There is a lot of interest in keeping fit, getting fit and fitness training systems. But what is fitness? Is it about improving one's health? Is it about developing muscle bulk and strength? Is it about building stamina and physical abilities?

Wikipedia has a definition: Physical fitness is a state of health and well-being and, more specifically, the ability to perform aspects of sports, occupations and daily activities. Physical fitness is generally achieved through proper nutrition, moderate-vigorous physical exercise, and sufficient rest. Wikipedia