Chapter 11 Plyometric Training Concepts:

• Know all definitions throughout the chapter
• Integrated performance paradigm
• The phases of Plyometric Exercise
• Figure 11.2 Program design parameters for reactive training
• OPT™ Level (adaptation): Stabilization, Strength, or Power (be familiar with all exercises listed, as well as how to regress and progress the exercises listed)
• Type of Exercise: Balance
• Table 11.1 Plyometric training program design

Principles of Plyometric Training

• Also known as jump or reactive training, form of exercise that uses explosive movements such as bounding, hopping, and jumping to develop muscular power.
• Plyometric training is type of training where individual reacts to the ground surface in such a way that they develop larger than normal ground forces that can then be used to project body with greater velocity or speed of movement.
• Reactive training refers to reaction stimulus clients encounter during plyometric training, which is ground surface in this case, therefore reactive and plyometric are used interchangeably.
• Individuals must possess adequate core strength, joint stability, and range of motion and have ability to balance efficiently before performing any plyometric exercises.

What is Plyometric Training?

• Enhanced performance during functional activities emphasizes the ability of muscles to exert maximal force output in a minimal amount of time(also known as rate of force production).
• Rate of Force Production – Ability of muscles to exert maximal force output in minimal amount of time. 
• Success in everyday activities and sport depends on speed at which muscular force is generated. Speed of movement is function of training, reactive neuromuscular control is function of learning. Key then is muscular overload and rapid movements during execution of training exercises.
• Plyometric (reactive) training – Exercises that generate quick, powerful movements involving an explosive concentric muscle contraction preceded by an eccentric muscle action. 
• Explosive muscular contractions can be seen in practical instances such as rebounding in basketball.
• Integrated Performance Paradigm – Move with efficiency, forces must be dampened(eccentrically), stabilized(isometrically), and then accelerated(concentrically). So muscles must slow down in eccentric phase, pause isometrically, then explosively accelerate in concentric phase.

Three phrases of Plyometric Exercise

• Eccentric Phase – First stage of plyometric movement, classified as eccentric phase, but also called deceleration, loading, yielding, counter movement, or cocking phase. Phase increases muscle spindle activity by prestretching the muscle before activation. Potential energy stored in the elastic components of the muscle during this loading phase much like stretching a rubber band.
• Amortization Phase – Dynamic stabilization and is time between end of eccentric muscle action and initiation of concentric contraction. Prolonged amortization phase results in less than optimal neuromuscular efficiency from a loss of elastic potential energy. Rapid switch from eccentric loading to concentric contraction leads to a more powerful response.
• Concentric phase – occurs immediately after amortization phase, involves concentric contraction.

Importance of Plyometric Training

• Plyo exercises enhance excitability, sensitivity, and reactivity of neuromuscular system and increase the rate of force production(power), motor unit recruitment, firing frequency(rate coding) and motor unit synchronization. 
• These exercises can be incorporated once client has achieved an overall strength base, proper core strength, and balance stabilization capabilities.
• All movement patterns that occur during functional activities involve a series of repetitive stretch-shortening cycles(eccentric and concentric contractions). Stretch-shortening cycles require neuromuscular system to react quickly and efficiently after an eccentric muscle action to produce a concentric contraction and impart necessary force(or acceleration) in the appropriate direction. Plyometric training prepares client for functional demands of specific activity.
• Plyometric training provides ability to train specific movement patterns in a biomechnically correct manner at more functionally appropriate speed. Ultimate goal of plyometric training is to decrease the reaction time of muscle action spectrum, this is what results in increased speed of movement in the individual.
• Speed of muscular exertion is limited by neuromuscular coordination. Means that the body will only move within a range of speed that the nervous system has been programmed to allow. Plyo training improves neuromuscular efficiency and improves range of speed set by CNS.
• Often overlooked in traditional training programs.

Designing a Plyometric Training Program

Stabilization Exercises

• Involve little joint motion. Designed to establish optimal landing mechanics, postural alignment, and reactive neuromuscular efficiency(coordination during dynamic movement). When individual lands they should hold the landing position for 3 to 5 seconds.
• Exercises: Squat jump with stabilization, box jump-up with stabilization, box jump-down with stabilization, multiplanar jump with stabilization

 

Plyometric Strength Exercises

• Exercises involve more dynamic eccentric and concentric movement through a full range of motion. Specificity, speed, and neural demand may also be progressed at this level. Exercises are intended to improve dynamic joint stabilization, eccentric strength, rate of force production, and neuromuscular efficiency of the entire human movement system. Performed in repetitive fashion(spending relatively short time on the ground before repeating the drill).
• Exercises: Squat jump, tuck jump, butt kick, power step-up

Plyometric Power Exercises

• Exercises involve entire muscle action spectrum and contraction-velocity spectrum used during integrated, functional movements. Designed to further improve the rate of force production, eccentric strength, reactive strength, reactive joint stabilization, dynamic neuromuscular efficiency, and optimal force production. Performed as fast and explosively as possible.
• Exercises: Ice-skaters, single-leg power step-up, proprioceptive plyometrics.

