enough time to recover from point to point that the energy continues to be used. From the length of the match point, having to chase down balls, and continually moving while waiting on a serve, the recovery time given is too short in order to fully recover from the point. The first 30 seconds of high-intensity movements requires energy from the ATP-PC. After the first 30 seconds is when the body then switches over to redeem most of its energy from glycolysis, still using some energy from ATP-PC. If given the appropriate amount of time to recover, the body would then begin to use ATP-PC for its energy.
Adaptations that may occur in the glycolysis system would be the increase in glycogen phosphorylase, phosphofructokinase and lactate dehydrogenase. Increases in the level of enzymes can be the result of endurance training and weight training. These enzymes can have a positive impact on performance, but many factors and variables can effect this including the intensity of training, the amount of time spent training,
etc.