Muscle and exercise physiology

The muscle cell is called

• Myofibril

• Muscle fiber

• Sarcomere

• Fascicle

Lecture plan

• Muscle structure

• Muscle types

• Exercise physiology

• Types of exercise

• Prescribing exercises

Muscle fiber structure

Structural unit of myofibril is a Sarcomere

Structure of Sarcomere

Muscle proteins

• Sarcomere proteins– Actin– Myosin– Titin– Nebulin– Tropomyosin– Troponin

• Extra fiber proteins– Vinculin– Dystrophin

Clinical significance

• Myosin: Cardiomyopathy, Coeliac disease, Gluten enteropathy, Chaga’s disease

• Actin: Cardiomyopathy

• Troponin T: Cardiac disease, COPD

• Troponin I : Renal Disease, Inflammatory muscle disease

• Vinculin: Autoimmune skin and liver disease, Duchenne

• Dystrophin: Muscular dystrophies

• Nebulin: Nemaline Myopathy

Muscle fiber types

• Type 1 (Slow Oxidative) 50%

• Type ll A (FOG) Red 35%

• Type ll B (Fast Glycosylated) White15%

Muscle physiology

What is the difference between the muscles of a sprinter vs a long distance runner

Types of contraction

• Isometric

• Eccentric

• Concentric

(Tension developed is most in eccentric then isometric then concentric)

Frank Starlings law

• Force of contraction is proportional to the stretch

Length

Tension

Define

• Hyperplasia

• Hypertrophy

Exercise physiology

What is therapeutic exercise?

• Customised exercise prescribed for specific therapeutic benefit

Vestibular exercises, abdominal exercises

Types of exercises

• Strength building (bulk)• Endurance building• Mobility improving (ROM)• Aerobic exercises • Relaxing (TROM)• Proprioception and balance improvingSpecial exercisesStability improving

Examples• Strength- weight training

• Endurance- repetitive exercises (cycling, jogging, swimming)

• Mobility- ROM exercises, stretching

• Relaxing- Yoga

• Aerobic – rhythmic dance

• Proprioception- Swedish ball, Theraband, inclined plane etc

Stabilisation- core Stabilisation

Composite exercise programmes

• Combine the benefits of all above

• Grade them sequentially– Start with strength, endurance, stabilisation

and ROM– Upgrade to proprioception– Relaxation last

• Ensure that exercise programme is continued

Which is ideal?

– Structured therapeutic exercise– Playing basket ball

Rational of exercise therapyGASS

• Generalized well being and weight reduction removes illness behaviour

• Aerobic activity increases circulation and psychological well being

• Stretching of muscle and ligaments so that they can

stretch with less pain • Strengthening the guy ropes and cantilevers so that

they can bear more load

Am. Academy Neuro Surgeons

Examples

• ACL reconstruction-Goals– Improve range of movement– Strengthen the dynamic stabilisers of the

knee– Improve proprioception of the reconstructed

and natural ligaments

Priority=Stabilization

ACL reconstruction

• ROM: active and passive/ assisted stretching

• Strengthening: increasing weights-Quads, Hams, Gastroc

• Proprioceptive: wobble board, Swedish ball, inclined plane, beech games

Total shoulder replacement

• ROM: active and passive/ assisted stretching

• Strengthening: increasing weights-Deltoid, Spinatii, Subscap, Lats, Pecs, Trapezius

• Endurance: increasing cycles for above

• Proprioceptive: classical dancing

• Priority=Stabilization: limiting TROM

Designing an exercise regime

Time

Intensity

aerobic

strength

endurance

proprioception

• What is the rationale for doing exercises for IVDP?

• Do you recommend Flexion or extension exercises for IVDP?

• Flexion exercises- Williams

• Extension exercises-McKenzie, Cyriax, Maitland

• Core stabilisation exercises

Foraminal stenosis

Guy rope Cantilever

Prescribing exercises for low back pain

• Depends on pain pattern– Fatigue endurance– Mechanical pain stabilisation– TROM pain and stiffness stretching

• Depends on Pathology– Spondylolisthesis no

extension– IVDP sciatic stretch

Goals of exercise therapy in LBP

• Increase stable zone

• Improve mobility

• Improve strength

• Improve endurance (effort tolerance)

• Increase proprioception (prevent injury)

• Empower the patient to help himself

• Prevent deconditioning

Exercise therapy do’s and don’t’s

• Avoid bending

• Avoid lifting

• Sleep on hard bed

• Avoid pillow

• Avoid 2 wheelers

Can back pain patients bend?

References• Mercer• Turek• Campbell• Apley

• Bridwell et al• White et al• Frymoyer • Aebi et al

• S Rengachary• Youman• Benzel E• McCullough

• Harrison• Price• Davidson

“Basic biomechanics of the musculoskeletal system”

Frankel and Nordin; 2001

What bed

Lifting, lying, extension

Pain avoidance behaviour

Pillow ?

Exercise in low back pain

• Should be tailored to the type of pain pattern

• And the pathology

• Eg: – Effort intolerance type of pain– Spondylolisthesis

Effort intolerance

• Example: doing house work; standing for long, sitting for long

Extensor strengthening without extension

• Example: extension of the spine causes impingement of the facets- spondylolysis

• Yet extensor strengthening is important for spondylolisthesis

• How to achieve this?

• Diagonal lifts; Dying bug exercises

Postural LBP

Postural back pain

Bad posture causing back pain is best treated by postural corrective devices (car seat back rest)

Yes

No

Postural LBP

• Of the chronic 80% are P.LBP

• Does not mean bad posture

• Means bad postural muscles

• Reflects urban life style and stressful living

Sagittal trunk alignment

Postural LBPthe person

• Young adult (male> female)

• Obese/ asthenic

• Sedentary employment

• Stressful life style

• Lack of physical activity

• 2 wheeler travel

Postural LBPPain pattern

• Dull aching• Increased by sitting/ standingIncreased by sitting/ standing• Decreased by walking• Not aggravated by bending/ squatting• Bilateral para-spinal pain• No Radiculopathy• Normal or non-contributary investigations

Therapy

• Enhance strength and ENDURANCE of the postural muscles

Core stabilisation exercises

• Improve pain free range of movements

• Prevent recurrent injury by strength and proprioception

Summary

• Exercise therapy is not a random act of ignorance

• Customised, carefully planned, scientific

THANK YOU

Deconditioning syndrome

Illness behaviour