Designing a Plyometric Training Program

Chapter 9 Core Training Concepts:

• Know all definitions throughout the chapter
• Local Stabilization System
• Global Stabilization System
• Table 9.1 Muscles of the Core
• It is your responsibility to learn how to categorize, progress, and regress body position while performing certain types of exercises.
• The OPT model is divided into three different blocks of training and each building block contains specific phases of training that systematically advances the student in a safe and progressive manner. Exercises can be categorized by adaptation and by type of exercise:
• OPT Level (adaptation): Stabilization, Strength, or Power (be familiar with all exercises listed, as well as how to regress and progress the exercises listed)
• Type of Exercise: Core
• Table 9.3 Core training program design

Core Musculature

• Core – Structures that make up lumbo-pelvic-hip complex(LPHC) including lumbar spine, pelvic girdle, abdomen, and hip joint.
  
• Core is where body’s center of gravity is located and where all movement originates. Strong and efficient core is necessary for maintaining proper muscle balance throughout the entire human movement system(kinetic chain).
• Optimal length-tension relationships, recruitment patterns, and joint motions in muscle of LPHC establish neuromuscular efficiency throughout entire human movement system. Allow for efficient acceleration, deceleration, and stabilization during dynamic movements, as well as prevention of possible injuries.

Local Stabilization System

• Local stabilizers are muscles that attach directly to vertebrae. Consist primarily of slow twitch type I fibers with high density of muscle spindles. Work to limit excessive compressive, shear, and rotational forces between spinal segments. 
• Primary muscles that make up local stabilization system include transverse abdominis, internal obliques, multifidus, pelvic floor musculature, and diaphram. INcrease intra-abdominal pressure(pressure within abdominal cavity) and generating tension in thoracolumbar fascia(connective tissue of low back), increasing spinal stiffness for improved intersegmental neuromuscular control.

Global Stabilization System

• Muscles of global stabilization system attach from pelvis to the spine. These transfer loads between upper extremity and lower extremity, provide stability between pelvis and spine, and provide stabilization and eccentric control of the core during functional movements.
• Primary muscles that make up global stabilization system include quadratus lumborum, psoas major, external obliques, portions of the internal oblique, rectus abdominis, gluteus medius, and adductor complex.

Movement System

• Movement system includes muscles that attach the spine and/or pelvis to the extremities. These muscles are primarily responsible for concentric force production and eccentric deceleration during dynamic activities. Primary muscles that make up movement system include latissimus dorsi, hip flexors, hamstring complex, and quadriceps.
• Collectively all muscles within each system provide dynamic stabilization and neuromuscular control of entire core (LPHC). These produce force(concentric), reduce force(eccentric), and provide dynamic stabilization in all planes of movement during functional activities. In isolation, these muscles do not effectively achieve stabilization of LPHC; rather it is through their synergistic interdependent functioning that they enhance stability and neuromuscular control.
• Training movement system muscles before training muscles of global and local stabilization systems would not make sense from structural and biomechanical standpoint. Doing so would be analogous to building a house with no foundaiton.

Importance of Properly Training the Stabilization Systems

• Some active individuals have developed strength, power, and muscular endurance in the movement system, which enables them to perform functional activites. Few people have developed the local stabilization muscles required for intervertebral stabilization. The body’s core stabilization system has to be operating with maximal eficiency to effectively use the strength, power, and endurance that has been developed in prime movers. If movement system musculature of the core is strong and local stabilization system is weak, the kinetic chain senses imbalance and forces are not transferred or used properly. This leads to compensation, synergistic dominance, and inefficient movements.
• Weak core can lead to inefficient movement and predictable patterns of injury. Resulting in lower back pain and injury.

Scientific Rationale for Core Stabilization Training

• Individuals with chronic LBP have decreased activation of certain muscles or muscle groups, including transverse abdominis, internal obliques, pelvic floor muscles, multifius, diaphram, and deep erector spinae. Also waeaker back extensor muscles and decreased muscular endurance. 
• Studies support role of core training in prevention and rehabilitation of lower back pain. Core stabilization exercises restore size, activation, and endurance of multifidus(deep spine muscle) in individuals with lower back pain. Programs that include specific core stabilization training tend to be more effective than manual therapy alone.
• Drawing-in Maneuver – Used to recruit the local core stabilizers by drawing the navel in toward the spine.
• Bracing – Occurs when you have contracted both the abdominal, lower back, and buttock muscles at the same time.
• Traditional low-back hyperextension exercises without proper lumbo-pelvic-hip stabilization have been shown to increase pressure on discs to dangerous levels.

