NSCA Chapter 17- Plyometric and Speed Training

Speed Training Warmup

Must begin with both general and specific warmups The specific warm-up for speed training should consist of low-intensity, dynamic movements Once mastered, many of the form drills provided at the end of chapter 17 may be incorporated into warmup drills

Physical Characteristics

220+ at increased risk for injury. Greater weight increases joint compressive forces. Should avoid high volume, high intensity plyometrics. No depth jumps greater than 18 inches

Sprint-Assisted Training

A method to increase stride frequency by having the client run at speeds greater than he or she is able to independently achieve Supramaximal speed forces clients to take more steps than they are accustomed to taking during a normal sprint. Assuming the stride length remains the same as during normal sprinting, increasing the frequency of strides will help them run faster Methods include downrade sprinting, high-speed towing, and use of a high-speed treadmill. Regardless of the method, sprint-assisted training should not increase speed by more than 10% of the client's maximal speed Sprint-assisted training is an advanced technique that requires careful instruction and demonstration on the part of the training, and clear understanding on the part of the client. SAT may cause clients to alter their technique, which will affect running without assistance. A proper warmup to each session should be mandatory

Training Area

Amount of space depends on drill Most bounding and running drills require at least 33 yards Some may require 109 yards Minimal surface area is needed for jumps, but adequate height is required (9.8-13.2 feet)

Stretch-Shortening Cycle

An active stretch (eccentric action) of a muscle followed by an immediate shortening (concentric action) of that same muscle. A component of plyometrics All functional activities are composed of a series of repetitive SSCs

Speed-Strength

Application of maximum force at high velocities People improve speed-strength in essentially the same way they improve muscular power production, by performing rapid movements both with and without resistance Ex: weightlifting-type movements and plyometrics. Performed quickly to potentiate muscle force through the release of stored elastic energy and the stretch reflex. Exercise prescription should rely on powerful exercises and avoid those requiring slow movement

Lower Body Plyometrics

Appropriate for clients involved in virtually any sport as well as in nonathletic activities/occupations that require muscular power production or quick changes of direction Allow client's muscles to produce more force in a shorter amount of time, thereby allowing the person to jump higher Wide variety of LBP drills with various intensity levels and directional movements

Recovery Phase

Begins the moment the client's foot completely leaves the ground. They immediately dorsiflex the ankle and extend the great toe. This place the leg in proper position so that upon contact with the ground, the ground can push back against the body. The client can then utilize the ground's reactiveforce to propel forward. Leaving foot on the ground for too long causes the foot to absorb too much of the ground's force that would otherwise be used to help the client move. They must also flex the knee, driving the foot directly toward the buttocks. This helps to shorten the lever, which allows the leg to swing forward more quickly. AS the heel moves towards the butt, the leg swings forward, the knee then extends to approximately 90 degrees then becomes nearly straight as the foot moves down and forward, driven toward the ground by the hip extensors. Increasing sprinting speedd should increase the height the foot moves towards the buttocks. Heel-toe is a common error. Causes balance issues as well as improper absorption of ground forces by the lower extremeity structures, leading to hamstring injuries over time

Equipment

Boxes must be sturdy, have a nonslip top, and should be closed on all sides. Few if any sharp edges. 6-42 inch height with a landing surface at least 18 x 24. Sturdy wood or heavy gauge metal. To made surface nonslip: add treads, mix sand into the paint, or affix rubberized flooring Cones from 8-24 inch can be used as items to jump over. Less likely to cause injury since they are flexible Stairs- concrete not preferred Medicine balls can be used for upper extremity plyometrics as well as in conjunction with some lower boy exercises. Should be easy to grip, durable, and of varying weights

Safety Considerations

Client understanding of technique and base of strength, speed, and balance Ankle and knee sprains are the most common injuries that occur due to breaks in form

Posture, Flexibility, and Stability

Clients need sufficient balance to prevent injury since plyometrics involve nontraditional movement patterns Assess client's ability to hold a half squat position to judge their potential to land properly. Then also do body weight swuat May begin low intenisty plyometric exercises once they can hold a proper double leg squat position and perform a proper body weight squat Client should be able to hold a single leg squat position before trainer increases the intensity

