B5 Fitness and Training

B.5.1  Define fitness

Fitness is the physical condition of a body that allows it to perform exercise of a particular type

  • Fitness is specific to the type of activity being performed (e.g. a strong swimmer may not be a strong runner)

B.5.2  Discuss speed and stamina as measures of fitness

  • Speed is the rate at which movement is performed and relies predominantly on fast-twitch muscle fibres
  • Stamina is the capacity for sustained exercise or performance and relies more on slow-twitch muscle fibres
  • Measures of fitness can be used to show improvement in performance (e.g. timing duration of activity: longer = ñ stamina; shorter = ñ speed)
  • As performance improves, there should also be a shortening of the time taken for the heart to return to resting rate

B.5.3  Distinguish between fast and slow muscle fibres

  • Fast and slow muscle fibres are differentiated by the time needed between contractions of the muscle fibres
  • Fast muscle fibres have greater oxygen needs, lower myoglobin levels and provide a maximum work rate over a shorter period of time (strength)
  • Slow muscle fibres have a very good blood supply, plenty of myoglobin and are capable of sustained activity and high rates of aerobic respiration

Comparison of Fast and Slow Muscle Fibres

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B.5.4  Distinguish between the effects of moderate-intensity and high-intensity exercise on fast and slow muscle fibres

  • Fast muscle fibres can release large amounts of energy in a short period of time via anaerobic respiration – they contain large amounts of glycogen
  • Slow muscle fibres release energy more slowly by aerobic respiration but continue for longer – they rely more on respiratory substrates in the blood
  • Moderate-intensity exercise (e.g. long-distance running or swimming) stimulate the development (in size) of slow muscle fibres
  • High-intensity exercises (e.g. sprinting or weight-lifting) stimulate the development (in size) of fast muscle fibres

Fast and Slow Muscle Fibres

fast and slow fibres

B.5.5  Discuss the ethics of using performance-enhancing substances, including anabolic steroids

Arguments For:

  • Some naturally occurring substances can vary according to individual genetics, so it would level out all athletes
  • Should be able to advance sporting performance to the maximum possible level (greater spectacle)
  • Allows injured athletes to recover faster
  • Would provide employment and economic benefit by opening up a new market

Arguments Against:

  • Many performance-enhancing substances have negative side effects (e.g. high doses of anabolic steroids can cause liver disease)
  • Would function to give some athletes an unfair advantage over others (wealthy would benefit at expense of the poor)
  • Some may be artificially synthesised and so not represent normal processes (i.e. are unnatural)
  • As currently illegal, using the substances provides profits for criminal organisations