In martial arts training we often touch on the topic of flexibility. Flexibility, or, as I prefer to call it, limberness, allows us to maintain a good range of motion for each joint or joints. When we are limber, our health and quality of life is enhanced. Likewise, loss of flexibility can dispose us to pain and injury, and also contributes to mis-balances in our body – especially as we age.
Flexibility is Relative
Rather than think about flexibility in absolute terms, (e.g., “I have to be able to do a beautiful karate roundhouse kick to the opponent’s head”), limberness is personal. It is affected by our natural body structure and genetics, as well as by our activity level history. A man who has not exercised in many years will typically not be as flexible as a woman who has trained in dance all of her life. It is a myth that some people are innately flexible throughout their entire body, while others are not. Rather, flexibility is specific to a joint or set of joints. For example, a person with very flexible hips may have very tight back. The good news is that, through proper training and exercise, we can maintain and increase our flexibility. That is, like any skill, stretching can be learned.
Flexibility is also specific to the types of activities for which the range of motion is desired. In martial arts, we typically desire dynamic flexibility, also called kinetic flexibility – the ability to move our muscles to bring a limb through its entire range of motion. Other types of flexibility are static-active flexibility, also called active flexibility – the ability to assume and maintain an extended position using our own muscles. A ballerina holding his or her leg up in a pose is an example of active flexibility. Active flexibility is also of interest in martial arts practice, as it is important to precise control of our limbs, e.g. in order to strike a desired target or pressure point in our opponent. Lastly, static-passive flexibility, also called passive flexibility is the ability to assume and maintain an extended position using gravity or an apparatus. A person performing the “splits” is an example of passive flexibility. When most people think of flexibility, they think of passive flexibility. In reality, active flexibility is more closely related to level of sport and martial arts achievement than passive flexibility. It is also harder to develop than passive flexibility, as it requires not just range of motion but also muscle strength and control.
As we strive to increase our flexibility, it is helpful to first understand the parts of our body that are involved in our joint’s range of motion. While muscle tissue (and, to some extent, yellow-tissue ligaments) can be stretched, tendons as well as white-tissue ligaments are not stretchy. Most “stretching” work is directed toward reducing the internal resistance of the soft connective tissues. This can be accomplished by almost anyone, regardless of fitness level, age or gender. Of course, older and less fit persons will take more persistent work to see results.
Physiology of Stretching
Since the main focus of stretching is elongating our muscles, it is helpful to know a couple of things about muscles. Although our muscles come in many shapes and sizes, they are all composed of strands of tissue called fascicles (think about the strands of muscles that you see when you cut meat or poultry). Fascicles, in turn, are composed of fascicule, which are bundles of muscle fibers. Our body can vary the force a muscle applies by contracting more or fewer of muscle fibers. However, each individual muscle fiber can either be contracted or elongated. There is no such thing as a partially contracted muscle fiber. Likewise, when we stretch a muscle, only some of its fibers will lengthen, while other fibers will remain at rest. The length of the entire muscle depends upon the number of stretched fibers — the more fibers stretched, the more muscle length will be developed in that stretch.
Our muscles typically work in cooperating groups. To keep things simple, we will consider the agonist muscles as those responsible for the primary motion, and the antagonist muscle as responsible for the reciprocal motion. For example, the triceps muscles are responsible for straightening our arm, while the bicep muscles are responsible for bending our arm. (There are also synergists muscles, which assist in the same joint motion as the agonist muscles, as well as fixator, a.k.a stabilizer muscles, which provide support and assistance in holding the body in place while the movement occurs.) When an agonist contracts, our body naturally relaxes the antagonist. This is called reciprocal inhibition, because our body prevents the antagonist from contracting. It is usually easier to stretch a muscle that is relaxed that to stretch a muscle that is contracting. We can take advantage of reciprocal inhibition in order to relax the muscle we are attempting to stretch by contracting the opposing muscle. For example, to help in stretching the hamstrings, you can contract the quadriceps.
