Stretching and Your Health
by Robert Forster, Physical Therapist and Performance Specialist
It has occurred to me that most people spend more time taking care of their teeth on a daily basis then they do the rest of their body. The human body is a mechanical device that requires maintenance just like any other machine. You would never think that your car, lawnmower or bicycle could be used consistently day in and day out without some effort to keep it in good working order. Yet, too many of us think we can get by with little attention to body maintenance. After 40 years of helping people get past injury and achieve their health and fitness goals, it is my opinion that stretching is second only to movement itself in maintaining good physical health. While athletes and those who exercise regularly have heard stretching is important, few understand why and most non- athletic people think they don't need to stretch at all.
Movement is Life
Movement is life! We were made to be in nearly constant motion. From early man up to the industrial revolution, our ancestors spent most of their waking hours in nearly constant movement. The search of food, water and shelter required it. Accordingly, for the body we have inherited, movement is vital to every bodily function from healthy digestion to proper brain function. Although our bodies were engineered for very efficient movement, the largely sedentary lifestyle we have adopted since the industrial revolution has robbed us of the efficiencies built into this otherwise economical machine. The average American is sedentary for far too many hours every day to not expect problems. Add up all your active hours and subtract from 24 and you will see your sedentary time ranges from 18-20 hours a day. (7-8 hours of sleep every night, 1-3 hours commuting in the car, 6-8 hours at your desk and then home for TV on the sofa or some combination thereof)
Without movement tissues lose their extensibility and research has shown that even those who spend 90 minutes a day at the gym experience detrimental changes at the cellular level with all the time spent motionless each day. Many of these sedentary hours are spent in the sitting position fighting gravity to remain upright. In this slumped forward posture the joints of the hips, shoulders and trunk are rounded forward allowing the soft tissues in the front of our bodies to become tight over time. Poor posture begins as bad habits but becomes fixed as the connective tissue elements of our body adapt to the poor alignment. Joints operating in poor alignment suffer damage and premature aging. To understand why this occurs and how to prevent it we must look at the physiology of connective tissue.
Connective Tissue Physiology
To comprehend the importance of stretching one must first recognize that the target of any stretching program is not the muscles themselves. Muscle fibers are elastic in nature and will stretch to many times their resting length. Instead it is the connective tissue structures in and around the muscles and joints that are the true target of your stretching efforts. Your body is held together by a fabric of connective tissues. While the bony skeleton provides the internal frame for the muscles to attach and provides protection for the vital organs, it is the connective tissue elements (also known the "soft skeleton") that holds everything together. Connective tissue gives our body its form and is integral to how it functions. All connective tissue structures are made of collagen fibers arranged in specific patterns that dictate a particular structure's strength and flexibility.
Connective tissue is ubiquitous throughout the body and its role in the musculo-skeletal system is vital to the discussion of structural health. Starting at the cellular level we find every individual muscle fiber is wrapped in a collagen casing called fascia. Fascia also wraps groups of muscle fibers into bundles and the bundles together to make up the muscle belly. Fascia separates muscle groups as well. (It is the white glistening material that can be seen in various cuts of meat separating the muscle tissue) Furthermore, where the muscle fibers dissipate towards the end of the muscle belly the connective congregates to form the tendon by which the muscle attaches to the bone. Under our skin the whole body is encased in what can be thought of a as an internal suit made of connective tissue. By now you get the point; connective tissue is everywhere and in many ways the connective tissue skeleton is so much more vital to health and function than the bony skeleton, but most people give it little thought. As Physical Therapists we spend our entire careers dealing with connective tissue and its dysfunction.
Accordingly, much research has been conducted in the area of collagen physiology. We have learned that collagen is constantly in a natural state of change. It adapts to the forces that it is exposed to; shoring itself up when it is exposed to stress and thinning out where is not. Lengthening only when we demand it do so, and shortening if we leave it alone. This is called Davis's law of connective tissue adaptation and the most important take away fact about collagen is its natural tendency is to shorten over time if it is left un-stretched. As connective tissues shorten they limit the range of motion of the joint they surround. A joint with limited range of motion operates with poor mechanics even in the available range of motion. When joint mechanics falter this leads to damage of the joint surfaces and other structures surrounding the joint.
Stretching is the Medicine that keeps us Moving
The number one reason everyone needs to stretch is to maintain proper joint function and mobility through out life. Stretching counteracts the natural tendency for our connective tissues to tighten and alter joint mechanics. Stretching helps preserves good posture against the forces of gravity. Just like we brush our teeth to prevent decay, we need to stretch every day to prevent joint problems. For the sedentary person stretching is the bare minimum requirement to maintain physical health For more active persons and athletes, stretching is a critical adjunct that helps prevent injuries and promotes recovery by keeping muscles from shortening after workouts. For athletes looking to improve performance stretching increases the range of motion of the bones around the joints allowing for the execution of the optimal bio-mechanics for their sport. I have worked with tens of thousands of athletes, from student athletes to pros and Olympic Champions, and none have reached their highest genetic potential without a sound flexibility routine.