Drawing-in Maneuver

• Research has demonstrated electromyogram (EMG) activity is increased during pelvic stabilization and transverse abdominis activation when an abdominal drawing maneuver is initiated before activity.
• Transverse abdominis, when properly activated, creates tension in thoracolumbar fascia, contributing to spinal stiffness, and compresses sacroiliac joint, increasing stability.
• Pull region just below navel toward spine and maintain cervical spine in neutral position. Maintaining neutral spine during core training helps improve posture, muscle balance, and stabilization. If forward protruding head is noticed during drawing-in maneuver, sternocleidmastoid (large neck muscle) is preferentially recruited, which increases the compressive forces in the cervical spine and can lead to pelvic instability and muscle imbalances as a result of the pelvo-ocular reflex. Important to maintain the eyes level during movement.

Bracing

• Co-contraction of global muscles, such as rectus abdominis, external obliques, and quadratus lumborum. Muscular endurance of global and local musculature, when contracted together, create the most benefit for those with LBP compared with traditional LBP training methods. 
• Bracing focuses on global trunk stability, not on segmental vertebral stability, meaning that the global muscles, given the proper endurance training, will work to stabilize the spine.

Guidelines for Core Training

• Core training should be systematic, progressive, functional, and emphasize the entire muscle action spectrum focusing on force production, force reduction, and dynamic stabilization. Core training program should regularly manipulate plane of motion, range of motion, modalities(tubing, stability ball, medicine ball, Bosu ball, Airex pad, etc.) body position, amount of control, speed of execution, amount of feedback, and specific acute training variables(sets, reps, intensity, tempo, and frequency).
• When designing core training program, personal trainer should initially create a proprioceptively enriched(controlled yet unstable) selecting appropriate exercises to elicit maximal training response.
• Core exercises performed in unstable environment(such as with stability ball) have been demonstrated to increase activation of local and global stabilization systems when compared to traditional trunk exercises.
• Safe and challenging, stress multiple planes in a multisensory environment derived from fundamental movement skills specific to activity.

Designing a Core Training Program

• Goal of core training is to develop optimal levels of neuromuscular efficiency, stability(intervertebral and lumbopelvic stability-local and global stabilization systems) and functional strength(movement system). Neural adaptations become focus of program instead of absolute strength gains. 
• Increasing proprioceptive demand is more important than increasing external resistance.
• Quality of movement should be stressed over quantity.
• Client beings at highest level at which they are able to maintain stability and optimal neuromuscular control(coordinated movement). Progresses through program once mastery of exercise in previous level has been achieved while demonstrating intervertebral stability and lumbopelvic stability. Client has appropriate lumbopelvic stability when able to perform functional movement patterns(squats, lunges, step-ups, single-leg movements) without excessive spinal motion(flexion, extension, lateral flexion, rotation, singly or in combination). Critical that core training program is designed to achieve following functional outcomes:
• Intervertebral stability, lumbopelvic stability, movement efficiency

Levels of core training

• Three levels of training within OPT model, stabilization, strength, power, proper core training program follows same systematic progression.
• Core-Stabilization Training – Exercises involve little motion through the spine and pelvis. Designed to improve neuromuscular efficiency and intervertebral stability, focusing on drawing-in and then bracing during the exercises. Traditionally spend 4 weeks at this level of core training.
• Core Strength – Involve more dynamic eccentric and concentric movements of the spine throughout full range of motion while clients perform the activation techniques learned in core-stabilization training. Specificity, speed, and neural demands are progressed at this level. Traditionally spend 4 weeks at this level of core training.
• Core Power – Improve rate of force production of core musculature. Prepare an individual to dynamically stabilize and generate force at more functionally applicable speeds. Rotation chest pass, medicine ball pullover throw, front MB oblique throw, soccer throw.
• Core musculature helps protect spine from harmful forces that occur during functional activities. Core program designed to increase stabilization, strength, power, muscle endurance, and neuromuscular control in LPHC. Core training programs must be systematic, progressive, activity or goal-specific, integrated, and proprioceptively challenging. Proper core training follows same systematic approach as OPT model: stabilization, strength, and power.

Implementing a Core Training Program

• Requires that fitness professional follow progression of OPT model. Ex if client is in stabilization level(phase 1) select core stabilization exercises. For client in strength level, select core-strength exercises.

Chapter 8 Cardiorespiratory Fitness Training:

Know all definitions throughout the chapter:

• Overtraining page
• General vs. Specific Warm-up
• Cool down Phase
• Figure 8.1 FITTE factors
• Table 8.9 Training Zones
• Circuit Training

Cardiorespiratory Fitness Training

• Cardiorespiratory Fitness – Ability of the circulatory and respiratory systems to supply oxygen-rich blood to skeletal muscles during sustained physical activity. One of five components to health-related physical fitness; others are muscular strength, muscular endurance, flexibility, and body composition. Top priority from standpoint of preventing chronic disease and improving health and quality of life.
  
