Role of inactivity in production of disease In recent years there has been a growing interest in the role of inactivity as a cause of disease. Although conclusions are not definite and a great deal of research needs to be done, students of physical education should recognize the potential in this broad field. The mechanized life in America leads to physical inactivity. This in turn is a large factor in a number of orthopedic, internal, and psychosomatic disease entities. The report further states that muscle tests may be used as a means of predicting the incidence of this disease group (hypokinetic disease) in a statistical population, and that study, treatment, and prevention of physical inactivity as an important etiologic factor of many disabling diseases is imperative for the national welfare.The results of studies are as follows: 1.  Coronary disease is twice as frequent in groups of sedentary persons as in the active.   2.  Diabetes, duodenal ulcer, and a number of other conditions, internal, surgical, or both, are more frequent in the sedentary than in the active.   3.  Electromyographic activity of tense muscle is highly increased and goes hand in hand with increase of pain after irritating interview. The tension syndrome produced by insufficient outlet for fight and flight response provides the basis for a large number of orthopedic difficulties, including stiff neck and painful back. Tension headaches also belong in this group.   4.  Lack of physical fitness parallels emotional difficulties.   5.  Incidence of dental caries is in inverse proportion to weakness of bite force.   Owing to the increasing population, to crowded metropolitan areas, and to more push buttons for performing physical labor, a rich new field has appeared to challenge physical educators everywhere.		Home Components of Physical Fitness Clinical Examination Differences Between Fit and Unfit Men Physiological Elements of Fitness The Step Test The Effects of Training on the Physiological Systems Work Output Physical Condition of Muscle Application of Muscular Force Maintaining Optimum Strength Tests of Muscular Strength Strength and appearance Strength as a measure of physical fitness Strength as affected by organic problems Strength as prophylaxis Role of inactivity in production of disease Lack of Sociability in Work Lactic Acid System Muscular Form Capillary Growth Heart Size Heart Rate Training produces physicochemical changes Muscular Strength Nervous Stimulation and Muscular Strength Quality of Champions Factors Which Limit Skill Blood Supply Kinesthesis Balance Reaction Time Skill Muscular Tension Visual Aim Skill Center in the Brain Endurance for Exhaustive and Moderate Work Distribution of Energy