Jonas entered the gym and waved to Fiona, his physical therapist. With her guidance, he walked across the floor with a walker, gently putting weight on his injured leg. Then he sat on the bench and lifted the weight she recommended. On the final repetition, he gritted his teeth in discomfort. Finally, he allowed her to demonstrate two new stretching exercises that would restore his flexibility. He tried each one dutifully and assured her that he would perform them every night. These details support which inference about Jonas?