Four Pillars of Successful Aging

Insights from more than two decades as a physical therapist

image of two older people doing yoga

One of my family members fell while he was home alone. He was determined to get himself back into his wheelchair. But, his weakness and impaired motor control from a neurological condition prevented him from getting up. 

He was stuck on the floor for several hours. 

When other family members arrived, he was too exhausted to try again. An EMS team arrived and helped him into his wheelchair.

He shared his experience and frustration in a recent conversation. As a lifelong athlete, he maintained a high fitness level and strength before his illness. He had always looked and felt much younger than his age. 

However, his condition made it nearly impossible to exercise and severely limited his functional mobility.

Functional Mobility

Maintaining functional mobility as we age contributes to a healthier and more active lifestyle. It’s also related to longevity.

Functional mobility is the physiological ability to move independently and safely in a variety of environments in order to accomplish functional activities or tasks and to participate in the activities of daily living at home, work and in the community.

– The National Institutes of Health

As a physical therapist, I treated thousands of patients with orthopedic and neurological conditions over two decades. I’ve seen firsthand how people can either thrive or deteriorate physically as they get older. 

Some embrace healthy lifestyles and retain impressive strength, balance, flexibility, and mobility into their 70s, 80s, and beyond. Others grow increasingly sedentary and struggle with basic movements.

The key difference? 

How well they could control their bodies in space.

Many factors contribute to our ability or inability to control our bodies. I developed a simplified framework based on four interrelated factors that impact functional mobility. That framework became part of my treatment plans and patient education programs.

Four Foundational Factors

The four foundational areas in the framework are strength, flexibility, balance, and body mass. Other Components include coordination and stamina, but I wanted to keep it simple. This section gives an overview of these factors, but specific exercise programs and protocols are beyond the scope of this article.


To move your body mass through the world, you must generate enough force to overcome the effects of gravity, inertia, and friction. If you can’t generate enough force, you can’t move. An example is the inability to rise from a chair or get up from the floor.

People often avoid strength training as they age. Some dislike traditional weight training. Others fear injury. There are many other ways to get stronger. 

Body weight exercises like free squats, box squats, and push-ups are great ways to improve functional strength. Other options include resistance tubes, kettlebells, and lifting household objects.

Start slow if you haven’t exercised for a while. Do less in the beginning and work your way up. It’s easy to make it more challenging, but you might get discouraged if you’re too aggressive in the early days.


For the purposes of this article, I’m using the term flexibility in a broad sense that includes muscle lengthening, joint mobility, range of motion, and connective tissue extensibility. It’s the ability to move freely through a range of motion without pain or limitations.

Traditional stretching exercises that target the legs, hips, shoulders, and spine are great for improving overall flexibility. But they can be tedious and difficult if you have significant restrictions.

If you hate stretching, try yoga, pilates, or tai chi. You could also try a more recent type of program called mobility training. All these activities are great for improving joint range of motion, increasing muscle length, and improving the quality of your movements.


Maintaining your balance is vital, but you also need to be able to recover your balance. When I talk about balance, I include static and dynamic balance. Both are important for maintaining safety and function.

Balance is your ability to control your center of gravity (COG) around your base of support (BOS). It’s what allows you to stay upright and steady under various conditions. When your COG moves too far outside your base of support, you will either fall or take a step to prevent it.

Balance training should include static and dynamic activities on stable and unstable surfaces. 

A typical sequence for progressing static balance training is:

1. Standing on stable surface with eyes open

2. Standing on stable surface with eyes closed

3. Standing on unstable surface with eyes open

4. Standing on unstable surface with eyes closed

You can use sophisticated specialized equipment, but it’s not necessary. In most cases, you can do basic balance activities at home if there are no underlying medical conditions causing balance problems. Standing on a pillow or cushion can create enough surface instability for most people.

Dynamic balance training can include reaching high and low to the same side and across your body. More advanced activities might add throwing and catching while standing on stable and unstable surfaces. 

Standing perturbations are another form of advanced training. This technique requires another person to nudge you from the front, back, and sides while standing. You can use the same progression as static balance training to increase the challenge.

The goal of dynamic balance training activity is to maintain stability while moving your center of gravity outside your base of support.

Body Mass

No matter what your body size, the key is to be able to move around safely. As long as you have enough strength and flexibility to move while maintaining good balance, body mass may not be a problem. 

When body mass is too high, it causes increased compressive force in the joints. Excessive compression in the joint can cause inflammation and joint surface damage that could lead to arthritis. The spine, hips, knees, and ankles are most susceptible to this damage.


John stood 6’ 8” tall and weighed 475 lbs. He was strong, and able to walk at his previous weight of 750 lbs. His static and dynamic balance were good. I was shocked when he demonstrated his flexibility by bending over and touching both palms to the floor without difficulty.

His main problem was the compression in his joints. According to the Harvard Medical School, the force on your knees is 1.5 times your body weight when you walk on level ground. Prior to his weight loss, the force on John’s knees was over 1100 lbs. He decreased that force by ~400 pounds when he lowered his body mass.

John’s body mass restricted his functional mobility.

Mr. C was a lean 68 year old man of average height. He had good static standing balance and reasonably good dynamic balance. But, he had some difficulty reaching outside of his base of support.

Unfortunately, his trunk and limbs were stiff and weak. Although his body mass was within the normal range on the Body Mass Index, he struggled getting up from a chair or bed. He had restricted range of motion in both shoulders and hips.

Mr. C’s weakness and limited flexibility restricted his functional mobility.

Mrs. L lived at the other end of the spectrum. She arrived in physical therapy with complaints of knee pain after gardening. During my evaluation, I discovered that she’d been in a squat position for nearly 3 hours when her symptoms started. She explained that this was a typical practice from growing up in China.

Although she appeared to be in her mid-60s, she was actually 93 years old. She was petite, but unusually strong. Her static and dynamic balance were outstanding, even for a much younger person. She could perform a deep squat and return to standing without losing balance.

Mrs. L had outstanding functional mobility from thriving in all four areas of strength, flexibility, balance, and body mass. Her knee pain was due to moderate inflammation from squatting for nearly three hours without a break. 


By understanding the impact of strength, flexibility, balance, and body mass, we can maintain control of our physical abilities. Rather than accept inevitable decline.

Just as we invest in financial planning and healthy diets, mindful efforts to exercise and maintain functional mobility allow us to thrive across all stages of life. 

Whether our goals are playing with grandchildren, enjoying activities, or simply getting around safely, deliberate investment in these four pillars pays dividends through an active, independent, and fulfilling life.