PE 254

Developing a Flexibility Program (Chapter 9)

FlexibilityThe ability of a joint to move through its full

range of motion (ROM)Important for general fitness and wellnessStatic versus dynamic flexibility

What Determines Flexibility?Joint structure—joints vary in direction and

range of movementJoint capsules = semielastic structures that give

joints strength and stability but limit movementMuscle 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

Muscle Elasticity and Length

Muscle Architecture

Force -Lengthand Muscle Architecture

Force - Velocityand Muscle Architecture

Effect of Stretch on Connective Tissue

Efferent vs. AfferentEfferent neural signals produce muscle

contraction.

Afferent neural signals provide the brain with signals from the senses.

Sensory Innervation - Muscle Spindle

Sensory Innervation

Golgi Tendon Organ

Nervous System ActivityStretch receptors control muscle lengthIf a muscle is stretched, receptors send a

message to the spinal cord, which then sends a signal back to the muscle telling it to contract

A strong muscle contraction produces an opposite reflex that causes the muscle to relax

Proprioceptive neuromuscular facilitation (PNF) = a technique for stretching muscles that relies on neuromuscular reflexes to stimulate training effects

Types of Stretching Techniques

Static stretching = slowly stretching a muscle and holding the stretched position

Ballistic stretching = suddenly stretching a muscle through a bouncing or swinging movement

Proprioceptive neuromuscular facilitation = obtaining a greater training effect by using neuromuscular reflexes; for example, contracting a muscle before it is stretched

Types of Stretching TechniquesPassive stretching = muscles are stretched

by force applied by an outside sourceActive 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&hl=en&emb=0&aq=5&oq=flexibility+#

http://www.youtube.com/watch?v=MdzdH_O1riw

How to Perform a PNF StretchThe process of performing a PNF stretch involves the

following. The muscle group to be stretched is positioned so that the muscles are stretched and under tension. The individual then contracts the stretched muscle group for 5 - 6 seconds while a partner, or immovable object, applies sufficient resistance to inhibit movement. Please note; the effort of contraction should be relevant to the level of conditioning.

The contracted muscle group is then relaxed and a controlled stretch is applied for about 30 seconds. The muscle group is then allowed 30 seconds to recover and the process is repeated 2 - 4 times.

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.

Benefits of Flexibility and Stretching Exercises

Joint healthPrevention of low-back pain and injuriesOther potential benefits:

Temporary reduction of postexercise muscle soreness, known as delayed-onset muscle soreness (DOMS)

Relief of aches and pains and muscle crampsImproved body position and strength for sportsMaintenance of good posture and balanceRelaxation

Lifetime wellness benefitsAssessment Issues

Creating a Successful Program to Develop FlexibilityApplying the FITT principle:

Frequency—how often to stretchIntensity—how far to stretchTime—how long to stretchType—which stretching exercises to perform

Frequency of ExerciseThe American College of Sports Medicine

(ACSM) recommends that stretching exercises be performed a minimum of 2–3 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

Intensity and Time (Duration) of ExerciseStretch to the point of slight tension or mild

discomfortHold each stretch for 10–30 secondsDo at least 4 repetitions of each exerciseRest for 30–60 seconds between stretches

A Flexibility Workout

Flexibility Exercises

Sample Flexibility Exercises

• 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

Low-Back HealthFunction of the spine

Provides structural support for the bodySurrounds and protects the spinal cordSupports body weightServes as attachment site for muscles,

tendons, ligamentsAllows movement of neck and back in all

directions

Skeletal System

Structure of the Spine7 cervical vertebrae in the neck12 thoracic vertebrae in the upper back5 lumbar vertebrae in the lower back9 vertebrae at the base of the spine fused

into the sacrum and the coccyx (tailbone)

Structure of the Spine

VertebraeVertebrae consist of a body, an arch, and

several bony processesIntervertebral 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

Vertebrae and Intervertebral Disk

Causes of Back PainAny movement that causes excessive

stressRisk factors:

Age greater than 34 yearsDegenerative diseasesFamily or personal history of back traumaSedentary lifestyle, overweightLow job satisfaction, certain occupationsLow socioeconomic statusSmokingPsychological stress or depression

Underlying Causes of Back PainPoor muscle endurance and strengthPoor posturePoor body mechanics

Preventing Low-Back PainLose weight, stop smoking, and reduce

emotional stressAvoid sitting, standing, or working in the

same position for too longUse a supportive seat and a medium-

firm mattressWarm up thoroughly before exerciseProgress gradually when improving

strength and fitness

Protecting Your Back

Protecting Your Back

Managing Acute Back PainSudden back pain usually involves tissue

injurySymptoms: Pain, muscle spasms, stiffness,

inflammationTreatment:

Ice, then heatOTC medication (ibuprofen or naproxen)Moderate exercise

Managing Chronic Back PainConsidered chronic if lasts longer than 3

monthsSymptoms: 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

Exercises for the Prevention and Management of Low-Back PainDo low-back exercises at least 3 days per

weekEmphasize muscular enduranceDo not do full range of motion spine

exercises early in the morningEngage in regular endurance exerciseBe patient and stick with your program