Flexibility: The Ability To Bend Without Breaking

Transcription

1 Flexibility: The Ability To Bend Without Breaking WARNING! Before you try and stretch someone, we think it s important to realize what you are actually stretching. Muscles attach to fascia, bone, or a tendon that transmits the force of the muscle through the bone. Let s begin with fascia. Your whole body is basically surrounded by fascia. Each myofibril is wrapped by a layer of connective tissue, or fascia, called the endomysium, that electrically insulates each fiber. The endomysium is also continuous with the fiber sarcolemma, or cell membrane. These muscle fibers (up to 150) are wrapped in groups called fasciculi. Fasciculi are wrapped in yet another layer of connective tissue called the perimysium that becomes continuous with the tendon. The entire muscle belly consists of many fasciculi bundled together and wrapped by another connective tissue sheath called the epimysium. The tendon attaches to the periosteum, which is a special type of connective tissue covering all your bones. In a comparison of the relative contribution of soft tissue to joint resistance, the muscle along with the fascia was found to account for 41% of the resistance. 4 The three-component mechanical model of the muscle consists of the contractile component, found CHAPTER 4 : FLEXIBILITY in the cross-bridging of the actin and myosin filaments, and two passive components: the parallel elastic component and the series elastic component. The parallel elastic component (PEC) consists of the endomysium, perimysium, and epimysium. The PEC is primarily responsible for the force exerted by a relaxed muscle when stretched beyond its resting length. Remember, the resting length of a muscle is the length the muscle would be if you cut it off your body and lay it on the table. Optimal length is approximately 1.2 times the resting length. However, 1.5 times resting length has very few crossbridges and approaches passive insufficiency. You also have the series elastic component (SEC), which consists of the tendon, cross-bridges, and z-discs. The SEC is immediately put under tension in an actively contracted muscle. That s why mechanical tension is stored in the muscle if you stretch too far. The elastic components store tension created by the contractile force, which can then be transferred to the bone. 2 There also exists an involuntary response that maintains muscle tonus. Proprioceptors located within the nerve endings are protective sensory receptors that provide rapid feedback, or stimuli, to the Central Nervous System (CNS). This action is referred to as Neuromuscular Inhibition. When stretching, your

2 Chapter 4: Flexibility: Page 56 muscles are protected by these proprioceptors. A stretch reflex occurs when a muscle is stretched. The stretch reflex is activated by a sensory receptor in the muscle cell called the muscle spindle. The muscle spindle lies parallel to the muscle fibers and detects both the length and the rate of stretch. The nuclear chain monitors muscle length, and the nuclear bag monitors muscle length and rate of change. When the muscle is being extended ballistically, or stretched too far, these receptors send a message to the central nervous system. If the muscle is either over-stretched or stretched too fast, the spinal cord sends an involuntary red flag reflex for the muscle to contract. Stretch reflex is a protective mechanism that prevents injury from overstretching. Muscle spindles causes stretch reflex, forcing a muscle contraction when the stretch is either too far or too fast. If the goal is to lengthen the muscle, it is important not to engage this reflex. Tendons, on the other hand, are mostly made up of collagen (the most abundant protein in the body), wound together like a rope. They attach muscle to bone. Tendons are resistant to tensile force and are not meant to be stretched. This is due to cross links between the collagen fibers and their relative inextensibility. They are meant to transmit force. If you had slack in your tendons, playing the guitar or performing any intricate motion would be impossible. There is also a sensory organ situated at the musculotendinous junction called the Golgi Tendon Organ. The GTO senses degree and extent of muscle tension by monitoring tendon length. When necessary, the GTO rapidly elicits an inhibitory response, causing the muscle to relax, or shut off. This is sometimes referred to as Reflex Inhibition. Ligaments do have elastic properties, meaning the ability to return to their original shape. They primarily contain collagenous fibers, rendering them highly resistant to tensile force. Their elastic properties allow freedom of movement. You don t want to overstretch your ligaments too much elasticity can create an unstable joint. So, before you start stretching, be aware of what you re trying to stretch. That s why stretching is not unlike any other component of fitness. It s an art. The Art of Stretching Out of the four components of fitness (flexibility, stabilization, strength, and cardiovascular) the most overlooked and under worked is flexibility. If you don t use it, you lose it. When we apply this to stretching and flexibility, we can see the potential to lose range of motion and the increased risk of joint and muscle injury. Range of motion (ROM). Defined as the possible movement about a joint in a static (held) or dynamic (moving) state, within the anatomical limits of the joint structure. Anatomical limits include the joint surfaces, joint capsule, soft tissue (ligaments and cartilage), and the bone itself. ROM can be an indicator of flexibility. Improved flexibility may reduce injury risk by allowing the muscles to work. Flexibility A joint should be capable of moving freely in every direction, specifically through a full or normal range of motion. Flexibility is developed by stretching or training through a full ROM, and can be developed at any age with the appropriate training. However, the rate of development is not always the same at every age. Although daily stretching is recommended, flexibility cannot be improved overnight. Too much flexibility is often associated with joint instability, and should be avoided. Additionally, flexibility is joint specific: An individual may be able to perform the splits yet unable to clasp their hands behind their back. Daily changes in muscular tension may affect flexibility. Therefore, if range of motion is more limited on some days, forcing a stretch may cause injury. Some of the factors that can influence or limit your joint mobility are: 1. Genetics: Genetics play a role in potential ROM. Some clients have natural stretching ability and can achieve greater ROM than others.

