We normally associate stress with inability to function optimally leading to undesired outcomes, and the popular thought is to avoid it. In sports, this stressful situation often occurs before big matches or events which may lead some sports persons not performing well due to stress of the moment.  This avoidance could be counter productive. 
        The definition of resilience is " The capacity to recover from difficulties; toughness." Psychologist Salvatore Maddi who dedicated his career to pin point that factor that distinguishes people who thrive under stress from those who do not. He discovered that those people who thrive are those who view stress as inevitable and try to engage it rather than avoid it!
       Recent understanding by science shows that the ability to learn from stress is ingrained into the basic biology of stress response. Typically, during a stressful situation, adrenaline floods into the body releasing energy, increasing heart rate and increasing tension in some muscles. Cortisol, which is another stress hormone is also released.
        At the same time, other stress hormones released help you recover from the stress. These recovery hormones include DHEA and nerve growth factor which in simple terms, help the brain to learn from experience (neuroplasticity). DHEA is a neurosteroid which helps the brain to grow stronger from psychological challenges which occurs for several hours after the stressful situation and the brain rewires itself to remember and learn from the experience.
        This recovery is called stress inoculation. It is precisely for this reason that putting people through stress is a key part of training for the SAS, NASA astronauts and elite athletes from all sports. The amount of stress inducing and  stress recovery hormones (DHEA) is therefore a relevant predictor in whether a stressful experience will be positive or negative. The ratio between DHEA in the blood to Cortisol is known as the Growth Index. The higher the value, the better is ones performance, greater learning and fewer post traumatic stress symptoms.
        In the game of hockey and football, when a younger player breaks into the first team, what all good coaches do  is to gradually introduce these youngsters, thereby providing the player valuable experience in stressful match situations that training cannot provide.
        Can we influence the growth index?
The main blueprint consists of changing the way a person thinks; changing the mindset. In terms of sports persons, it needs to be instilled into their mind that stress is helpful and that the experience should be viewed as an opportunity to learn and grow for the better. Players should be constantly put in regulated stressful situations during training, friendly matches and eventually full matches.
        These players should be constantly reminded that they should view a stressful situation as an opportunity to improve ones skills, knowledge and strength makes it more likely that one will experience stress inoculation resulting in improved future performance.