For the most thorough results, your veterinarian should evaluate walking, trotting, and running.  You (the pet owner) should evaluate the remaining index variable.  As you continue to work closely with your veterinarian, you will also learn how to correctly identify possible pain at the walk, trot, or run.  You will know your pet's behavior best as you will  bee able to observe him/her on a day-to-day basis.  However, working closely with your veterinarian will help you identify subtle changes in your dog and the team approach will ensure the most accurate assessment of your dog.