Lecture 7: Training Biomechanics

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Lecture 7Training Biomechanics
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Human Machine System

• components
• mover source of input energy (muscle)
• machine changes energy into more useful form
  (bones joint)
• resistor load

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• human machine systems
• levers
• wheel-axle machine types I II
• pulley

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Skeletal Muscle

• muscle activation
• concentric
• eccentric (plyometric)
• isometric
• isokinetic

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Skeletal Muscle

• muscle fiber
• threadlike
• wide range of size variation
• growth in size

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• twitch vs. tetanus
• twitch response to single stimulus (lt100 ms)
• tetanus sustained maximal tension

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• fiber types
• type I SO (slow-twitch, oxidative)
• high endurance
• type II
• IIa FOG (fast-twitch, oxidative, glycolytic)
• IIb FG (fast-twitch, glycolytic)
• high power

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• motor unit
• motor neuron muscle fibers innervated
• functional unit of the muscle

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• Innervation ratio
• number of fibers in a unit
• smaller fine movement (eyes fingers)
• larger gross powerful movement (gastrocnemius,
  power zone)
• fiber composition
• same type in a motor unit
• both types of motor units in a muscle

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• the size principle
• smallest available motor unit first
• fatigue onset recruit a new fresh motor unit
• type I -gt type II

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• fiber arrangements
• parallel more shortening, motion
• pennate more fibers, force

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• roles assumed by skeletal muscles
• agonist
• antagonist
• stabilizer
• neutralizer

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• Hills muscle model
• contractile component (CC)
• parallel elastic component (PEC)
• series elastic component (SEC)

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• force-length relationship
• isometric characteristic
• active curve CC
• passive curve EC

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• force-velocity relationship
• dynamic characteristic
• concentric phase
• eccentric phase

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• electromechanical delay
• EMD 20 100 ms
• SEC
• FT fibers
• pre-stretching

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• multi-joint muscles
• hamstrings, rectus femoris, gastrocnemius
• maintain muscle length

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Functional Aspects

• muscular strength
• max isometric force
• factors affecting muscular strength
• force generation capability / cross-sectional
  area
• muscle composition
• innervation

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• muscular power
• m. power muscle force contraction velocity
• FG unit contents

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• muscular endurance
• Ability to exert tension over time
• force speed requirement
• SO unit contents

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Kinetic Quantities

• force vs. torque
• force torque vs. resistance torque
• equipment type vs. actual load

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• work
• power

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Training Equipment

• isotonic equipment
• free weight
• constant resistance
• joint angle vs. resistance torque
• elastic band
• non-constant resistance
• Young modulus force/unit deformation
• machine angle, angle of pull

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• pulley type
• alters direction of the resistance
• resistance torque vs. angle of pull
• wheel-axle type
• direction of force changes
• resistance acts on the axle
• constant resistance torque
• bilateral load

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• isokinetic equipment (Cybex)
• wheel-axle system
• constant angular velocity
• non-constant torque
• power (torque) x (angular velocity)
• (force) x (arm length) x (angular
  velocity)
• flexor extensor load
• concentric eccentric load
• rehabilitation power training

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• bicycle ergometer
• pulley wheel-axle type
• Wingate test

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• treadmill