Power Development Aaron Wellman University of Michigan Football Director of Strength and Conditioning

Power Development

Aaron WellmanUniversity of Michigan Football

Director of Strength and Conditioning

Youth Sport Injuries

Dr James Andrews…• Five to sevenfold increase in injury rates in youth sports• Many with mature-type injuries

Why?1. Specialization• Almost ½ of sports injuries in adolescents stem from overuse

2. Professionalism• Training kids as if they are professional athletes

Dr. Andrews recommendations• Kids need at least 2 months off each year to recover from a specific sport,

preferably 3 to 4 months.

Don’t confuse reading with believing! -Martin Rooney

•Programs based on “Science.” Special Warfare Community

•Science has been proven wrong over and over again!

•Base Your Program on Scientific Principles AND Pragmatic Experience

The ART of S&C is what sets you apart!

What “Science” Says About Fatigue…

2012 study by Noakes, Frontiers in Physiology

Archibald Hill (English physiologist) Peripheral Model of Fatigue

•Assumed that lactic acid is only produced under anaerobic conditions and that increased muscle lactate concentrations are the cause of peripheral fatigue.

•We now know that BOTH of these assumptions are invalid.

•Acidosis has little or no effect on the strength of contractions in skeletal muscle of mammals (Bandschapp, et. Al.)

Fatigue

Noakes suggests:

• Exercise performance is not limited by a failure of skeletal muscle. Rather, exercise performance is regulated in anticipation specifically to insure that no such biological failure can occur.

•Believes fatigue is not a physical event but an emotion used by the brain to regulate exercise performance.

• He notes in the final stages of any given race, perhaps as many as 65% of the muscle fibers in both the leading athletes’ legs are inactive and do not contribute to the physical effort. Why? Brain-generated sensations of fatigue place a moveable limit on performance.

• Conclusions…

Fatigue

Noakes Concludes with the following hypothesis…

•In the case of a close finish, physiology does not determine who wins. He suggests, that, because of the sensations of fatigue, which originally evolved to prevent damage or even death to the body, the brains of the second placed finishers accept defeat in the final stages.

•He suggests that the winner is the athlete for whom defeat is the least acceptable rationalization and who is able to withstand the unpleasant feelings of fatigue the most successfully.

Our Philosophy

Maximize Speed, Strength, and Power while Minimizing Orthopedic Stress (certain exercises possess more inherent risk than others)

• Demand Investment: Program has to challenge them

• Coach: Technique, Effort, Discipline, Accountability, Toughness

• Motivation: (Red Shirts, Victors Board, Before and After Photos)

• Basic, Progressive Exercises

• Prepare!

Power Development

1. Power Defined

2. Which Exercises?

3. Post-Activation Potentiation (PAP)

4. Programming

Strength vs. Power

• Strength: The ability to exert a maximal force against a resistance (independent of speed)

• Power: The ability to exert a maximal amount of force in the shortest possible time interval.

Power (P) = Force (F) x Velocity (V)

Simplifying:1. Get Stronger and/or

2. Get Faster

Power Development

To some degree every athlete will need to develop power!

“Even a marathon runner needs to sprint to the finish line.” Louie Simmons

An athlete’s ability to display a high level of explosive power is believed to be one of the most important factors in determining athletic success. (McBride)

A Fundamental Relationship Exists Between Strength and Power

• Stronger athletes possess favorable neuromuscular characteristics that form the basis for superior power production. (Cormie)

• The strength level of an athlete will always dictate the upper limit of their potential to generate maximal power because the ability to generate force rapidly is of little benefit is maximal force is low.

• An athlete does not have to do an inordinate amount of power training until a solid foundation of strength is developed

An increase in strength directly effects power output.

A Fundamental Relationship Exists Between Strength and Power

Your choice of resistance exercise will lead to velocity-specific adaptations.

• Heavy Loads: improve the high-force, low-velocity portion of the force-velocity curve

• Light Loads: improve the low-force, high-velocity portion of the force-velocity curve.

Train both high-force AND high-velocity movements!

Force-Velocity Relationship

Force-Velocity-Power Relationship

Effect of Training on F-V Curve

Choosing Velocity Appropriate Exercises

High Force/Low Velocity

(Lower Body)

• Squat Variations (Front, Back, Box, Chains, Single Leg)

• Hex Bar Deadlift

Low Force/High Velocity

(Lower Body)

• Keiser Speed Squat• Olympic Variations• Hex Bar Power Pull• Squat Jumps• KB Swings

What Are The Best Exercises

For Developing Power?