Resistance, Plyometric, and Speed Training

Combining Plyometric and Speed Training with resistance training requires careful consideration to optimize recovery while maximizing performance. Guidelines: Clients should perform either lower body plyometrics, speed training, OR lower body resistance training on a given day, but not more than one of these Appropriate to combine lower body resistance training with upper body plyometrics, and upper body resistance with lower body plyometrics Performing heavy resistance training and plyo on the same day is not usually recommended. However, some athletes may benefit from complex training (combo of resistance and plyometrics) by performing plyometrics followed by high intensity resistance training. Adequate recovery is essential Traditional resistance training exercises may be combined with plyometric movements to further enhance gains in muscular power. For example, performing a squat jump with approximately 30% of ones 1RM squat as an external resistance further increases performance. This is an advanced form of complex training that should be performed only by clients w/ previous participation in high intensity plyometrics

Stretch-Shortening Cycle Model

Describes the strech reflex and stored elastic energy-induced increases in concentric force production that follow a rapid eccentric muscle action Three distinct phases Eccenctric/deceleration phase: preloading the agonist muscle group. SEC stores elastic energy and the muscle spindles are stimulated (crouching before jump shot) Amortization/transisiton phase: time between eccentric and concentric phases. Critical for power development. Spinal cord begins transmitting signals to the agonist muscle group. If it lasts too long, stored energy is released as heat Concentric phase- body's response to the events occurring in the first 2 phases. Energy stored in the SEC is used to increase the force of the movement or dissipated as heat. The elastic energy increaes the force produced during the concentric phase movement to a level above that of an isolated concentric muscle action.

Speed Training

Designed to use these same mechanical and neurophysiologic components, in concert with technique and muscular strength, to produce larger ground forces, thereby allowing clients to run faster

Mode

Determined by the general parts of the body that are performing the given exercise

Speed Training Program Mode

Determined by the speed characteristics that the given drill is designed to improved. Speed training focuses on 3 areas: Form, Stride Frequency, and Stride Length Improving sprint technique may be accomplished in a number of ways, including sprint performance, stride analysis, and form drills. Drills are great to include in the warmup since they are performed slower. As stride frequency and stride length improve, speed increases During the start, speed is highly dependent on stride length. Drills should be performed anywhere from 60-105% of optimal stride length, but the trainer should mark the distances of the optimal stride length so the client has a target As sprinting speed increases, frequency becomes the more important variable. Stride frequency is likely the more trainable, as stride length is highly dependent on height and leg length. Stride frequency is improved through the use of fast leg drills, resisted sprinting, and sprint-assisted training.

Age

Does the client's age predispose the client to injury and therefore preclude plyometric training?

Sprinting Leg Action

Driving Phase Recovery Phase

Sprinting Posture

During the acceleration phase, the body should lean forward approximately 45 degrees for 13 to 16 yards After the 13-16 yards of acceleration, the client should quickly move upright to a less than 5 degree lean during a maximal speed Head, torso, and legs should be aligned at all times in a relaxed upright position

Sprinting Arm Action

Each elbow should remain relaxed and be flexed to approximately 90 degrees. Movement must be an aggressive front to back action originating from the shoulder with minimal frontal plane motion The arm movement must be an aggressive backward hammering or punching motion and occur opposite to the leg motion in order to assist in balance and provide momentum for the legs If client is aggressive with driving the warms back, the stretch reflex at the shoulders will activate and automatically force the arms forward. Hands should rise to shoulder level during anterior arm swing and should pass the buttocks when moving posteriorly Common errors: locking upper arm into place and only moving lower arm, allowing arm to cross body's midline, improper arm swing distance, emphasizing forward motion of the arm rather than the backward motion

Mechanical Model of Plyometric Exercise

Elastic energy in tendons and muscles is increased with a rapid stretch (as in an eccentric muscle action) and then briefly stored. If a concentric muscle action follows immediately, the stored energy is released, contributing to the total force production

