fitness prog Chapter 10-11

Flexibility and health

• questionable whether flexibility should be included as a health related fitness component

  • equivocal association to low back pain and injury prevention

  • unknown health benefits

• important for functional independence

• extreme

  • ankylosis

  • hypermobility

Basics of flexibility

• flexibility and joint stability are highly dependent on

  • joint structure and 

  • strength and number of ligaments and muscles spanning the joint

What is flexibility

• ability to move through a full ROM 

• Types

  • static- is a measure of total ROM at the joint, limited by the extensibility of the musculotendinous unit 

  • Dynamic- is a measure of the rate of torque or resistance developed during stretching throughout the ROM 

ROM 

• is highly specific to the joint and depends on morphological factors such as the following:

  • joint geometry

  • joint capsule

  • ligaments

  • tendons

  • muscles spanning the joint

Relative contribution of soft tissues to total resistance encountered by the joint during movement:

• joint capsule: 47%

• muscle and its fascia : 41%

• tendon and ligaments: 10%

• skin: 2%

Factors affecting flexibility

• joint structure

• soft tissue tightness

• body composition

• age

• sex

• physical activity

• muscle temperatur e

Dynamic flexibility

• measure resistance during muscle elongation

• impractical; lab test

static flexibility 

• direct measures of ROM 

• indirect measures of ROM 

General guidlines of flexibility testing 

• have client perform general warm-up followed by static stretching prior to the test 

• avoid fast, jerky movements, and stretching to the point of pain 

• administer three trials of each test item 

• compare client’s best score to norms to obtain a flexibility rating for each test item

• use the test results to identify joints and muscle group in need to improvement 

Direct measures of static flexibility

• measure joint ROM in degrees

• measurement devices

  • goniometer

  • electrogoniometer

  • leighton flexometer

  • inclinometer and inclinometer smart apps

Goniometer 

protractor like device with two steel or plastic arms that measure the joint angle at the extremes of the ROM 

leighton flexometer

consists of a weighted 360 degree dial and weighted pointer

inclinometers and inclinometer smartphone apps

measures the angle between the long axis of the moving segment and the line of gravity

validity and reliability of direct flexibility measures Dependent of the following:

• joint being measured 

• technician skill

validity and reliability of direct flexibility measures tester needs these skills

• knowledge of anatomy 

• knowledge of standardized procedures 

• training and practice 

Indirect measures of static flexibility

• linear measurement

• sit and reach test

  • moderately related to hamstring flexibility

  • poorly related to low back flexibility

• skin distraction test

• back scratch test

Sit and reach test variations 

• standard: box 26cm starts 

• v-sit or YMCA: yardstick, 15in (38cm) start

• modified: box start relative to arm length 

• back saver: box, single leg, 26 cm start

• modified back saver: bench single leg 26 cm start 

Skin distraction test 

• low back flexibility 

• 0cm mark :Lumbar spine at level of posterior superior iliac spine 

• 15 cm mark 

• maximal truck flexion 

• scoring: increased distance beyond 15 cm start 

Flexibility test of older adults

• important for functional independence

• part of senior fitness test

  • chair sit and reach: lower body

  • back scratch: upper body

older adults: chair sit and reach test

• start: client sits at edge of 17 inch (43 cm) chair ‘

• test 

  • one leg extended, heel on floor, ankle dorsiflexed

  • trunk flexion to reach toes

• Score: measure reach from toe

  • beyond toe is +

  • short of toe is -

Older adults: back scratch test

• start: client standing 

• test 

  • one hand: client reaches over shoulder and down back 

  • other hand: client reaches up the middle of the back 

• Score: measure from middle finger to middle finger 

  • overlap is +

  • gap is -

principles of flexibility

• Flexibility training is a systematic program of stretching

exercises designed to progressively increase the range

of motion (ROM) of joints over time.

