HPE110 Lecture Notes - Lecture 9: Hyperplasia, Stretch Reflex, Plyometrics
HB101-Lecture 9
Strength
-Factors affecting
-Responses to training
-Injury risks
Speed
-Description
-Neural, muscular, anthropometric factors
Power
-Strength speed relationship
-Factors affecting
-Training principles
Strength, Speed and Power
Strength
The aout of foe o toue a idiidual a podue i oe aial epetitio
‘M.
Speed
How much distance can be covered over a certain period of time?
Power
The ailit to deelop foe o toue oe tie.
Factors Affecting Strength
• Fibre type
Motor unit activation
Muscle architecture
Joint orientation
Muscle length and contraction velocity
Strength and Fibre Type
Type I; slow twitch muscle fibres
Type IIa & IIb; fast twitch muscle fibres
Generate more force via greater metabolism capacities
Enables greater cross bridge turnover in sarcomeres
Therefore greater overall force
Strength and Motor Unit Recruitment
Size; Activation of muscle fibres in parallel will increase the force production of the
muscle
Frequency; Number of action potentials will also increase the force generation of a
motor unit
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Size Theory of Motor Unit Recruitment
Small motor units recruited first
Fine motor control
Larger motor units recruited later when high forces required
All o othig piiple fo ax force / power
Strength and Muscle Architecture
PCSA represents number of muscle fibres in parallel
More fibres in parallel = more force production
Pennation angle enables greater PCSA
PCSA =
Vol x Penn Angle
Fibre Length
Hypertrophy important!
Strength and Joint Orientation
Joint angle affects lever arm of muscle and load
Therefore affects torque production of muscle and load
Length – Tension and Force – Velocity Relationships
Strength Training Adaptations
Neural Drive
Early strength gains are likely the result of increased neural drive and coordination instead
of muscular mechanical adaptations
i.e. – greater motor unit recruitment, less cocontraction
Hypertrophy fibre size
Enlargement of muscle fibre size due to;
-increase protein filament size and number
-connective tissue mass (tendons, fascia)
Hyperplasia fibre number
An increase in the number of parallel muscle fibres
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
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