3 Page 57: Flexibility: Chapter 4 2. Age: After age 25, most individuals, especially those with inactive lifestyles, undergo significant changes in the connective tissue that ultimately results in a loss of flexibility. Aging causes a loss of elasticity (decreased elastin, collagen breakdown, bone demineralization, tissue dehydration) in the connective tissue that surrounds muscle. The lack of water in soft tissue structures diminishes lubrication and the flow of nutrients to the site, resulting in a more fragile unit. The more active a person tends to be throughout the aging process, the more flexible they will remain. 3. Hypokinesis: A fancy word for physical inactivity or low physical activity, which allows adaptive shortening to connective tissues. This shortening will diminish the connective tissue s ability to reach its full range of motion. When connective tissue becomes shorter and less resilient, injury due to imbalance and improper alignment of the body becomes more likely. 4. Gender: In general, females are more flexible than males. Women are designed for a greater range of flexibility, specifically in the pelvic region, in order to accommodate childbirth. Some of the structural characteristics of the female pelvis that distinguish it from the male pelvis are: Lighter and smoother bones. Round brims. Shallower, more capacious cavities. Larger outlets. Wider sacrosciatic notches. Acetabula that are farther apart. Wider pubic arch. Wider, more curved sacrum. 5. Body type: Many comparisons have been made between body type and flexibility. Recent studies have shown little or no correlation between weight, body type, and the ability to achieve range of motion. Many still believe weight training causes the body to become musclebound and lack overall flexibility. While it is true that overdeveloping muscles may encourage muscular imbalances if stretching is not incorporated into the training program, the perception that strength training independently decreases flexibility is a myth. Since each person may have different concerns with regard to musculature, joint structure, dysfunction, and genetic composition, you want to create programs that are individual to each of your clients. 6. Body Temperature: Body temperature has a direct effect on joints and ROM. A warm up is essential to prepare the body for what is to come. A warm up will elevate the client s core temperature, increase circulation, muscle warmth, and the flow of synovial fluid to joints. This will allow your body to be gently eased in and out of hard work. It is important to warm up first and cool down after. Warm up should last between five and fifteen minutes. Individual design of the warm up depends on various factors, such as: time of day. weather conditions. special populations (e.g., older clients, arthritis, high blood pressure, pregnant, etc.). Warm up should mimic a slower, less intense version of the movements required by the activity. Simply going through the motions for a few minutes works well. A warm up can be used to prepare soft tissue structure for the flexibility necessary in any particular activity. Benefits of a Good Warm Up Increase in body and tissue temperature. Increase in heart rate, which prepares the cardiovascular system for work. Increase in the rate at which energy is released in the body (i.e., the metabolic rate). Increase in respiration, helping the exchange of

