EXERCISE AFTER STROKESpecialist Instructor Training Course

L5Physical fitness after stroke

background

Overview of talk

• Physical activity and fitness defined

• Components of physical fitness

• Impact of stroke on fitness

• Relation between fitness and function after stroke

• The need for exercise!

Learning outcomes

After this session you should be able to:

• Define “physical fitness”

• Describe and explain the impact of stroke on fitness

• Describe and explain the impact of reduced fitness on function after stroke

Physical activity

• All bodily movement produced by the contraction of skeletal muscle and which substantially increases energy expenditure (USDHHS 1996)

• Includes the muscular work required for – Walking– Maintaining posture – Activities of daily living– Occupational, leisure and sporting activities

What happens to physical activity after stroke?

• After major stroke, patients are often immobile due to the neurological effects of stroke

• Stroke in-patients: only 13% of time engaged in physical activity (Bernhardt 2004)

• Even relatively minor neurological deficits may lead to a reduction in physical activity

• Paucity of literature on levels of physical activity after stroke, particularly after minor stroke

ActivPalTM physical activity monitoring

Physical fitness………….

Is a set of attributes, which people have or achieve, that relate to the ability to perform physical activity (USDHHS 1996)

Is improved by activity and reduced by inactivity

Physical fitness essential for physical activity

Cardiorespiratory

Muscle strength and power

Components of physical fitness Cardiorespiratory fitness Relates to an individual's ability to perform physical activity for an extended

period. Conferred by Central capacity of the circulatory and respiratory systems to supply oxygen

(USDHHS 1996)Peripheral capacity of skeletal muscle to utilise oxygen (Saltin & Rowell

1980).

Muscle strength Maximum force that can be generated by a muscle or muscle groupAbility to sustain repeated muscular actions or a single static contraction is 'muscular endurance' (USDHHS 1996)

Muscle powerRate of generation of strength

Body composition Includes total and regional bone mineral density, and the relative amounts and distribution of adipose tissue, muscle and other vital parts of the body (USDHHS 1996).

What happens to physical fitness after stroke?

• Physical fitness is related to physical activity

• After stroke, activity falls

• So might physical fitness be reduced?

Aerobic fitness (endurance) after stroke

Bachynski1985

Mackay et al.2002

Fujitaniet al 2001

Duncan2003

Kelly 2003

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Potempaet al. 1995

Macko et al

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Rimmeret al. 2001da Cunha

et al. 2001

Ryanet al2001

Eng 2004

Pang 2004

Peak V02 synthesised from 16 studies (Dave Saunders 2007 unpublished)

Muscle strength and power after stroke

We recruited 11 patients who had made an apparently full neurological recovery several months after their stroke

We measured – Muscle strength – Power output of both lower limbs

We found that muscle strength and power output in both limbs were significantly lower than age and sex matched values from the population

Greig et al 2001

Measurement of maximum voluntary isometric knee extensor strength

Measurement of lower limb extensor power during a single maximal leg extension

Might these impairments in aerobic fitness, muscle strength and

muscle power have consequences for function, mobility, quality of life?

Influence of impaired leg extensor power on

function after stroke? • In 66 ambulatory patients, who had completed their

rehabilitation, there were associations between impaired LEP in both the affected and unaffected limbs and – Timed up and go– Sit to stand– Functional reach– Comfortable walking velocity – FIM– Rivermead motor index– Nottingham extended ADL– SF36– Elderly mobility scale (Saunders et al 2008)

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LEP and function in 66 people after stroke (STARTER)

Affected (■) and unaffected (□) legs

Relationship between aerobic fitness and function

• 74 people with chronic hemiparetic stroke demonstrated that walking ability was independently related to – Cardiovascular fitness– balance– paretic leg strength

Patterson 2007

Why is fitness impaired after stroke?

• Reduced physical activity after stroke

• Reduction in fitness may pre-date stroke (age and co-morbidities)

• Direct effect of hemiparesis

Mechanisms of reduced fitness after stroke

FitnessImpairments

PhysicalInactivity

FunctionalLimitations

DISABILITY

OtherImpairments

Process ofDisablement

Cycle ofDetraining

STROKEPathology

Increasing Age

Comorbid Disease

Direct Effectof Stroke

Courtesy Dave Saunders 2008

Summary

• Physical fitness is reduced after stroke– Muscle strength– Muscle power– Aerobic fitness

• Mechanisms include – Direct effect of hemiparesis– Pre-stroke impairments – Reduced physical activity after stroke

• Impairments in physical fitness are associated with reductions in functional ability

Essential ReadingFurther detail about the topics discussed in this

session can be found in section L5 of the course syllabus.