Rehabilitation Flashcards
What are the 5 main principles of exercise?
Warm up/Cool down FITT Safety monitoring Progressive overload Specificity
Describe the warm up/cool down principle in reference to exercise physiology
Warm up
- Prepares the body mentally for the task
- increases heart rate and therefore blood flow to the muscles
- Increased muscle temperature increase muscle extensibility thereby reducing the risk of muscle damage from overstretched muscle fibers.
Cool down:
• Aerobic exercise reduces DOMS by increasing circulation and removal of noxious waste products in the exercised muscles, provision of o2.
• it allows the heart rate to decrease slowly and the body to return to its homeostatic state – this is a state of metabolic equilibrium
Explain the FITT principle for aerobic exercise
Frequency -
NHS and ACSM guidelines recommend exercising 3-5 x a week, mixture of aerobic and resistance exercise
Intensity -
50% - debilitated, unfit persons at the beginning of a program
60-80% aerobic threshold
85% - anaerobic for sports/athletes
Intensity zones can be calculated using a maximal fitness test, 220-age (very simplistic).
Using HRR =
HRR = Max HR – Resting HR. e.g. 220 – 20 = 200 – 56 = 144
Do 60 and 80% of HRR:
60% of 144 = 86.4
80% of 144 = 115.2
Then add these to the HRrest to work out training zones.
86.4 + 56 = 142.4 (60% zone)
115.2 +56 = 171.2 (80% zone)
Intensity is monitored via:
• HR recovery time
• % of max HR
• HR Reserve
• RR
• Lactate threshold – starts at 50-60% of VO2 max in untrained individuals.
• VO2 max - 60% of VO2 max = 70% of Max HR (ACSM)
• METS - an accurate way of calculating o2 consumption at different intensities. VO2 is on average 250mls per min at rest, however this fluctuates with the size, gender, age and fitness levels of the individual. It is better to use 3.5mls per kg per min at rest = 1 MET.
• BERG’s RPE – add 0 to the patients score to give a rough estimate of HR.
• Power (Watts)
Time
- NHS recommends 20-60 mins of exercise a day - ACSM says 30 mins.
100-180mins a week for aerobic exercise for a duration of 3-4 months to see aerobic adaptations.
Type
- Low volume, high intensity training (LVHIT) - 80%+ intensity e.g. interval training and HIIT.
- Not suitable for pulmonary conditions and primarily uses the anaerobic respiration.
- Effects are similar to that of HVLIT, but takes a lot less time. Also burn more calories – EPOC (2 hour window post exercise where calories are still being burnt to restore the body to pre-exercise levels due to increased contractility of muscles – 6-15% increase in calories.
- Any exercise modality e.g. 1:1 (2 mins on, 2 mins off) - High volume, low intensity training (HVLIT) - within the 60-80% aerobic threshold and includes 30mins + of aerobic exercise such as aerobic circuit training
Describe the specificity principle
Specificity
• How relevant is the exercise to what the patient/physio wants to achieve.
• Functional exercise to improve ADL’s
• Pt goals
Describe the progressive overload principle
- Allows cardiopulmonary and musculoskeletal adaptations to exercise, therefore minimising the risks of injury or incidents – potentially fatal if care not taken.
- Use of training diaries to log daily exercise intensity, duration, type, monitor any symptoms such as pain or fatigue - provides patient a visual cue to see what level of exercise is suitable.
Describe the safety and screening principle
BP -
• A drop in systolic BP of 20mmHg or more shows heart is not coping with the demands of the activity, or failure of systolic BP to increase with exercise.
• Isometric exercises increases BP due to increased vascular resistance.
• Upper body increases BP, VO2 and HR due to reduces vasodilation and increased effect of gravity which increases the resistance.
Physio -
• Give clear instructions before, explaining test and discussing endpoints e.g. dizziness, pain, cold clammy skin.
• Monitor BP, HR, o2 sats, and breathlessness score before and after. If high, repeat after 5 mins.
• Watch for signs of fatigue, symptoms during.
What are the expected responses of the CV system to aerobic exercise?
- Increased HR (Bradycardia) - occurs due to SNS activation and released of adrenaline from adrenal medulla
- Increased SV - (vol of blood pumped out of the heart per beat) by 110mls in an untrained individual if over 40% aerobic threshold to approx 40-60% of VO2 max then levels off.
Increased BP - Increased CO
(vol of blood pumped out the heart per minute) increased by 4-5x in an untrained adult– occurs due to the need to supply the increased metabolic demand of the respiring muscles – removal of co2 and perfusion of O2 to aid aerobic respiration, reduce the build-up of lactic acid. 95% of the CO is diverted to the heart and active skeletal muscles.
Increased venous return
• More deoxygenated – about 25% oxygenated
• Due to contractility of the abdominal and skeletal muscle pumps - need for deoxygenated blood to return to the R atria via the Vena Cava and then transported to the lungs via the pulmonary arteries on the R side of the heart to become oxygenated via gaseous exchange.