After this chapter you will be able to

Explain the mechanics and physiology of plyometric and speed-enhancing exercises Identify the phases of the stretch-shortening cycle Understand the different roles of plyometric and speed training Recommend proper equipment or use during plyometric exercise performance Design safe and effective plyometric and speed training programs Provide instruction in correct technique and recognize common errors

Proper Footwear

Good ankle and arch support Good lateral stability Wide, noslip sole

Training Experience and Current Training Level

Has the client been resistance training? If so, what types of exercises have they been performing? Have they participated in ploymetrics before? When?

Acceleration

In general, it will take the client approximately 13-16 yards of acceleration to acheive the proper technique. During these first yards, the client focuses on increasing both velocity and stride length. Initially, foot strike will occur behind the body, rather than in front of the center of gravity, but this changes quickly. The client will have increased body lean and be focused more on the driving phase and less on the recovery phase of the sprint technique. This increased lean positions the client so they can place stronger emphasis on front-side running mechanics and minimal emphasis on backside mechanics During a sprint, support time should be kept brief while braking forces at ground contact are minimized and the backward velocity of the lower leg and foot at touchdown is maximized. Maximizing sprinting speed depends on a combo of optimal body posture, leg action, and arm action

Speed Training Safety Considerations

Injuries during speed training commonly occur because of insufficient strength or flexibility, inadequate instruction or supervision, or an inappropriate training environment Pretraining Evaluation- client must understand proper technique and possess a sufficient base of strength and flexibility Physical Characteristics- previous injuries or abnormalities of the spine, lower extremeties, and upper extremities may increase a client's risk of injury. An area of concern is hamstring flexibility and strength, as the swing leg transitions from an eccentric muscle action to concentric, the hamstring must be prepared to undergo extreme amounts of stretch followed by nearly instantaneous concentric muscle action Technique and Supervision Trainer must demonstrate and monitor proper movement patters and sprint technique to maximize drill effectiveness and to minimize the risk of injury. Exercise surface and Footwear Landing surface for speed training drills must possess adequate shock-absorbing properties but must not be so absorbent as to significantly increase the transition between the eccentric and concentric phases of the SSC. Grass, suspended floors, and rubber mats are good surface choices. Footwear with good ankle and arch support

Injury History

Is the client currently injured? Have they experienced an injury that might affect their ability to participate in plyometrics?

Benefits of Plyometric and Speed Training

Jump higher Run faster Injury prevention ability to control decelerative forces enhanced coordination increased agility

Combining Plyometrics and Speed Training With Other Forms of Exercise

Just parts of a client's overall training program. Many sports and activities use multiple energy systems or require other forms of exercise to properly prepare athletes for their competitions or help reach goals. A well-designed training program must address each energy system and training need

Plyometric and Aerobic Exercis

Many sports and activities require both a power an an aerobic component. It is necessary to combine multiple types of training to best prepare clients for these types of sports. Because aerobic exercise may have a negative effect on power production during a given training session, it is advisable to perform plyometrics prior to the longer, aerobic endurance-type training. The design variables do not change and should complement each other to most effectively train the athlete for completion or help a client meet their goals

Optimal Stride Length

Men: Leg length x 2.3 or 2.5 Women: Leg length x 2.5-2.7

Supervision

Must be closely monitored to ensure proper technique Not intrinsically dangerous when performed correctly; poor form may predispose a client to injury Especially important for trainers to to monitor client jumping and landing technique for lower extremity drills (avoid extremes of lateral knee motion, minimize time on the ground)

Plyometric Warm Up

Must begin with general and specific warm ups like any program General- light jogging/stationary bike Specific- low intensity, dynamic movements similar in style to those performed during plyometric exercises Table 17.7 Lunging Toe jogging straight-leg jogging Butt kick Skipping Footwork

