Developing research has demonstrated that many of the benefits of exercise are mediated through the role of skeletal muscle as an endocrine organ. That is, contracting muscles release multiple substances known as myokines, which promote the growth of new tissue, tissue repair, and various anti-inflammatory functions, which in turn reduce the risk of developing various inflammatory diseases.[13]
According to the Centers for Disease Control and Prevention (CDC), physical fitness is defined as 'the ability to carry out daily tasks with vigor and alertness, without undue fatigue, and with ample energy to enjoy leisure-time pursuits and respond to emergencies.' Based on this definition, fitness involves everything from getting out of bed to hiking to performing CPR.
There are different categories or types of physical fitness training. Each corresponds to a defined purpose or fitness goal such as the development and improvement of one or more of the five dimensions of physical fitness, or for participation in a particular type of sports and rehabilitation through physical training, among others. Note that the different types of training also correspond to the different categories or types of exercises.
A comprehensive fitness program tailored to an individual typically focuses on one or more specific skills,[7] and on age-[8] or health-related needs such as bone health.[9] Many sources[10] also cite mental, social and emotional health as an important part of overall fitness. This is often presented in textbooks as a triangle made up of three points, which represent physical, emotional, and mental fitness. Physical fitness can also prevent or treat many chronic health conditions brought on by unhealthy lifestyle or aging.[11] Working out can also help some people sleep better and possibly alleviate some mood disorders in certain individuals.[12]

Fitness is defined as the quality or state of being fit.[5] Around 1950, perhaps consistent with the Industrial Revolution and the treatise of World War II, the term "fitness" increased in western vernacular by a factor of ten.[6] The modern definition of fitness describes either a person or machine's ability to perform a specific function or a holistic definition of human adaptability to cope with various situations. This has led to an interrelation of human fitness and attractiveness that has mobilized global fitness and fitness equipment industries. Regarding specific function, fitness is attributed to persons who possess significant aerobic or anaerobic ability, i.e. endurance or strength. A well-rounded fitness program improves a person in all aspects of fitness compared to practicing only one, such as only cardio/respiratory endurance or only weight training.
Studies have shown an association between increased physical activity and reduced inflammation.[34] It produces both a short-term inflammatory response and a long-term anti-inflammatory effect.[35] Physical activity reduces inflammation in conjunction with or independent of changes in body weight.[36] However, the mechanisms linking physical activity to inflammation are unknown.

Push Up Test - This test measures muscular endurance. Men should perform this test using 'military style' (knees straight) while women should use the 'bent knee' position. Participants should perform as many pushups as possible while keeping proper form until exhaustion. An adult male performing 25-30 repetitions and an adult female performing 20-25 repetitions are considered 'above average.'
Endurance is your ability to perform physical activity over time. You might be able to serve aces and hit winning forehands and backhands, but if your muscles cramp or you run out of energy after a few games, you won’t win any matches. You build endurance by exercising for longer periods without stopping, working at a slower speed than when you interval train. This type of exercise is usually aerobic, calling on your slow-twitch muscle fibers and burning more fat than glycogen, depending on the speed you work. The slower you work, the higher percentage of your calories burned comes from fat.
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