Hi, As there is no mention about the injury this appears to me as hamstring tightness which may have be associated with the nerve tightness. This might be leading to hamstring not allowing the quadriceps to do its functions well and straightening the knee leading to sound. I will advice to do simple low intensity exercises like - core stability, spinal muscle strengthening exercises, hip muscle strengthening exercises, static hamstring, static Quadriceps, straight leg raise, ankle toe movements as well. Also I will advice to do simple lunges in the sides and stretching for the hamstring which will allow the biomechanics of the muscle contraction to be improved and allow the knee joint space to be maintained. The above exercise prescription should help you get rid of the symptoms. Hope I have answered your query. Let me know if I can assist you further. Regards, Jay Indravadan Patel, Physical Therapist or Physiotherapist