4 Chapter 4: Flexibility: Page 58 oxygen from hemoglobin. Increase in the speed at which nerve impulses travel, facilitating body movements. Increase in viscoelasticity of tissue. Increase in physical work capacity. Increase in the efficiency of the reciprocal innervation process (thus allowing muscles to contract and relax faster and more efficiently). Increased metabolism (enzyme activity) by 10-13%. Psychological enhancement of the athlete. Increase force production potential by 2-4% (length/tension ratios). Increase of blood flow through the active muscles. Appropriate neuroendocrine response for supplying energy and rebuilding tissue. Decrease in muscular tension. The general purpose of stretching is to restore muscles that are shortened, tight, or weak to their optimum length. Tight, shortened muscles are more susceptible to tearing, limiting normal ROM and increasing the risk of injury. Types of Stretches Static (active or passive). Hold the body part in a stationary position to stabilize the muscles and connective tissues safely at their greatest length. Lengthening the muscle requires a slow, smooth movement. Breathe into the movement as you stretch. When you feel a natural limit to your range of motion, stop and relax. Forcing yourself or letting an outside force (gravity) push you past that position or into pain can involve the Golgi tendon organ, create injury, or make you sore. Use moderation and don t overstretch or force a muscle. Back off at the point of pain or shaking (stress). The standard duration of stretch per muscle group is approximately seconds. The best results can be achieved with durations of 30 seconds to 1 minute. Dynamic (active) stretch. The body s own movement causes the stretch. Slow rhythmic movement, similar to the training of sport/recreation activity. Begin slowly, restricting the range of motion, and gradually increase to a greater ROM, ending with the activity you re stretching for. This stretch can involve speed, strength, power, and neuromuscular coordination during physical activity to achieve a greater ROM (High force/short duration). This type of dynamic stretching is controlled and is designed to challenge the elastic characteristics of connective tissue, thus increasing their elastic qualities, preparing you for your goal. Ballistic stretching. Uncontrolled bouncing, jerking, bobbing, or pulsing to achieve greater ROM. This technique incorporates a high force, short duration stretch. Although ballistic stretching may appear to be effective, the speed of bouncing during ballistic movements may elicit the stretch reflex. This stretch may cause the muscle to contract, leading to possible tearing of muscle fibers and connective tissue. Because of the possible risks of injury and soreness, ballistic stretching is not the preferred stretching technique for the general population. The disadvantages to ballistic stretching are: The tissues don t have adequate time to adapt to the stretch. It can engage the stretch reflex, increasing muscular tension, making it more difficult to stretch out the connective tissues. Inadequate time for neurological adaptation to take place. Ballistic stretching is sport-specific and thus appropriate for some athletes. PNF stretching (Proprioceptive Neuromuscular Facilitation). Another type of stretching that was developed by physicians and physical therapists for the rehabilitation of patients. These exercises require a knowledgeable and well-trained partner. This technique uses the reflex action of two proprioceptors, the muscle spindle and the Golgi tendon organ, to facilitate muscle relaxation and a fuller ROM stretch. There are two types of PNF. You must use clear and concise communication when using these types of

5 Page 59: Flexibility: Chapter 4 stretching. C-R (contract relax). This technique uses assistance to move a joint or stretch a muscle to its maximum ROM. The client isometrically contracts the desired muscle (agonist) for a count of eight, followed by a short period of relaxation. Then the limb is actively moved further (by the client themselves) into the desired range. Repeat the sequence three to five times. With increased muscle relaxation, you should bypass the stretch reflex. C-R-A-C (contract relax antagonist contract). Repeat the isometric contraction of the desired muscle group for a count of eight, then immediately contract the antagonist muscle for six seconds before relaxing. The client should be able to move into a deeper, fuller range of motion stretch, because the amount of inhibition in the agonist muscle will lessen. Benefits of Stretching Improves muscular balance and body alignment awareness. Reduces lower back pain. Increases neuromuscular coordination. Studies have shown that nerve impulse velocity (the time it takes an impulse to travel to the brain and return) was enhanced with dynamic flexibility training. Increases maintenance of ROM, due to an increase in the quantity and decrease in the viscosity (thickness) of synovial fluid, enhancing a better nutrient exchange. Healthier synovial fluid allows a greater freedom of movement and may decelerate joint degenerative processes. Decreases risk of injury. Increasing ROM decreases the resistance in various tissues and clients are less likely to incur injury by exceeding tissue extensibility during activities. Reduces stress and helps promote mental relaxation. Enhances bodily awareness while increasing physical efficiency and performance. A flexible joint requires less energy to move through its ROM. Helps prevent or reduce delayed onset muscle soreness (DOMS) by increasing blood supply and nutrients to joint structures. Also contributes to improved circulation and nutrient transport, allowing greater elasticity of tissues. Reduces severity of painful menstruation (dysmenorrhea) for female clients. Precautions to Stretching You need to be aware of potential dangers associated with overtraining for excessive flexibility. Excessive stretching can lead to injury caused by joint instability from over-stretched ligaments. Muscle tissue that is over-stretched for prolonged periods has a tendency to develop stretch weakness and lose contractile force, which may increase vulnerability to injury even in mild daily activities. Remember to use balance in everything. Too much of a good thing can turn out to be detrimental. When Not to Stretch When CT or muscles are injured (Sprain, strain). When a bone has recently been fractured. When a muscle or joint is inflamed. When osteoporosis is suspected or known. When stretching produces sharp pain in either muscle or joint. When you suffer from certain vascular diseases. When there is a loss of function or decrease in ROM. Stretching Limitations * Genetics, age, gender, prior stretch patterns. Although daily stretching is advocated, flexibility cannot be increased overnight and shouldn t be rushed. Flexibility/ROM about a joint is affected by: a) bone structure b) ligaments (attach bone to bone) c) elasticity of skin d) muscles e) tendons (attach muscles to bones) f) fascia * Avoid hyper extending, hyper flexing, or torquing any joint

