It’s been several years since I underwent physical therapy for impingement syndrome, so I was a little nervous about the new round of treatment, this time at a different place on a different part of my anatomy — my left knee. It all began with Dr. Knee’s concern about the pain I’ve been experiencing for several years when I walk down stairs.

I was joined in the waiting area by a woman with a crutch, who asked, “Is this your first time here?” Nod. “You will love it!” I took this as an assertion, not a command.

While I waited, she hobbled back and forth to the desk a few times, and an older woman issued forth, walking very slowly and very gingerly toward the elevator and reaching out to the wall for support — a prime candidate for an assistive device. I wondered just how far she was going to have to walk to get to her transportation and her destination, every step painful and precarious. I remembered that, at the other therapy office, I had always appeared to be in much better shape than my fellow sufferers, with no obvious injury or limp. But when the shoulder pain kicked in, invisibly, it was excruciating and debilitating.

The sound of my name startled me out of a half slumber, and reluctantly I hauled myself out of the chair and followed H. to the very back. She directed me to a far less comfortable chair and pulled the hospital-style curtain closed for privacy. Unlike my previous PT experience, there were to be no witnesses to my efforts. She did say, however, that in the future we would venture out into the “gym.”

After asking me why I was there, how long my knee had hurt, and other questions, she had me perform various tricks, such as balancing for as long as I could on each leg (I was able to last almost three times longer on the right than on the left) and bending my knee as far back as possible while lying down (left knee is more flexible than right). She dug into the front and side of my thigh with her palm and into my knee with her fingers. The side hurt more than I would have expected, and she found a tender spot in my knee above the patella (“I’m going to use the proper terms”), right where it hurts when I descend stairs. She explained the anatomy and the underlying weakness. The tendon (I think) is tight, and although x rays revealed no patella problems, she confirmed something I had noticed — the left kneecap is loose. Physical therapy is going to strengthen the function — at least that’s the idea.

I find it fascinating that my two legs have separate lives, but she said that it’s not uncommon.

After all these contortions and measurements of my flexibility, we were ready to get to work. Lie on your side. Lie on your back. Lie on your stomach. Raise your hips. Raise your feet. Repeat 10 times and rinse.

Unlike with my shoulder exercises, nothing hurt.

We finished off with an ultrasound treatment (“this shouldn’t hurt, but it may feel warm,” she said as she spread icy cold sonic gel on my knee) and then a cold wrap to reduce the small amount of inflammation remaining from my August fall.

With exercise handout in hand, I walked out self-consciously — the more normally I tried to walk, the more gimpy and awkward I felt I looked.

While I didn’t exactly exert myself, I felt sore this morning — partly due to the little workout, partly due to being chained to a chair eight hours a day during an especially (and poorly planned) intense time.

Now my shoulders hurt.