Chapter 5
暂无描述。系统推荐的高质量记忆内容，适合每天坚持背诵学习。
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Flexibility
The ability of a joint to move through its full range of motion
Static flexibility
is the ability to assume and maintain an extended position at one end or point in a range of motion
Static flexibility depends on?
1) the structure of the joint 2) tightness of muscles, tendons, & ligaments 3) tolerance for pulling sensations in muscles
Dynamic flexibility
is the ability to move a joint through its range of motion with little resistance.
Dynamic flexibility depends on?
• static flexibility • strength • coordination • resistance inherent in a particular movement
What are some Benefits of Flexibility?
• Promotes Good Joint Health • Decreases risk of bone and joint disease • May prevent low-back pain & injuries • possible reduction of post-exercise muscle soreness (DOMS) • relief of aches & pains that may develop from stress or after prolonged sitting • Improved body position for sports & life - permits more efficient body positions & exertion of force through a greater range of motion • Reduces risk of injury from “slips and falls” • Improves impaired mobility from illnesses, etc. • Maintenance of good posture • Relaxation
What Determines Flexibility?
joints vary in direction + range of movement Joint capsules = semi-elastic structures, give joints strength and stability but limit movement ligaments inside and outside the capsule strengthen and reinforce cartilage lines bone surfaces synovial fluid lubricates and cushions bones Heredity plays a role in joint strength + flexibility
Collagen =
white fibers, provide structure + support
Elastin =
yellow fibers, are elastic and flexible
Titin =
muscle filament with elastic properties
cause fibres to lengthen and return to original length
elastic elongation
safe, regular stretching causes long-term lengthening in tissues
plastic elongation
overstretching causes
damage to tissues
lack of stretching activity causes
tissues to shorten
during periods of growth, added hormones can temporarily
increases flexibility
stretches should be done when muscles are
warm
Proprioceptors send information about the muscle length and skeletal systems to the?
nervous system
If a muscle is stretched, signals between the stretch receptors and nervous system control?
the speed, force, and extent of muscle length / movement and protect muscles from injury
If a muscle is stretched suddenly or forcefully, the _______ send signals to the spinal cord.
muscle spindles (a type of stretch receptor)
strong muscle contractions produce a reflex of the opposite type, the __________.
inverse stretch reflex
If a muscle is contracted, receptors (golgi tendon organs) can trigger a?
relaxation response
Proprioceptive Neuromuscular Facilitation (PNF) = a technique for stretching muscles that relies on?
neuromuscular reflexes to inhibit the stretch reflex and stimulate muscle relaxation and lengthening
Regular stretching trains all of the proprioceptors to?
react / anticipate reactions
Proprioceptors _____ very quickly to stretching and lack of stretching
adapt