Ear Anatomyhttp://www.nlm.nih.gov/medlineplus/magazine/issues/fall08/articles/fall08pg12a.html

Stretching Good for Arteries, figure from Kenta Yamomoto et al., Poor trunk flexibility is associated with arterial stiffening. American Journal of Physiology: Heart and Circulatory Physiology, Oct. 2009, Vol. 297.http://ezproxy.library.yorku.ca/login?url=http://dx.doi.org/10.1152/ajpheart.00061.2009

Michael Tetley. Instinctive sleeping and resting postures: an anthropological and zoological approach to treatment of low back and joint pain BMJ VOLUME 321 23–30 DECEMBER 2000http://www.jstor.org.ezproxy.library.yorku.ca/stable/25226542

Cannot post in lecture slides

What is Physical Fitness?

Musculoskeletal Fitness as a Function of Age

Warburton et al. CMAJ • March 14, 2006 • 174(6)http://ezproxy.library.yorku.ca/login?url=http://go.galegroup.com/ps/i.do?id=GALE%7CA143162648&v=2.1&u=yorku_main&it=r&p=AONE&sw=w&asid=712842f

bce56fd60eb26f5c8d8c2ffa8

Balance

Signals upon which balance is dependent:• Semi-circular canals of inner ear• Kinesthetic sensors in muscles, tendons

and joints• Visual perception• Co-ordination of the above stimuli

(spastic lock coordination)

Image courtesy of Neuromechanics / Wikimedia Commonshttp://en.wikipedia.org/wiki/Golgi_tendon_organ

Golgi Tendon Organs

• Embedded in the tendons, close to the muscle insertions. • Detect tension in the tendon of a contracting muscle.

Muscle Spindles

Image courtesy of Neuromechanics / Wikimedia Commonshttp://en.wikipedia.org/wiki/File:Muscle_spindle_model.jpg

• Located muscle between muscle fibres. • Provide information on muscle length, tension, and load• Highest density in small muscles designed for fine motor

control

Muscle Spindles

Image courtesy of Neuromechanics / Wikimedia Commonshttp://en.wikipedia.org/wiki/File:Muscle_spindle_model.jpg

• Function is to resist stretch by stimulating contraction• Also send inhibition signal to opposing muscle group• After stroke or spinal cord injury the spindles may be

oversensitive and cause muscle stiffness

Joint Kinesthetic Receptors

• Located in the connective tissue of a joint capsule. • Signal the extremes of joint range

• Respond to mechanical deformation occurring in the joint capsule and ligaments during dynamic movement. • Respond more to passive than active movement

Bruce Blaus, “Knee Anatomy Side.” Wikimedia Commons. http://en.wikipedia.org/wiki/File:Blausen_0597_KneeAnatomy_Side.png#filelinks

Balance

Affecters of Balance Performance:1. Body weight2. Strength / Power3. Center of gravity4. Fear5. Co-ordination

Measurement of Balance

CATEGORY CLASSIFICATION

Eyes open

Eyes closed

Balancing stunts

Balancing objects

Dizziness tests

DYNAMIC

Beam walk

Beam walk

Walk on hands

Shuttle run balancing object

Walk around finger

STATIC

Squat stand

Stork stand

Teeter board

Stick balance

Centrifuge

Improvement of Balance

1. Practice the specific balance test items.2. Practice basic skills which demand a

high degree of balance.3. Participate in sports which demand a

high degree of balance.

© Rhphotos | Dreamstime Stock Photos Image courtesy of arztsamui / FreeDigitalPhotos.net

Image courtesy of chanpipat/ FreeDigitalPhotos.net

Elderly-Loss of Balance & Aging

• Balance deteriorates progressively with aging

• 1/3 of persons over age 70 fall each year & the incidence is 1 ½ - 2 x higher in females than males

• Due to the concurrent loss of bone mineral density, the incidence of fractures is high

• 90% of hip fractures are due to falls

Image courtesy of Simon Howden/ FreeDigitalPhotos.net

Image courtesy of njaj/ FreeDigitalPhotos.net

Elderly-Loss of Balance & Aging

• Older adults have lower strength a lower rate ofstrength development (power) than younger adults(males > females)

• Major difference between individuals and those whofall or who do not is not reaction time- it is the rate ofstrength development (power)

• Older adults who engage in strength &power training maintain or improve theirpower and balance which leads to reducedfalls and longer independent functioning

Flexibility

Definition: – Range of movement about a joint or joints.

