Week 7

Question 1

Resistance training results in strength increases because of what?

Answer 1

Muscle hypertrophy (bigger muscle fibres)
Muscle hyperplasia (more muscle fibres)
Neural adaptations

Question 2

What are the benefits of resistance training?

Answer 2

Yields strength gains via neuromuscular changes
After 3-6 months 25-100% strength gain
More effective force production (physiological adaptations)
Or is it optimisation of movements (technique)

Question 3

In what way can strength gains occur without hypertrophy?

Answer 3

Normally motor units are recruited asynchronously
In resistance training, increased synchronous recruitment, so increased strength
May also result from greater motor unit recruitment
- increased neural drive during maximal contraction
- increased frequency of neural discharge
- decreased inhibitory impulses

Question 4

What is autogenic inhibition?

Answer 4

Normal intrinsic inhibitory mechanisms
- Golgi tendon organ (inhibits contraction if tension too high to prevent damage)
Decreasing inhibitory responses and impulses
- training leads to increased force
- superhuman feats of strength (under immense stress)

Question 5

What is the relationship between agonist and antagonist muscles?

Answer 5

Co activation

• normally antagonists oppose force but there is always some coactivation
• reduced coactivation may result in slight strength gain

Question 6

Differences between short and long term strength gains

Answer 6

Short

• substantial increase in maximum force
• increase in voluntary neural activation
• neural factors critical in first 8-10 weeks

Long
- associated with fibre hypertrophy
- net increase in protein synthesis takes time to occur
a hypertrophy major factor after first ten weeks

Question 7

What is the difference between transient and chronic hypertrophy?

Answer 7

Transient

• directly after exercise bout
• due to edema formation from plasma fluid
• disappears within hours

Chronic

• long term
• reflects actual structural change in muscle
• fibre hypertrophy (bigger fibres)

Question 8

What impact does eccentric and concentric training have in hypertrophy?

Answer 8

Maximised by eccentric - increased force

Concentric may limit hypertrophy because exercising in negative velocity range

Question 9

What is eccentric training?

Answer 9

Muscle lengthens as it contracts

Disruption of sarcomere z lines - protein remodelling - overreaching

Short term performance may reduce but long term benefits

Question 10

How does resistance training affect protein synthesis?

Answer 10

During exercise: decreased synthesis, increased degradation

After exercise: increased synthesis, decreased degradation

Question 11

How can hormones affect hypertrophy?

Answer 11

Testosterone facilitates fibre hypertrophy (natural anabolic steroid hormone)

Synthetic anabolic steroids - large increases in muscle mass

Question 12

What is hyperplasia?

Answer 12

Fibre splitting - each half grows to size of parent fibre

Some evidence in animal studies but very limited in humans

Question 13

What fibre type alterations happen with training?

Answer 13

Type 11 fibres become more oxidative with aerobic training

Type 1 fibre become more anaerobic with anaerobic training

Question 14

Is fibre type conversion possible?

Answer 14

High intensity treadmill or resistance training (type 1 –> type 11a)

Heavy resistance training programme ( %11x decrease, %11a increase)

Question 15

How does exercise damage muscle?

Answer 15

Sarcomere z disks: anchoring points of contact for contractile proteins

• transmit force when muscle fibres contract
• z disk, actin/myosin damage after eccentric work

Question 16

What is delayed onset of muscle soreness?

Answer 16

1-2 days after exercise
Muscle strain
Major cause is eccentric contractions
Level run pain < downhill run pain
Cycling: mostly concentric, mostly no DOMS
Not caused by increases in BLa
Indicated by muscle enzymes in blood (e.g. creatine kinase)
Suggests structural damage to muscle membrane (‘leak’)

Question 17

DOMS and inflammation

Answer 17

White blood cells (macrophages/neutrophils defend body against foreign material/clear up damaged cells
Muscle damage - inflammation - pain
Damaged muscle cells attract neutrophils
Neutrophils release attractant chemicals
This stimulates pain nerves
Macro gates remove cell debris

Question 18

How does DOMS affect strength?

Answer 18

Loss of strength
Loss of contractile protein
Failure in excitation-contraction coupling (appears to be most important)

Question 19

What are some strategies to reduce DOMS?

Answer 19

Minimise eccentric work early in training
Start with low intensity train g and gradually increase
Warm up