Principles of Flexibility
Chapter 8 and 9
What is Flexibility?
 Definition: The
range of motion
(ROM) of a single joint (i.e.,
knee) or a series of joints (i.e.,
spine)
 Flexibility is joint specific
 Total body flexibility is hard if
not impossible to determine
Two Subdivisions of Flexibility

Active Flexibility
– Dynamic
– ROM created by muscle

Passive Flexibility
– Static
– ROM created by some external force
– Is typically greater than active flexibility
Benefits of Flexibility








Increased mobility
Reduce muscle soreness (fatigued muscles tend to
shorten)
Reduce risk of low back pain
Improves posture
Coordination
Reduces risk of injury
May allow for improved athletic performance
Relieves stress and tension
Factors That Influence
Flexibility

Genetics
 Joint Structure (shoulder, knee)
 Sedentary living
 Soft Body Tissue
– Muscle, connective, fat, scar

Age (tie shoes)
 Gender
 Muscle Temperature (next slide)
 Pregnancy
Muscle Temperature
 Warm
- up before stretching
 Optimal temperature for muscle
elongation: 102 -110 F
(connective tissue becomes softer)
 Soft tissue temperature changes
can increase or decrease flexibility
by as much as 20%
Two Types of
Elongation Of Soft
Tissue
Elastic
Elongation
Plastic Elongation
Elastic Elongation
Definition:
A temporary
increase in the length of
soft tissue
Plastic Elongation
Definition:
permanent
lengthening of soft tissue

Does not result in a change in the elastic
properties of the connective, ligament, or
capsular tissues.
Elastic Elongation Leads To
Plastic Elongation

Example
Three Types of Stretches
Static
Stretching (Slow
Sustained Stretching)
Dynamic or Ballistic
Stretching
Proprioceptive
Neuromuscular Facilitation
(PNF)
Static Stretching (Slow
Sustained Stretching)
 Most
common
 Most often recommended
 Associated with limited muscle
soreness
 May help reduce muscle soreness
 Associated with little risk of injury
Static Stretching Cont’d
 Stretch
the muscle to the point of slight
or mild discomfort (overload)
 Hold each stretch for 10 to 30 seconds
 Repeat the stretch 4 times
 Flexibility exercise sessions should
occur 3 to 5 times per week
Dynamic or Ballistic Stretching
 Most
dangerous of the stretching
procedures
 Involves
the use of repetitive,
bouncing.
 Virtually abandoned
 May
lead to soreness and muscle injury
Proprioceptive Neuromuscular
Facilitation (PNF)

Involves:
– Isometric contraction
– Contraction and relaxation phases (stretch
phase)
– Normally performed with a partner

Hold the isometric contraction 6 seconds
 Repeat 4 times each session
 3-5 times per week
Contraindicated Movements
Contraindicated Movements
Contraindicated Movements
Contraindicated
Contraindicated
Contraindicated
Other Precautions

Avoid deep knee squats or lunges
 Avoid waist circles
 Avoid backbends
Recommended Stretching
Activities Are Included in
Chapter 9