Considerations:– Not a general characteristic (site specific)– Static (range of motion)– Dynamic (stiffness or looseness reflected

in speed of movement or power)

Importance: – Avoiding injuries– Enable proper form in certain sports– Power development (Plyometric)– Muscle relaxation

Limitations of Flexibility1. Mechanical factors: bone structure and muscle bulk2. Soft tissue crossing a joint (NB for sports)3. Injuries and disease - reduced tissue elasticity4. Inactivity5. Age: 6 – 18 increase

18 – 28 plateau28 - 35 slight decline35 on more rapid decline

6. Temperature (achieved passively or actively):- warming a joint to 113 ºF increases flexibility by 20 %- cooling a joint to 65°F decreases flexibility by 10-20%

7. No difference between males and females when largenumber of articulations are considered

8. Why is only one measure of flexibility included in health relatedfitness assessments?

Measurement of Flexibility

1. Goniometry• Modified protractor• Overhead- projected goniometer• Electrogoniometer- (developed for

horses to train stride length)2. Performance measures

• Criticism; body proportions• How to avoid?

3. Flexometer (Leighton)• Usually only used for research

Important of Flexibility

How:

Types of Stretching

1. Slow, static, passive2. Active, dynamic, bouncing, ballistic3. Proprioceptive neuromuscular facilitation

(PNF). Maximal isometric contraction of the muscle being stretched relaxes the antagonistic muscle.

Image courtesy of -Marcus-/ FreeDigitalPhotos.net

• PNF is superior to static and ballistic in increasing flexibility. However, these exercises are complicated and often require a trainedpartner

• Static stretches are an effective compromise. Ballistic stretches aregenerally not recommended.

Image courtesy of Neuromechanics / Wikimedia Commonshttp://en.wikipedia.org/wiki/Golgi_tendon_organ

Golgi Tendon Organs

• Activation causes inhibition of contracting muscle (relaxation)

Importance of Flexibility

Considerations1. Too much flexibility could reduce the stability of a joint

and increase the susceptibility to injury.2. Hold passive stretches for 10 to 30 sec3. Daily4. Develop strength about the joint at the same time.5. The optimum flexibility of a joint for a specific sport

may mean decreasing its flexibility.6. Optimal flexibility for normal living?

Benefits of a Flexibility Training Program

Sit-and-reach flexibility & Risk of Lower Body Musculoskeletal Injuries

Table 18 from David Cowan et al., The Epidemiology of Physical Training Injuries in U.S. Army Infantry Trainees: Methodology, Population, and Risk Factors. Defence Technical Information Center Nov. 1988. http://oai.dtic.mil/oai/oai?verb=getRecord&metadataPrefix=html&identifier=ADA206551

Stretching and Injuries

• Inconclusive• Most studies in jogging say ‘no’• Studies in football or handball say ‘yes’• Likely speaks to differences between

sports and the importance of flexibility in preventing injuries.

Stretching and Performance

• Static stretching may be negative for strength

• Static stretching may be negative for sprinting and jumping

• Dynamic stretching does not appear to change sprint or jumping performance

• More negative effect in lower body as compared to upper body

Low Back Pain

• ~39% of individuals will experience low back pain at some time in their lives

• Costs $50 billion per year in the US• Low back pain is the single leading cause

of disability worldwide (Global Burden of Disease 2010).