• Integrated Cardiorespiratory Training – Cardiorespiratory training programs that systematically progress clients through various stages to achieve optimal levels of physiological, physical, and performance adaptations by placing stress on the cardiorespiratory system. Personal trainers fail to take into effect the rate of progression, rate of progression critical to helping clients achieve personal health and fitness goals in most efficient and effective use of time and energy.
• Initial exercise prescription should reflect initial fitness level of client, fitness assessment results, and whether the client has any significant risk factors or health limitations to exercise. Warm-up, conditioning, cool-down.

Warm-up Phase

• General Warm-Up – Low intensity exercise consisting of movements that do not necessarily relate to the more intense exercise that is to follow.
  
• Specific Warm-Up – Low-intensity exercise consisting of movements that mimic those that will be included in the more intense exercise that is to follow.
• Suggested warmup activities – Self myofascial release, static stretching, cardio exercise. Sedentary clients or health limitations or previous injuries may have half or more dedicated workout time to warm-up activities.

Cooldown Phase

• At rest only 15-20% of circulating blood reaches skeletal muscle, but during intense vigorous exercise it increases up to as much as 80 to 85% of cardiac output. During exercise blood is shunted from major organs and redirected to skin to promote heat loss. Blood plasma volume also decreases, increased blood pressure forces water from vascular compartment to interstitial space. Plasma volume can decrease by as much as 10 to 20%. Cool-down period helps gradually restore physiological responses to exercise close to baseline levels.

General Guidelines for Cardiorespiratory Training

• FITTE – Frequency, intensity, time, type, enjoyment
• Frequency – number of training sessions in a given timeframe. Usually expressed as per week. Recommended frequency of activity is every day of week for small quantities of time for general health, for improved fitness levels frequency is 3 to 5 days per week at higher intensity.
• Intensity – Level of demand that a given activity places on the body. Established and monitored in numerous ways including calculating heart rate, power output(watts), or calculating VO2 max. Moderate exercise is 60% VO2 max or less. Talk comfortable during exercise for general health.
• VO2 max – Highest rate of oxygen transport and utilization achieved at maximal physical exertion.
• Oxygen Uptake Reserve – Difference between resting and maximal or peak oxygen consumption.

Methods for prescribing exercise intensity

• Peak VO2 Method. Traditional gold standard for measuring cardiorespiratory fitness. VO2 max. Maximal volume of oxygen per kilogram of body weight per minute. Maximal amount of oxygen that individual can use during intense exercise. Difficult to measure.
• Peak Metabolic Equivalent(MET) Method – One MET is 3.5 ML O2 per KG per Min, or equivalent of average resting metabolic rate for adults. Activity with 4 METS will require 4 times energy that person consumes at rest.
• Peak Maximal Heart Rate (MHR) Method – Most used formula is 220-Age. Never use 220-Age to calculate max heart rate as absolute.
• HR Reserve(HRR) Method – Karvonen method. Establishing training intensity based on difference between predicted maximal heart rate and resting heart rate. Most common and universally accepted method of establishing exercise training intensity. THR = [(HRmax – HRrest) x desired intensity] + HR rest
• Ratings of perceived exertion method – Used to express or validate how hard a client feels he or she is working during exercise. (RPE) method person is subjectively rating perceived difficulty of exercise. 6 is no exertion at all, 20 is maximal exertion.
• Talk test method – Informal method used to gauge exercise training intensity.
• Ventilatory threshold – Point during graded exercise in which ventilation increases disproportionately to oxygen uptake, signifying a switch from predominately aerobic energy production to anaerobic energy production.
• Time – Length of time an individual is engaged in a given activity. Adults should accumulate 2 hrs and 30 mins of moderate intensity aerobic activity or 1 hr 15 mins of intense aerobic activity.
• Type – Mode or type of activity selected. For exercise to be considered aerobic it must be rhythmic in nature, use large muscle groups, and be continuous in nature.
• Enjoyment – Amount of pleasure derived from performing a physical activity. 

Cardiorespiratory Training Methods

Stage Training

• Purpose of stage training is to ensure that cardiorespiratory training programs progress in an organized fashion to ensure continual adaptation and to minimize risk of overtraining and injury.
• Overtraining – Excessive frequency, volume, or intensity of training, resulting in fatigue. 

Stage 1

• Designed to help improve cardiorespiratory fitness levels in apparently healthy sedentary clients using target heart rate of 65 to 75% or max HR. 12 to 13 on rating of perceived exertion scale. Client should be able to hold a conversation during activity. Stage 1 clients start slowly and gradually work up to 30 to 60 minutes of continuous exercise in zone one. Clients who can maintain zone one HR for at least 30 minutes two to three times per week will be ready for stage II. 