• Flexibility programs should be individualized to address

the needs, abilities, and physical activity interests of

each client.

training principle applied to flexibility programs

• specificity: joint specific 

• overload: stretch muscle beyond resting length but not beyond pain free ROM 

• Interindividual variability: stretch tolerance 

• progression 

  • stretch duration 

  • number of repetitions

Stretching methods and techniques

• techniques

  • active

  • passive

  • active assisted

• methods 

  • ballistic

  • static

  • dynamic

  • proprioceptive neuromuscular facilitation (PNF)

• one method is not definitively better than others 

 

Ballistic stretching 

• fast bouncing movements 

• least studied of the four stretching methods 

• improvement due to increased stretch tolerance 

• the claim that this method increases risk of injury is not supported by research 

static stretching

• slow sustained muscles lengthening

• muscle spindle adapts (slow speed); stretch reflex is lessened

• habitual static stretching can increase ROM and decrease passive resistance 

Dynamic stretching

• slow deliberate repeated movement through full ROM 

• Mechanism of improved ROM is unclear

  • decreased MTU stiffness

  • increased stretch tolerance

PNF stretching

• combination of isometric action and active and passive stretching 

• numerous variations: equally effective 

  • contract relax (CR)

  • contract relax agonist contract (CRAC)

  • stretch return contract (SRC)

• requires knowledgeable partner 

recommended PNF procedure

1. active stretch to end of ROM 

2. Static muscle action against partner: 3 to 6 sec at 60% to 65% MVC

3. relax and partner- assisted stretch: 10 to 30 sec

4. contract relax agonist contract (CRAC): contract opposing muscle group: 3 to 6 sec 

Autogenic inhibition

Inhibitory signals from GTO during static muscle action

Reciprocal inhibition

Targeted muscle relaxes with contraction of opposing muscle

Viscoelastic stress relaxation

Muscle loses its ability to resist elongation

Gate control theory

GTO becomes accustomed to stretch = ↓ inhibition

Passive

•Targeted muscle does not contract

•Viscoelastic relaxation

Active

•Muscle contracts during stretch

•Muscle length increases (stimulates sarcomere production)

exercises

each major muscle group

Method: depends on client preference

•Warm-up: dynamic or ballistic

•Cool-down: static or PNF

Frequency

•2 to 3 days/wk minimum

•Dose-response: ↑ frequency = ↑ ROM

Intensity

mild discomfort, but not pain

Volume

accumulate 30 to 90 sec per muscle group

Flexibility Training Aids

•Vibration platform

•Foam rolling

•Towels and stretch straps

Stretching for Injury Prevention and Athletic Performance

•Evidence of injury prevention is equivocal

•Evidence of reducing DOMS is equivocal

•Athletic performance

•↑ ROM is critical in some sports

•PNF and static stretching >60 sec are not recommended immediately before power and speed activities

Low Back Pain

•A leading cause of chronic disability

•Prevalence increases with age

•Exercise reduces risk of low back pain

Possible Predictors of Low Back Pain

•Trunk flexibility

•Trunk muscular endurance

•Balance

•BMI

low back pain prevention programs Traditional

•Stretching: ↑ ROM of hip flexors, hamstrings, and back extensors

•Muscular strength: abdominals and low back

Alternative

•Lumbar stability

•Muscular endurance

Developing Lumbar Stability

•Bracing: static muscle action of abdominals and low back

•Maintain neutral spine during activity

•Avoid end ROM of trunk during exercise

•Emphasize muscular endurance rather than strength

Core Stability

•There’s no universal definition of the “core”

•Core stability: ability to control the trunk over the pelvis

Assessing Core Stability

•Sahrmann Core Stability Test

•Kahraman core stability test battery

•Strength: partial curl-up test

•Endurance: side bridge and trunk flexor tests

•Flexibility: sit-and-reach

•Functional: single-leg hop and lateral step-down

•Motor control: unilateral stance

Strategies for Developing Core Stability

•Lifting: ground-based free weights

•Resistance exercises on unstable surfaces

•Pilates