Hoy DG, Bain C, Williams G, March L, Brooks P, Blyth F, Woolf A, Vos T, Buchbinder R: A systematic review of the global prevalence of low back pain. Arthritis Rheum 2012, 64(6):2028–2037.Goetzel RZ, Hawkins K, Ozminkowski RJ, Wang S. The health and productivity cost burden of the ‘‘top 10’’ physical and mental health conditions affecting six large U.S. employers in 1999. J Occup Environ Med 2003;45:5–14.http://www.acatoday.org/level2_css.cfm?T1ID=13&T2ID=68

Causes of Back Pain

1. Herniated, ruptured or bulging disc (“slipped” disc)

2. Degenerative changes: wear and tear arthritis (rheumatoid

osteoarthritis) inflammatory

3. Vertebral misalignments; pinched nerve

4. Osteoporosis; deterioration of bone density leading to vertebral

fractures or collapse

5. Tension and emotional problems

6. Poor posture, lack of exercise or overeating

7. Back sprains; overuse, twisting bad lifting habits

Proper Posture – Neutral Spine

Spine load from Matt Wallden, The neutral spine principle, Journal of Bodywork and Movement Therapies Oct. 2009, 13(4), pp. 350-361http://ezproxy.library.yorku.ca/login?url=http://resolver.scholarsportal.info/resolve/13608592/v13i0004/350_tnsp.xml

Neutral Spine Lordosis

Hypolordosis

Muscle and other soft tissues help to absorb

forces on body

Force on spine from walking impact per

day:

700, 000 to 2,100,000 kg

Herniated Disc

http://en.wikipedia.org/wiki/Spinal_disc_herniation

Spinal Disc Herniation

- Disc herniation can result in no symptoms to debilitating pain

- Can be corrected by surgery

Large Hernia. Wikipedia. http://en.wikipedia.org/wiki/File:Lagehernia.png.

Annotated diagram of preconditions for Anterior cervical discectomy and fusion. Wikipedia. http://en.wikipedia.org/wiki/File:ACDF_coronal_english.png

Osteoporosis

Image Courtesy of Anatomy & Physiology, Connexions Web site. http://cnx.org/content/col11496/1.6/, Jun 19, 2013. Osteoporosis is an age-related disorder that causes the gradual loss of bone density and strength. When the thoracic vertebrae are affected, there can be a gradual collapse of the vertebrae. This results in kyphosis, an excessive curvature of the thoracic region. Assessed on http://en.wikipedia.org/wiki/Osteoporosis

Image Courtesy of BruceBlaus. Osteoporosis was assessed on http://en.wikipedia.org/wiki/Osteoporosis

Proper Lifting Techniques

Lifting Techniques. US Army Center for Health Promotion and Preventative Medicine. http://www.yorku.ca/dohs/documents/armylift.pdf

Proper Lifting Techniques

Lifting Techniques. US Army Center for Health Promotion and Preventative Medicine. http://www.yorku.ca/dohs/documents/armylift.pdf

Proper Lifting Techniques

Lifting Techniques. US Army Center for Health Promotion and Preventative Medicine. http://www.yorku.ca/dohs/documents/armylift.pdf

Score = 3 Severe Loss of Frontal Plane

Position

Active Hip Abduction and Low Back Pain

Starting Position

Score = 0 No Loss of Frontal

Plane Position

Score = 1Minimal Loss

of Frontal Plane Position

Score = 2 Moderate Loss

of Frontal Plane Position

Nelson-Wong, E., T. Flynn, and J. P. Callaghan. 2009. “Development of Active HipAbduction as a Screening Test for Identifying Occupational Low Back Pain.” Journal of Orthopaedic & Sports Physical Therapy 39 (9): 649–657.

Lower Back Pain & Smoking

• Greater prevalence of LBP in smokers• Perhaps a marker for other behaviours???

– Smokers are less active– Related to anxiety & depression– Chronic coughing disc pressure

• Possibly hormonal changes leading to a decreased bone mineral density

Lower Back Pain & Smoking

0.0

0.5

1.0

1.5

2.0

Former Current Former Current

Male Female

Prevalent LBP in last month

Incident LBP in last year

Odd

Rat

io * * * **

Shiri et al Association between Smoking and Low Back Pain. The American Journal of Medicine, Vol 123, No 1, January 2010http://ezproxy.library.yorku.ca/login?url=http://resolver.scholarsportal.info/resolve/00029343/v123i0001/87e7_tabsalbpam.xml

Lower Back Pain & Fitness

Future LBPTrunk Strength 5/17Trunk Endurance 3/12

"Image courtesy of Ambro/ FreeDigitalPhotos.net".