Stage 2

• Designed for clients with low to moderate cardiorespiratory fitness levels whoa re ready to begin training at higher intensity levels. Focus on increasing workload(speed, incline, level) Stage 2 helps increase cardiorespiratory capacity needed for workout styles in strength level of OPT model.
• Interval training, intensities varies throughout workout.
• Start by warming up in zone one for 5 to 10 minutes.
• Move into 1-minute interval in zone two. Gradually increase workload to raise heart rate up to zone two within that minute. Once heart rate reaches zone 2 of maximal heart rate, maintain it for rest of that minute. After 1 minute interval return to zone one for 3 mins.
• Repeat this, most important part of interval is to recover back to zone one between intervals.
• Stage 2 it is important to alternate days of the week with stage 1 training. Alternating sessions every workout.

Stage 3

• For advanced client who has moderately high cardiorespiratory fitness level base and will use heart rate zones one, two, and three. Stage III training increases capacity of energy systems needed at the power level of the OPT model.
• Warm up in zone one for up to 10 minutes.
• Increase workload every 60 seconds until reaching zone three. Require slow climb through zone two for at least two minutes.
• After pushing for another minute in zone three, decrease workload. One minute break is important to help gauge improvement.
• Drop client’s workload down to the level he or she was just working in, before starting zone 3 interval.
• As improvements are made during several weeks of training, heart rate will drop more quickly. Faster HR drops, stronger heart is getting.
• If client is not able to drop appropriate heart rate during 1-minute break, assume he or she is tired and about to overtrain. Solution is stay in zone one or two for rest of workout.
• If heart rate does drop to a normal rate, then overload the body again and go to next zone, zone three, for 1 minute.
• After this minute go back to zone one for 5-10 minutes and repeat if desired.
• Rotate all three stages, low stage(stage 1), medium(stage II), and high-intensity(stage III) to help minimize risk of overtraining.

Circuit Training

• Allows for comparable fitness results without spending extended periods of time to achieve them. Very time-efficient manner in which to train a client and will be thoroughly described as it pertains to cardiorespiratory training.
• Circuit-training consists of series of strength-training exercises that an individual performs, one after another, with minimal rest.
• Circuit training was just as beneficial as traditional forms of cardiorespiratory exercise for improving or contributing to improved fitness levels.
• Circuit training resulted in higher postexercise metabolic rates as well as strength levels.

Chapter 7 Flexibility Training Concepts:

Know all definitions throughout the chapter

• Figure 7.10 Integrated flexibility Continuum
• Table 7.2 Examples of stretching within the Flexibility Continuum
• Myofascial Release
• Table 7.3 Static Stretching Summary
• Table 7.4 Active-Isolated Stretching summary
• Table 7.5 Dynamic Stretching summary

Mechanoreceptors = a Golgi tendon organ (GTO) and muscle spindle fibers

GTO	Muscle Spindle Fibers
Senses muscle tension	Senses muscle lengthening
Relaxes the muscle in response	Contracts the muscle in response
Normal reaction to avoid injury	Normal reaction to avoid injury

There is a lot of useful information page 183 of the NASM Essentials of Personal Fitness Training and it will take some time to remember all of that information.  There are various strategies you can try as you attempt to retain that information.  One is to make your studying interactive by asking friends and family members to volunteer for the Overhead Squat Assessment and practice trying to locate compensations.  Another way to learn the probable overactive and probable underactive muscles is by creating flash cards.

You can also look at each overactive muscle and refer back to Appendix D (pages 575-596).  Look at each muscle’s “Isolated Function”.  Some muscles will over-do their “Isolated Function”.  Other muscles tend to be “victims of association”.  This means that they may become synergistically dominant because a muscle nearby becomes underactive/lengthened/weak.

In addition, by having a general idea of what each muscle’s “Isolated Function” is, you will be able to figure out exercises that directly work those muscles.

Think of muscles in terms of antagonistic (one is an agonist while the other is an antagonist) actions. When an agonist contracts, the antagonist will relax. Also keep in mind that several muscles may have similar actions and that the exact movement of a bone will be the result of a coordinated effort involving many muscles (force couples).  Muscles function in integrated groups to allow for neuromuscular control during movement.  A muscle’s integrated muscle function is the action it naturally tends to perform when it works in conjunction with other muscles.  By isolating each muscle on the other hand, and tracing them from their point of origin to their insertion, one can gain a better understanding of that muscle’s main function. A muscle’s isolated function is what that individual muscle is meant to do, alone, and isolated from all other muscles.

