The Principles of Training help to guide athletes and coaches in creating training sessions that meet both athlete and competition needs. The principles of training are specificity, progressive overload, reversibility, variety, training thresholds, and warmup/cooldowns. When the training principles are thoroughly applied and followed regularly, the body responds by adapting or adjusting to the new levels of stress placed upon it. These adaptations for an endurance athlete include resting heart rate, haemoglobin level, stroke volume, and cardiac output, muscle hypertrophy, oxygen uptake, lung capacity, and slow-twitch muscle fibres. Therefore, applying the Principles of training to an endurance athlete will produce adaptations that enhance performance.
The progressive overload principle states that adaptations occur only when training intensity is greater than the normal intensity, and gradually increases as the body adapts and improves (Minifie, 2020). For endurance-based athletes, training loads are gradually increased by varying the type, volume, and intensity of training. However, if the load does not increase incrementally, then the effect will plateau, and further improvements and adaptations will not occur. For example, Don Ritchie who was an ultra-runner, based his training on this principle. He had a 10-week build-up to any event, which consisted of gradually increasing the base mileage from about 170 km to about 260 km a week (Hawley, 2000). In response to progressive overload, endurance athletes are likely to lower their resting heart rates, have increased cardiac output, stroke volume, and oxygen uptake, as well as muscle hypertrophy of the heart. These adjustments are observed because endurance athletes focus on the overload of the aerobic system. Stroke Volume refers to the amount of blood pumped out of the left ventricle each time the heart beats (Minifie, 2020). As athletes progressively overload, they increase the hypertrophy of the muscle walls of the heart as well as increase the physical size and ventricles. As the heart is now bigger and the walls are stronger, it allows for more blood to be ejected each time. This increase in stroke volume will lead to a higher cardiac output, as the amount of blood leaving the heart each minute is increasing (Minifie, 2020). The more blood that the heart can push out, the more oxygen will be delivered to working muscles, which will result in a lower resting heart rate. These adaptations to progressive overload are particularly evident for cyclist Miguel Indurain who has a resting heart rate of 28 beats per minute and 50 litres per minute of cardiac output.
Variety refers to the use of different drills and techniques for athletes to be challenged by the activity to maintain motivation (textbook, 2018). For endurance athletes this can be done by changing the altitude of training sessions, changing the pace or distance run in training sessions, even performing training sessions where the key focus might be lifting weights instead of running. For example, leading into a competition Eliud Kipchoge would do gym aerobics for one month, and weekly training sessions including track workouts, and a variety of fartlek workouts. Kipchoge also varies the altitude of which he trains at. The variation in training sessions allows for more stress to be placed on different aspects of the body leading to a variety of adaptations. Endurance athletes are likely to experience adaptations to their oxygen uptake, haemoglobin levels, and resting heart rate. Haemoglobin is responsible for absorbing oxygen from the lungs and transporting it through the blood so when aerobic training stimulates the increase production of haemoglobin, oxygen uptake would increase as well. This adaptation that allows for greater transport of oxygen means the hart does not have to contract as frequently, decreasing the resting heart rate. (Minifie, 2020. Although Kipchoge has never undertaken a VO2 max test or lactate threshold it is clear to see how variety has allowed for Kipchoge’s body to adapt and improve his performance. For example, these adaptations have allowed him to be the first person to break 2hours in a marathon.
The principle of specificity implies training to be targeted towards the demands of the sport. It involves creating training programs that focus on the energy systems predominately used in an event, as well as targeting certain muscle groups and components of fitness (textbook, 2018). This principle allows for the body to better equipped for the demand of their sports, as the body has adapted to the stresses resembling the activity. For Example, Kilian Jornet a sky runner does 33-40% of his total training at above 2000m and over 200 hours of his training at over 4000m. He does this as it places stress on the predominant parts of his body used in competition at altitude. Another example includes Lance Armstrong, who predominately targets his aerobic capacity with the majority of his training involving cycling. This resulted in an increase in haemoglobin levels, lower resting heart rate, increase in slow-twitch muscle fibres and an increase in oxygen uptake and lung capacity. Slow-twitch muscle fibres use oxygen to generate ATP for muscular contraction over a long time and therefore are highly important for endurance-type activities. When slow-twitch fibres are subjected to specific endurance activities they are recruited for the movement because they are more efficient in meeting the immediate metabolic demands of the working muscles (Minifie, 2020). This endurance training will cause the capillaries surrounding the muscle fibres to increase improving muscular efficiency. (textbook, 2018). For Example, Lance Armstrong has a resting heart of 32 beats per minute with a peak exertion of up to 200 beats per minute. Not only this but he has adapted his lung capacity to be around 85ml/kg compared to the average male of 40ml/kg. As well, the Coyle Study predicted that his slow-twitch muscle fibres increased from 60% to 80% and muscular efficiency increased by 8%. For Kilian Jornet, this specific altitude training changed the amount of haemoglobin saturated by oxygen. At the beginning of his training, his saturation levels would drop to as low as 70% but as the months progressed it eventually increased to 85% which was a good sign that his body had adapted.
There are no physical adaptations that directly relate to warm up and cool down however it used for creating an efficient training session, therefore, allowing for the adaptations to occur. Warmups are used to decrease the possibility of injuries or soreness by increasing the blood flow to the muscles thus increasing body temperature causing the muscles, ligaments, and tendons to become more elastic. Cooldowns help to metabolise lactic acid concentration, replenish the body’s energy stores and to replace the oxygen used. It is used to recover the body after the intense training session. Dennis Barker the coach of Team USA Minnesota said “It’s during recovery that adaptions from the hard training take place/ If a runner doesn’t recover, the body is not going to adapt”
Training Thresholds refers to the level of intensity that our body works at to cause adaptations. The size of improvement is roughly proportional to the threshold level at which we work (Textbook, 2018). As an endurance athlete’s main energy source is from the aerobic energy system, to improve the cardiorespiratory system an athlete will need to work closer to the anaerobic threshold of 70-85% of VO2 max. This results in increased capacity and function of the cardiovascular system, for example, due to increased stroke volume and oxygen uptake, which improves aerobic endurance and efficiency. For example, Kilian Jornet does 88% of is training at low intensity and 10% at high intensity. He then performs 2% of the training at maximum intensity (Jornet, 2018). As a result, the adaptations for Jornet are a lower resting heart rate of 34 bpm compared to the average of 70 bpm and a VO2max of 92 ml/kg/min, one of the highest ever recorded (Jornet, 2019). All of this has allowed him to train harder and longer, but to also withstand longer and more gruelling events.
The reversibility process concludes that in the same way the body responds to training by increasing adaptations, these adaptations can be lost by the lack of training. The rate at which an athlete will lose these adaptations is similar to that of which it is gained. (Minifie, 2020). For endurance athletes, significant detraining effects will be seen 4-6 weeks after training stops. For example, Oskar Svendsen a Norwegian Cyclist recorded the highest VO2 max of 97.5ml/kg/m in 2012, but in 2015 after 15 months without formal training, his VO2max tested at 77.0ml/kg/min. Not only this but a study found that endurance cyclists reduced their VO2 max values by an average of 7% in 21 days and 16% in 56 days of no training (Kenney, Wilmore and Costill, 2012). As well a different research study found that endurance elite athletes reduced their time to exhaustion tests by 9-25% after 2 weeks of detraining, 8-21% in 4 weeks of detraining and in 5 weeks 23% (Mujika and Padilla, 2001).