3) Stengthening: Muscle Atropthy

Question 1

Arrangement of Muscle

Answer 1

Made up of contractile and non contractile tissue

> Epimysium very dense surrounds whole muscle

> Perimysium surrounds fascicles which are bundles of muscle

> Fascia supports muscle - surrounds it

forms pathways for nerves blood vessles and lymphatics- good blood supply for continuous muscle contraction

> Endomysium surrounds individual muscle fibres- thin and inner part is called the basal lamena

Question 2

Normal muscle

Answer 2

Variance in fibre type :between muscles, individuals and genders

Question 3

Type 1

Slow oxidative

Answer 3

Soleus

Slow oxidative contraction- eg maintain posture

Slow & Small motor unit

Slow conduction rate

High fatigue resistance

Weak contraction

High concentration of myoglobin enable aerobic energy metabolism

Mo farah

Question 4

Type 2a

Fast oxidative glycolytic

Answer 4

Tibialis anterior

Quick contraction

Medium motor unit

Fast conduction rate

High resistance to fatigue

Medium contraction

Low concentration of myoglobin enabling anaerobic energy metabolism

Ronaldo

Question 5

Type 2b

Fast glycolytic

Answer 5

Lateral head rectus femoris

Very quick contraction

Large motor unit

Very fast conduction rate

Fast to fatigue

Powerful contraction

Low concentration of myoglobe in enabling anaerobic energy metabolism - creatinephosphate

Usain bolt

Question 6

Motor unit

Answer 6

All muscle fibres that are innervated by the same motor neurone = same type

Large motor neuron phasic,fast twitch, type 2a 2b,
large motor unit 300–800 muscle fibres

Small motor neuron,tonic,slow twitch type 1
small motor unit 12–180 muscle fibres

How many muscle fibres contract from 1 innervating motor unit

Question 7

Size of motor neurone

Answer 7

Varies between muscles and within muscles eg triceps and quads

1 motor neurone supplying fewer muscles= better control of muscles

Speed,force = eye muscle

Question 8

Muscle strength

Answer 8

Larger motor neurone synchronised = greater the strength

Larger the muscle= greater strength

Question 9

Atrophy

Answer 9

Decrease in muscle fibre size resulting from the lack of stimulation

ie lack of activity - obesity aswell

Question 10

Why do muscles become weak

Answer 10

Inactivity- use it or lose it 
Neurological disruption
Bedrest
Injury – in a cast
Non-weightbearing
Pathology
Ageing
Malnutrition - proteins electrolytes

Question 11

Preventing atrophy

Answer 11

Mechanical loading – muscles under stress- lifting weights

Increased load or resistance is paramount for protein synthesis and turnover

Question 12

Hypertrophy

Answer 12

▪️Increase muscle mass
▪️Increased strength
▪️Increased cross-sectional area of muscle fibres
▪️Increased connective tissue
▪️Alteration of fibre type
▪️Alteration of metabolic capacity of muscle
▪️Alteration in myosin heavy chain isoforms
▪️Increased capillary density, myoglobin, enzyme activity of mitochondria and oxidative power

Question 13

What must happen for hypertrophy to occur

Answer 13

Satilite cells need to be actively involved

Muscle stem cells

Proliferate and differentiate into myoblasts

Basal lamina and sarcolema of muscle dormant until stimulated

More nuclei leads to more protein synthesis and myofibril becoming bulkier

More mitochondria

*cytokines

Question 14

Muscle strength

Answer 14

Ability of a muscle to produce tension and a resulting force in one maximal effort:

• Dynamic
• Static
• In relation to demands placed on it very adaptable

More info travelling via more efficient motor neurones= stronger

Question 15

Hypertrophy is the physiological process

Answer 15

Mechanical load= actin and myosin increase which increase muscle bulk increase size and number sarcomeres

Increased rate if mitochondria= ATP

X4 weeks

Vascularisation areound muscle uses o2 more effective

Question 16

Power vs Endurance

Answer 16

Determined by the strength of contraction and the distance moved in the specified time. Velocity of contraction. T2a T2b

Ability to contract repeatedly or sustain tension over a prolonged period of time. T1

Question 17

Principles of training

Answer 17

Specificity
Progression
Overload- FIT 
Reversibility
Tedium

Individuality,motivation,learning, diminishing returns

Question 18

Diminishing returns

Answer 18

More injured patients are more likely to improve more in comparison to those patients who are already in good physical condition

Question 19

Overload

Answer 19

In order to strengthen muscle it must be fatigued

*Intensity needs to be 60% of one repetition marks of maximum voluntary contraction

Some regimes= power other endurance

Fit principal

Resistance offered by free weights bodyweight theraband

Question 20

Strengthening regimes

Answer 20

8-12 repetitions

3 times a week minimum twice a week

Start slow with low intensity

Upper limb 30-40% of 1RM
Lower limb 50-60% of 1RM

Once able to complete 12 reps increase by 5%

Progression of weight 1 –2 weeks or if elderly 2–4 weeks

Question 21

Specificity

Answer 21

E.g Strengthening glutes for walking

Eccentric muscle contraction appears to be effective and efficient increasing muscle strength

If movement isn’t possible due to pathology isometric exercises will improve isometric strength and enhance isotonic strength and movement is allowed

Speed of isotonic contraction is can affect the strength of changes
The speed of muscle needs to contract for specific functional task is the ideal speed of the exercise

Question 22

Muscle strength factors

REVIEW E LECTURE

Answer 22

Type of contraction
Frequency of firing motor units
Number of motor units activated
Psychological factors
Angle of pull
CSA of muscle
Age and fitness
Length/tension relationship
Neural factors
Length of lever arm
Strength and stiffness of connective-tissue
Speed of contraction
Genetics

Question 23

Measuring strength

Answer 23

MRC

Circumferential measurement - not a good test for strength

Dynamometers- isokinetic ( cybex biotex) or handheld

Question 24

Newton’s laws

Law inertia

Answer 24

Body will remain at rest or in a state of uniform motion unless acted upon by an external force

Weak quads reduce inertia

Question 25

Law acceleration

Answer 25

The acceleration of the body is parallel directly proportional to the force acting on the body Is in the same direction of the force and inversely proportional to the mass of the body

Make exercise faster - Mobilising

Or slower for strengthening more demanding of motor units

Question 26

Law action/inaction

Answer 26

To every action there is an equal and opposite reaction

Resistance is equal

Question 27

Physiological process atrophy

Answer 27

Decrease protein synthesis rate

No stimulus body takes away protein synthesis = wastage

Question 28

How do you know strengthening programme has worked

Answer 28

Worked/Reached fatigue

Sweating,facial expressions, compensating,unable to work through range, phasiculation (tremor)

Question 29

Strengthening programme

Answer 29

Motivation-start easy then progress
Competition 
Tempo
Slower
Through range- start mid range 
Power/endurance

Type of contraction- concentric is easiest
Eccentric is the hardest