6 Chapter 4: Flexibility: Page 60 Dangers of Hyper Flexibility Over flexibility may cause joint instability Precautions during pregnancy would include moderate stretching. Contraindicated: Cervical strain, disc bulge or herniation, spondolythisis (although rare in this region). Everyone Can Benefit From Stretching! Muscles stretched: Upper trapezius, levator Scapulae, and scalenes. Muscles stretched: Upper trapezius, levator scapulae, and sub-occipital. Contraindicated: Cervical strain, disc bulge or herniation, spondolythisis (although rare in this region). Contraindicated: Cervical strain, disc bulge or herniation, spondolythisis (although rare in this region). Comments: John is performing a more progressive stretch by pulling on the arm and contracting the latissimus dorsi on the same side. Muscles stretched: Sternocleidomastoid, longissimis, anterior scalenes. Muscles stretched: Levator scapulae, upper

7 Page 61: Flexibility: Chapter 4 trapezius, posterior and middle scalenes. Contraindicated: Central stenosis. Contraindicated: Cervical strain, disc bulge or herniation, spondolythisis (although rare in this region). Muscles stretched: Latissimus dorsi. Contraindicated: Shoulder laxity; elbow, wrist, finger pain or injury. Muscles stretched: Pectoralis major, anterior deltoid, corachobrachialis, biceps, and anterior shoulder capsule. Comments: Note the angle between Kelly s shoulder and her extended arm. John is performing a more progressive stretch. Contraindicated: Shoulder subluxation or dislocation. Comments: Do not let the chin jut forward. Muscles stretched: Triceps brachii (long head is emphasized). Muscles stretched: Latissimus dorsi.

8 Chapter 4: Flexibility: Page 62 Muscles stretched: Quadriceps. Comments: Don t arch the lumbar vertebrae. Don t yank on the foot. Muscles stretched: Hip flexors. Contraindicated: Lumbar strain/injury or hip injury. Muscles stretched: Soleus or gastrocnemius. Contraindicated: Ankle injury. Comments: John s leg is straight, emphasizing the gastrocnemius; while Kelly s leg is bent, emphasizing the soleus.

9 Page 63: Flexibility: Chapter 4 Muscles stretched: Adductors. Muscles stretched: Hamstrings and lower back. Contraindicated: Lower back injury, muscle strain. Comments: John is performing a more progressive stretch than Kelly. Contraindicated: Muscle strain. Comments: Keep the spine straight. Imagine you re being pulled upward by a string through your spine. Muscles stretched: Assisted adductor stretch. Muscles stretched: Hamstrings and lower back. Contraindicated: Lumbar strain, disc bulge or herniation, spondolythisis, hamstring strain, or some knee injuries. Contraindicated: Muscle strain. Comments: This is a more progressive stretch. Don t pull on your client. Comments: Don t let knees hyperextend.

