Impact to the buttocks area could indicate a contusion of the sciatic nerve which would cause the symptoms you complain of. There is also a rare syndrome called “piriformis syndrome” where this muscle could be compressing the nerve. Normally an EMG will pick this up, especially if there is muscle atrophy as long as the electromyographer tests the atrophied muscles. General treatment is PT and time.
Donald Corenman, MD, DC is a highly-regarded spine surgeon, considered an expert in the area of neck and back pain. Trained as both a Medical Doctor and Doctor of Chiropractic, Dr. Corenman earned academic appointments as Clinical Assistant Professor and Assistant Professor of Orthopaedic Surgery at the University of Colorado Health Sciences Center, and his research on spine surgery and rehabilitation has resulted in the publication of multiple peer-reviewed articles and two books.