Although the terms "flexibility" and "mobility" are often used interchangeably, technically they have different – but related – meanings. From the perspective of body mechanics, flexibility refers to the ability of a muscle to stretch in response to some applied force. Muscle flexibility is completely passive because a muscle does not have the ability to lengthen itself; it can only contract. Mobility, on the other hand, refers to the capacity of a joint to move through a full range of motion without restriction or discomfort. Unlike muscle flexibility (which is passive), joint mobility involves active movement through muscle contraction. To illustrate, a person may have enough muscle flexibility to get very low when squatting a 200 lb barbell, but not enough joint mobility or muscle strength to get back up. Conversely, another person may have sufficient joint mobility and muscle strength to squat 200 lbs, but insufficient muscle flexibility to get low. Muscle flexibility, muscle strength, and joint mobility are each important in daily activities, but particularly so for older adults who want to preserve an independent lifestyle.
A Quick Tutorial on Body Movement
Bones are the skeletal structure that supports the body. Joints are located between the bones, and allow the skeletal structure to move in a flexible way. Each type of joint – hinge, pivot, and ball-and-socket – has a different range of motion. Bones do not touch each other directly. Rather, they are cushioned by cartilage, synovial membranes, and lubricating fluid. Skeletal muscles – also referred to as lean muscle mass – attach to bones via tendons. By contracting, muscles provide the force necessary to move the bones within the joint's range of motion. The brain controls the muscles, but its ability to coordinate voluntary movement is directly impacted by the capacity of the particular muscles, joints, and bones.
The Impact of Age on Joint Mobility
Regardless of general health, age-related changes in the joints affect most older adults, ranging from minor stiffness to severe arthritis. The Centers for Disease Control and Prevention report that 42% of people between the ages of 45 and 64 indicate they have arthritis or chronic joint symptoms. That percentage increases from 42% to 59% for those adults who are 65 years and older. With age, joint movement can become stiffer and less mobile because the amount of lubricating fluid inside the joint decreases, and the cartilage becomes thinner. Ligaments also tend to shorten and lose flexibility over time, which can also make the joints feel stiff. In addition, minerals may form in or around the joints (a process known as calcification), which is particularly common in the shoulder joint. Hip and knee joints may also lose cartilage due to degenerative changes. Regardless of the cause, however, joint stiffness restricts body movement, causing it to slow and become more limited.
How Age Affects Muscles
As we age, our bodies begin to lose lean muscle mass and strength. Leg muscle, for example, has been observed to decrease beginning in early adulthood, with the rate of muscle loss accelerating at about age 50. Complicating the matter, a decrease in leg muscle is often accompanied by an increase in leg fat and connective tissue. As might be expected, the loss of muscle size leads to a corresponding loss of muscle strength, but muscle strength per unit of muscle mass declines as well. Lean muscle mass accounts for up to 50% of the total body weight of young adults but decreases to about 25% in older adults aged 75 to 80. The age-related decline in muscle mass is known as sarcopenia. However, muscle mass may also decrease as a direct result of not engaging in muscle-strengthening activities. While muscle atrophy affects both young and old alike, a recent study concluded that older adults must engage in resistance training more often than young adults to maintain the muscle mass they have. Apparently, the adage "use it or lose it" becomes even more important over time. Finally, if muscles are not regularly stretched through the full range of joint motion, they tend to shorten over time.
Retirement: A Good Time to Focus on Strength, Flexibility, and Mobility
Although reduced joint mobility, restricted muscle flexibility, and declining muscle strength are of concern to most adults, they are even more troubling for older adults. Fortunately, it is never too late to take action. Greg Bishop, an attorney in Park City, explains that many age-related changes to the joints and muscles are directly related to the lack of muscle-strengthening exercise. He notes that recent studies of inactive older adults demonstrate strength training reverses joint pain, improves joint mobility and muscle flexibility, and increases muscle strength. For example, one study concluded after 16 weeks of resistance training that older adults experienced significant improvement in mobility and flexibility. Specifically, there was a 38% increase in hip extension, a 30% increase in shoulder extension, a 15% increase in shoulder flexion, a 9.5% increase in hip flexion, and a 7% increase in elbow and knee flexion. A similar study of 32 sedentary men (average age of 70) found that a 12-week strength training program not only increased muscle mass, but it improved mobility in most of the major joint ranges tested. Finally, a study of older adults with osteoarthritis determined that a strength training program resulted in significant improvement in muscle strength and joint mobility, as well as a significant reduction in joint pain.
About Greg Bishop, Attorney
Greg Bishop is a business-oriented corporate attorney who always strives for improvement. He makes it a practice to only hire people who are smarter than him so that his team can raise the bar in helping the company be successful. He is passionate about living life to the fullest and helping others reach their full potential.
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