Once formed, citric acid enters the krebs cycle which takes place in the matrix of the mitochondria. 1. Citric acid is oxidised whereby hydrogen is removed from the compound. 2. As a result, carbon and oxygen are left; they combine to produce carbon dioxide, excreted via the lungs. 3. In addition energy sufficient to resynthesise ATP is released. During the Krebs cycle, the glucose molecule has been downgraded to release hydrogen and carbon dioxide. The hydrogen is taken to the electron transport system which is the final stage of the process.
It is important for me to train all energy systems to maximum efficiency in order to utilise the glucose. This is because in tennis all three pathways are used. For example, the ATP-PC pathway in the serve, followed by the lactic acid system in a short, intense rally, followed by the aerobic system when the rally is less intense (i.e. when you have control over the rally). It is important to choose a correct method of training that is relevant to my sport.
This is a type of training, which develops endurance and puts stress upon the aerobic energy. It is a performance of rhythmic exercise at a steady rate or low intensity, which use the large muscle groups of the body over a long period of time. Jogging, swimming and cycling are all ways of continuous training. This type of training means it takes longer for a lactate build up, meaning I can carry on for longer as I will not be suffering from fatigue and cramp that lactic acid causes. There is however a danger of injury to my joints and muscles as they are being put under an excessive amount of stress. It is not sport specific as there is no skill work involved. It can also be very tedious as it is so repetitive. However it is essential to include some continuous work to improve the cardio-respiratory system.
Fartlek, or speedplay This is a slightly different version of continuous training, as it involves a change in speed or intensity throughout the activity. This means that I can train both the aerobic and anaerobic. Fartlek sessions should last for a minimum of 45 minutes. Intensity can vary from a low intensity walk, to a high intensity sprint. Here is an example of a session:Fartlek training is ideal for tennis. This is because both aerobic and anaerobic systems are needed in tennis, as there is much speed change. For example, a short jog to the back of the court from the net to receive a lob, followed by a sprint to the net to receive a drop shot.
Intermittent training This is where a session is broken down into short periods of intense activity and recovery breaks. This means that I am unlikely to find the session dull, and can focus on anaerobic exercise. This can be useful in tennis, as activity can be very intense and continuous over a short period, for example I was volleying at the net, where would be receiving the ball quicker than if I let the ball bounce. Also a short burst of power is needed in the serve.
Interval training This is a very popular type of training used in sport. This is because it can be adapted to suit any sport, although is most commonly used in swimming, cycling and athletics. It can be also used for either aerobic or anaerobic abilities. It enables my body to exercise at the specific intensity necessary to train the relevant energy system for that activity. For tennis, it is important to train all three energy systems; the alactic acid or ATP-PC system, the lactic acid system and the aerobic system. Interval training can train all of these systems. In order to train the relevant energy system, the following variables have been identified which can be manipulated:
1. Distance of the work interval (duration) 2. Intensity of the work interval (speed) 3. The number of repetitions within a session 4. The number of sets within a session 5. Duration of the rest interval 6. Activity during the rest interval When deciding on what activity will take place in the actual interval training session, these guidelines must be followed in order use, or train the relevant energy system: 1. To train the ATP-PC system, the duration of the work period should last between 3-10 seconds, or an equivalent distance that can be covered in that time at the highest intensity.
2. Intensity should be calculated by the athlete working at a percentage of their maximum effort or personal best time for the distance. It should be 90-100% for the ATP-PC system. 3. The number of repetitions depends upon the duration of the session. For the ATP-PC system, the work interval is very short, and up to 50 short intense bouts within a session can be completed. 4. To avoid fatigue, the repetitions should be divided into sets. For example, if I was doing strength training by performing 50 triceps extensions, I could do 5 sets X 10 reps at all out effort of 90-100%.
5. Between each set is a period of rest. The length of this period of rest is determined by how long it takes for the heart rate to return to about 150 beats per minute. It can be compared to the work interval time, expressed as the work: relief (rest) ratio. For the ATP-PC system where the work interval is relatively short, the rest period may take three times that before the heart lowers to 150bpm this would be expressed as work: relief ratio of 1: 3. 6.
The type of activity that takes place duri8ng these rest intervals differs, depending upon the energy system being trained. The ATP-PC system for example requires no activity apart from light stretching, and the lactic acid system will require light jogging or walking to get rid of the build up. For the lactic acid system, an exercise period of between 15 seconds and 90 seconds should be performed at a moderate intensity.
To get rid of lactic acid build up, up to twelve repetitions may be completed over two or three sets with a work to relief ratio of 1: 2. To speed up the removal of lactate during the resting period, jogging or light walking should be completed. To train the aerobic system, the work interval should be longer, roughly seven or eight minutes. The intensity should be moderate but faster than the pace of continuous training. Fewer sets are needed, as the exercise periods are longer. For example, three or four repetitions in one set. The requirements of an interval training session can be expressed as the interval training prescription
Circuit training Circuit training involves performing a number of calisthenic exercises in succession. This could include abdominal curls, press-ups, step-ups etc. Each exercise (or station) is usually performed for a set amount of time or for a set number of repetitions. You can adapt the circuit to meet the specific fitness requirements of a given sport or activity therefore, for my tennis specific training programme, I will make it relevant and specific to tennis.