Heart Rate With training there is a small but consistent reduction in the resting heart rate. Although the heart beats more slowly each contraction is more powerful and the increased stroke volume more than compensates for the slower heart rate, so that the minute volume (cardiac output) is not reduced and may actually be greater than average. Training does not increase the rapidity with which the heart rate accelerates at the beginning of exercise, but the heart rate returns to normal more quickly at the cessation of exercise in the trained subject. There was little difference between the circulatory measurements of 14 college athletes and 11 nonathletes when they were studied under basal conditions. Increased diastolic pressure after exertion is an outstanding characteristic of the trained subject. Nervous System Changes in the central nervous system as a result of training are evidenced by improvements in motor skills. Improved mechanical efficiency follows as a consequence of greater skill which eliminates unnecessary muscle contractions. Practice guides soldiers in selecting the metabolically most economical step length for every change in road grade, it conditions athletes to inhale at the physiologically and mechanically most opportune moment in a rowing stroke and it improves the stride and the arm-leg coordination in runners. In industrial work training usually levels the individual differences in rather simple tasks, while in more complicated operations training increases the individual differences. Psychological factors and specific skills are so important in determining individual performances in exhaustive exercise that improved performance can be acquired with almost no improvement in fundamental physiological capacities. It is practically impossible, therefore, to assess physiological effects of athletic conditioning unless some direct physiological determination, such as oxygen debt measurement, is made. Cross Education When work is practiced with one hand, not only does the mechanical ability of that hand improve, but there is also significant improvement in the other hand which remained idle. This suggests that the nature of the motor nervous system is such that the whole body is responding, even when only a part of the body appears to be performing the work. It also suggests that both sides of the body should be exercised in order to secure the most rapid return of normal neuromuscular function following injury or disease.		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 Kinesthesis Balance Reaction Time Muscular Tension Visual Aim