Gemma Steel has admitted that no decision has been made regarding which distance she will run at next year's Olympic Games in Rio de Janeiro.
As it stands, the European Cross-Country champion has the choice between the 10,000m and the marathon.
"I am sort of borderline going for marathon or 10,000m on the track, so that's the big question at the minute. We have now just got to have a chat with my coach and see where I am going with that," she told BBC Sport.
"I think the marathon is, in the future, where I could win a medal, but 10,000m on the track I am more comfortable with the distance. My coach is training me for the marathon, so I am prepared for it.
"I have only been going up to 15 miles in my training, but once I get comfortable with that and 17 miles, then 20, I think I will get more confidence."
Steel, 29, has never previously represented Great Britain at the Olympics.