Hex Bar vs. Power Clean

• Swinton looked at power outputs of 19 male powerlifters and found average peak power output of hex bar (speed) deadlift to be 4,872W, with individual outputs as 6,145W.

• Winchester et. al. and Cormie et. al. reported maximum peak power output values of 4,230 W and 4,900W respectively for college athletes performing the power clean.

Performing “traditional” exercises with submaximal loads may be ineffective for developing muscular power because of the period of deceleration prior to

the barbell stopping.

Hex Bar Power Pull

• Swinton (2012) compared hex bar ‘power pull’ to barbell squat jumps.• Hex bar produced higher power outputs than squat jumps at 20%, 40%, and

60% of 1 RM• Highest power output was recorded with 20% of 1 RM Deadlift

0% 20% 40% 60%0

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Squat Jump Power Output

Straight BarHex Bar

% of 1 RM

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r (W

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Power Outputs• Kawamori (2005) peak power outputs highest for hang clean @ 70% of 1 RM

power clean.• Intensities between 50-90% Not Significantly Different!• Kilduff (2007) did not find any significant differences in peak power between

loads of 50-90%.• Comfort (2011) looked at power outputs using 60% 1 RM PC load for each.

Power Clean Hang Clean Mid-Thigh Clean

Mid-Thigh Clean Pull

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Rate of Force Development• Comfort (2009 & 2011) compared rate of force development

• Both studies found RFD was maximized by mid-thigh clean and mid-thigh clean pull.

Power Clean Hang Clean Mid-Thigh Clean Mid-Thigh Clean Pull

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UM Football (Athlete A)Compared movements and recorded highest peak power outputs of each

• CM Squat Jump• Hang Clean (135, 155, 185, 205, 225)

• Hang Clean Pull• Hex Bar Power Pull (No Counter Movement!)

Squat Jump (Bdy Wt. - No Arms)

Hang Clean (155) Hang Clean Pull (155) Hex Bar Power Pull (185)

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Peak Power Outputs (Athlete A)

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UM Football (Athlete B)Compared movements and recorded highest peak power outputs of each

• CM Squat Jump• Hang Clean (135, 155, 185, 205, 225)

• Hang Clean Pull• Hex Bar Power Pull (No Counter Movement!)

Squat Jump (45) Hang Clean (185) Hang Clean Pull (225) Hex Bar Power Pull (185)

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Peak Power Outputs (Athlete B)

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Hex Bar Power Pull

Hex Bar Power Pull

Hex Bar Power Pull: From Pad

Hex Bar Power Pull: From Pad

Calculating Power Using Vertical (CMJ) Jump

Johnson & Bahamonde Formula (1996)

Power-peak (W) = 78.6 · VJ (cm) + 60.3 · mass (kg) - 15.3 · height (cm) - 1,308

Power-avg. (W) = 43.8 · VJ (cm) + 32.7 · mass (kg) - 16.8 · height (cm) + 431

6’0” 200 lb athlete

VJ: 32”

Peak Power: 7,699 W

6’0” 225 lb athlete

VJ: 30”

Peak Power: 8,052 W

UM Power Development

• Generally performed following proper warm-up at beginning of workout, preferably in the absence of fatigue.

• No more than 3 reps per set (power output stays at or above 90% of Pmax)

• Train both max strength and speed strength in a manner which allows for optimal rest, recovery, and adaptation to occur.

• Certain exercises are better suited than others… (explosive pushup vs. bench press)

• Actual Speed vs. Intent to Move Fast

– Behm and Sale (1993) proposed that it’s the intention to move a given load quickly, not actual speed that determines training response.

• Athletic men performed jump squats with either 30% (JS30)or 80% (JS80)of 1 RM Squat

•Agility test, 20 m sprint and jump squats with 30, 55, and 80% were done pre- and post-

Results• The JS30 group had improved velocity capabilities regardless of the load, which did not occur in the JS80 groups.

•JS80 group showed improved force capabilities, with no effect (in some cases a negative effect) on velocity capabilities.

•JS80 group significantly improved their agility times but performed significantly worse in 20 m sprint.

•Heavy resistance training may increase initial acceleration while velocity is slow, but light resistance increases acceleration capabilities during higher velocity movements.

