What does overloading your muscles accomplish

The principal is about continuously increasing the demands on the muscoloskeletal system witch is over leading your muscles so that you can make gains in muscle size, strength, and endurance.

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.

Regular exercise and physical activity promotes strong muscles and bones. It improves respiratory, cardiovascular health, and overall health. Staying active can also help you maintain a healthy weight, reduce your risk for type 2 diabetes, heart disease, and reduce your risk for some cancers.

Physical fitness reduces your risk of a heart attack, manages your weight better, lower the risk of type 2 diabetes and some cancers, lower blood pressure, stronger bones, muscles and joints and lower risk of developing osteoporosis.

The World Health Organization defined physical fitness as the ability to per- form muscular work satisfactorily. These researchers have suggested that the components of health-related physical fitness are cardiorespiratory endurance, muscular strength, muscular endurance, body composition, and flexibility.

Hope it will help you to have some idea! :)