10 Chapter 4: Flexibility: Page 64 Muscles stretched: Hamstring, lower back, and adductor. Contraindicated: Muscle strain, disc problems, lumbar strain, or spondolythisis. Comments: The client can bend their knee if it starts to tremble. For a more progressive stretch, try dorsi flexing or extending the ankle on the extended leg. Muscles stretched: Pectoralis major, anterior deltoid, corachobrachialis, and biceps. Contraindicated: Weak anterior wall from shoulder subluxation, rotator cuff injury, muscle strain, or wrist injury. Comments: Keep the spine straight and try not to jut the head forward. For some people, sitting on their knees will not be comfortable. Muscles stretched: Hamstrings and lower back. Contraindicated: Muscle strain, disc problems, lumbar strain, or spondolythisis. Comments: The client can bend their knees if they start to tremble. For a more progressive stretch, try dorsi flexing or extending the ankles. Muscles stretched: Quadriceps, hip flexors. Contraindicated: Knee or lower back problems. Comments: John is performing a more progressive stretch. Do not perform this stretch if there are knee problems.

11 Page 65: Flexibility: Chapter 4 Muscles stretched: Latissimus dorsi and lower back. Contraindicated: Shoulder subluxation, rotator cuff injury or muscle strain. Muscles stretched: Neck extensors. Contraindicated: Cervical strain, disc bulge, or herniation. Comments: Never yank or drop someone s head. Muscles stretched: Abdominals. Contraindicated: Lower back pain, injury. Comments: Most people won t need to stretch their abdominals. Muscles stretched: Upper trapezius, scalenes, splenius capitis. Contraindicated: Cervical strain, disc bulge, or herniation. Comments: Watch their face and move slowly. Muscles stretched: Quadriceps. Contraindicated: Knee problems. Comments: Notice John s foot is inverted because the girth in his thigh won t allow that much range of motion. That was the only way he could bring his foot to his glute.

12 Chapter 4: Flexibility: Page 66 Muscles stretched: Levator scapulae, upper trapezius. Contraindicated: Cervical strain, disc bulge, or herniation. Comments: Aim the chin toward the armpit. Always maintain the head directly over the body in neutral. Do not flex the head forward or extend the head backward. Muscles stretched: Obliques, gluteus maximus, external rotators, lower back, chest. Contraindicated: Lower back strain, spondolythisis, hip injury, or shoulder injury. Comments: Do not try to make a sound or crack their back. That s not the goal. Muscles stretched: Hamstrings. Muscles stretched: Latissimus dorsi. Contraindicated: Shoulder laxity, impingement, frozen shoulder, rotator cuff injury. Contraindicated: Hip replacement, hip pain, low back injury, knee pain, muscle strain. Comments: This is a great position in which to perform Proprioceptive Neuromuscular Facilitation (PNF). Keep the shoulder close to the knee. Comments: Stabilize the client by cupping their anterior superior iliac crest. Don t go so far that you affect the head.

13 Page 67: Flexibility: Chapter 4 Muscles stretched: Quadriceps. Contraindicated: Knee injury. Comments: Monitor the ankle as well. Muscles stretched: Hip flexors, external rotators, lower back. Contraindicated: Hip replacement, hip pain, lower back injury, muscle strain. Comments: This stretch just feels good. Keep proper alignment yourself. Try not to hyper-extend the lumbar spine. Muscles stretched: Soleus. Contraindicated: Ankle injury. Comments: Keep good posture yourself. Muscles stretched: Hip flexors (iliopsoas). Contraindicated: Hip injury, lower back injury, muscle strain. Comments: Watch the range in the hip extension.

14 Chapter 4: Flexibility: Page 68 References 1. Norkin, C. C., & Levangie, P. K. (1992). Joint structure and function: A comprehensive analysis (2nd ed.). Philadelphia: F. A. Davis Company. 2. Hamill, J., & Knutzen, K. M. (1995). Biomechanical basis of human movement. Hagerstown, MD: Lippincott William & Wilkins. 3. McArdle, W. D., Katch, F. I., & Katch, V. L. (1986). Exercise physiology: Energy, nutrition, and human performance (2nd ed.). Philadelphia: Lea & Febiger. 4. Simon, Mitch, RTS Manual, Mastery Course 3rd edition Advanced flexibility is required to perform this motion