State the names of the muscles at X and Y.

X:

Y:

Identify the movement at the elbow joint during the upward phase from position A to position B in the diagram.

Outline the type of muscle contraction of the agonist at the elbow joint during the upward phase from position A to position B in the diagram.

The diagram shows a skeletal muscle.

[Source: adapted from sportsinjuryclinic.net]

Identify the structures X and Y in the diagram.

X:

Y:

Compare and contrast the structure of fast-twitch (type IIa and IIb) muscle fibres.

Distinguish between genotype and phenotype.

Suggest how genetic and environmental factors may affect muscle fibre type expression.

Explain the physiological causes of peripheral fatigue in endurance activities.

Describe delayed onset muscle soreness.

X: triceps brachii ✔

Y: tibialis anterior ✔

extension ✔

<isotonic> concentric, the muscle shortens under tension ✔

X = epimysium ✔

Y = fascicle/perimysium ✔

Sub max [3]

genotype is influenced by genes whereas phenotype is influenced by the interaction between genes and environmental factors/ reflects the expression of our genes ✔

muscle fibre type <cross-section> is inherited from parents ✔

environmental factors, such as training/climate, may affect the characteristics of muscle fibre types ✔

training maximizes the likelihood of achieving a performance level with a genetically controlled ceiling ✔

aerobic performance is hindered by a depletion in glycogen stores as ATP resynthesis slows ✔

a reduction in Ca²⁺ release reduces the ability of muscles to contract effectively ✔

depletion of acetylcholine reduces the ability of an action potential to pass to the muscle fibres ✔

electrolyte loss occurs through sweating, which can lead to cramp ✔

dehydration can occur due to loss of essential fluids used to help with temperature regulation ✔

overheating can impair muscle function ✔

Max [1] for a list of two or more causes of peripheral fatigue

a high-intensity exercise programme involving eccentric exercise is likely to generate the most soreness ✔

is associated with injury <within the muscle>/micro tears of fibres/inflammatory actions/overtraining ✔

normally occurs 24–72 hours after exercise ✔

symptoms can last up to 5 days ✔