An advanced knowledge in anatomy is required to identify muscle functions such as agonists, antagonists, synergists, and stabilizers. For example, most stabilizers are proximal to the joint they stabilize, but it is dependent on the movement that is occurring. Stabilizers are generally smaller in size, made up of type I muscle fibers (slow twitch), and they are prone to weakness.

Some examples of stabilizers include (1) rotator cuff – shoulder (2) core inner unit – multifidus, transverse abdominus, pelvic floor muscles, internal oblique – stabilize pelvis and spine (3) knee- VMO, popliteus – knee. For the exam you only need an understanding of this concept to the degree the textbook discusses. If you want to learn more, then the CES does a good job explaining these concepts in more detail.

Current Concepts in Flexibility Training

• Flexibility – Normal extensibility of all soft tissues that allows the full range of motion of a joint.
  
• Extensibility – Capability to be elongated or stretched. 
• Dynamic range of motion – Combination of flexibility and the nervous sytem’s ability to control this range of motion efficiently. 
• Neuromuscular efficiency – Ability of neuromuscular system to allow agonists, antagonists, and stabilizers to work synergistically to produce, reduce, and dynamically stabilize the entire kinetic chain in all three planes of motion. Ability of nervous system to recruit correct muscles(agonists, antagonists, synergists, stabilizers) to produce force, reduce force, and dynamically stabilize body’s structure in all three planes of motion. When performing cable pulldown, latissimus dorsi(agonist) must concentrically accelerate shoulder extension, adduction, and internal rotation while middle and lower trapezius and rhomboids(synergists) perform downward rotation of the scapulae. Same time rotator cuff musculature(stabilizers) must dynamically stabilize the glenohumeral(shoulder) joint throughout the motion.
• To allow for optimal neuromuscular efficiency, individuals must have proper flexibility in all three planes of motion.

Review of Human Movement System

• Postural distortion pattern – Predictable patterns of muscle imbalances.
  
• Relative Flexibility – The tendency of the body to seek the path of least resistance during functional movement patterns. Prime examlpe are people who squat with feet externally rotated, because of tight calf muscles they lack proper dorsiflexion at the ankle to perform squat with proper mechanics. Another example is overhead press with excessive lumbar extension(arched lower back). Individuals who possess tight latissimus dorsi will have decreased sagittal-plane shoulder flexion (inability to lift arms directly overhead), and as a result they compensate for this lack of ROM at shoulder in lumbar spine to allow them to press load completely overhead.

Muscle Imbalance

• Muscle imbalances – Alteration of muscle length surrounding a joint. 
  
• Muscle imbalances can be caused by – postural stress, emotional duress, repetitive movement, cumulative trauma, poor training technique, lack of core strength, lack of neuromuscular efficiency
• Reciprocal Inhibition – simultaneous relaxation of one muscle and the contraction of its antagonist to allow movement to take place. To perform elbow flexion during biceps curl, biceps brachii actively contracts while triceps brachii(antagonist) relaxes to allow the movement to occur.
• Altered reciprocal inhibition – Concept of muscle inhibition, caused by tight agonist, which inhibits its functional antagonist. Example tight psoas(hip flexor) would decrease neural drive of the gluteus maximus (hip extensor). Altered reciprocal inhibition alters force-couple relationships, produces synergistic dominance, and leads to the development of faulty movement patterns, poor neuromuscular control, and arthrokinetic (joint) dysfunction.
• Synergistic Dominance – Neuromuscular phenomenon that occurs when inappropriate muscles take over the function of a weak or inhibited prime mover. Example if psoas(hip flexor) is tight, leads to reciprocal inhibition of gluteus maximus, which in turn results in increased force output of synergists for hip extension (hamstring complex, adductor magnus) to compensate for weakened glutes. The result of synergistic dominance is faulty movement patterns, leading to arthrokinetic dysfunction and eventual injury(such as hamstring strains).
• Arthrokinematics – Motion of joints in the body. 
• Arthrokinematic dysfunction – Altered forces at the joint that result in abnormal muscular activity and impaired neuromuscular communication at the joint. Altered joint motion can be caused by altered length-tension relationships and force-couple relationships, which affect joint and cause poor movement efficiency. Example, squatting with externally rotated feet(outward) forces tibia(shin bone) and femur(thigh bone) to also rotate externally. This posture alters length-tension relationships of muscles at the knee and hips, putting glutes in a shortened position and decreasing its ability to generate force. Further, biceps femoris(hamstring muscle) and piriformis(outer hip muscle) become synergistcally dominant, altering the force-couple relationships and ideal joint motion, increasing the stress on the knees and low back. With time, stress associated with arthrokinematic dysfunction can lead to pain, which can further alter muscle recruitment and joint mechanics.

