EXERCISE AFTER STROKE Specialist Instructor Training Course L5 Physical 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)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

ActivPal TM 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)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)USDHHS 1996 Peripheral capacity of skeletal muscle to utilise oxygen (Saltin & Rowell 1980).Saltin & Rowell 1980 Muscle strength Maximum force that can be generated by a muscle or muscle group Ability to sustain repeated muscular actions or a single static contraction is 'muscular endurance' (USDHHS 1996)USDHHS 1996 Muscle power Rate 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).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 Peak V0 2 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)

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 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 Reading Further detail about the topics discussed in this session can be found in section L5 of the course syllabus.