Chapter 5

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• Joint structure—joints vary in direction and range of movement
• Joint capsules = semielastic structures that give joints strength and stability but limit movement
• Muscle elasticity and length
• Collagen = white fibers that provide structure and support
• Elastin = yellow fibers that are elastic and flexible
• Titin = muscle filament with elastic properties; contributes to flexibility.

• Proprioceptors send information about the muscle and skeletal systems to the nervous system
• Stretch receptors (muscle spindles)
• Golgi tendon organs
• If a muscle is stretched, signals between the stretch receptors and nervous system control muscle length and movement and protect muscles from injury

• Proprioceptive neuromuscular facilitation (PNF) = a technique for stretching muscles that relies on neuromuscular reflexes to stimulate training effects
• Regular stretching trains all of the proprioceptors
• Proprioceptors adapt very quickly to stretching and lack of stretching

• Joint health
• Prevention of low-back pain and injuries
• Other potential benefits:
• Relief of aches and pains
• Relief of muscle cramps
• Improved body position and strength for sports
• Maintenance of good posture and balance
• Relaxation
• Lifetime wellness benefits

• Applying the FITT principle
• F requency—how often to stretch
• I ntensity—how far to stretch
• T ime—how long to stretch
• T ype—which stretching exercises to perform

• The American College of Sports Medicine (ACSM) recommends that stretching exercises be performed a minimum of 2–3 days per week; ideally 5-7 days per week
• Stretch when muscles are warm, either after a workout or after the active part of a warm-up
• Do not stretch before a high-performance activity

• Stretch to the point of slight tension or mild discomfort
• Hold each stretch for 15–30 seconds
• Do 2–4 repetitions of each exercise
• Rest for 30–60 seconds between stretches

• Static stretching = slowly stretching a muscle and holding the stretched position
• Ballistic stretching = suddenly stretching a muscle through a bouncing or swinging movement
• Dynamic stretching = stretching by moving joints slowly through their range of motions in a controlled manner
• Proprioceptive neuromuscular facilitation = obtaining a greater training effect by using neuromuscular reflexes; for example, contracting a muscle before it is stretched

http://www.youtube.com/watch?v=4GWlJMSAlu4
The athlete and partner assume the position for the stretch, and then the partner extends the body limb until the muscle is stretched and tension is felt.
The athlete then contracts the stretched muscle for 5 - 6 seconds and the partner must inhibit all movement. (The force of the contraction should be relevant to the condition of the muscle. For example, if the muscle has been injured, do not
apply a maximum contraction).
The muscle group is relaxed, then immediately and cautiously pushed past its normal range of movement for about 30 seconds. Allow 30 seconds recovery before repeating the procedure 2 - 4 times.

• Passive stretching = muscles are stretched by force applied by an outside source
• Active stretching = muscles are stretched by a contraction of the opposing muscles
• Safest technique is active static stretching, with an occasional passive assist http://video.google.com/videosearch?q=flexibility+training+exercises&h l=en&emb=0&aq=5&oq=flexibility+#

• Warm up 3-5 minutes before stretching
• Stretch to a point of mild tension
• Exhale as you move into the stretch; remember not to hold your breath
• Prevent bouncing movement when stretching
• Hold each stretch for 10 to 30 seconds
• Repeat each stretch 3 to 5 times
• Dynamic stretching = pre-exercise
• Static stretching = post exercise
Sample Flexibility Exercises

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• Provides structural support for the body
• Surrounds and protects the spinal cord
• Supports body weight
• Serves as attachment site for muscles, tendons, ligaments
• Allows movement of neck and back in all directions

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7 cervical vertebrae in the neck
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12 thoracic vertebrae in the upper back
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5 lumbar vertebrae in the lower back
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9 vertebrae at the base of the spine fused into the sacrum and the coccyx
(tailbone)

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Vertebrae consist of a body, an arch, and several bony processes
Intervertebral disks = elastic disks located between adjoining vertebrae; consist of a gel- and water-filled nucleus surrounded by fibrous rings; serve as shock absorbers
Nerve roots = base of pairs of spinal nerves that branch off the spinal cord

• Core muscles include those in the abdomen, pelvic floor, sides of the trunk, back, buttocks, hip, and pelvis
• Core muscles stabilize the spine and help transfer force between the upper body and lower body
• Lack of core muscle fitness can create an unstable spine and stress muscles and joints
• Whole body exercises and exercises using free weights or stability balls all build core muscle fitness

Whole body exercises and exercises using free weights or stability balls all build core muscle fitness

• Any movement that causes excessive stress
• Risk factors:
• Age greater than 34 years
• Degenerative diseases
• Family or personal history of back trauma
• Sedentary lifestyle, overweight
• Low job satisfaction, certain occupations
• Low socioeconomic status
• Smoking
• Psychological stress or depression

• Poor muscle endurance and strength
• Poor posture
• Poor body mechanics

• Considered chronic if lasts longer than 3 months
• Symptoms: Stabbing or shooting pain, steady ache accompanied by stiffness, pain that is localized or that radiates to other parts of the body
• Treatment: Many options, including medication, exercise, physical therapy, massage, acupuncture, education, and surgery

• Do low-back exercises at least 3 days per week
• Emphasize muscular endurance
• Do not do full range of motion spine exercises early in the morning
• Engage in regular endurance exercise
• Be patient and stick with your program

• No assignment for Chapter 5
• Internet Project 2 due on Wednesday, November 21 st .