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.