Lecture 12: Power development principles

Question 1

What is power?

Answer 1

Force x velocity

Question 2

Motor recruitment and power

Answer 2

Want exercises that involve high motor recruitment

Question 3

Is power task specific?

Answer 3

Yes, power produced is relative to a specific exercise

Question 4

Ballistic exercises

Answer 4

Exercises that involve either you or a med ball becoming a projectile; follows through the end range of motion

Question 5

Examples of ballistic exercises

Answer 5

Med ball throw
Bench press throw
BB squat jump

Question 6

Benefit of ballistic exercises

Answer 6

Improved maximal power output that caries over to sport demand

Question 7

Force velocity relationship

Answer 7

Inversely related
Heavier loads= slower
(force= y-axis, velocity= x-axis)

Question 8

Order of types of exercise on the force velocity curve

Answer 8

1. Max strength
2. Accelerative strength
3. Strength-speed
4. Speed-strength
5. Speed

Question 9

How does resistance training change the force-velocity relationship?

Answer 9

Moves force end to the right

Question 10

How does ballistic/ explosive training change the force-velocity curve?

Answer 10

Shifts velocity end up

Question 11

What is power on the force velocity curve?

Answer 11

Strength-speed and speed-strength

Question 12

Strength-speed training

Answer 12

Moving traditional barbell/db exercises with submaximal weight as fast as possible

Question 13

What is strength speed also called?

Answer 13

Dynamic effort method

Question 14

Speed-strength training

Answer 14

Moving traditional Olympic lifts/jumps or other triple extension movements with high speed

Question 15

How does intent impact power production?

Answer 15

Most crucial aspect in regards to improving power production, moving as rapidly as possible

Question 16

Plyometrics

Answer 16

Involves body weight exercises that aim to maximize utilization of the stretch shortening cycle

Question 17

What happens when the muscle spindles are stimulated such as with plyometrics?

Answer 17

Stretch reflex is stimulated, sending input to the spinal cord via Type Ia nerve fibres
After synapsing with the alpha motor neurons in the spinal cord, impulses travel to the agonist extrafusal fibres causing a reflexive muscle action

Question 18

What is the stretch shortening cycle?

Answer 18

Muscle action where an essentric contraction is immediately followed by a concentric contraction
Combines mechanical and neurophysiological mechanisms
Basis of plyometrics

Question 19

How does the stretch shortening cycle work?

Answer 19

1. A rapid eccentric muscle action stimulates the stretch reflex and storage of elastic energy
2. Increases the force produced during the subsequent concentric action

Question 20

Why does the SSC occur?

Answer 20

Tendons store elastic energy
The greater the release of elastic energy, the greater the reduction in cross bridge formation and force output from muscle(energy conservation)
Beneficial for power/speed sports and endurance sports

Question 21

What is the half life of SSC?

Answer 21

0.85s and therefore at 1s the ability to use SSC is diminished by 55%
You want the ground contact time to be as short as possible

Question 22

What does tendon recoil do?

Answer 22

Responsible for increases in power output and energy conservation

Question 23

Tendon stiffness

Answer 23

Constant

Question 24

Muscle stiffness

Answer 24

Variable and depends on forces exerted

Question 25

What is required when we develop muscular stiffness?

Answer 25

Greater stretch of the tendon

Question 26

What does higher tendon stiffness result in?

Answer 26

Shorter ground contact times and greater rates of force production

Question 27

Short SSC

Answer 27

100-250 ms ground contact time

Question 28

Examples of short SSC exercises

Answer 28

Sprinting Long jump Vball attack Basketball block High jump Multiple hurdle jump

Question 29

Long SSC

Answer 29

>250 ms ground contact time

Question 30

Examples of long SSC exercises

Answer 30

CMJ Broad jump Vball block Box jump Drop jump

Question 31

Three components of the stretch shortening cycle

Answer 31

I. Eccentric II. Amortization III. Concentric

Question 32

Eccentric phase of stretch shortening cycle

Answer 32

Stretch of agonist muscle

Question 33

Amortization

Answer 33

How long you spend on ground

Question 34

Concentric phase of SSC

Answer 34

Shortening of agonist muscle fibres Creating force in opp direction

Question 35

Plyometrics to enhance SSC

Answer 35

Progressive and based on technical mastery Precede with strength training to improve strength of musculotendinous system and improve quality and quantity of type 2 muscle fibres Prioritize jumping and landing components Focus on quality of movement

Question 36

Things to consider with plyometrics

Answer 36

1. The greater the speed of movement, the greater the intensity 2. Single leg drills are more intense loading than double leg but shorter ground contact time (harder) 3. The greater the amplitude (jump height) the greater the intensity 4. Consider the impact of extra load and athletes body mass as indicators of higher intensity

Question 37

Plyometric principles

Answer 37

Slow before fast Bilateral before unilateral Low before high Extensive before intensive Uniplanar before multiplanar Simple before complex Quality over quantity Strength before power Leave room to adapt (dont rob yourself twice)

Question 38

What does leave room to adapt mean?

Answer 38

If you introduce advanced plyometrics too early, athletes can't properly perform it. But then when you go to reintroduce it their body wont have that initial adaptation to a new stimulus and wont see novel training effects

Question 39

Philosophy of training power for team sports

Answer 39

1. Triple/hip extension (lower) and end range (upper) 2. Multi-directional 3. Teachable to all training ages 4. Time appropriate

Question 40

Example of an exercise to improve power in baseball pitcher

Answer 40

Rotational med ball throw

Question 41

How much should we increase jumping volume by each week?

Answer 41

<10%

Question 42

What is the foundation for true power development?

Answer 42

TRIPLE EXTENSION

Question 43

What is key to improve for plyometric activities?

Answer 43

Improvements in amortization phase

Question 44

Queens plyometric progressions

Answer 44

1. Landing (snap down-drop-mini hurdle) 2. Extensive (pogos) 3. Box jumps (seated to standing) 4. Jumps in place (broad jumps) 5. Continuous jumps 6. Jump over object 7. Loaded jump 8. Depth jumps (jump off box) 9. Drop jumps (immediately jump back up)

Question 45

Example of uniplanar to multiplanar progression

Answer 45

Vertical-->horizontal-->lateral-->rotational

Question 46

Reactive strength index scores (RSI)

Answer 46

<1.5 low reactive strength ability 1.5-2.0 moderate 2.0-2.5 Well established >2.5-3.0 High >3.0 World class

Question 47

Plyometrics

Answer 47

Rapid engagement of muscle spindle High velocities Short ground contact times Maximal intent