The 2019 Blood Rock 100 or 50 mile trail race will likely be the hardest 100 or 50 you have ever run. The 100 will have well over 50,000 feet of elevation change, the 50 mile, 25,000 ft. However, the elevation gain is not what makes the race so hard. It is the terrain. Our little mountain at Oak Mountain State Park is only 600 feet tall and about 8 miles long but what it lacks in size it makes up for in brutally steep technical climbs and descents, treacherous trails and endless miles of rocks and roots. Then again, there are also some very gentle and very runable trails.