Zach Bitter is an endurance athlete, ultra-marathon runner and coach. He holds the current American 100-mile record at 11:40:55.Zach Bitter is an endurance athlete, ultra-marathon runner and coach. He holds the current American 100-mile record at 11:40:55.Zach Bitter is an endurance athlete, ultra-marathon runner and coach. He holds the current American 100-mile record at 11:40:55.