What principle of physical training emphasizes that training should be gradually increased to match an individual's abilities?

The principle of physical training that emphasizes the gradual increase in training intensity, volume, or duration to match an individual's abilities is known as progression. This principle is fundamental in ensuring that athletes and individuals improve their performance and fitness levels over time while minimizing the risk of injury.

By applying the principle of progression, a person starts with a manageable level of exercise and progressively increases their training load as their body adapts. This approach allows for continual improvement and helps avoid plateaus or burnout that can occur if one were to increase training intensity too quickly. It's important to consider personal capabilities and adjust the training stimulus accordingly to ensure effective and safe progression in a training regimen.

In contrast to this principle, the ideas of variety, specificity, and balance focus on different aspects of training. Variety promotes different types of exercises to prevent boredom and maintain motivation, specificity relates to training in a way that is directly relevant to the individual's goals, and balance ensures an even development of various physical capacities. Each of these principles plays a role in a well-rounded training program, but they do not specifically address the gradual adjustment of training intensity as progression does.