PART 2: Characteristics of a Safe and Effective Stretching Program
Stretching Before and After Every Workout:
The most misinformed aspect of stretching is that it is dangerous to stretch the body when it is "cold". I agree when you are dead you should not stretch; however, shy of death our bodies are never "cold". While collagen stretches better when the tissue is warmed up, it stretches just fine at the normal resting body temperature. To bear this out all we need to do is look at dancers; ballerinas don't go in the dance studio and run around to break a sweat before they stretch.
The first thing they do is walk over to the bar and put their leg up and stretch and they generally have better flexibility than any other athlete. Yogis, martial artists, and gymnasts all have renown levels of flexibility and the first thing they do is stretch, then warm up and stretch some more. As long as the stretching positions are safe and we follow the "subsiding tension" principle, then stretching before workouts and competition is safe and effective to increase performance and help avoid injury. Those who think they don't need to stretch before workouts as long as they "start slow and warm up" are seriously misdirected or they are just lazy. I hear this from time pressed coaches and athletes all the time, but the truth is if you don't have time to stretch you don't have time to work-out!
Following workouts the muscles are "pumped" i.e. left in a shorten state with the blood vessels in and around the muscle laden with waste products of muscle physiology. Post workout static stretching promotes recovery by returning the muscle to its normal resting length while pulling the connective tissue taught to wring waste products out of the muscles and the associated vascular structures. Research has shown that stretching reduces delayed onset muscle soreness (DOMS) and allow us to recover quicker and workout again sooner and stronger.
Stretching is an act of relaxation. Muscles must be coaxed into lengthening and not coerced. The muscle fibers must be relaxed for the stretch to effectively target the connective tissue elements in and around them. Accordingly, each stretching posture must be chosen carefully to promote relaxation and protect all the surrounding joints and especially those of the spine. Lower body muscles need to be relieved of their load, i.e. be non-weight bearing to allow the stretch to be effective. This can only be achieved by laying on the ground in positions that allow for muscle relaxation and easy breathing. For the upper body the limb must be relaxed in a cradled or supported posture.
Subsiding Tension Principle:
Muscles should be stretched slowly allowing the stretch sensation to register in the brain and then modulated by going deeper into the stretch or letting up based on that sensation. If the tension in the muscle increases while holding a position then one should let up a bit. If it decreases, then move deeper into the stretch. Deep belly breathing will further relax the muscle and allow for the best result.
Static Stretching vs Dynamic Warm Up:
Recently many personal trainers and fitness professionals have been advising against static stretching based on a few studies supporting active or "dynamic warm" up versus static stretches for athletic performance. The studies have shown that power and strength output were reduced immediately following static stretching. In my opinion, the studies were poorly designed and the findings misquoted and misused. There exists decades of research that shows collagen lengthens best under long sustained stretching forces and that a static stretch results in the most permanent elongation of the tissue. Well informed performance experts never meant for static stretching to be abandoned but instead augmented by dynamic movements as part of a well-designed pre-activity warm up. Stretching before workouts or competition allows athletes to execute the correct bio-mechanics of their sport and indeed my athletes have performed static stretching exercises immediately before stepping on to the track to set world records and win gold medals.
Quick Release and Longer Holds:
Before and after activities, whether workouts or housework, one need only to release the muscle to its normal resting length with two repetitions of each stretch for a 5-10 second hold. To improve flexibility it's best to hold the stretch a little longer and perform three repetitions of each posture. The longer holds to increase flexibility are better done after workouts or in the evening when our peripheral body temperature is naturally higher. Low intensity stretches, held for up to 60 seconds or longer, will result in a more permanent elongation of the collagen fibers and will improve the chronically tight areas of your body.
Sport Specific Stretching:
This is an over blown concept. While certain parts of the body may need more or less attention to ready us for a given sport, in general all the big muscles must be addressed in everybody, all the time. Furthermore there are only a few safe stretch positions for most of the larger muscle groups so when a volleyball player wonders why they are performing the same stretches as the baseball player I tell them "you have a quadricep and so does he, and they both need to be stretched". Additionally, there are areas of vulnerability in the human body that we all share and therefore need to be stretched in everyone. To avoid the common injuries of the spine, shoulders, pelvis and knees there is no getting around certain stretches that target our shared vulnerabilities.
Stretching for Recovery, Relaxation and Injury
During exercise and in our daily activities the connective tissues are damaged under the stress of exertion. With adequate rest the body responds by laying down new collagen fibers to repair and shore up the tendons, fascia and ligaments under strain. This is how we become more resilient to injury. The new collagen fibers are laid down in a haphazard pattern at first and only become a meaningful "scar" when stretching and movement prompts the fibers to align themselves in a direction parallel to the stresses that are applied to that structure. Overuse injuries occur when further load is placed on the structure before the scar is matured, i.e. our activities have outpaced our ability to adapt to the stress. Stretching speeds up the processes of adaptation to avoid injury and improve recovery time by stimulating more functional scarring. Likewise, at the end of a long workday muscle tension builds as we fight gravity to maintain upright postures and from the emotional stress of modern life. Stretching is the most natural and productive stress reliever. Stretching exercises, along with deep breathing, in relaxed postures allow us to release the stress from the muscle and has been shown to decrease levels cortisol in the blood, a stress hormone that is problematic for health.
For a stretching routine to be sustainable it has to be completed in 5-8 minutes before and after exercise. In the evening stretching to address problem areas and for relaxation can be accomplished in 12-15 minutes with longer holds and multiple repetitions.