A good example of this is penalty kicks in soccer. A player who can casually score in training or in other times during the game may struggle when faced with fans screaming and a goalkeeper trying to put them off.
This is where biofeedback can help. It’s about focusing, getting into “the zone” where you focus solely on what you have to do as opposed to all the other distractions that could cause you to miss.
In some respects, this is a good metaphor for how beneficial sports psychology in general. Every athlete will know their goals, but it can be easy to be distracted by family life, personal issues or in some cases (and this will sound strange) pushing too hard so that you end up missing the goal more. This can equally apply to trying to hit your personal best, picturing beating an opponent or getting through a gruelling marathon.
In short, sports psychology can give you the clarity you need to know where your goal is and what you have to do in order to achieve it. Overcoming mental obstacles can be the marginal gain an athlete needs in order to succeed in achieving their own personal targets.