Chapter Objectives
• Identify the benefits and components of a preexercise warm-up.
• Assess the suitability of performing stretch-ing exercises for a warm-up.
• Identify factors that affect flexibility.
(continued)
Chapter Objectives (continued)
• Describe flexibility exercises that take advantage of proprioceptive neuromuscular facilitation.
• Explain the mechanisms that cause the muscular inhibition that improves the stretch.
• Select and apply appropriate static and dynamic stretching methods.
Warm-Up
• Warming up can have the following positive impacts on performance:– 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
(continued)
Warm-Up
• Warming up can have the following positive impacts on performance (continued):– 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
Warm-Up
• Stretching During Warm-Up– Research suggests dynamic stretching is the
preferred option for stretching during warm-up.
– Consider the range of motion and stretch-shortening cycle requirements of the sport when designing a warm-up.
Warm-Up
• Components of a Warm-Up– A general warm-up period may consist of 5 to 10
minutes of slow activity such as jogging or skipping.
– A specific warm-up period incorporates movements similar to the movements of the athlete’s sport. It involves 8 to 12 minutes of dynamic stretching focusing on movements that work through the range of motion required for the sport.
Section Outline
• Flexibility– Flexibility and Performance– Factors Affecting Flexibility
• Joint Structure
• Age and Sex• Connective Tissue• Resistance Training With Limited Range of Motion• Muscle Bulk• Activity Level
– Frequency, Duration, and Intensity of Stretching
– When Should an Athlete Stretch?
– Proprioceptors and Stretching
Flexibility
• Flexibility is a measure of range of motion (ROM) and has static and dynamic compo-nents.
• 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.
Flexibility
• Flexibility and Performance– Optimal levels of flexibility exist for each activity.
– Injury risk may increase outside this range.
Flexibility
• 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.
(continued)
Flexibility
• Factors Affecting Flexibility (continued)– 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• An active person tends to be more flexible than an inactive
one, but activity alone will not improve flexibility.
Flexibility
• Frequency, Duration, and Intensity of Stretching– Acute effects of stretching on ROM are transient.
– For longer-lasting effects, a stretching program is required.
Flexibility
• When Should an Athlete Stretch?– Following practice and competition
• Postpractice stretching facilitates ROM improvements because of increased muscle temperature.
• Stretching should be performed within 5 to 10 minutes after practice.
• Postpractice stretching may also decrease muscle soreness although the evidence on this is ambiguous.
Flexibility
• When Should an Athlete Stretch?– 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.
Flexibility
• Proprioceptors and Stretching– Stretch reflex
• A stretch reflex occurs when muscle spindles are stimulated during a rapid stretching movement.
• This should be avoided when stretching, as it will limit motion.
Flexibility
• Proprioceptors and Stretching– Autogenic inhibition and reciprocal inhibition
• Autogenic inhibition is accomplished via active contraction before a passive stretch of the same muscle.
• Reciprocal inhibition is accomplished by contracting the muscle opposing the muscle that is being passively stretched.
• Both result from stimulation of Golgi tendon organs, which cause reflexive muscle relaxation.
Section Outline
• Types of Stretching– Static Stretch
– Ballistic Stretch
– Dynamic Stretch
– Proprioceptive Neuromuscular Facilitation Stretch• Hold-Relax• Contract-Relax• Hold-Relax With Agonist Contraction• Common PNF Stretches With a Partner
Types of Stretching
• Static Stretch– A static stretch is slow and constant, with the end
position held for 30 seconds.
• Ballistic Stretch– A ballistic stretch typically involves active muscular
effort and uses a bouncing-type movement in which the end position is not held.
• Dynamic Stretch– A dynamic stretch is a type of functionally based
stretching exercise that uses sport-specific move-ments to prepare the body for activity.
Types of Stretching
• Proprioceptive Neuromuscular Facilitation (PNF) Stretch– Hold-Relax
• Passive prestretch (10 seconds), isometric hold (6 seconds), passive stretch (30 seconds)
Positions for PNF Hamstring Stretch
• Figures 13.1 and 13.2 (next slide)– Starting position of PNF hamstring stretch
– Partner and subject leg and hand positions for PNF hamstring stretch
Hold-Relax
• Figures 13.3, 13.4, and 13.5 (next slide)– Passive prestretch of hamstrings during hold-relax
PNF hamstring stretch
– Isometric action during hold-relax PNF hamstring stretch
– Increased ROM during passive stretch of hold-relax PNF hamstring stretch
Types of Stretching
• Proprioceptive Neuromuscular Facilitation Stretch– Contract-Relax
• Passive prestretch (10 seconds), concentric muscle action through full ROM, passive stretch (30 seconds)
Contract-Relax
• Figures 13.6, 13.7, and 13.8 (next slide)– Passive prestretch of hamstrings during contract-
relax PNF stretch
– Concentric action of hip extensors during contract-relax PNF stretch
– Increased ROM during passive stretch of contract-relax PNF stretch
Types of Stretching
• Proprioceptive Neuromuscular Facilitation Stretch– Hold-Relax With Agonist Contraction
• During third phase (passive stretch), concentric action of the agonist used to increase the stretch force
Hold-Relax With Agonist Contraction
• Figures 13.9, 13.10, and 13.11 (next slide)– Passive prestretch during hold-relax with agonist
contraction PNF hamstring stretch
– Isometric action of hamstrings during hold-relax with agonist contraction PNF hamstring stretch
– Concentric contraction of quadriceps during hold-relax with agonist contraction PNF hamstring stretch, creating increased ROM during passive stretch
Key Point
• The hold-relax with agonist contraction is the most effective PNF stretching technique due to facilitation via both reciprocal and autogenic inhibition.
Types of Stretching
• Proprioceptive Neuromuscular Facilitation Stretch– Common PNF Stretches With a Partner
• Calf and ankle• Chest• Groin• Hamstrings and hip extensors• Quadriceps and hip flexors• Shoulder
Partner PNF Stretching
• Figures 13.12-13.16 (next two slides)– Partner PNF stretching for the:
• Calves• Chest• Groin• Quadriceps and hip flexors• Shoulders
Types of Stretching
• Guidelines for Static Stretching– Get into a position that facilitates relaxation.
– Move to the point in the ROM where you experience a sensation of mild discomfort. If performing partner-assisted PNF stretching, communicate clearly with your partner.
– Hold stretches for 30 seconds.
– Repeat unilateral stretches on both sides.
Types of Stretching
• 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.
Types of Stretching
• 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.