MUSCLE FIBRE TYPES

1
MUSCLE FIBRE TYPES

• Slow twitch
• Fatigue resistant
• Low power output
• Fast twitch
• Easily fatigued
• High power output
• Type iia iib

2
FAST TWITCH FIBRES

• TYPE IIA
• Fog (fast oxydative glycolytic)
• TYPE IIB
• FG (Fast glycolytic)
• Most forms of high intensity exercise converts FG
  to FOG

3
MUSCLE FIBRE COMPOSITION

• Most muscles have a combination of fibre types
• Gastrocnemius - high fast
• Soleus - high slow
• Composition changes due to training stimulus

4
MUSCLE FIBRE COMPOSITION

• High no. of TYPE I
• Greater VO2 MAX
• Greater endurance capacity
• High no. of TYPE II
• Greater strength power potential
• Lower VO2 MAX

5
MUSCLE CONTRACTIONS

• ISOMETRIC
• TENSION - NO MOVEMENT
• ISOTONIC
• TENSION - MOVEMENT
• CONCENTRIC - SHORTENING
• ECCENTRIC - LENGTHENING
• ECCENTRIC MOST EFFICIENT

6
FACTORS WHICH MODIFY FORCE PRODUCTION

• Length tension relationship of muscle
• Force velocity relationship
• Muscle fibre recruitment

7
FORCE-VELOCITY RELATIONSHIP
Force (N)
Velocity (m/sec)