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A large portion of our time as strength and conditioning coaches is spent considering the various factors that go into the creation of an athlete’s workout program. The types of exercises, the number of sets and reps and the length of rest periods are all things that we spend hours considering and fine tuning for the athletes who we program for. Each of these factors is important, however, a key factor that is often overlooked is the prescribed speed at which movements should be executed. There are probably several reasons for this not the least of which is safety as it is often assumed that results are best when resistance training is performed in a slow and controlled manner.

Most of the athletic movements in baseball in game situations are explosive. As players advance through various levels the game, the need for explosive strength becomes increasingly more important for success because the game becomes faster and the competition becomes more skilled. The average Major League Baseball player can run at a speed of 27 feet per second1. The average MLB batter swings his bat at 70 miles per hour2 and the ball leaves the bat with an average exit velocity of 88.4 mph1. The average fastball velocity of MLB pitchers is 93.2mph1. To meet these demands, a player’s strength and conditioning program should include some form of high-speed training. High-speed training will help players develop explosiveness, adapt to high speed movements and meet the physical demands of the game.

Plyometric training (“plyos” for short) is a form of training that is performed at high speeds and designed to improve power. Plyometric exercises often used in baseball include various forms of running, jumping, throwing, swinging and skipping exercises. Virtually all professional baseball players are doing plyos in some form and most strength coaches regularly program plyometric exercises into training sessions3. Since there is such widespread use of plyometrics, the purpose of this post is to review the research on plyometric training and provide information on how they can be used to improve performance.

Plyometrics are exercises that train the stretch-shortening cycle within the muscle-tendon complex (MTC). The stretch-shortening cycle is a phenomenon where the MTC is able to shorten more rapidly after it has undergone an eccentric pre-stretch. The rapid shortening is able to occur because the MTC has elastic properties. The pre-stretch produces reflexive muscle activation and generates potential elastic energy in the MTC similar to stretching a rubber band. There are typically three distinct phases to the stretch-shortening cycle: 1) an eccentric loading phase in which the tissue of the MTC is stretched; 2), a transitional amortization phase during which there is an isometric action of the MTC; and 3) a concentric contraction phase in which there is a rapid, forceful shortening of the MTC. The MTC is able to store the elastic energy from the stretch for a short period of time during the amortization phase and apply it to a subsequent concentric contraction to generate more force than a concentric contraction without a pre-stretch4-6.

Plyometric training has been shown to be effective for improving the stretch-shortening cycle. These improvements are due to improved biomechanical efficiency and neuromuscular adaptations. The effectiveness of the training, however, depends on the execution of proper exercise technique. As previously stated, the elastic properties of the MTC allows the energy from a pre-stretch to be stored by the MTC and used to enhance a subsequent shortening. The elastic energy from the pre-stretch, however, can only be stored for a very short period of time in the amortization phase. Because the amortization phase lasts only a fraction of a second, the stored elastic energy from the pre-stretch can be lost within the muscle and released as heat if the amortization phase is too long. A lengthening of the amortization phase can result in slower and less forceful muscular contractions. In order for the athlete to realize the full benefit of a plyometric exercise, the strength and conditioning coach should teach a quick transition from muscle lengthening to shortening during the execution of that exercise. Reducing the amortization phase will allow energy to be transferred more efficiently in the movement, enhance the propulsive forces generated by the stretch-shortening cycle activity and produce more explosive movements4-6.

Before starting a plyometric program, there are basic guidelines that must be followed in order to produce a safe and effective training program. A summary of these guidelines is presented below.

 

Program Guidelines:

 

  • Safety first: Safety should be the number one priority when prescribing plyometric exercises.

 

  • Previous injury: An athlete with a previous injury to the lower body or spine may be disqualified or limited with plyometric training. Medical clearance is recommended before starting plyometric training with these individuals.

 

  • Exercise selection: Plyometric exercises range from simple, low-impact exercises like jump roping to complex, high-impact exercises like depth-jumps. Low-intensity plyometrics provide low-risk and high rewards. High-intensity plyometrics provide high-risk and high-rewards. Coaches should make sure that every exercise is appropriate for the age and physical readiness of each athlete.

 

  • Age: Older players tend to have more baseball “mileage” and more wear and tear on their joints. While older athletes need to be explosive, exercises must be selected that have low-risk, minimize the risk of injury and allow adequate recovery.

 

  • Strength level and training age: Power is the product of strength times speed. Therefore, athletes must have a minimal level of strength and an adequate training background. Young athletes with minimal resistance training experience should focus on getting stronger and start with simple, low-intensity exercises like jump roping and medicine ball drills.

 

  • Weight and body composition: Heavier players, i.e., those weighing more than 220 pounds, will experience higher impact forces during jumping, hopping, running and bounding exercises. These players should start with low-impact exercises. Having excess amounts of body fat and/or lacking adequate eccentric strength are factors that might also disqualify an athlete from participation in some forms of plyometric exercises.

 

  • Volume and season: Plyometrics are a high-intensity form of exercise and the volume (sets and reps) should be low especially during the season. The athlete’s sport skills performed during games and practice sessions and strength and conditioning training must be included when determining total training volume. When skill practice involves a significant amount of plyometric movements, additional plyometric training may be unnecessary.

Plyometric exercises for baseball:

The following five plyometric exercises have been successfully incorporated into some of the more effective strength and conditioning programs designed for professional baseball players. A low volume (2-3 sets of 5 reps performed twice per week) is an appropriate starting point for each exercise. Players should strive for a quick transition from muscle lengthening to shortening during the execution of each exercises.