Landing Surface

Must have adequate shock-absorbing properties but not be so soft that it significantly increases the transition between the eccentric and concentric phases Good choices: grass, field turf, suspended floor, rubber mats Bad surfaces can lead to a variety of lower extremity injurities

Speed Training volume

Number of reps and sets performed during a session and is normally expressed as the distance covered Should vary according to cleint's goals

Speed Training Frequency

Number of speed training sessions per week. Depends on client goals Resarch on optimal frequency is limited Must rely on practical experience For clients who are athletes in a sport, 2-4 speed training sessions per week is common. Nonathletic clients can benefit from 1-2 sessions per week

Series Elastic Component

Passive elasticity derived from tendons when a tensed muscle is stretched Primary contributor to force production during plyometric exercises

Intesnsity

Plyometric Intensity refers to the amount of effort exerted by the muscles, connective tissues, and joints during performance of an exercise Controlled by type of drill and the distance covered Intensity should be determined by both the ability of the body to handle the load and the ability of the client to maintain proper technique. If technique suffers, trainer should reduce intensity Should be kept at a low level for beginners. Double leg standing jumps in place, double leg standing jumps, and simple skips Efforts should focus on ensuring proper technique to prevent injury Can be increased by raising platform height, increasing the distance of bounds, and incorporating more advanced exercises

Strength

Plyometric Training requires significant strength and muscle control, especially during the eccentric phase For this reason, clients should be encouraged to perform a resistance training program that includes standard exercises before beginning a plyometric training program Standards Lower body: 1RM squat 1.5x body weight Upper body: 1RM bench of 1x body weight if 220 or higher, 1.5x if under 220 OR 5 clap push ups in a row These standards ensure that the client has sufficient strength to engage in plyometric exercise. Not necessary for low to moderate levels of plyometric activity Core strength is also important to assess Body's ability to control its center of mass in response to forces on the trunk generated by other parts of the body Responsible for maintaining balance and postural stability Weak core- increased amoritzation phase time, which will compromise the plyometric effect

Age and Maturity

Plyometric training places great stress on the body so it is important to consider all factors to ensure that the client's health is not compromised. Plyometrics are safe for the majority of populations at certain intensities, but modifications to intensity and volume must also be made based on age Safe for youth, and youth bodies are moldable and adept and learning these motor skills Youth should not focus on competing, rather on form Low intensity plyometrics for adolescents until they master then move to moderate intensity Aging population: decreasing bone strength- may need to avoid high intensity plyometrics Still very beneficial for older people to train the SSC by integrating low to moderate intensity plyometrics Mental maturity is also necessary before beginning plyometric training

Progression

Plyometrics are a form of resistance training so they must follow the principles of progressive overload- a systematic increase in training frequency, volume, and intensity through the use of various combinations Typically as intensity increases, volume decreases All plyometric exercises should be done on 2 legs until client has fully adjusted to the stress of training Intermediate clients can begin moderately intense exercises

Factors Affecting Intensity of LBP Drill

Points of contact- double or single leg Speed- drill's speed of movement Multiple response added- decrease amortization phase by moving from pausing on landing into multiple responses on the ground Height of the drill- raise body's center of gravity by increasing the height of the drill Participant's weight- add weight in the form of vests, ankle wights, and wright weights Distance of drill- add horizontal component

Medical History

Previous injuries or abnormalities may increase client's risk of injury during plyometric exercise History of muscle strains, pathological joint laxity, or spinal dysfunction should exercise caution Illness, osteoporosis, arthritis, or diabetes may not respond well to plyometrics

Plyometric Training and Work Performance

Production of muscular power is a key to movement efficiency and may improve job output Police, firefighters, military

Landing Position

Proper landing technique is essential to maximize the effectiveness of the exercise and minimize the risk of injury If the center of gravity is offset from teh base of support, performance will be hindered and injury may occur During landing: shoulders should be over the knees, knees over or slightly posterior to toes, with ankles, knees and hips flexed and feet approximately shoulder width apart Should land softly and maintain a dorsiflexed position of the ankle with the feet with full contact to the ground. Weight should be more on the ball of the foot and not on the heel. Allows for a quick turnaround Analyze with jumps w/ freeze in landing position Focus on knees and thumbs up

