I believe the correct term is hitting a 'plateau', or something like that. It's where you are training enough, but failing to see any real progression. I feel that perhaps I've hit something like this. For the past few months I feel as if I haven't really progressed in fitness at all, despite me being more dedicated towards my training more than ever. I ran a personal best on my 3.5 mile run about 6 weeks ago and haven't really got near it since. Before that, I use to do a regular 4 mile run with a best time of 28 minutes which I haven't got anywhere near either. And just my fitness in general seems to have maintained over the months. Perhaps a complete revamp of my training routine is in order. Anybody else experience this?