20 markers

Question 1

Velocity/time graph graph showing the motion of a hockey ball that is hit at the goal and rebounds of the post.

• explain the motion of the ball using the graph
• intermittent exercise of differing intensities and durations
• anaylyse the interplay of energy systems during intermittent exercise and the factors that affect the systems
• use examples of team sports

Answer 1

1) Explain the motion of the ball with reference to the V/T graph
- N1 (Law of Inertia)
- ball hit
- moves N2 (Law of Acceleration)
- Reaches uniform velocity
- Hits post and N3 (Law of Reaction)

2) What is intermittent exercise
- where the intensity and duration of the activity constantly changes with varying rest periods
- ball will be in play for varied intervals

Energy Continuum
- due to the intermittent exercise the energy system used during games will constantly change
- they do not work in isolation so all three will make contributions

Energy thresholds
- point at which the performer predominant energy systems switches to another
ATP-PC: up to 10 seconds (maximal)
LA system: 10 seconds to 3 mins
Aerobic: 3 mins plus

3) Example: Football

ATP-PC
- predominant for explosive, dynamic movement that is short in duration (up to 10 seconds)
- trying to dribble past an opponent and shoot in football
- PC – P + C + ENERGY (1ATP)
- muscle cell sarcoplasm

Lactic system
- for prolonged high intensity movement requiring muscular speed/endurance
- glycogen — glucose —-energy (2 ATP)
- Glycogen is stored in the muscles whilst glucose can be delivered via the bloodstream
EXAMPLE: After a period of defending the performer has to sprint up the pitch to join a counter attack

Aerobic system
- for low/moderate intensity activity (longer than 3 mins)
- the aerobic energy system is vital for recovery of the anaerobic energy systems
-glycogen can be used as fuel and O2 is required for aerobic respiration
- yield is 1:38
- EXAMPLE: football game lasts 90 mins, performer can jog back and track opponents

Factors:
- Fitness Levels (Higher aerobic threshold means the performer can work at a higher intensity without using the LA system (delayed OBLA) - can lead to quicker recovery as well
- Standard & Motivation (Footballer at an elite level will be playing at a higher intensity to a recreational footballer, an elite performer will run further during a game meaning that the other performer is more likely to be at a lower intensity so aerobic might be predominant)
- Tactics and Position (Goalkeeper is going to be predominantly aerobic , A high pressing strategy would require much more high intensity running)