Minimum Requirements for Participation in a Plyometric Training Program

Proper technique for each drill At least 3 months of resistance training experience Sufficient strength, speed, and balance for the level of drill No current injuries to involved body segments

Upper Body Plyometrics

Rapid, powerful upper body movements are requisites of several sports and activities (gof, baseball, softball, tennis) Not used as often as LBP drills; still essential to athletes requiring upper body power Medicine ball throws, catches, and push-up variations

Speed Training Intensity

Refers to the physical effort required during execution of a given drill, and is controlled both by the type of drill and teh distance covered Ranges from low-level form drills to sprint-assisted and resisted sprinting drills that apply significant stress to the body Sprinting should be performed at close to maximum speed to ensure proper mechanics, stride length, and stride frequency Distance is determined according to the goals of the client Training acceleration requires covering short distances, whereas training maximum velocity requires covering longer distances

Speed Training Recovery

Requered to ensure maximal effort with each rep since ST drills involve maximal efforts Time between reps is determined by a proper work to rest ratio and is specific to volume and type of drill Higher intensity drills require more rest Recovery for form training may be minimal, wehreas rest between reps of downrade running may last 2-3 minutes Less than 100% recovery may actually be beneficial because it may be more specific to the type of tasks they will have to accomplish Consistently training fatigued will slow a client down, though Recovery from sessions should last 24-48 hours depending on the intensity of the previous session

Speed Training Progression

ST must follow the principles of progressive overload- systematic increase in training frequency, volume, and intensity through various combos Typically, as intensity increases, volume decreases 1. Low to high volume of low-intensity speed drills 2. Low to high volumes of moderate intensity 3. Low to high volumes of moderate to high entensity

Plyometric Exercise and Injury Prevention

Studies have shown that athletic injury rates decrease following participation in a plyometric training program Research also shows that proper plyometric training improves bone mineral content, muscle recruitment, strength, body control, and balance Client develops the ability to control all joints in the kinetic chain since plyometric training teachers the neuromuscular system to quickly perform an SSC while also focusing on proper technique/biomechanics Jumping/landing correctly Eccentric training may be a compromise for those for whom plyometric training is not appropriate

Sprinting Technique

Technique evaluation is an important tool to use when assessing movement efficiency and to improve speed Training should initially focus on optimizing form and correcting faults The form and faults that typically need correction center on posture and action of the legs and arms

Speed-Endurance

The ability to maintain running speed over an extended duration (typically longer than 6 seconds) Helps prevent a client from slowing down during a maximal speed effort

Speed

The ability to move rapidly is essential before a client begins a plyometric program Guidelines: Lower body- 5 reps of a squat with 60% body weight in 5 seconds Upper body- 5 reps of bench press with 60% body weight in 5 seconds If they lack these, they can still start a lower instensity program

Stretch Reflex

The body's involuntary response to an external stimulus that cuases a rapid stretching of the muscle In response to this rapid stretch, a signal issent to the spinal cord, which in turn sends a message back, resulting in a concentric contraction of the same overstretched muscle The stretch reflex responds to the rate at which the muscle is stretched Example: knee hammer

Driving Phase

The lead foot, driven by the hip extensors, lands on the lateral aspect of the forefoot, just in front of the client's center of gravity. At foot strike, the quads must contract to prevent excessive knee flexion resulting in the loss of elastic energy. The ankle should remain dorsiflexed and the great toe extended. The gluteals and hamstrings should then contract so the client pulls themself over the body's center of mass. The client should begin plantarflexing the foot once the hip crosses over the foot until the completion of toe-off. Ground contact time should be minimal

Plyometric Program Must include...

