Taylor, D. E. M. (1979). Human endurance - mind or muscle? British Journal of Sports Medicine, 12, 179-184.

Subjects were 5 male officer cadets, aged 19-23 years exposed to a variety of "atmospheres" while undergoing particularly challenging and enduring tasks.

1. If stress is added to exercise there may be a diminution of performance by a combination of an inappropriate sympatho-adrenal response and a central overriding of some of the normal cardiorespiratory systems.

   Implication. Do not add stress in competitions - the disruption has a physiological cost. Do not change the perception of external pressures or the task once a contest begins.

2. A potentially rewarding situation increased maximum muscle power and the ability to maintain effort (41% increase).

   Implication. Self-efficacy is increased if there is a perceived probability of positive outcomes.

3. A potentially punishing situation increased a psychological-stress cardiovascular type response with an inappropriate blood pressure increase. A deterioration in awareness and alertness was observed. These changes were not sensed by standard psychological tests.

Implication. Performance threats during an activity are stressful and reduce performance potential and the quality of the performance.

If a person believes he/she will not be successful or survive, then a psychological stress-spiral is induced resulting in an inappropriate cardiovascular response with tachycardia and hypertension in excess of cardiac output changes stimulated by the exercise. It is caused by too much adrenaline rather than too little. When a person believes he/she will be successful, no change in cardiovascular response will occur while performance will be improved by increased power and sustained effort.

If an athlete views a competitive situation as being stressful or negative, then physiological functioning will be less efficient than when it is viewed in a positive light.

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