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Lesson 8a - Components of Fitness

Components of Total Physical Fitness

  • Cardiovascular / aerobic - efficiency of heart, lungs and blood vessels
  • Muscular strength
  • Muscular endurance
  • Flexibility - range of movement at a joint. Improved by stretching muscles after exercise.


Cardiovascular Fitness

  • Moderate exercise including rhythmic activities which use the large body muscles
  • Activities should be sustained comfortably for a long duration eg running, cycling, swimming, aerobics, rowing.

These activities should be performed:

  • Three to five times per week (ideally varying the activities)
  • Intensity should cause the pulse rate to go up to 55-90% of maximum, dependent upon fitness - fitter people can aim for a higher percentage. Maximum heart rate is calculated as 220 - age. This is very approximate (has a standard deviation of 10-12 beats per minute - which means (statistically) that 98% of the population have a maximum heart rate falling within the range (220 +/- 24 - age).
  • Activity should be sustained for between 15 and 60 mins, again dependent upon fitness.
  • Activities should be rhythmic, use large muscles and aerobic.

Effects of Aerobic Exercise

Short term:

  • Increased heart rate
  • Increased carbon dioxide production
  • Increased cardiac output
  • Increased blood pressure

Long term:

  • Improved stroke volume
  • Improved circulation
  • Decreased resting heart rate
  • Improved respiratory function

Muscular Strength

Incorporates high resistance with a low number of repetitions. Designed to make the muscles strong enough to support the skeleton and maintain posture.

Muscular Endurance

Incoporates lower resistance with an increased number of repetitions.

Exercises should be:

  • Arranged in sets
  • Include all major joint movements, especially weaker postural muscles (eg abdominals)
  • Work opposing groups to achieve muscle balance

Health Benefits of Muscular Fitness

  • Reduced incidence of back pain
  • Joints more stable and less susceptible to injury
  • Improved posture and tone
  • Increased blood supply
  • Increased bone density and a decreased risk of osteoporosis
  • Improved performance in recreational and sporting activities
  • Improved self confidence


Poor flexibility can lead to tear and sprain injuries. Flexibility is restricted by the elasticity of the muscles, the length of the tendons and the shape of the bones at the joint.

Reflex Actions During Stretching

The reflex causes muscles to contract to prevent overstretching. To minimise the effect of this reflex, you should:

  • Ensure muscles are warm
  • Develop the stretch slowly
  • Hold the stretch for around 8 seconds to allow the stretch reflex to relax (to maintain flexibility).

Golgi Tendon Organ Reflex

When a muscle stretch is maintained over a longer period, tension builds up causing a reflex to relax the muscle to prevent injury. Holding a stretch for long enough to build up this tension is called a developmental stretch and should be held for lat least 30 seconds (to improve flexibility).

Static Stretches:

  • Active - determined by strength of contracting muscle
  • Passive - use an external force


Performed with bouncing movements. Not recommended due to increased injury risk to muscles, tendons and joints, and no flexibility gains as the stretch is not held long enough.

The post stretch will increase the range of movement at the joints, reduce the muscle tension and lengthen the muscles again after use.

Motor Skills

  • Agility
  • Balance
  • Coordination
  • Power
  • Reaction time
  • Speed

Gross motor skills - large movements; fine motor skills - small movements. Enhanced motor skills can lead to enhanced performance in a work out and have a positive effect on posture.