Neuromuscular Efficiency

• Neuromuscular efficiency, ability of neuromuscular system to properly recruit muscles to produce force(concentric), reduce force(eccentric), and dynamically stabilize(isometric) the entire kinetic chain in all three planes of motion. Because nervous system is controlling factor behind this principle, it is important to mention that mechanoreceptors(sensory receptors) located in the muscles and tendons help to determine muscle balance or imbalance. Mechanoreceptors include muscle spindles and Golgi tendon organs.

Muscle Spindles

• Muscle spindles are the major sensory organ of the muscle and are composed of microscopic fibers that lie parallel to the muscle fiber. Muscle spindles are sensitive to change in muscle length and rate of length change. Muscle spindle’s job is to help prevent muscles from stretching too far or too fast. 
• When a muscle on one side of a joint is lengthened(because of a shortened muscle on the opposite side), the spindles of the lengthened muscle are stretched. This information is transmitted to brain and spinal cord, exciting the muscle spindle and causing the muscle fibers of the lengthened muscle to contract. This often results in microspasms or feelings of tightness.
• Hamstring complex is prime example when pelvis is rotated anteriorly, meaning the anterior superior iliac spines(front of the pelvis) move downward(inferiorly) and the ischium(bottom posterior portion of pelvis, where the hamstrings originate) moves upward(superiorly). If attachment of hamstring complex is moved superiorly, it increases the distance between the two attachment sites and lengthens the hamstring complex. When a lengthened muscle is stretched, it increases the excitement of the muscle spindles and further creates a contraction(spasm) response. With this scenario, the shortened hip flexors are helping to create the anterior pelvic rotation that is causing the lengthening of the hamstring complex. Instead, hip flexors need to be stretched.
• Another example is individual whose knees adduct and internally rotate(knock-knees) during a squat. The underactive muscle is the gluteus medius(hip abductor and external rotator), and the overactive muscles include adductors(inner thighs) and tensor fascia latae(hip flexor and hip internal rotator). Thus, one would not need to stretch the gluteus medius, but instead stretch the adductor complex and tensor fascia latae which in this case are overactive, pulling the femur into excessive adduction and internal rotation.

Golgi Tendon Organs

• Autogenic Inhibition – Process by which neural impulses that sense tension are greater than the impulses that cause muscles to contract, providing an inhibitory effect to the muscle spindles. 
  
• Golgi Tendon Organs are located within musculotendinous junction(point where muscle and tendon meet) and are sensitive to changes in muscular tension and rate of tension change. When excited, Golgi tendon organ causes the muscle to relax, which prevents muscle from being placed under excessive stress, which could result in injury. Prolonged Golgi tendon organ stimulation provides an inhibitory action to muscle spindles(located within same muscle). This neuromuscular phenomenon is called autogenic inhibition. Occurs when neural impulses sensing tension are greater than impulses causing contraction. This phenomenon is termed autogenic, inhibited by its own receptors.

Scientific Rationale for Flexibility Training

• Flexibility training is key component of all training programs, used for variety of reasons including – correcting muscle imbalances, increasing joint range of motion, decreasing the excessive tension of muscles, relieving joint stress, improving extensibility of musculotendinous junction, improving neuromuscular efficiency, improving function
• Pattern Overload – Consistently repeating same pattern of motion, which may place abnormal stresses on the body. Pattern overload is consistently repeating same pattern, such as baseball pitching, long-distance running, and cycling, with time places abnormal stresses on the body.

Cumulative Injury Cycle

• Poor posture and repetitive movements create dysfunction within the connective tissue of the body. This dysfunction is treated by body as another injury, and as a result, body will initiate repair process termed cumulative injury cycle.
• Any trauma to tissue of the body creates inflammation. Inflammation, in turn, activates body’s pain receptors and initiates protective mechanism, increasing muscle tension or causing muscle spasm. Heightened activity of muscle spindles in particular areas of muscle create a microspasm, and as result of spasm, adhesions(or knots) being to form in the soft tissue. These adhesions form a weak, inelastic matrix(inability to stretch) that decreases normal elasticity of the soft tissue, resulting in altered lenght-tension relationships(leading to altered reciprocal inhibition), altered force-couple relationships, and arthrokinetic dysfunction(leading to altered joint motion). Left untreated adhesions can begin to form permanent structural changes in soft tissue that is evident in Davis’s law.
• Davis’s Law – Soft tissue models along the lines of stress. Soft tissue is remodeled (or rebuilt) with inelastic collagen matrix that forms in a random fashion, usually it does not run in same direction as the muscle fibers. If muscle fibers are lengthened, these inelastic connective tissue fibers act as roadblocks, preventing muscle from moving properly which creates alterations in normal tissue extensibility and causes relative flexibility.
• If a muscle is in a constant shortened state(such as hip flexor musculature when sitting for prolonged periods every day), it will demonstrate poor neuromuscular efficiency(as a result of altered length-tension and force-couple relationships). In turn this will affect joint motion(ankle, knee, hip, and lumbar spine) and alter movement patterns(leading to synergistic dominance). Inelastic collagen matrix will form along the same lines of stress created by the altered muscle movements. Because the muscle is consistently short and moves in a pattern different from its intended function, the newly formed inelastic connective tissue forms along this altered pattern, reducing the ability of the muscle to extend and move in its proper manner. This is why it is imperative that an integrated flexibility training program be used to restore the normal extensibility of the entire soft tissue complex.

