Overview • How to Warm-up • Flexibility • Terminology • Why Stretch • Frequency, Duration and Intensity • Stretching Techniques
Physiological Effects of a Warm-Up • Warming up can have the following positive impacts on performance:
Physiological Effects of a Warm-Up • Improved oxygen delivery due to the Bohr effect (increase of carbon dioxide in blood causes decreased affinity of hemoglobin for oxygen) whereby higher temperatures facilitate oxygen release from hemoglobin and myoglobin • Increased blood flow to active muscles • Enhanced metabolic reactions
Warm-Up • Components of a Warm-Up • A general warm-up period may consist of 5 to 10 minutes of steady state activity such as jogging, cycling, elliptical • Why do a general warm up? Because it increases: • Heart and respiration rates • Blood Flow • Muscle temperature • Sweat • Decreases viscosity of joint fluids
Warm-Up • A Specific Warm-Up or Dynamic Warm-Up incorporates movements similar to the movements of the athlete’s sport • It involves 8 to 12 minutes of sport-specific movements that work through the range of motion required for the sport • Examples: • Soccer players performing bounding or other polymeric exercises • High knees, carioca, shuffles, etc • Throwing athletes warming up their shoulders
General Guidelines of a Warm-Up • Before Activity/Competition • Start off with general warm-up • Light jog • Next work into dynamic stretching • Leg swings, arm circles • Follow this with static stretching • Partner or single • End with dynamic, or sports specific, warm-up • High knees, carioca, bounding • After Activity • Static stretching
Range of Motion (ROM) • Degree of movement that occurs at a specific joint • Glenohumeral Joint typically has 180 degrees of flexion and abduction • ROM is determined by many factors:
What Is Flexibility? • Flexibility is a measure of range of motion (ROM) and has static and dynamic components. • Static flexibility is the range of possible movement about a joint and its surrounding muscles during a passive movement. • Dynamic flexibility refers to the available ROM during active movements and therefore requires voluntary muscular actions. • Optimal levels of flexibility exist for each activity.
Factors Affecting Flexibility • Joint Structure • Structure determines the joint’s range of motion. • Age and Sex • Older people tend to be less flexible than younger people;females tend to be more flexible than males. • Connective Tissue • Elasticity and plasticity of connective tissues affect ROM.
Factors Affecting Flexibility • Resistance Training With Limited Range of Motion • Exercise through a full ROM and develop both agonist and antagonist muscles to prevent loss of ROM. • Muscle Bulk • Large muscles may impede joint movement. • Activity Level • Active people tend to be more flexible, but activity alone will not improve flexibility.
Flexibility Summary • Also refers to ROM • Static Flexibility • Passive movement with no voluntary muscle contraction • Does not elicit the stretch reflex because its is performed slowly • Dynamic Flexibility • ROM during movements requiring muscular contraction
Terminology • Golgi Tendon Organ • Muscle Spindle • Stretch Reflex • Proprioceptor • Reciprocal Inhibition • Autogenic Inhibition • Connective Tissue
Golgi Tendon Organ • Sensory neuron located at the junction of the muscle and the tendon • Safety mechanism for the muscle • When stimulated, GTOs will cause • Extremely intense stretching is necessary to active GTO • Responds primarily to amount of tension on the muscle
The body of the organ is made up of strands of collagen that are connected at one end to the muscle fibers and at the other merge into the tendon proper. Each tendon organ is innervated by a single sensory fiber.
Muscle Spindle • Miniature muscle fibers and nerve endings encapsulated within a sheath of connective tissue that run within and sometimes parallel to muscle fibers • Contain two types of sensory endings that respond to both the speed of the stretch and new length of the muscle • When the muscle is stretching, it is rapidly adapting. As soon as the muscle stops changing length, and holds a new position, the muscle spindle adapts to the new length and stops firing. • Safety mechanism for the muscle • When stimulated, muscles spindles
Stretch Reflex • A stretch reflex occurs when muscle spindles are stimulated during a rapid stretching movement • It is the muscle’s response to a sudden, unexpected increase in its length • This reflex will cause the muscle to contract to minimize the increase in it’s length • This should be avoided when stretching as it will limit motion • Patella reflex • A person standing in the upright position begins to lean to one side. The postural muscles on the side will stretch. Because of this, muscle spindles cause the muscles to contract to correct posture.
