Most types of stress require varying’ degrees of anatomical, physiological and psychological fitness. Anatomical fitness implies possession of all the parts and organs of the body which arc essential to the performance of the task. A man who loses an arm, a leg or an eye may lose his fitness for one task but remain fit for another type of activity.
Physiological fitness implies the capacity for skillful performance and rapid recovery. All activities require some degree of muscular strength, motor skill and endurance. The relative importance of one of these components in the performance of a particular task may determine a man’s fitness for that task.
For example, a man with weak muscles may excel in an activity requiring a high degree of motor skill but be totally unfit for a task requiring great muscular strength. Psychological fitness for a task implies that the subject possesses the necessary emotional stability, drive or motivation, intelligence, and educability. Without these, he may fail even though he is anatomically and physiologically fit for the particular task.
Difficulties in Measuring Fitness
Before fitness can be assessed with any accuracy the precise nature of the stress must be under. stood. This is tire most difficult task confronting the investigator who wishes to make an estimate of fitness. He must attempt to differentiate the factors which constitute tile particular stress and then to determine t},c relative importance of each factor.
Following this analysis he must validate the measure of each factor, refine each measure until it is reliable, and assign a score 10 each measure. This degree of accuracy in the quantitative assessment of fitness has understandably not yet been achieved. The only precise estimate of fitness which is now available is the uneconomical procedure of making a long and careful study of the performance of the individual at the particular task.
It is frequently desirable to estimate the fitness of a large group in a very short time. This can be accomplished at present only by sacrificing precision. At best, present estimates of fitness reduce the errors of judgment and chance selection.