The principles of training are foundational guidelines used to design effective exercise programs. They ensure that training leads to optimal improvement in fitness and performance while minimising the risk of injury and overtraining. The principles of training help to guide the trainer in selecting the correct training type and method in creating training sessions that will improve performance. They help the trainer choose the workload for the athlete to ensure they are not levelling out or failing to improve. The trainer uses them in order to ensure their training matches competition and is specific to the adaptations needed. 

The training principles help to ensure the athlete does not lose physiological adaptations due to inactivity and helps to ensure the athlete is provided with a wide variety of activities that are still relevant to their competition needs. These principles help guide the trainer in selecting the correct training intensity so that the athlete is training in the right training zone, whether this be the aerobic or anaerobic zone.

And finally, the principles of training ensure the trainer includes a warm up and cool down to help prevent injury and speed the recovery process.

• Training thresholds: The intensity level at which training becomes effective for achieving specific aerobic or anaerobic adaptations.

• Variety: Changing activities or methods to maintain interest, engagement and prevent plateaus.

• Reversibility: Fitness gains are lost when training ceases or is significantly reduced.

• Progressive overload: Gradually increasing the intensity, duration or resistance to continually challenge the body and stimulate physical adaptations.

• Warm-up and cool-down: Prepares the body for exercise and aids recovery post-exercise. Warm-ups increase heart rate and muscle temperature; cool-downs help return the body to resting state.

• Specificity: Training should mimic the demands of the sport or goal, targeting specific muscles, energy systems and movements used.

The principles of training are universally applicable to both aerobic and strength training, but their implementation differs based on the physiological demands of each. A well-structured program applies these principles systematically to achieve desired adaptations, maintain motivation and minimise injury risk.

Progressive Overload

Progressive overload is when the workload for a training session progressively increases as the athlete adapts to training. This increase in workload is usually done to maintain the same intensity of training after the adaptations have occurred. Progressive overload is essential in both aerobic and strength training to drive improvement, but must be managed carefully to avoid overtraining or injury.

Aerobic Training - For aerobic training progressive overload requires that the workload is increased. This increase can come with an increase in speed or duration of the training. If an athlete has been training for soccer by doing a 80% HRM treadmill run at 20 incline, at 16Km/h for 45 min 4 times a week, then the athlete will adapt to this training and eventually it will become easier for them and then decreases to 75% HRM. This requires an adjustment in training so that training is still at 80% HRM and still producing a stress that can cause further adaptation. Progressive overload could be done by: increasing the incline, increasing the speed or the duration. Increased distance, speed or duration enhances cardiovascular efficiency and endurance. For example, a runner adds 500m to their weekly long run.

Strength Training - For resistance training progressive overload requires that the workload is increased. This increase can come as an increase in resistance, reps, or sets. Alternatively the rest period between sets can be reduced. So if an athlete is training for rugby league by doing 3 sets lifting 110Kg, which is their 12RM with a 2 min rest between sets, this training will produce an adaptation in the athlete so that they can now bench 100Kg 16 times and so it is no longer their 12RM, but their 16RM. The athlete will no longer adapt, unless the principle of progressive overload is used changing the load in order to place a sufficient stress upon the body to cause further adaptations. This increase in workload could be done by getting the athlete to complete 5 sets (though this is time consuming), increasing the weight to 120Kg, which might be his new 12RM, or decreasing the rest period to 1 minute between sets. The best way to use progressive overload in resistance training is to increase the resistance by increasing the weight; this results in improvements in strength, as well as developing recovery times and muscular endurance. Increasing weight, reps or sets stimulates muscle growth (hypertrophy) and strength gains. For example, an athlete increases their squat load by 5kg each fortnight.

Training thresholds refer to the level of intensity needed in order to stress the body enough to cause an adaptation or improvement in performance. Effective training must target the correct threshold based on the desired adaptation; therefore intensity must match goals. Training thresholds are identified by measuring when lactate begins to rise above resting levels and when they pass the lactate inflection point (when lactate concentration begins to increase rapidly). These are often then converted to measurements of intensity and can be either a % MHR or % VO2max. There are generally two training thresholds: the aerobic threshold and the anaerobic threshold.

The aerobic threshold is the intensity needed in order to produce an adaptation that will improve someone’s aerobic capacity or VO2max. The aerobic training threshold is normally between 65% and 70% MHR and is defined as the point at which lactate begins to rise in the blood above normal resting levels. 

The anaerobic threshold is the intensity needed in order to produce an adaptation that will improve someone’s anaerobic capacity, normally by increasing the bodies ability to break down and remove lactic acid. The anaerobic training threshold is normally between 80% and 85% MHR and is also known as the lactate inflection point – where blood lactate levels begin to rise rapidly because your body cannot remove it as fast as it is being produced.

Aerobic Training - Includes aerobic threshold (lower end) and anaerobic threshold (upper end) to improve cardiovascular function. For example, interval runs at just above lactate threshold.The intensities between the two thresholds are called the aerobic training zone and include the intensities that should be trained at in order to improve aerobic performance. The higher the training intensity within this zone the greater the adaptations. This is the same for the intensities above the anaerobic training threshold, these are called the anaerobic training zone and the higher the intensity the greater the gains. In fact, there is now plenty of evidence suggesting that you will have greater increases in aerobic capacity if you combine both aerobic training and anaerobic training, because you want to increase the workload for your lactate inflection point. 

