Using examples, outline the function of the axial and appendicular skeleton during physical activity.

Describe the mechanics of inspiration in the final stages of a cycling race.

Explain the relative contributions of the three energy systems during a hockey or soccer match.

Explain how characteristics of type IIb muscle fibres could enhance the performance of a sprinter.

Axial skeleton:
provides protection of vital organs ✔

eg, skull protects the brain «during a tackle in rugby» ✔

supports the weight of the upper body ✔

eg, vertebral column supports the weight of the upper body «while balancing on a beam in gymnastics» ✔

Appendicular skeleton:
provides attachment for muscles ✔

eg, scapula provides attachment for rotator cuff muscles «which support the shoulders during the rings and vaulting» ✔

provides levers to allow movement ✔

eg, humerus and ulna articulate to form a lever «that allows for a more effective release of a javelin» ✔

Award [2 max] per skeleton type for both function and example.

Award [1 max] if either an outline or example has not been provided.

Accept any other suitable examples.

diaphragm contracts
OR
flattens ✔

«external» intercostal muscles contract ✔

raising the rib cage upwards and outwards ✔

this increases the thoracic volume ✔

this decreases the thoracic pressure ✔

final stages of the race accessory muscles contract (eg, pectoralis minor, sternocleidomastoid and scalenes) increase (thoracic) volume further ✔

Award [4 max] if there is no reference to accessory muscles.

all energy systems work in a continuum during physical activity depending on the intensity / duration / fuel availability / oxygen availability ✔

ATP-CP System/PC system/alactic system:
resynthesizes ATP during brief high intensity exercise «for more than 3 seconds to less than 10 seconds» ✔

eg, in hockey/soccer when performing a sprint/explosive movement for the ball at speed 20-60 m ✔

The lactic acid system / anaerobic glycolysis:
resynthesizes ATP during short/medium high intensity exercise «between 10s−2 mins range» ✔

eg, in hockey/soccer during transition of play such as a counter attack from defense ✔

Aerobic system:
hockey/soccer requires moderate/high intensity movements but is ongoing «more than 2 minutes» ✔

used during recovery between high intensity bouts or during lower intensity periods ✔ [2 max]

eg, returning to the half way line after a goal is scored ✔

Accept any reasonable ranges for duration. Accept other suitable examples.

Award [5 max] if all three systems are not mentioned.

Award [3 max] without applied examples.

greater fibres per motor neuron therefore more fibre recruitment per contraction ✔

fast motor neuron conduction transports action potential quickly ✔

a highly developed sarcoplasmic reticulum helps spread the action potential across the muscle fibre quickly ✔

«therefore» delivery of calcium is increased to the muscle cell ✔

«therefore» the contractile speed is fast ✔

high PC and ATP stores provide immediate source of energy for fast muscle contraction ✔

high glycogen stores provide energy for high intensity movements ✔

have a high anaerobic capacity «which is important for sprinters» ✔

can produce an explosive performance «which is required at the start of the event» ✔

Overall, this was a very popular and well answered question. Candidates who struggled with this question failed to provide appropriate examples for physical activities particularly with regards to appendicular skeleton.

Overall, this question was answered more poorly than anticipated because candidates did not answer about the mechanics of inspiration, but rather, about the causes of laboured breathing, energy systems, the mechanics of gaseous exchange, or blood distribution, and therefore and missed the focus of the question. A very limited number of candidates identified that accessory muscles are used during maximal exercise or final stages a race.

Overall, candidates did not appear to be well prepared for this question. Candidates were able to provide simple comments regarding intensity. However, many candidates focused on how ATP is produced during each energy as opposed to the contribution of each system to different types of exercise over the course of a match. Often the concept of all three energy systems working at the same time was not explicitly stated by candidates.

There was a large variety of answers to this question. Overall, candidates identified a few of the main characteristics of type IIb fibres but many failed to connect characteristics with enhanced performance of a sprinter. Both concepts were needed in order to be awarded many of the individual mark points. Confusion with type I muscle fibres was common.