Strength

• What are the 5 types of strength?

  Maximal

  Explosive

  Static

  Strength Endurance

  Dynamic
• Static strength is when the force is applied against a resistance without any movement occurring. This is isometric contraction.
• Give an example of static strength?

  Crucifix position on the rings in gymnastics
• Dynamic strength is force applied a resistance where muscles change length eccentrically or concentrically. Also known as power output.
• Give an example of dynamic strength?

  Hop, skip and jump phases in triple jump
• Maximum strength is the ability to produce a maximal amount fo force in a single muscle contraction. Also known as 1 rep max
• Give an example of maximal strength?

  Olympic deadlift
• Explosive strength is the ability to produce a maximal amount of force in one or a series of rapid muscular contractions. Also known as elastic strength due to the stretch and reflex mechanisms within a muscle.
• Give an example of explosive strength?

  sprint start for 100m
• Strength endurance is the ability to sustain repeated muscular contractions over a long period of time, withstanding fatigue.
• Give an example of strength endurance?

  Rowing

  Swimming
• What are the factors affecting strength?

  Age

  Gender

  Cross-sectional area

  Fibre types
• How does cross-sectional area affect strength;

  • the greater the cross-sectional areas of the muscle, the greater strength
  • maximum of 16-30 newtons of force per square centimetre of muscle cross-section
• How does fibre types affect strength;

  • the greater the percentage of fast glycolytic and fast oxidative glycolytic, the greater the strength over a short period of time
  • Fast twitch fibres have large motor neurons, forming large motor units with rapid, high force contractions
  • Greater the recruitment of fast glycolytic fibres, the greater the force of contraction.
• How does gender affect strength;

  • males have higher strength than females
  • males have higher muscle mass & cross-sectional area due to increase in testosterone
  • when strength is expressed per unit of cross-sectional area, the difference between genders largely disappears
• How does age affect strength;

  • peak male strength = 18-30 years old
  • peak female strength = 16-25 years old
  • strength development peaks at 20-30 then decreases with age
  • decrease is due to less efficient neuromuscular system, loss of elasticity and testosterone
• What are the test for evaluating strength?

  UK abdominal curl test (strength endurance)

  Vertical jump test (explosive strength)

  Grip strength dynamometre (maximal strength)

  One rep max test (maximal strength)
• How to carry out UK abdominal curl test?

  1. subject performs continuous sit ups at progressive intensities till exhaustion
  2. each sit up will be timed to an audio cue
  3. the test is over when the subject cannot complete two consecutive sit ups in the allocated time or when technique significantly deteriorates
  4. a stage and sit up number will be given which indicates a strength endurance level from a standardised comparison table
• Advantages of UK abdominal curl test:

  • Large groups can perform the test at the same time
  • Only simple and cheap equipment is required
  • Abdominal muscles can be isolated
  • Valid and reliable test
• Disadvantages of UK abdominal curl test:

  • Good technique is essential
  • Safety concern over repeated strain on lower spine
  • Maximal test to exhaustion limited by subject motivation
  • Test is not sport specific
• How to carry out vertical jump test:

  1. Using wall-mounted vertical jump board or chalked fingers, the performer marks the highest point with one arm outstretched
  2. With a bend and swing of the arms, the performer will mark the highest point jumped
  3. The difference between the resting and jump height represents explosive strength and can be assessed using a standardised comparison table
• Advantages of vertical jump test

  • Using a formula the data gained can be converted into a power output estimate
  • Easy test with minimal equipment
  • Test could be administered by the participant
• Disadvantages of vertical jump test:

  • The measure is not isolated to one muscle group
  • Only estimates explosive strength in legs
• How to carry out grip strength dynamometre:

  1. Adjust grip for hand size
  2. Participant will zero the dial and hold dynamometer with a straight arm above the head
  3. The arm is then brought down when they squeeze the grip maximally
  4. Three attempts are recorded from the dominant and non-dominant hand
  5. Results can be assessed by a comparison table
• Advantage of grip strength dynamometre:

  • Simple and objective to measure
  • inexpensive equipment
  • High reliability
• Disadvantages of grip strength dynamometre:

  • Only the forearm muscles are assessed
  • Test is not sport specific
• How to carry out one rep max test:

  1. Subject chooses a high weight achievable in one repetition on a specific piece of gym equipment or free weight to assess an isolated muscles’ maximum strength
  2. Increase the weight until only one maximal rep can be achieved.
  3. Ensure full recovery between repetition to prevents fatigue
• Advantages of one rep max test:

  • Direct objective measurement of isotonic maximum strength
  • Easy procedure on accessible equipment 
  • Most muscle groups can be tested
• Disadvantages of one rep max test:

  • Difficult to isolate individual muscles
  • Trial and error may induce early fatigue
  • Potential for injury performing maximal lifts
• Weight training:

  • free standing weight
  • very high resistance and low repetitions
  • increase muscle size and strength
  • flexible and specific
  • specific to muscle group or joint
  • potentially dangerous and a spotter is often required
• Multi-gym:

  • multiple components to perform a wide range of exercises
  • generic muscle movements
  • adjustable weight
  • specific strength requirements
  • space efficient
  • safe
  • hard to suit specific movement patterns requirements for sporting actions
• Plyometric training:

  • involves a series of explosive exercises to improve speed at which a muscle shortens
  • involves hopping, skipping and jumping
  • associated with lower body
  • high injury risk
  • stretch reflex
• Circuit and interval training:

  • circuit training involves a set number of exercise stations
  • adapted to be sport specific
  • variables can be manipulates e.g intensity and duration
  • large groups
  • multi-gym, free weights and plyometric can be arranged in a circuit
  • strength endurance
• Neural pathways:

  • increased recruitment of motor units and fast glycolytic and fast oxidative glycolytic fibre types = increased force of contraction, improved co-ordination
  • decreased inhibition of the stretch reflex = increased force of contraction from the agonist muscle, decreased inhibition from the antagonist and increased stretch of the antagonist

  overall: increased speeds, strength and power output
• Muscle and connective tissues:

  • increased strength of tendons and ligaments = increased joint stability and decreased risk of injury
  • increased bone density and mass - increased absorption of calcium = decreased risk of osteoporosis

  Overall: increased muscle mass and increased speed, strength and power output
• Metabolic function:

  • increased enzyme activity= increased activity of ATPase = reduces the onset of fatigue
  • Increased muscle mass = increased metabolic rate
  • Increased ATP = increased capacity for very high intensity energy production
• Metabolic function:

  Overall:

  • increased anaerobic fuel stores and energy production

  increased anaerobic theshold and delayed OBLA, which increases the intensity and duration of performance

  increased metabolic rate, increasing energy expenditure and managing weight