•Squat max correlates well to the first 15 m of sprinting in high school aged athletes. (Keiner, Wirth, and Schmidtbleicher, 2012)

Post-Activation Potentiation

Post-activation Potentiation (PAP)PAP is induced by a voluntary conditioning contraction performed typically at a maximal or

near-maximal intensity, and has consistently been shown to increase both peak force and rate of force development during subsequent twitch contractions.

• Examples: • Barbell Squat > Weighted Vertical Jump• Hex Bar Power Pull > Body Wt. Vertical Jump

Muscular performance characteristics are acutely enhanced as a result of their contractile history.

Post-activation Potentiation

How does PAP work…from scientific standpoint?

1. Phosphorylation of myosin regulatory chains: max contraction alters structure of myosin head and leads to increased sensitivity of myosin head to ca+ ions released by the sarcoplasmic reticulum.

2. Increased recruitment of higher order motor units: max contraction activates adjacent motoneurons via afferent neural volley and H-Reflex enhancement which increases neurotransmission.

3. Change in pennation angle: max contraction decreases pennation angle which increases force transmission to tendon. (Tillin and Bishop, 2009)

Post-activation Potentiation

How does PAP work…from Non-scientific standpoint?

When you perform a 3-5 RM followed by a light explosive set…to your nervous system, it’s like “lifting a ½ can of water when you think it’s full.” -Verkhoshansky

PAP: What We Need to Know…

• It’s been shown that contractions of maximal or near maximal (>80% of dynamic or isometric MVC) optimize PAP. (Sale) (Rahimi) (Saez et. al)

• Peak PAP is achieved immediately after a conditioning contraction, but instantly begins to decrease. (Vandervoot, et, al., Gossen and Sale, Baudry and Duchateau)

• Fatigue is also present immediately after!

• Fatigue seems more dominant in the early stages of recovery, and consequently, performance of subsequent voluntary activity is diminished or unchanged.

Fatigue subsides at a faster rate than PAP, so potentiation of performance can be realized at some point during the recovery period.

Post-activation Potentiation (PAP)

The conditioning contraction may also cause fatigue, and it’s the balance between PAP and fatigue that will determine the net effect on performance of a subsequent explosive activity. (Robbins)

Fatigue

PAP


• Fatigue diminishes force-generating capabilities, while PAP potentiates or excites them.

• PAP and fatigue develop and dissipate at different rates


This relationship is affected by a combination of factors including: (Robbins)

1. Volume of conditioning contraction (sets, reps and rest interval between sets)

2. Intensity of conditioning contraction (contractions >80% optimize PAP)

3. Type of conditioning contraction (dynamic or isometric)

4. Subject characteristics (strength, fiber-type distribution, training status)

5. Type of subsequent activity

Fatigue

PAP


1. Volume of conditioning contraction• PAP may develop faster than fatigue, so possible to use immediately after a low

volume conditioning contraction.• As CC volume increases so does fatigue, so rest interval may be required before PAP

is realized.

French et. al. (2003)• Peak torque increased after 3x3 sec. isometric contractions• Peak torque significantly decreased after 5x3 sec. isometric contractions

The specific recovery period required for different CC volumes has yet to be determined!


2. Intensity of conditioning contraction• The consensus is that maximal contractions (> 80%) optimize PAP.

3. Type of conditioning contraction• Doesn’t seem to be a clear relationship between contraction type (isometric vs.

dynamic) and PAP response.• Studies on each type have shown both significant increases and little to no changes in

subsequent explosive activity.• We typically use 1-3 reps at 85-90% immediately (0-60 sec) followed by explosive

movement:

Hex Bar concentric only Deadlift Body Weight VJ


4. Subject Characteristics

Muscular Strength: • Gourgoulis (2003) found 4.0% increase in CMJ height after 5 sets of back squats in those

would could squat 350 lbs or more.• Only .4% increase in those who could not squat 350 lbs.• Kilduff (2007) also reported a correlation between CMJ peak power potentiation 12

minutes after a 3 RM Back squat

WHY??

Possibly due to subject fiber-type distribution.

Those with a higher percentage of Type II fibers may achieve greater PAP responses.



Muscular Strength: • Gourgoulis (2003) found 4.0% increase in CMJ height after 5 sets of back squats in those

would could squat 350 lbs or more.• Only .4% increase in those who could not squat 350 lbs.• Kilduff (2007) also reported a correlation between CMJ peak power potentiation 12

minutes after a 3 RM Back squat

WHY??

