If you want to be able to play with your grandkids without pain, paying attention to flexibility is a must. Most movements involve multiple joints. It is important to maintain flexibility of our joints if we want to maintain the ability to function as normal as we age, however, it is often an under-trained aspect of health. Flexibility refers to how much a joint can move through a normal range of motion while being comfortable and pain-free. Any comprehensive exercise program should always be accompanied by flexibility training.
With age, we gradually lose the ability to move a joint through a full range of motion. By age 70, 25%-30% of overall flexibility is usually lost (in an average population). Some joints are affected more than others. A shoulder flexion loss of 15% was observed in one study between 20-30 year olds and 70 year olds whereas a study on hamstring flexibility observed a 30% loss between similar age groups.
Why does this decline happen? There are several causes. Increased rigidity of the tendons and ligaments around the joint. This is caused by changes in connective tissue collagen fibers which make up these structures. These changes include tightening of the cross-links which makes the joint less able to bend. Another cause is a reduction in elastin content which gives these structures elasticity. There is also a general deterioration in cartilage, ligaments, tendons and a reduction in fluid within the joint (synovial fluid) along with tightening and dysfunction of muscles surrounding the joint.
The good news is that these changes can be slowed down dramatically. Physical activity in general slows down deterioration in flexibility. Multiple studies have shown that individuals who are physically active can achieve a significantly greater range of motion than sedentary individuals including in older age.
When looking for markers that reflect biological age, I prefer “functional markers” that are actionable. These are markers that 1) directly reflect the function of certain organs or systems in the body, 2) Show a correlation with age and 3) have the ability to improve with certain interventions.
Flexibility markers fulfill all three criteria. That’s why I believe they should be included in any comprehensive assessment of health and aging. To give an example, the range of motion (ROM) of the shoulder joint shows a fixed decline with age in a normal population. The rate of this decline can be decreased with the right stretching exercises and an improvement in flexibility is linked to better overall health.
Flexibility of a certain joint refers to the ROM we can achieve without pain. ROM is measured using goniometric measurement. Although there is no agreed upon assessment for general flexibility, there are standard practices recommended by the American College of Sports Medicine. One of them is the sit-and-reach test. This is how it is done:
Special sit-and-reach boxes are used by professionals which are set at 26 cm at the point where the fingertips meet the level of the feet. A “good” to “excellent” score for an individual aged 20-30 would be between 30-40 for a male and slightly higher (33-41) for a female. A score of 30 means they can extend their fingertips 4 cm beyond their toes (subtract 2-3 points for every 10 years of age for older individuals). This is according to the YMCA Fitness Testing and Assessment Manual. This test focuses on the flexibility of the hamstrings, hip, and lower back.
There are several ways to improve flexibility and increase joint ROM. They all involve
some form of stretching. There are three types of stretching. These are static, dynamic, and proprioceptive neuromuscular facilitation or PNF.
Static stretching is putting tension on a muscle to near its furthest point and then holding that position. Our bodies are roughly arranged in opposing muscle groups. Arm flexors are opposed by extensors. The same goes for our legs. The chest pectoral muscles are opposed in action by the muscles of the back. These are called antagonistic pairs. This is important because one of the most important factors in flexibility is length of opposing muscles. You can only use the muscles of any joint to the degree that the opposing muscles can stretch. The way to improve this is by static stretching. A study by Nelson and Bandy showed that static stretches of 30 seconds, 3 days a week, for 6 weeks, improved hamstring flexibility significantly when compared with unstretched controls. These were repeated by subsequent studies.
Despite the popularity of static stretching, there is a growing amount of evidence that it should be limited to short bouts of 10-30 seconds if performed prior to a physical activity, especially if one is aiming for the best performance. This is due to a potential negative effect on performance and strength gain. This is why it is likely better to keep static stretching to separate days or after other forms of exercise.
Dynamic stretching consists of active movements where joints and muscles go through a full range of motion. This is the preferred form of stretching when warming up prior to an exercise or vigorous activity and has been shown to improve performance as opposed to static or no stretching. But these movements should not be “ballistic” as this may impede performance. Dynamic stretches should be similar in movement to the activity we are warming up to perform. The aim is to activate the same tissues involved with less tension and intensity.
Proprioceptive neuromuscular facilitation or PNF includes active and passive techniques and is performed under the guidance of an experienced trainer. These techniques are thought to affect a less understood aspect of flexibility, which is how our nervous system interacts with joints and surrounding muscles to influence flexibility. Some researchers have suggested, however, that the benefits of PNF are mainly due to its effects on the stretched muscle alone.
Throughout stretching, it is important to maintain a correct posture by maintaining a neutral position of the spine and hips and keeping the shoulders back. Proper breathing technique is often helpful allowing for movement through a full range of motion. Never push through pain and always consult a healthcare specialist before performing these activities especially if you have conditions such as arthritis, muscular imbalance, osteoporosis, or hip fracture/replacement.