I regularly trail run/hike and mountain bike these trails.
The maintence is pretty good, during the height of summer the brush can start to crowd the trail a little. The big issue I seem to have is that the trails stay very slick after rain events. There are many hills with tight twisty turns, between the rocks, roots, leaves and mud this place stays pretty difficult to secure traction sometimes.
Nice trail ran in to a few people with dogs so had to stop and walk my bike around them other than that it was a great ride the lake trail was my favorite didn't get to ride all the trails so I will go back ran into 1 down tree on a down hill run which wrecked me.
I like the trails here. Only complaint would be the lack of quiet at places on the trail. Traffic and other sounds can be heard. Not a huge deal though. Pretty views of the lake. Whoever was complaining about bikes ruining the trail is a whiner. I met several bikes and everyone was very courteous, and I had no issue hearing them coming.
This review is about the part of Concord Park that lies east of the marina. It used to be a great park for walkers and hikers. Not any more. Since the Knox County Parks Dept. has allowed recreational and mountain bikers to use the narrow trails of this park, it has become unusable for pedestrians. Bikers and pedestrians cannot co-exist on these single-track trails. You cannot even walk these trails side-by-side. So if a biker approaches a walker from behind he will create a dangerous situation for both himself and the the pedestrian unless the pedestrian quickly get out of the way or unless the biker dismounts and walks his bike past the pedestrian. In several years of hiking these trails, I have never met a biker who does not insist on having the right of way forcing me to jump aside and let him pass. What if I refuse to yield my right of way and the biker runs into me causing bodily injury? Who is going to pay for a very expensive medical evacuation and subsequent lawsuit?
This is a great trail system. I rode three of the different trails (west loop, main loop. and inner loop), and they were all fun and challenging. It was wet and VERY muddy. I would recommend riding these trails ONLY when there is dry weather. It was certainly hard while riding a single speed. There were a lot of technical areas. Go for it!