I am fortunate to have a dear friend who, for purposes of this article, we will refer to as Jack. Jack is 85 years old, a businessman, a Marine and a former outstanding athlete.

Jack and I met in the early ’70s at a tennis club. We played with and against each other for years. We also became friends socially, and we developed an attorney-client relationship. We lost touch in the mid-1990s when I began playing more racquetball than tennis and he began playing more golf.

We didn’t see each other for years until we ran into each other in a restaurant around 2010. It didn’t take us long to renew old acquaintances.

I found out that, like me, he had been stalked by the orthopedic reaper. I had just had a hip replaced and had back surgery. Jack had had both shoulders and both knees replaced.

I had just begun lifting again and was trying to get ready to compete. I offered to help Jack train and rehab his most recent shoulder replacement. We worked together, sporadically for a time, making a little progress, then losing it.

After a year or so of intermittent training, Jack came to see me. He was walking with a cane. He had fallen and broken five ribs and had been diagnosed with Parkinson’s disease. I didn’t believe he had Parkinson’s because I had not seen any decline in his physical ability, but his fall had alarmed his doctors.

As soon as his ribs allowed, we went to work. Except for a brief respite in 2013, we have not stopped.

Before I describe what we did and the conclusions I drew, let me say I am not a scientist. My degrees are not in any science involving the body. They are in history and law. What little I know about physical training came from my days as an athlete, from Donnie Thompson, Dave Tate, Jim Wendler and Mark Rippetoe, and from the athletes and columnists of EliteFTS, whose articles and logs I read.

My friend Dr. Bryan Mann might be appalled at my lack of scientific method, but because I do not expect a peer review in a scientific journal, here is what we did.

I tried to use compound movements and a powerlifting mindset and techniques to build strength first. I told Jack, “I don’t care if you fall. I want you to be strong enough to get back up.”

We first concentrated on squats, and we still do. Jack made great progress getting his legs stronger and increased his core strength. Both helped tremendously in his ability to walk better.

In addition, farmer’s carries have helped his posture, and deadlifting has helped his squat and vice versa. Because he had both shoulders replaced, we had a tough time with the bench press. I also have a shoulder problem, so I bought a shoulder saver from EliteFTS, and it has helped us both.

We used dumbbells for a while to help with Jack’s stability, but we still had severe bench press problems.

Before we could address those issues, more severe problems presented themselves. After being stalked by the orthopedic reaper, we now both were confronted by the internal reaper.

I had open-heart surgery with five bypasses in February 2013 and prostate surgery that July. Jack said he caught whatever I had, and he suffered a heart event that required a stent in April 2013.

We were in cardiac rehab together, and at its conclusion we both vowed to come back stronger than we had been.

We have.

We went to work in July 2013, and, with some exceptions for life, family and work, we haven’t stopped. Last summer the doctor stopped the Parkinson’s medication with no consequences after finally realizing that Jack does not have the disease.

Jack told me he experienced a fall on a family vacation at the beach. I asked what he did, and he replied, “I got back up!”

Back to our bench press problem. At a visit to the doctor who replaced his shoulder, Jack explained that he was lifting weights but was having shoulder problems. The doctor asked whether we could work around it. That gave me an idea.

I tried to work all the muscles I could think of around the deltoids: biceps, triceps, lats, traps and all the back muscles whose names I don’t know. Wonder of wonders, the bench press improved. More important, there was no pain.

If we continue that regime, I expect the bench press to improve dramatically.

Recently Jack made a date for golf. He was concerned that he might fall. I told him if he did, just to get back up and keep playing. Not only did he not fall, but he also hit the ball farther than he ever had.

It’s easy to work with a former excellent athlete. Often what made Jack excellent was his determination to succeed, and he still never gives up.

As the athletic prowess diminishes as we get older, the mindset, the determination, and the will to succeed and get better never do. Jack has done wonders, and we are only going to get better and stronger.

The broader takeaway is that compound exercises work. They help make us stronger.

Age is more than a number. It brings physical changes we can’t avoid. It can take away our athleticism. But it cannot take away our will, our desire, our determination and our diligence.

At any age, we can get stronger, better and more functional. At any age, hard work brings results. Consistent hard work can produce exceptional results. There is no time when we can’t do all we can do.

Today Jack walks without any difficulty and without a cane. He plays golf regularly and is my biggest cheerleader at my powerlifting meets. Never underestimate the will of two old friends.

Jeff Guller is a personal trainer, fitness columnist and record-setting powerlifter in Gastonia, N.C.