Another part of our anatomy that is helpful to understand when training to increase our range of motion involves our neural system. Spindle cells stretch receptors are located in the belly of each of our muscles. When those stretch receptors sense that a muscle is approaching its full length, they send a message for the muscle to contract. In this way, our musculoskeletal system protects us from tearing our own muscles. This is called the stretch reflex – a muscle reaction in response to stretching within the muscle. An example of the stretch reflex is the “knee-jerk” reaction with which we are all familiar: when our family doctor strikes our patellar ligament with a hammer, the spindle activates the muscle spindle receptors in our quadriceps muscles, which causes the quads to contract, and our knee to straighten. As we stretch, unchecked, the stretch reflex will tend to work against our stretch, contracting the muscles we are attempting to elongate. Learning to relax, and learning how to work with our stretch reflex rather than against it are keys to safe and productive stretching. Another type of receptors that are important to understand for proper stretching are Golgi tendon organ (also called the Golgi receptor). The Golgi tendon organ senses when a tendon is being places under high strain, and command the respective muscle to relax (so as to protect the tendon from tearing). The Golgi tendon organ detect and respond to changes in muscle tension, and are therefore not active during passive stretches. An example for the Golgi reflex is when we drop a weight that our body senses is too heavy for us to lift safely. One of the reasons for holding a stretch for a period of time is that as we hold the muscle in a stretched position, that muscle’s spindle receptors become accustomed to the stimulus, and reduce their signaling. This allows us to gradually (and the emphasis is on “gradually”) train our stretch receptors to allow greater lengthening of our muscles. This lengthening reaction is also made possible because the signaling from the Golgi tendon organ telling to muscle to relax is powerful enough to overcome the signaling of the muscle spindle reactors telling the muscle to contract. We will discuss techniques to accomplish this is just a few moments.
Stretching Techniques and Practice Tips
With a basic understanding of the physiology, we can turn to discuss the different types of stretching. In general, there are five types of stretches:
- Ballistic stretching, which uses the momentum of our body or limb to force it beyond its normal range of motion, and typically involved “bouncing” into and out of a stretched position. Generally speaking, researchers and physicians consider ballistic stretching to not only not be useful for developing flexibility, but also expose the practitioner to a high risk of injury. Consequently, ballistic stretching should not be practiced.
- Dynamic stretching, which involves moving parts of your body and gradually increasing reach, speed of movement, or both. Two examples of dynamic stretching we perform in class are the “leg swing” exercise in which we gently swing our legs through their entire range of motion, as well as the gentle torso twists. It is important not to confuse dynamic stretching with ballistic stretching. In dynamic stretching, our aim is to gently move ourselves to limit of our range of motion. There are no bounces or jerky movements, as are used in ballistic stretching to move the limb beyond its range of motion. Dynamic stretching improves dynamic flexibility, and is very useful as part of a warm up for martial arts practice.
- Active stretching (also called static-active stretching) involves assuming a position using our own muscles, and holding that position with no assistance other than our agonist muscle. This will cause the antagonist muscle (the reciprocal muscle) to relax, and facilitate the stretch. For example, in the Yoga “warrior 2” pose that we often practice in class, one of the objectives is to contract the gluteal muscles in order to stretch the muscles in the front of our hips. In fact, most yoga poses (yoga asanas) employ active stretching.
- Passive stretching (also called static-passive stretching) involved assuming a position, and then holding it with the use of another body part of an apparatus. For example, in the seated forward bend stretch we perform in class, we use gravity to hold fold our hips and torso over our legs, as we stretch our hamstrings and back. Passive stretching is helpful for cool down and post-workout.
- Isometric stretching is a type of static stretch which involves isometric contraction of the stretched muscle (isometric contraction is a type of muscle contraction in which the joint angles and muscles length do not change). In the typical isometric stretch, we assume the position of a static stretch. Then, we tense the muscle for 7 to 15 seconds. Lastly, we relax the muscle for 20 seconds or more. The yoga “guerilla pose” we do in class (in a fold, placing our palms under our feet, and then contracting our hamstrings as if we are trying to rise) is an isometric stretch for the hamstrings and back of the body. Another isometric stretch that will be familiar to most is the calf stretch performed while pushing against a wall. Isometric stretching should be practiced carefully, as it is easy for inexperienced practitioners to over stretch. Ideally, we will start with strength training before engaging in isometric stretching for the respective muscles. Also, we will not engage in more than one isometric stretching session in a day for each given muscle. Isometric stretching is effective because it takes a muscle that is already at the limit of its static stretch, and allows muscles’ stretch receptors habituate to a status of further lengthened position. The intense muscle contraction, which is maintained for a period of time, serves to fatigue the contracting muscle, which makes body’s stretch reflex less effective. Also, the tension generated by the intense contraction activates the Golgi tendon organ, which inhibit contraction of the muscles during the relaxation phase. In other words, isometric stretching helps us “trick” the body’s stretch reflex.
