The Methodology of Training To Develop Endurance In Sport. In order to improve endurance, the athlete must learn to overcome fatigue and this is done by adapting to the training demand. Any degree of adaptation is reflected in the improvement of endurance. According to the specifics of the sport/event the two types of endurance, aerobic or anaerobic have to be primarily developed. The development of these two types of endurance is dependent upon the type of intensity and the methods used in training. Although in training other classifications of intensities are used the absolute intensity in endurance training is linked with the energy supply systems. Thus, Zatzyorski (1980) considers the following three intensities:
- The subcritical intensity, when the speed is reduced, with a low energy expenditure, and the O2 demand is below the athlete's aerobic power. The O2 supply meets the physiological demand: therefore the work is performed under the steady state condition.
- The critical intensity is achieved when the speed is elevated, and the O2 demand reaches the O2 supply capacity. The critical intensity is performed in the anaerobic threshold zone, thus the speed is directly proportional to the athlete's respiratory potential.
- Supra critical speed refers to the types of activities which are above the critical speed. The work is performed under O2 demand usually increases faster than the speed of performance.
Training parameters for aerobic endurance
The physiological threshold of various organs and systems involved in aerobic activity increases and apparently is more efficiently developed when training consists of low intensity, long duration work. If the activity is continuous, the maintenance of O2 consumption, so specific for aerobic endurance, is a difficult task for an athlete's body. Usually, the duration of work under maximum 0% consumption cannot exceed 10-12 minutes except for highly trained athletes (Zatzyorski, 1980). Elite class athletes from sports like running, cross-country skiing, rowing, swimming, etc., may maintain a velocity close to the critical level for between 1-2 hours (heart fate: 150-166 bpm).
As a general outline, the following training parameters are significant for the development of aerobic endurance.
- THE INTENSITY of training has to be below 70% of the maximum velocity (Herberger, 1977). As a criteria to follow, the intensity may be measured by the time of performance per a given distance, the velocity in meters per second, or the heart rate (140-164 bpm). Training stimuli which does not elevate the heart race above 130 bpm does not significantly increase the aerobic capacity (Zatzyorski, 1980).
- THE DURATION of an isolated stimuli (i.e., one repetition) has to be of several varying magnitudes. While sometimes it must be around 60-90 seconds in order to improve anaerobic endurance which is an important component during the beginning of a race, very often long repetitions (3-10 minutes) are used and needed for the perfection of aerobic endurance. However, the general composition of a training program depends on the phase of training, the characteristics of the sport, and the needs of the athlete.
- RESTING INTERVALS have to be calculated in such a way that the following stimulus occurs during the period of favorable changes provoked by previous work; According to Reindel et al. (1962) it has to be between 45-90 seconds. However, for aerobic endurance the resting interval should definitely not exceed 3-4 minutes because during a longer rest the capillaries (the blood vessels that connect the arteries with veins) shrink, and during the first minutes of work blood flow is restricted (Hollmann, 1959). The same author suggests that the heart rate method may also be considered for the calculation of the rest interval. Usually when the rate drops to 120 bpm working commences.
- ACTIVITY DURING THE REST INTERVAL is normally of a very low intensity to stimulate biological recuperation. In athletics a walk or jog (for very well trained athletes) is the familiar activity.
- THE NUMBER OF REPETITIONS is determined by the athlete's physiological capacity to stabilize O2 consummation at a high level. If this stabilization does not occur at a sufficiently high level the aerobic system will be unable to meet the energy demands. Consequently, the anaerobic system takes up the slack putting a severe strain on the body and resulting in the onset of fatigue. As suggested by Zatzyorski (1980) the heart rate may be a good indication of the level of fatigue. As fatigue develops the heart rate increases while performing equally strenuous repetitions. Once above 180 bpm or so, which is reflective of a high level of fatigue, the heart actually has less power of contraction resulting in the delivery of less O2 to the working muscles. At this point, or shortly before, training should be ceased.
Training parameters for anaerobic endurance
Most of the means utilized for the development of anaerobic endurance are cyclic in nature and are performed with high intensity. The brief presentation that follows may be used by the coach as a general guideline in training:
- THE INTENSITY may range from submaximum up to maximum limits. Although in training, a variation of intensities is employed, for the purpose of the improvement of anaerobic endurance, intensities around 90-95% of maximum ought to prevail.
- THE DURATION of work may be between 5-120 seconds, depending on the type of intensity employed.
- THE REST INTERVAL following an activity of very high intensity must be long enough to replenish the O2 debt Since the interval of recuperation is a function of the intensity and duration of work it may be within the limits of 2-40 minutes. For, a more efficient recuperation and replenishment of fuel to provide the required energy it is advisable to divide the total number of repetitions into a few series of 4-6 repetitions. The longest rest interval (6-10 minutes) is planned between the sets so that the accumulated lactic acid will have sufficient time to oxidize and the athlete may start the new set almost totally recovered.
- ACTIVITY DURING REST has to be light, relaxing. Total rest, (i.e., lay down), is unadvisable since the excitability of the nervous system may decrease to unacceptable levels (Zatzyorski. 1980).
- THE NUMBER OF REPETITIONS must be low since the work aimed at developing anaerobic capacity is of an intense nature and can not have many repetitions without accumulating lactic acid (LA). If work continues the glycolytic resources become exhausted and the aerobic system has to assume the responsibility of providing the required energy. Under this circumstance, the velocity is decreased, and consequently the work will not benefit the anaerobic capacity. Therefore, it seems that the best method is to divide the planned number of repetitions into several sets, say 4 sets of 4 repetitions. The rest interval between repetitions may be that which was planned (i.e., 120 seconds) but the rest between sets has to be long enough (i.e., up to 10
minutes) to replenish the O2 debt and consequently to oxidate LA.