Proprioceptors • Proprioception means "sense of self". • Proprioceptors (muscle spindles and golgi tendon organs) are sensors that provide information about joint angle, muscle length, and tension, which is integrated to give information about the position of the limb in space. • The muscle spindle monitors muscle length. Since muscle activation produces contraction not stretch, the stretch would be due to an external force acting on the muscle, such as an increase in load, or the contraction of an antagonist. • Golgi tendon organs monitor muscle tension, and are best stimulated when muscles contract
Reciprocal Inhibition • If the agonist muscle contracts, the antagonistic muscle will relax to allow the movement to occur without resistance • The muscle spindle is responsible for reciprocal inhibition • For example, if the biceps are contracted, the triceps should relax to allow the elbow to flex
Autogenic Inhibition • Relaxation in the same muscle that is experiencing muscle tension • The is responsible for autogenic inhibition • The will trigger if a stretch is sustained (for longer than six seconds) or if the muscle contracts forcefully • Examples: • Proprioceptive Neuromuscular Facilitation • Static Stretching
Connective Tissue • Supports the various structures of the body • Two types • Collagenous • Made up of collagen • Limited ROM (think garden hose) • Ligaments • Elastic • Muscle fascia (think rubber band)
Connective Tissue • How connective tissue limits flexibility • Joint Capsule (collagenous sack-like structure that encloses the ends of bones-47%) • Muscle fascia (41%) • Tendons/ligaments (10%) • Skin (2%)
Why Stretch • Physiologically • Reduce muscle soreness, muscle tension and stiffness • Reduce the risk of joint sprain and muscle strain • Enhance performance • Permits ease and grace in movement
Why Stretch • Physiologically • Help reset the “stretch-reflex,” allowing for a greater stretch • Sheaths surrounding muscles may undergo semi-permanent increases in length • Stimulate the production and retention of glycoaminoglycans (gelatin-like substance that acts to lubricate connective tissues and fibers)
Faster muscle contraction and relaxation of both agonist and antagonist muscles Improvements in the rate of force development and reaction time Improvements in muscle strength and power Lowered viscous resistance in muscles Improved oxygen delivery due to the Bohr effect whereby higher temperatures facilitate oxygen release from hemoglobin and myoglobin Increased blood flow to active muscles Enhanced metabolic reactions Why Stretch
Why Stretch • Mentally • Promote the development of body awareness • Help your client to mentally and physically relax • Allow you to add value to what you do for your clients
Frequency, Duration and Intensity • Frequency • Daily is ideal, but at least five times per week • For longer-lasting effects, a stretching program is required • Intensity • Mild discomfort-Yes • Screaming in pain-No
Frequency, Duration and Intensity For an athlete following practice and competition: Stretching should be performed within 5 to 10 minutes after practice. Postpractice stretching facilitates ROM improvements because of increased muscle temperature. Postpractice stretching may also decrease muscle soreness although the evidence on this is ambiguous.
Frequency, Duration and Intensity Stretching an athlete as a separate session: If increased levels of flexibility are required, additional stretching sessions may be needed. In this case, stretching should be preceded by a thorough warm-up to allow for the increase in muscle temperature necessary for effective stretching. This type of session can be especially useful as a recovery session on the day after a competition.
