(first of all, sorry if a make a few mistakes writing, english is not my mother language).
About Jane´s question: yes, a sport psychologist may be the answer. As an sport psychologist and orienteering runner (also), I now quite well what the problem is about. It could take a long time and words to explain all the theories behind the problem (miss focus) so I will give you a small explanation about how I will face the situation with and athlete.
1. There´s two differentes types of thoughts, the one´s that HELPS, and the one´s that doesn´t HELPS. Example type one: “run to the stone and after run to find de path”. Example of type two: “is this runner in my cathegory?”, “do I know him?”, “is he looking for the same point than me”? Both of them are type of thoughts we use to have while running.
2. All of this thoughts, are the self talk, which is the voice that is speaking to as all the time inside our heads. The problem appears when the selftalk is saying something different to the thing that is really important in a particular moment. While running, remember the example one (till the stone and till path) is exactly what I need to find the point. Obviously, example two is not helping me to find the point and then, the catastrophy is served: shit! I make a mistake! I did it again! I´m lossing 30 seconds! I have to run my race… and all the staff that come´s with a mistake, resuming, lost focus so lost time.
3. Unfortunately, there´s no way to prevent losses of focus (is happening all the time). Fortunately, what we can do is training to keep the focus for a longer periodes and even so important, be very quick focusing again in the main cues of the activity (it doesn´t matter if running, driving, cooking…), or what is the same, be aware about if what we are thinking helps me in that moment or not. As Lizzie said, mindfulness can be a very useful tool (I use it with my athletes and of couser, with my self very often).
Well, the only secret once you have the plan is training, training and training. The sport psychologist can´t help you with a “masterclass”. He can help you with a plan that you have to execute one time, two times…. and all the times you need to improve your performance in that point.
Hope it helps and give a small idea of what a sport psychologist can do!
Best regards from Spain!