Plyometrics - Link Between Strength and Speed

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Plyometrics

Link BetweenStrength and Speed

04/2012 d:\Faculty\Allsen\EXSC 468\Winning Edge\EXSC46806Plyometrics

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I. Plyometricsa possible link between strength and speedA. Read the articles in the appendix at the end of this unit

1. Plyometric Exercise, p. 2722. Explosive-Plyometric Exercise, p. 278

B. Plyometric exerciseexercises which encompass a rapid stretching of a muscle group that isundergoing eccentric stress and followed by a concentric, rapid contraction of that muscle groupfor the purpose of developing a forceful movement over a short period of time

C. Absolute speedacceleration in running is the act of overcoming the inertia of ones body at anever-increasing rate. Pushing back against the running surface and more rapid leg movementsare paramount to success in this activity. Absolute speed is the act of sustaining peak speed onceit has been attained.1. The worst enemy of a runner is deceleration or dropping below the peak speed of

movement attained at the end of accelerationD. Formula for jumping off the ground

1. Force (ft lbs of force being applied to the ground) Time (time of contraction or time foot spends on the ground)

= Power (meters per second of vertical speed)

a. Flopper400 ft lbs .12 (time spent on ground)

= 33 units of power

b. Straddler800 ft lbs .24 (time spent on ground)

= 33 units of power

E. Terminology important to understand plyometrics1. Elasticitythe ability to return to original size and shape. Contributes to elastic energy2. Myotatic reflexthis type of stretch reflex causes motor unit contraction3. Athletic movementseccentric actions are used to decelerate the body. Eccentric muscle

actions are many times followed by very rapid concentric actions in many sportsa. Eccentricconcentric coupling

(1) Eccentric action immediately preceding concentric action will significantlyincrease the force generated concentrically due to the apparent storage andrecovery of elastic energy coupled with myotatic reflex potentiated via musclespindle discharges

(2) This is very important in events demanding a high speed of movementF. Physiology of plyometrics

1. Storing of elastic energy in the tendons and the contractile elements (actin and myosin)during eccentric action is important

2. Myotatic reflexa. A slight lengthening of a muscle, done very rapidly, will result in a faster, more

effective movement in the opposite direction

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G. Types of plyometric exercises1. Depth jumping

2. Vertical boundingsingle or double leg

3. Horizontal boundingsingle or double leg

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4. Bench jumping

5. Hurdle jumping

6. Rope jumping

7. Angle boxsince many athletes have to be able to change direction in their sport, the use ofan angle box can be used in plyometric training to bring about a change in direction

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H. Intensity scale for plyometric exercise

I. Skills developed by plyometric exercises

SkillJumps-in-Place

StandingJumps

MultipleJumps

BoxDrills Bounding

DepthJumps

Start Speed T T T T

Acceleration T T T

Change-of-Direction T T T T

Vertical Jump T T T T

Horizontal Jump T T T T

J. Number of foot contacts by season for plyometric training

Level

Beginning Intermediate Advanced Intensity

Off-SeasonPre-SeasonIn-SeasonChampionship Season

60100100250

100150150300

depends on sportrecovery only

120200150450

LowModModHighModerate

ModHigh

K. Recovery1. Work to rest ratio = 1:51:10

a. Example = set of exercises requires 10 seconds to complete, then 50 (1:5) to 100 (1:10)seconds of recovery should be allowed

b. Train twice a week with 23 days of recoveryc. Only train when rested

L. Strength needed for plyometrics1. Weight = 60% of body weight

a. Should be able to complete 5 repetitions of a parallel squat in 5 secondsb. If subject cannot meet the requirements, emphasis should be given to a strength

program and the intensity of any plyometric training should be at a low to moderatelevel

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M. Height of boxes1. Beginners = 20 to 40 cm2. Elite athletes = .75 meter to 1.0 meter3. Jump from various heights and when jump reach begins to diminish, this is an indication of

the optimal heightN. Problems encountered in beginning plyometrics

Problem Cause Correction

1. Athlete stays on the groundtoo long

2. Excessive trunkmovement/poor distance ofheight

3. Sore back or settling intoground upon contact

4. Excessive balance loss inmid air

a. Landing flat-footed or w/weighttoo far back

b. Not keeping concept of lightfeet in mind

Improper arm swinga. Elbows not locked at 90b. Arms not swinging from

shoulder in natural arc fromcheck to check

Athlete not landing in good athleticposition usually by excessive hipflexion

Excessive trunk/hip flexion notdriving knees to chest or heels tobuttocks

Get center of gravity forwardland onballs of feetPromote mental set of light, quick feet. Yell up as athlete makes contact withthe ground

Have athlete stand in place and just swingarms with the elbows locked at 90 frombuttocks cheek to face cheek. Beginslowly and increase velocity to maximum

Stress chest over knees over toes withthe head up. Good basic athleticposition

Verbally instruct the athlete to driveknees to chest or heels to buttocks. Stresskeeping chin and chest up

O. Example of plyometric training incorporated into the total training program

Program 1 Program 2 Program 3

Monday

Tuesday

Wednesday

Thursday

Friday

Weight training

Plyometrics (lowerextremities)

Weight training


Weight training


Weight training

Plyometrics (upperextremitiesmedicine ball)

Weight training



Plyometrics (upperextremitiesmedicine ball)

Running program


Rest

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IT IS THE POSITION OF THE NATIONAL STRENGTH AND CONDITIONING ASSOCIATION THAT:

The stretch-shortening cycle, characterized by rapid deceleration of a mass followed almostimmediately by rapid acceleration of the mass in the opposite direction is essential in theperformance of most competitive sports, particularly those involving running, jumping, and rapidchanges in direction.

A plyometric exercise programwhich trains the muscles, connective tissue and nervous system toeffectively carry out the stretch-shortening cyclecan improve performance in most competitivesports.

A plyometric exercise program for athletes should include sport-specific exercises.

Carefully applied plyometric exercise programs are no more harmful than other forms of sportstraining and competition, and may be necessary for safe adaptation to the rigors of explosivesports.

Only athletes who have already achieved high levels of strength through standard resistance trainingshould engage in plyometric drills.

Depth jumps should only be used by a small percentage of athletes engaged in plyometric training. As a rule, athletes weighing over 220 lbs. should not depth jump from platforms higher than 18inches.

Plyometric drills affecting a particular muscle/joint complex should not be performed on consecutivedays.

Plyometric drills should not be performed when an athlete is fatigued. Time for complete recoveryshould be allowed between plyometric exercise sets.

Footwear and landing surfaces used in plyometric drills must have good shock absorbing qualities.

A thorough set of warm-up exercises should be performed before beginning a plyometric trainingsession. Less demanding drills should be mastered prior to attempting more complex and intensedrills.

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APPENDIX

1. Plyometric Exercise

2. Explosive-Plyometric Exercise

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Plyometrics UnitPlyometrics Appendix

Plyometrics - Link Between Strength and Speed

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