Frequency, Duration and Intensity • Duration • General consensus in the literature: • Perform each stretch at least twice • Each static stretch should last between 15 and 30 seconds and has been shown to be more effective than shorter durations
Stretching Techniques • Static • Ballistic • Dynamic • Proprioceptive Neuromuscular Facilitation (PNF)
Static Stretching Static (see pages in NSCA 308-318 for pictures and explanations of static stretches) • Stretching to the farthest point and holding the stretch • Passive or with a partner • Easy to teach and do, however, not very real-world or sports specific • Minimal injury risk as it does not invoke the stretch-reflex • Makes use of autogenic inhibition • A static stretch is slow and constant, with the end position held for 30 seconds
Ballistic Stretching Ballistic • A ballistic stretch typically involves active muscular effort and uses a bouncing-type movement in which the end position is not held. • Momentum of moving body or limb is used to forcibly increase ROM • High risk of injury as bouncing movements don’t allow the muscle spindles to relax, thereby invoking the stretch-reflex
Dynamic Stretching • Unlike static stretching, dynamic stretching helps promote the temperature related benefits of the general warm-up • The use of dynamic stretches must always be coordinated with appropriate sport techniques and should never compromise technique
Proprioceptive Neuromuscular Facilitation (PNF) • PNF uses the concept that muscle relaxation is necessary to elongation of muscle tissue • It uses the GTO and muscle spindle to relax or inhibit the muscle in order to gain a more effective stretch • It uses autogenic inhibition and reciprocal inhibition • PNF stretching exists in many different forms, but the only ones discussed here will be: • Hold-Relax (HR) • Contract-Relax (CR) • Hold-Relax with Agonist Contraction
Proprioceptive Neuromuscular Facilitation (PNF) • Hold-Relax • Passive prestretch (10 seconds), isometric hold (6 seconds), passive stretch (30 seconds) • Autogenic Inhibition • Contract-Relax • 10 second stretch, move through ROM, 30 second stretch • Autogenic Inhibition • Hold-relax with agonist contraction • Passive prestretch (10 seconds), isometric hold (6 seconds), passive stretch with a concentric action of the agonist to add to the stretch force (30 seconds) • Autogenic Inhibition and Reciprocal Inhibition
Positions for PNF Hamstring Stretch • Figures 13.1 and 13.2 • Starting position of PNF hamstring stretch • Partner and subject leg and hand positions for PNF hamstring stretch • May have to adjust your positioning to make your client feel comfortable
Stretching Summary • Precautions for Static Stretching • Decrease stretch intensity if you experience pain, radiating symptoms, or loss of sensation. • Use caution when stretching a hypermobile joint. • Avoid combination movements that involve the spine (e.g., extension and lateral flexion). • Stabilizing muscles should be active to protect other joints and prevent unwanted movements.
Stretching Summary • Guidelines for Dynamic Stretching • Carry out 5 to 10 repetitions for each movement, either in place or over a given distance. • Progressively increase the ROM on each repetition. • Increase the speed of motion on subsequent sets where appropriate. • Contract the muscles as you move through the ROM.
Stretching Summary • Precautions for Dynamic Stretching • Move progressively through the ROM • Move deliberately but without bouncing (movement must be controlled at all times). • Do not forsake good technique for additional ROM.
Self-Myofascial Release • Utilizing an individual’s body weight and a foam roller, deep pressure is created and applied to tender areas within the soft tissue complex
Self-Myofascial Release • A stretching technique that focuses on the nervous and fascial system in the body • Fascial System: • Fibrous tissue that surrounds and separates muscle tissue
Self-Myofascial Release • By applying gentle force to a “knot” or adhesion, the elastic muscle fibers are altered from a bundled position into a straighter alignment with the direction of the muscle
Self-Myofascial Release • Gentle pressure applied with a foam roll will stimulate the Golgi Tendon Organ and create autogenic inhibition, decreasing muscle spindle activity
Benefits of Self-Myofascial Release • May correct muscle imbalances • May increase joint range of motion • May decrease muscle soreness and relieve joint stress • May increase extensibility of musculo-tendinous junctions • May increase neuromuscular efficiency • May maintain normal functional muscle length