Strength Training - Resistance training usually uses repetition maximum to speak about the intensity being used. Within resistance training there are a number of goals that can be achieved and the threshold required varies depending on the goal. Studies suggest that the best maximal strength and power gains can be made using 1-6RM. Training between 8-12RM has been shown to produce significant increases in strength and is the most effective intensity in order to produce muscular hypertrophy. Training between 12-15RM is the best range to significantly improve local muscular endurance. All of this resistance training develops the anaerobic systems, with the higher intensities developing the alactacid system and the lower intensities developing the lactic acid system, though these are not completely isolated from one another.

 Reversibility is the fact that when training stops the adaptations made are lost. Adaptations are generally lost at a similar rate to which they were gained. So if an athlete has put on 10Kg of muscle in 1 month, then gets injured they will lose the muscle very quickly. However, if the athlete as developed that muscle slowly over 6 months or maintained their muscle gain for 6 months then the loss occurs at a slower rate. The more adaptations that have happened the more you have to lose. So elite level athletes tend to lose more than a recreational athlete because they have more to lose. Athletes need to avoid the reversibility that will occur if training ceases. Training can cease for multiple reasons, the two main reasons are: injury and the end of a season. Reversibility can be avoided by maintaining some level of training during the off-season or when injured. This is more problematic for an injured person, but can be achieved by training the uninjured parts of the body while recovering. Detraining effects occur faster in aerobic fitness than strength.

Aerobic Training - Cardiovascular fitness declines quickly with inactivity (within 1–2 weeks). For example, a swimmer’s VO₂ max declines during off-season.

Strength Training - Muscle strength and size diminish over time, though more slowly than aerobic capacity. For example, a weightlifter loses muscle tone after a break due to injury.

 The principle of specificity means that adaptations to training are specific to the training. Specificity applies to the muscle group trained, the speed of training, the intensity of training, the movements of training and the energy systems utilised. Specificity is that physiological adaptations only occur in response to the stress placed on the body and only to the sections that experience this stress. Specificity is highly effective for performance transfer; alack of specificity limits training benefits.

Aerobic Training - Training must reflect the movement pattern, intensity and energy system used (e.g. cycling for cyclists) so that your adaptations improve your performance in that sport. Training should be done at a pace and in an environment that best replicates competition in order to get the best specific gains or adaptations for competition. For example, rowers do on-water sessions and ergometer training.

Strength Training - Exercises must target the specific muscles and movement patterns (e.g. deadlifts for rugby forwards). Training should also seek to replicate similar movements from the sport at a similar speed. For example, sprinters focus on explosive lifts like power cleans.

The principle of variety is ensuring training sessions use multiple training types and methods, as well as exercises within these methods. Variety is needed in training, not only to prevent boredom, but also to ensure complete and full development of fitness. An example would be for a Rugby League player to use various training types throughout the week, such as aerobic, strength, flexibility and anaerobic training, all of which are needed to play the sport as well as possible. Within these the sessions would use a variety of methods, so that the anaerobic training was not always short interval training, but also included other forms of resistance training or plyometrics. Furthermore, interval-training sessions would not always be the same, but would include a variety of exercises. This could include: shuttle runs, repeated tackling for 1 min, followed by a 2 min rest x10, and 20 sec agility runs followed by 40 sec rests x20.

Aerobic Training - Includes mixing modalities (e.g. swimming, cycling), terrain or intensity. For example, a triathlete rotates between pool, open water and cross-training.

Strength Training - Incorporating different resistance tools (e.g. machines, free weights, bands) and exercise types. For example, changing rep schemes or swapping bench press for incline press.

Crucial for injury prevention, performance optimisation and recovery in both training types. A warm up is the process whereby an athlete goes through a range of exercises in order to get their body ready for competition or training. Warm up exercises move from low intensity to high intensity and from general movements to sport specific movements. Warm ups prepare the body for physical activity by: increasing the heart rate, the respiratory rate, the cardiac output and the blood flow to the muscles being used. It causes the liver to release glucose into the blood and opens muscle cells so that blood glucose can easily enter the muscle for energy production. Warm ups also increase the body temperature, which increases joint mobility, decreases the risk of injury and speeds up the chemical reactions which produce ATP. 

Cool downs are essentially the opposite of a warm up. They involve movements that help speed up recovery and enable the body to slowly adjust its systems and bring the body back down to rest. These movements move from medium intensities to low intensities and from sport specific movements to general movements. The goal of a cool down is to allow the body to remove: left over lactate and pyruvic acid, carbon dioxide and water. This helps prevent fluid pooling in the used muscles, as muscular contraction helps transport blood and the lymphatic system back towards the heart. If the heart continues to pump blood to the muscles being used and the muscles are resting, then the fluid does not return to the heart at the same rate that it arrives, which leads to pooling.

Aerobic Training: Increases heart rate, oxygen delivery and joint mobility. Cool-down helps return heart rate to baseline and removes metabolic waste. For example, a light jog followed by dynamic stretches; walking and static stretching to finish.

Strength Training: Prepares muscles and joints for load and range of motion; cool-down promotes recovery and reduces muscle soreness. For example, warm-up sets with lighter weights; static stretching post-session.