Pe- muscle fibre recruitment and muscle effects (copy)

How does blood flow work to working muscles

1. Blood vessels dilate during exercise improving oxygen and nutrient supply to tissues and stimulating waste removal (lactic acid / CO2)

2. Allows for oxygen demand to be met and enhanced aerobic performance

3. Blood flow is directed to working muscles and reduced from the digestive system

Effects on muscles :Temperature

• when muscles contract they produce heat

• increased blood flow also increases the temperature and pliability of muscles, which in turn helps to improve flexibility and range of motion.

• Improved elasticity of muscle aids performance and recovery, and reduces delayed onset muscle soreness (doms).

Effects on muscles : micro tears

• overload from strength and endurance exercises creates stress on the muscles

• The excess creates micro tears within the muscles

• WHEN micro tears repair, the muscle rebuilds.

• the process is normal and increases strength and muscular hypertrophy.

• training improvements, such as increased muscle strength and size, are made if the body has sufficient rest to repair.

How can micro tears in muscles affect sport’s performance

• if there is not enough rest between training sessions the body does not fully repair the muscles.

  This may happen because of:

• Overtraining

• High volume of training poor scheduling

Type 1 characteristics

• slow twitch

• High resistance to fatigue

• Low power output

• High aerobic metabolism

Type lla characteristic

• fast twitch

• Medium resistance to fatigue

• Medium power output

Type llx characteristics

• high power output

• Small resistance to fatigue

• Fast twitch

• anaerobic metabolism

Order of recruitment

• Type 1 muscle fibres are recruited first as the smallest, contract more slowly and generate less force.

• Type lla muscle fibres are then recruited,

• Type llx muscle contracts in response to a stimulus. the force production or duration of contraction is relative to the type of exercise.

Frequency of stimulation

the force production or duration of contraction is relative to the type of exercise

what is a twitch?

a single contraction in response to a stimulus

wave summation

Repeated stimulation (twitches), acts to increase muscular tension.

1Tetanus

is when a muscle is in a complete sustained contraction due to rapid stimulation of the muscle.

the frequency of stimulation influences what?

the relative tension within the muscle

as intensity increases,

muscle recruitment moves from slow twitch fast twitch (type I then type lla fibre to type llx)

Muscular endurance

the muscle develops the type i fibres. This allows for efficient performance of repetitive slow isotonic contractions but a decrease in strength capacity.

Muscular strength

type iia and type iix fibres are recruited and act at a quicker and faster rate to produce the force required.

- type iia fibres help to produce sustained power.

- type iix fibres are faster, but fatigue more rapidly