The Flexibility Continuum

• Three types of flexibility continuum, corrective, active, and functional.

Corrective flexibility

• Corrective flexibility is designed to increase joint ROM, improve muscle imbalances, and correct altered joint motion. Corrective flexibility includes self-myofascial release(foam roll) techniques and static stretching. Self-myofascial release uses the principle of autogenic inhibition to cause muscle relaxation, whereas static stretching can use either autogenic inhibition or reciprocal inhibition to increase muscle length depending on how the stretch is performed. Corrective flexibility is appropriate at the stabilization level (phase I) of the OPT model.

Active Flexibility

• Active flexibility uses self-myofascial release and active-isolated stretching techniques. Active-isolated stretching is designed to improve the extensibility of soft tissue and increase neuromuscular efficiency by using reciprocal inhibition. Active-isolated stretching allows for agonists and synergists muscles to move a limb through a full range of motion while functional antagonists are being stretched. For example, supine straight-leg raise uses hip flexors and quads to raise leg and hold it unsupported, whiel antagonist hamstring complex is stretched. Active flexibility appropriate at strength levels(phase 2,3, and 4) of OPT model.

Functional Flexibility

• Functional flexibility uses self-myofascial release techniques and dynamic stretching. Dynamic stretching requires integrated, multiplanar soft tissue extensibility, with optimal neuromuscular control, through the full range of motion, or essentially movement without compensations. Therefore, if clients are compensating when performing dynamic stretches during training, then they need to be regressed to active or corrective flexibility. Appropriate at power leve(level 5). 

Stretching Techniques

Myofascial Release

• Self-myofascial release is stretching technique that focuses on the neural system and fascial system in the body. By applying gentle force to an adhesion or “knot,” the elastic muscle fibers are altered from a bundled position(which causes the adhesion) into a straighter alignment with the direction of the muscle or fascia. The gentle pressure will stimulate the Golgi tendon organ and create autogenic inhibition, decreasing muscle spindle excitation and releasing the hypertronicity(tension) of the underlying musculature. Gentle pressure(similar to massage) breaks up knots within muscle and helps to release unwanted muscular tension.
• When person finds tender spot(indicates presence of muscle hypertonicity) and sustain pressure on that spot for minimum of 30 seconds. This will cause Golgi tendon organ activity and decrease muscle spindle activity, thus triggering autogenic inhibitory response. It may take longer, depending on client’s ability to consciously relax. Process will help restore body back to its optimal level of function by resetting proprioceptive mechanisms of soft tissue. Self-myofascial release is suggested before stretching because breaking up fascial adhesions(knots) may potentially improve tissue’s ability to lengthen through stretching techniques.

 

Static Stretching

• Static Stretching – Process of passively taking a muscle to the point of tension and holding the stretch for a minimum of 30 seconds.
  
• By holding muscle in stretched position for prolonged period, Golgi Tendon organ is stimulated and produces inhibitory effect on muscle spindle(autogenic inhibition). This allows muscle to relax and provides for better elongation of the muscle. In addition, contracting the antagonistic musculature while holding the stretch can reciprocally inhibit the muscle being stretched, allowing it to relax and enhancing the stretch.
• Static stretching should be used to decrease muscle spindle activity of a tight muscle before and after activity.

 

Active-Isolated Stretching

• Active-Isolated Stretch – Process of using agonists and synergists to dynamically move the joint into a range of motion.
  
• Increases motorneuron excitability, creating reciprocal inhibition of muscles being stretched. Active supine biceps femoris stretch is good example of active-isolated stretching. Quads extends the knee, this enhances the stretch in two ways. First, increases the length of biceps femoris, second contraction of the quadriceps causes reciprocal inhibition(decreased neural drive and muscle spindle excitation) of hamstring complex, which allows it to elongate.
• Active-isolated stretches are suggested for preactivity warm-up(before sports competition or high-intensity exercise), as long as no postural distortions are present. 5-10 reps of each stretch are performed and held for 1-2 seconds each.

 

Dynamic Stretching

• Dynamic Stretching – Uses force production and momentum to move the joint through the full available range of motion.
  
• Uses the concept of reciprocal inhibition to improve soft tissue extensibility. One can perform one set of 10 reps using 3 ot 10 dynamic stretches. Hip swings, medicine ball rotations, and walking lunges are good examples of dynamic stretching.