- Proprioceptive Neuromuscular Facilitation (PNF) stretching is a technique for combining isometric stretching with passive stretching. It is the fastest and most effective way for increasing static-passive flexibility. It does come with a price, which is that non judicious use of PNF stretching can quickly lead to muscle tearing, over stretching and injury. PNF works by taking advantage of the increased muscle length generated in an isometric stretch, by immediately placing the muscle in a static stretch. There are two PNF stretching techniques that we use in class (other PNF techniques are very advanced, and should only be used by athletes who have developed excellent control of their muscles’ stretch reflexes – otherwise, they are almost guaranteed to lead to injury). The first is the hold-relax PNF technique: after entering an initial passive stretch, we isometrically contract the stretched muscle for 7-15 seconds. We then briefly relax the muscle for a few seconds, and immediately enter a static stretch that stretches the muscles even further than the initial static stretch. We then relax for about 20 seconds, before attempting to repeat the PNF cycle. The second if the hold-relax-contract PNF technique. First, we assume a static stretch. Then, we isometrically contract the stretched muscle for 7-15 seconds. Lastly, we relax the stretches muscle while contracting the antagonist muscle, and position is held for another 7-15 seconds. We then relax the muscle for 20 seconds before performing another PNF technique. The same caveats mentioned above in our discussion on isometric stretching should be followed when utilizing PNF techniques. That is – no more than one session per day for a given muscle.
Having discussed the various types of stretches, let’s talk about when to stretch. A good rule is to start our activity with a sport-specific warm up. Proper warm raises our body temperature, and prepared our body for the activity. Aerobic activity, and joint rotations are good components of a warm up routine. As our body becomes warm, we can incorporate static and dynamic stretches, which will prepare us for our martial arts workout. Since martial arts uses almost every part of our body, we stretch our back and sides, head and neck, arms and wrists, groin and thighs, as well as chest, hamstrings, calves, shins, feet and insteps. The aim of these pre-workout stretches is not to develop added muscle length, but rather to limber our bodies before exercise. The proper time to perform developmental stretches, i.e., stretches aimed at increasing our range of motion, is following exercise, or on our off days (of course, following a proper warm up).
An important component of a good stretch is breathing. This is well known by experienced yogis and other athletes. Proper breathing helps relax the body, while increasing blood flow. As a general rule, you should take deep, slow abdominal breaths while stretching. The breath cycle starts with diaphragmatic breath that first fills the lower belly, rises to the lower rib cage, and finally fills the upper chest and throat. In yoga, this is called Ujjayi breath. You have probably experienced a similar form of breathing in Qigong practice. You can control the rate of your breathing by using the glottis in the back of your throat. By restricting the glottis, you will produce a very soft and soothing ocean sound from deep within your throat. This will allow you to extend your exhale cycle and deepen your breath. You should not labor on your breath – it should be natural and relaxed. Aim to exhale as your muscle is stretching. With proper breathing, the increased blood flow to the stretched muscles will improve their elasticity.
You should listen to your body when performing stretches, and especially developmental stretches designed to increase your range of motion. Some discomfort during the stretch is natural, but it is up to you to get in touch with your own body and discern when you can “go deeper” and when you should back off. If you feel any intense pain during the stretch you should immediately back off. Also, if you don’t feel pain during the stretch, but are sore the following day (and I am not talking about the soreness of a person who has not worked out regularly and is just starting in a workout routine), then you may be overstretching. Learning to get in touch with your body is another benefit of an exercise and stretch program.
Stretching and strengthening are yin and yang. They should both be part of a martial arts training program, and should be in balance. It is not productive to do too much of one or too little of the other.
And, to finish up, and in time for the Holidays, here is a collection of three “stretching videos”.
The first is of Jean Claude Van-Damme, performing the so-called “Epic Split”. This is actually a commercial for Volvo trucks and is quite impressive (if you ever tried to drive a big rig / semi-trailer truck backwards, you know that this is not an easy feat).
No to be undone, Chuck Norris (not really), bettered Jean Claude Van-Damme with Chuck’s version of the “Epic Split”, just in time for Christmas. If you ever tried formation flying, especially in a C-5 Galaxy military transport, and with only one foot of separation, you know that this is very impressive — wink wink. But — who can argue with Chuck Norris.
And, last but not least, Master Ken of Ameri-Do-Te YouTube fame performing his own version of the Epic Split here:
Stay healthy, and keep on training!
Do you have a question or comments about stretching? Is there a particular stretching routine that has worked for you? Please comment below!