Possibly due to subject fiber-type distribution.

Those with a higher percentage of Type II fibers may achieve greater PAP responses.



Training Level: • Athletes accustomed to higher levels of training develop fatigue resistance, and may be

more likely to realize PAP (Chiu, 2003)• Some evidence shows that PAP works better for strong athletes who are not very

powerful; i.e. they have trouble converting their strength to power (Schneiker, 2006)

Conclusions: Evidence suggests that individuals most likely to benefit from PAP include those with a

greater muscular strength, a larger percentage of type II fibers (although fatigue may also be greater in these individuals) and a higher level of resistance training.


5. Type of Subsequent Activity

• While a CC might enhance performance in a particular dynamic activity, it may have no effect or decrease performance of another activity.

• Important to match the kinematics of the CC to those of the subsequent explosive activity!

• This becomes a challenge when attempting to use PAP to enhance specific explosive sporting activity (sprinting, long jump, etc)


Implementation

Heavy Bench Press > MB throw, Plyo Push Ups (select athletes only)

Squats or HB Deadlift > Vertical Jumps, Split Jumps

Straight Bar Deadlift, RDL > Sprints, Broad Jumps

Summer Template

Summer Program

Anatomical Adaptation (Weeks 1-2)

Purpose: • To prepare the athlete for high-intensity training that takes place during the next phase.• Prepare the muscles tendons and ligaments for the Max Strength Phase

Weight Training:• Use a variety of exercises at sub-maximal loads• Circuits work well in this phase

Running:• Use sub-maximal intervals: full gassers, ½ gassers, 110’s, 200’s, 300’s

Jumping:• High frequency/Low amplitude Jumps (hops): Line jumps, dot drill, QF ladder jumps

Summer Program

Max Strength: 3-5 (Weeks 3-6)

Purpose: • To develop max strength in the Upper Body Pressing movements and Compound Lower

Body movements.

Weight Training:• Train these exercises in the 3-5 rep range• Use Relative Intensities to program training

Running:• Resisted Sprints

Jumping:• CMJ, Box Jumps, SL Box hops

Summer Program

Power: (Weeks 7-10)

Purpose: • To develop max power in the Upper Body Pressing movements and Compound Lower

Body movements.

Weight Training:• Train at MaxP (HVP = MaxP -10%, LVP = MaxP + 10%)• Include PAP

Running:• Sprints out of 3 pt. or position stance

Jumping:• Plyos (< .25 sec GCT)

Phase Week #Monday Tuesday Thursday Friday

Jumping RunningUpper Lower Upper Lower

Anatomical Adaptation

Week 1Bench Press SL Leg Lower Unilateral (DB) Upper Barbell Squat

Hi Vol / Low Amp (Dot Drill,

Line Jumps)

Interval Running

4x8 @ 65-70% 4x8-10 ea 4x8 4x8 @ 65-70%

Week 2Bench Press SL Leg Lower Unilateral (DB) Upper Barbell Squat

4x6-8 @ 70-75% 4x8-10 ea 4x6 4x6-8 @ 70-75%

Max Strength

(3-5)

Week 3Bench Press Squat: 4x5 @ 90% of Fri

Bench Press or CG Bench

Barbell Squat

Box Jumps, SL Box Jumps

Resisted Running

4x5 @ 75-80%Front Squat, Hex Bar, or

SL4x5 @ 90% of Mon 4x5 @ 75-80%



Barbell Squat


SL4x4 @ 90% of Mon 4x4 @ 77-82%



Barbell Squat


SL5x3 @ 90% of Mon 5x3 @ 82-87%

Power

Week 6Bench Press + PAP Clean Var./HB PP Push Press Hex Bar DL + PAP

Hurdle Plyos

Sprints (3 pt. or athletics

pos.)

4x2 @ 85-90% + MB Throw

4-5x2-3 4-5x34-5x2 Con. Only +

2 VJ


4x2 @ 85-90% + MB Throw

4-5x2-3 4-5x34-5x2 Con. Only +

2 VJ


4x2 @ 85-90% + MB Throw

4-5x2-3 4-5x34-5x2 Con. Only +

2 VJ

Documents

Power Development Aaron Wellman University of Michigan Football Director of Strength and Conditioning