The term training refers to the acquisition of knowledge, skills, and competencies as a result of the teaching of vocational or practical skills and knowledge that relate to specific useful competencies. It forms the core of apprenticeships and provides the backbone of content at technical colleges and polytechnics. In addition to the basic training required for a trade, occupation or profession, observers of the labor-market recognize today the need to continue training beyond initial qualifications: to maintain, upgrade and update skills throughout working life. People within many professions and occupations may refer to this sort of training as professional development.
Some commentators use a similar term for workplace learning to improve performance: training and development. One can generally categorize such training as on-the-job or off-the-job:
Physical training concentrates on mechanistic goals: training-programs in this area develop specific skills or muscles, often with a view to peaking at a particular time.
In military use, training means gaining the physical ability to perform and survive in combat, and learning the many skills needed in a time of war. These include how to use a variety of weapons, outdoor survival skills, and how to survive capture by the enemy, among others. See military education and training.
For psychological or physiological reasons, people who believe it may be beneficial to them can choose to practice relaxation training, or autogenic training, in an attempt to increase their ability to relax or deal with stress. While some studies have indicated relaxation training is useful for some medical conditions, autogenic training has limited results or has been the result of few studies.
In religious and spiritual use, training may mean purifying mind, heart, understanding and actions to obtain a variety of spiritual goals such as closeness to God or freedom from suffering. Note for example the institutionalized spiritual training of Buddhism, the Threefold Training, or discipleship in Christianity.
Researchers have developed training-methods for artificial-intelligence devices as well. Evolutionary algorithms, including genetic programming and other methods of machine learning, use a system of feedback based on "fitness functions" to allow computer programs to determine how well an entity performs a task. The methods construct a series of programs, known as a “population” of programs, and then automatically test them for "fitness", observing how well they perform the intended task. The system automatically generates new programs based on members of the population that perform the best. These new members replace programs that perform the worst. The procedure repeats until the achievement of optimum performance. In robotics, such a system can continue to run in real-time after initial training, allowing robots to adapt to new situations and to changes in themselves, for example, due to wear or damage. Researchers have also developed robots that can appear to mimic simple human behavior as a starting point for training.