The many elements essential to effective training program design Needs analysis Variables to be included: Mode Intensity Frequency Recovery Volume, Program Length Progression Warm-Up

Frequency

The number of plyometric training sessions per week Depends on client's age, ability, and goals Frequency and intensity are often inversely proportional Research shows training 2x per week is best and results in improved jumping ability, jump contact times, maximal concentric and isometric strength, and 22 yard spring time For youth and adolescents, up to 2x a week on nonconsecutive days

Recovery

The time between reps, sets, and workouts Many trainers focus on recovery time between plyometric training sessions rather than frequency Complete, adequate recovery is required since plyometric drills often involve maximal efforts Generally speaking, rest times of 60-120 seconds between drills should allow for full or nearly full recovery 48-72 hours between sessions is a typical guideline when one is prescribing plyometrics

Neurophysiological Model of Plyometric Exercise

This model involves potentiation (change in the force-velocity characteristics of the muscle's contractile components caused by stretch) of the concentric muscle action by use of the stretch reflex.

Volume

Total work performed during a single workout session Typically expressed as the number of reps and sets performed during a session Often expressed as the number of contacts per workout (each time a foot, feet, or hand contact the surface) May also be expressed as distance Suggested volumes in 17.6 Session should not exceed 30 minutes for beginners Sets are suggested at 8-12 reps with fewer reps for exercises that are more intense Fatigue should not be a guideline Plyometrics should be perfomred before other exercise

Needs Analysis

Trainer must perform a needs analysis to evaluate a client's current abilities. Also assessed the requirements of the client's activities and lifestyle.

Plyometric Program Design

Trainers must rely on the methodology used during the design of resistance and aerobic endurance training programs and on practice experience when prescribing plyometric exercise. When in doubt about volume, frequency, or intensity, it is best to err on the side of caugtion Lack of research on optimal program variables

Plyometric Training and Sport PErformance

Training regiment must mimic movements occuring in the sport Train clients to produce greater muscular force (power) at faster speeds will provide them the edge in performance they are looking for An ideal exercise mode when the goal is to improve muscular power production Prepares athletes for the deceleration-acceleration and chance of direction requirements in most sports by improving their ability to perform these types of tasks Improved "running economy" i.e. less oxygen used

Resisted Sprinting

Used to help a client increase stride length, as well as speed-strength, b increasing the client's ground force production during the support phase (which is arguable the most important determinant of speed). Clients may use uphill sprinting, running in sand or in water, or sprinting while being resisted by a sled, elastic tubing, a partner, or a parachute Resisted sprinting is used especially to improve the acceleration of the sprint Resisted towing and uphill running are two exercises that work well to improve the acceleration of the sprint as they increase trunk lean, stance duration, and horizontal force production during the propulsive phase of the stance. Resisted sprinting should not increase external resistance by more than 10% The trainer should use heavier resistance when the goal is to improve the acceleration phase and lighter resistance when the goal is to improve maximum velocity. Too much resistance may alter running mechanics, thereby compromising performance outcomes. Another measure is to use a load that is less than or equal to 15% of the client's body mass. If performance decreases by more than 10%, the load being used is too heavy and will have detrimental effects on sprinting technique. Resisted sprinting should be performed over relatively short distances- anywhere from 11 to 33 yards Targets clients wanting to improve speed-strength. Adding resistance to a nonathletic client's gait may improve function May be too advanced for some A more general mode of speed training that most client's can easily perform is interval sprinting

Physical Testing Results

What are the client's current abilities as they relate to muscular power production?

Training Goals

What does the client want to improve? A specific movement? A particular skill? A on-the-job activity?

Incidence of injury in a client's job or chosen activity

What is the risk of injury in the client's chosen activity? Is the activity relatively sedentary? Does the activity require constant change of direction? If the activity is dynamic, is the client prepared for it physically?

Starting Levels for Plyometrics

When a client is ready for plyometrics, test vertical jumps, depth jumps, box jumps, and medicine ball toss

Plyometric Movement

quick powerful movement consisting of an eccentric muscle action, also known as a countermovement or prestretch, followed by an immediate powerful concentric muscle action Purpose is to use the stretch reflex and natural elastic components of both muscle and tendon to increase the power of subsequent movements and strengthen the muscles and tendons functionally