• Venous return may decrease in anaerobic exercises due to the unsustainable workload.
• May also decrease in long distance exercise if blood plasma levels fall due to dehydration – blood shunting due to viscera vasoconstriction to re-direct blood flow to muscles (due to SNS stimulation of organs)
Blood vessel
• Increased blood vessel vasodilation – increased body temperature
• Allows more blood flow to the muscles and transportation of nutrients e.g. glucose from mitochondria to aid muscle contraction –
Blood pressure
• Increased systolic blood pressure from 110mmHg at rest to 210mmHg at VO2 max
• Due to the increased contractility and work load of the heart, thus SV and CO.
• Diastolic pressure maintains around norm
• Dependent on if UL or LL exercise; higher BP in isometric and UL exercises due to reduced effect of gravity and reduced vasodilation.
What are the expected responses of the Respiratory system to aerobic exercise?
- Increased respiratory rate (tachypnoea)
- Increased oxygen uptake (VO2) – normal values are 3.5mls/kg/min at rest – this can increase up to 10x. There is also an increased arterial-venous difference. Normally around ¼ of oxygen in the blood is used at rest. This increases up to ¾ in exercise.
- Increased tidal volume – neural stimulation of the diaphragm
- Increased thoracic expansion
- Increased minute volume
- Improved V/Q matching - increased GE
- PaO2 drops slightly but maintained at 10-12mmHg.
- Lactic acid build up at 50-60% of vo2 max.
Define SV and explain it’s significance
SV is the total volume of blood pumped out of the heart per beat at rest. (roughly 70mls at rest). It is equal to EDV - ESV.
- It is affected by gender, fitness levels, age and heart size. A more trained athlete will have a greater SV
- CO = SV X HR
- A greater SV is required in exercise and conditions such as stress due to SNS stimulation of the heart. This increased by
1. Increased VR (Preload) - Frank Starling mechanism; Increased VR causes stretch on cardiac muscle cells which increases the force of contraction (due to vasoconstriction of BV and abdominal/ms pumps) increasing SV.
2. increased contractility of the heart - increased SNS stimulation, adrenaline release
3. Reduced afterload - pressure ventricles must overcome to eject blood (e.g. due to pulmonary/systemic circulation) - occurs via vasodilation
Describe the Mitral valve and it’s significance
One of 2 AV valves.
Separates the LA from LV
Open on atrial systole (P wave)
Closes when pressure in the ventricles > atria to prevent back flow. Instead blood is directed through the semi lunar valves into the systemic circulation via aorta.
Describe the cardiac muscle and it’s significance
Cardiac muscle is one of 3 main types of muscle.
It is involuntary
It is striated
It consists of the middle layer of the heart (myocardium) - the other 2 being epi and pericardium
It has inherent rythmicity due to the presence of gap junctions situated between fibres to allow transmission of SA electrical impulses = coordinated contraction of heart.
Describe what the SA node is and what it’s significance is
The heart’s natural pacemaker, located in the R atrium
Consists of small, modified muscle cells that generate electrical impulses across the cardiac tissue
This travels to the AVN, then to the purkinje fibres and Bundle of His, allows contraction of the ventricles from the bottom up.
It is controlled by cardiac center in medulla – it can increase and decrease HR buy spontaneously generating an electrical stimulus 60 to 100 times per min
This allows continual, automatic, involuntary contraction of the heart.
What is the SNS and what is it’s significance?
The SNS is a division from the autonomic NS, the other being the PNS
It is involved in the ‘fight or flight’ response to a stimuli, therefore involved in the excitation of neurones.
This causes an increased HR and increased contractility of the heart, therefore increasing SV, CO and BP. This is also done through the vasomotor centre causing vasoconstriction.
It also stimulates the adrenal medulla, causing the release of adrenaline and noradrenaline which increase the metabolic rate and increased glucose production from the liver.
The SNS is triggered by a change in temp, blood acid and blood pressure
Describe the conducting system of the heart
This system generates and conducts electrical impulses from the SA node, located in the R atrium, to the muscles of the heart, enabling heart contraction.
The SA node sends electrical impulses to the AV node, situated in the interatrial septum.
A short delay occurs here allowing the ventricles to fill with blood.
The AVN then conducts these electrical impulses down the Bundle of His and the Purkinje fibres.
These fibres conduct the action potential from the interventricular septum, down to the apex of the heart and then upwards through the ventricles, causing the heart to contract.
Explain the expected physiological effects of an eight-week endurance training (aerobic) exercise programme on the CV system system at
At rest: Bradycardia Reduced BP vascularisation myocardial hypertrophy Increased SV - due to increased EDV, therefore the cardiac muscle is chronically stretched. This increases the blood flow to the working muscles and vital organs supplying O2/nutrients and removing waste.
