Post-activation, Potentiation

Question 1

A theory that purpose that the contractile history of a muscle influences the mechanical performance of subsequent muscle contraction.

Answer 1

Post-activation and potentiation

Question 2

Contractile history

Answer 2

• Warm-up
• Prior exercise
• Intensity
• Duration
• Frequency
• Specificity

Question 3

Decrease in force production, contraction velocity and power

Answer 3

Fatigue

Question 4

Enhanced force production, contraction velocity and power

Answer 4

Potentiation

Question 5

• CNS regulates exercise performance to prevent catastrophic physiological failure
• Sensory feedback from working muscles
• Accumulation of ammonia
• Increases in serotonin in the brain

Answer 5

Central Fatigue

Question 6

• Accumulation of fatigue causing metabolites in muscle fibers (lactate, inorganic phosphates, and ammonia)
• Depletion of ATP-producing fuels (Phosphagen and glycogen)

Answer 6

Peripheral fatigue

Question 7

The magnitude of skeletal muscle force production is determined by;

Answer 7

• Motor unit recruitment
• Muscle twitch characteristics

Question 8

Motor nuit recruitment
Size principle

Answer 8

• Smallest (type 1) –> largest (type 2)
• higher frequency = higher force

Question 9

Mechanisms of Potentiation

Answer 9

-Post-activation potentiation;
1) Improved sensitivity of actin-myosin complex to calcium
2) increased excitability of motor neurons and/or the quantity of released neurotransmitters

Question 10

Appears to be a means for acutely increasing force and power production, and thus, athletic performance

Answer 10

Post-activation potentiation

Question 11

Is the most established method for eliciting a PAP effect, but it lacks specificity and presents logistical issues

Answer 11

Traditional resistance exercise

Question 12

Are more practical and specific methods for stimulating PAP, but appropriate prescription is unknown.

Answer 12

Plyometrics and resisted jumping/sprinting

Question 13

sensitivity of actin-myosin complex

Answer 13

• Calcium in sarcomere binds with troponin and calmodulin
• Calmodulin (messenger protein) activates regulatory light chains(RLC)
• RLC’s cause myosin head t move away from thick filament backbone
• Quicker transition from relaxation to a force producing state (i.e; rate of force production)

Question 14

Motor neuron excitability

Answer 14

• Acetylcholine (ACH) is stored at the terminal end of motor neuron’s axon
• Calcium allows ACH to be released into synaptic gap (cleft)
• More calcium increases probability of ACH release
• Greater stimulus for muscle contractions

Question 15

• 10-second isometric maximal voluntary (MVC) contraction increased peak torque 71% at 5 seconds-post MVC
• By 30 to 60 seconds post-MVC, peak torque decreased to +44% and +31%, respectively
• Potentiation continued to gradually decrease, but was still +12% at 300 seconds-post MVC

Answer 15

Hamada et al. (2000)