Activation of trunk muscles duringstanding and walking is minimal / non-existent (less than 5% MVC even whena 32 kg weight is added to the torso)(Andersson et al., 1996, White and McNair, 2002).

Lederman. The myth of core stability. Journal of Bodywork & Movement Therapies (2010) 14, 84e98Hamberg-van Reenen et al. A systematic review of the relation between physical capacity

and future low back and neck/shoulder pain. Pain 130 (2007) 93–107

Lower Back Pain & Fitness

Future LBPTrunk Strength 5/17Trunk Endurance 3/12

"Image courtesy of Ambro/ FreeDigitalPhotos.net".

May be differences in motor control instead.

Byström MG, Rasmussen-Barr E, Grooten WJ. Motor control exercises reduces pain and disability in chronic and recurrent low back pain: a meta-analysis. Spine (Phila Pa 1976). 2013

Mar 15;38(6):E350-8.

0

0.5

1

1.5

2

OW Obese OW Obese

Men Women

Obesity and Low Back Pain

Cross-sectional Incident

Shiri et al. The Association Between Obesity and Low Back Pain: A Meta-Analysis. Am J Epidemiol 2010;171:135–154

**

*

Preventive Measures For a Healthy Back

1. Proper posture; 2. Avoid frequent bending, twisting and

excessive sitting3. Flexibility of hamstrings and low back4. Proper lifting and carrying techniques5. Proper sleeping posture6. Maintain healthy body weight

Speed

The ability to perform a movement in a short period of timeComponents:

Movement Time- the rate at which a person can propel his body or parts of his body through space.Reaction Time- the interval of time between the presentation of the stimulus and the initiation of the response.

Image Young Fit Woman Exercising Stock Photo courtesy of -Marcus-

/ FreeDigitalPhotos.net

Improvements in Speed

• Reaction time• Technique• Strength• Power• Flexibility

Image Young And Muscular Guy Holding A Barbell. Crossfit Dead Lift Ex" courtesy of David Castillo Dominici / FreeDigitalPhotos.net

Speed1. Speed of Movement

• Total Body Movement- measurement• Limb Movement- measurement

2. Reaction Time- measurement

Image “Male Runner On Starting Blocks" Courtesy of stockimages / FreeDigitalPhotos.net

Image “Athletes Running On Race Track" Courtesy of stockimages / FreeDigitalPhotos.net

Reaction and Movement Time

3. Nelson Reaction Timer; Research Findings:a. Low correlation between RT and MTb. Speed improves from childhood to early adulthood, peaks for a

decade then declinesc. RT and MT of college males are 14% and 30% respectively

greater than that of females and peak MT and RT is maintained longer by males

d. RT is highest in the morning hours and drops off later in the day .e. A small amount of consumed alcohol slightly improves the

reactions of some individuals, but large amounts impair themf. Athletes have faster RT and MT's than non-athletesg. Speed of movement is very specific--an individual with fast arm

movement may well have slow leg movementh. Strength training does not result in slower MTi. MT and RT can be improved with training

Nelson Reaction Timer

• Based on the law of constant acceleration of free falling bodies.

• The timer is scaled in time as computed from the following formula:

Time = 2 x Distance the stick fallsAcceleration due to gravity

Agility

Definition: the rapidity and ease with which an individual can change the direction of movement of the body or its parts

• Compound motor fitness factor involving speed, coordination and balance

Agility

Measurement:a. Running tests- shuttle run, zig zag runb. Non running tests- 4 and 6 count burpeec. Criticisms: shoes, floor, person’s height

Pro-agility20 m Shuttle Run

Start/Finish

Illinois Test

Start Finish

Agility

Findings:

a. Males are more agile than femalesb. Agility in males increases to maturity then plateaus

For approximately 10 years before declining. However, females stop improving shortly after puberty and begin to decline earlier than males

c. Athletes perform well on agility testsd. Performance on agility tests has been observed to

improve with practice.

Agility

Improvement:

• Increasing speed specific to the requirement (e.g. sport)

• By practicing the sport