 

  1. Line Hops. Hops are performed on one foot. The athlete takes off and lands on the same foot. Hops are a fundamental plyometric exercise that helps improve explosive movements used in running and jumping.
  • How to do them:
    • Stand on the foot with the right side of the body parallel to a line or a piece of tape placed on the floor.
    • Brace the core and keep the body straight and upright.
    • Hop to the right over the line using the ankle to produce the movement.
    • Land on the other side of the line and then immediately hop back.
    • Beginners might need to reset after each hop to regain balance.
    • Advanced athletes can hop continuously side-to-side for the prescribed number of reps.
    • This exercise may also be performed forward and backwards and at an angle over the line.
    • Minimize the ground contact time.
    • A coaching cue is “the floor is lava” or “you’re walking on hot coals”.

 

 

 

 

 

 

 

  1. Squat Jumps. Jumps are performed on both feet. The athlete takes off and lands on both feet. Jumps are an effective exercise for helping develop lower body power.
  • How to do them:
    • Stand with feet shoulder width apart.
    • Inhale, brace the core and perform a downward counter-movement by extending the shoulder and flexing the hip, knee and ankle.
    • Make a quick transition from the downward counter-movement to jumping up by exhaling and forcefully extending the hips, knees and ankles while driving the arms up.
    • Land safely on both feet and absorb body weight gradually (no stiff landings) and control the body’s center of mass.
    • Reset and perform the next rep.
    • Athletes who demonstrate adequate eccentric strength and body control can land and immediately proceed into the next jump.

 

 

 

 

 

 

 

  1. Skater Jump. This exercise involves side-to-side movements similar to those seen in speed skaters. This is a good exercise for athletes, especially pitchers, who need to gain explosiveness while moving laterally.
  • How to do them:
    • Stand in a balanced position with most of the body weight on the inside of the right foot.
    • Inhale, brace the core and perform a counter-movement by flexing the hip, knee and ankle of the right leg.
    • Lift the left leg off the floor and extend it back behind the right leg.
    • Swing the arms in a reciprocal pattern similar to the action when running.
    • Make a quick transition from the counter-movement to a lateral jump by exhaling and forcefully extending the hip, knee and ankle of the right leg.
    • Flex and drive the left leg up and across the body laterally into the jump.
    • Swing both arms to assist in driving the body upward and laterally into the jump.
    • Land under control on the left leg and gradually absorb body weight (no stiff landings), balance and control the center of mass.
    • Beginners may need to reset on the left leg to start the next rep.
    • Athletes who demonstrate adequate strength and control in a single leg stance, may immediately go into the next lateral jump upon landing.
    • Continue jumping side-to-side for the prescribed number of reps.

 

 

 

 

 

 

 

  1. Kettlebell (KB) Swings. This is a high intensity exercise that helps develop explosive power through the hips.
  • How to do them:
    • Select an appropriate-sized kettlebell.
    • 16kg or 20kg KBs are good starting points for the average male athlete.
    • Stand with feet shoulder-width apart and approximately 1 foot behind the KB.
    • Hinge (bend) at the hips as if doing a deadlift while keeping the spine neutral.
    • Grasp the KB firmly with both hands using an overhand grip.
    • Inhale and hike pass the KB between the legs.
    • Quickly transition from the hike pass into the swing phase by exhaling, driving the feet into the ground and explosively extending through the hips and knees.
    • Swing the KB through the legs and up to shoulder height.
    • As the KB begins to fall, guide it back between the legs at or above knee height.
    • When the KB passes through the legs, re-hinge the hips.
    • As the hips hinge and the KB swings back between the legs, there will be a stretching and loading of the hamstring muscles.
    • Quickly transition from the stretch to the swing phase.
    • Keep the spine and the arms straight and maintain a firm grip on the KB throughout the movement.
    • Perform the prescribed number of reps and set the KB down safely.

 

 

 

 

 

 

 

 

 

  1. Medicine Ball (MB) Rotational Throw. This exercise helps build rotational power through the hips.
  • How to do it:
    • Choose an appropriately sized MB.
    • A 6-10lb ball is a good starting size.
    • Find a sturdy wall or workout partner that you can throw the ball to.
    • Stand in an athletic stance with the body “squared up” and perpendicular to the target.
    • Hold the MB at chest height with the left hand on top of the ball and the right hand under the ball.
    • Perform a counter-movement by rotating the trunk to the left and away from the target.
    • Quickly transition from the counter-movement into a rotational throw of the MB by driving down into the ground through the feet and explosively rotating the hips to the right and toward the target.
    • “Finish” the movement by following through with the trunk, extending the back arm and projecting the ball directly at the target.
    • Beginners may need to reset before the next rep.
    • Advanced athletes can use the return bounce or throw to lead into the next rep.
    • Keep the core tight and the arms relaxed during the movement.
    • The hips and core are the main power source for this movement.
    • Perform the prescribed number of reps and then switch sides.

 

 

 

 

 

 

 

 

 

References

  1. mlb.com/statcast
  2. blastmotion.com/blog/baseball-swing-speed
  3. Ebben WP, et. al., Strength and conditioning practices of Major League Baseball strength and conditioning coaches. J of Strength Cond Res. 19(3):538-546, 2005.
  4. Baechle TR and Earle RW. Essentials of Strength Training and Conditioning. Champaign, IL: Human Kinetics, 2008.
  5. Verkhoshansky Y and Siff MC. Supertraining. Rome: Verhoshansky, 2009.
  6. Turner AN and Jeffreys I. The stretch-shortening cycle: proposed mechanisms and methods for enhancement. Strength and Cond J. 32(4):87-99, 2010.

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Nate Tamargo, MS, RSCC, is the Assistant to the Minor League Strength and Conditioning Coordinator-Rehab, Cincinnati Reds.

 

 

 

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