1. Proprioception, Core Strength, and Plyometrics For The Injured Athlete
Grady J. Hardeman, M.Ed., LAT, ATC, CSCS
Cabarrus County Schools
Cabarrus County Sports Medicine Symposium
January 20th, 2007

2. Objectives
Define Core Strength, Proprioception, and discuss how they relate to Plyometrics.
Review the basic muscle physiology of plyometrics.
Discuss the factors to consider when implementing plyometrics into the rehabilitation program.
Understand how plyometrics can benefit the injured athlete
Provide Sample Plyometric Exercises for the Upper and Lower extremities, and the Trunk.

3. What is The Core???
Where the bodies center of gravity is located, and all movement is initiated
Anatomy:
Hip, Back, and Abdominal musculature

4. Proprioception Knowing where the body is in space.
Also known as Kinesthetic Awareness or Sense.
Becomes impaired after injury, and needs to be re-trained in order for the athlete to return to activity safely.
Required for plyometric and other closed-chain rehabilitation activities.

5. Proprioception Exercises

6. Plyometrics
It is not always the strongest OR the quickest athlete that prevails. It is usually the one who is the strongest AND the quickest.
Plyometric exercise enhances both strength and speed.
Speed + Strength = POWER

7. Muscle Physiology Review
Muscle Spindle: A specialized proprioceptor that is sensitive to both muscle length and the rate at which the muscle lengthens.
This structure is what is responsible for the stretch reflex.
This reflex is important in the development of good kinesthetic sense, and is also responsible for the increased force production during the stretch shortening cycle (Plyometric).
When a spindle is stretched it sends an impulse to the spinal cord which in turn sends an impulse back to the same muscle. This impulse causes a contraction.

8. Muscle Spindle
Diagram taken from The Essentials of Strength Training and Conditioning 2nd Ed. Pg. 19: Fig. 2.2

9. Stretch Shortening Cycle
Three Phases
Eccentric or Pre-loading phase
Muscle lengthens as it contracts.
Isometric or Amortization phase
Muscle length does not change.
Concentric or Explosive Phase
Muscle shortens as it contracts.
If the Amortization phase is too long there will be a decrease in force production due to the loss of elastic energy.

10. How Does It Work
During the eccentric phase elastic energy is stored within the muscle. It is released during the concentric phase and provides a more forceful contraction.
The muscle spindle is activated during the stretch (eccentric phase), and sends a signal to the spinal cord which activates the agonist muscle to contract. This is known as the “stretch reflex”.

11. Benefits To The Injured Athlete
Aids in the restoration of the “Neuromuscular Control” that is lost due to injury.
The athlete is more capable of subconsciously reacting to unanticipated joint loads during activity.
Enhances mental preparation for return to sport.
Restores confidence
Enhances muscle force production.

12. Factors To Consider When Implementing Plyometrics Into A Rehabilitation Program.
Three Important Questions?
What was the injury?
Where is the athlete in the healing/rehab. process?
What is the athletes history with plyometric exercises?
Progression
Volume
Frequency
Specificity

13. Progression To Plyometrics
There must be a solid foundation of core strength and proprioception prior to initiating plyometric activities.

14. Progression Strengthen the “Core” first.
Learn how to land (Proprioception)
May begin the process in the pool to decrease the stress applied to the lower extremities.
Start slow and then increase intensity and speed when necessary.
Move from bilateral to unilateral.
Progress from stable to unstable surfaces when appropriate.

15. Volume Measured by foot contacts.
Per exercise
Per session
Dependant upon the intensity of the exercise.
The higher the intensity, the lower the volume.
Example:
The Jump Rope Exercise may have more foot contacts than the Box Jump Exercise.

16. Frequency There should only be 1-2 exercise sessions per week.
There should be 48 – 72 hours in-between training sessions.
Expect Delayed Onset Muscle Soreness (DOMS)
Mon
Tues
Wed
Thurs
Fri x

17. Specificity
When possible try to make the exercise mimic the movements of the athletes sport.

18. Make It Safe Warm-up properly prior to plyometric exercise.
Make sure that the exercise area is free from clutter.
Work on the appropriate surface.
Rubberized flooring, gymnastic floor, soft dry grass.
Use plyometrics at the beginning of the rehabilitation session.
Monitor the athlete for fatigue.
Focus on Quality of exercise not quantity.
Give the athlete appropriate feedback.

19. Upper Extremity Push-up → Plyometric Push-up Medicine Ball Exercises
High-speed tubing exercises that incorporate an eccentric contraction.
Eccentric Phase of the Plyometric Push-Up
Concentric Phase of the High-Speed Tubing Exercise

20. Lower Extremity Jumps in Place Multiple Jumps Standing Jumps Box Jumps
(Chu, ATT, Plyometrics in Sports Injury Rehabilitation, May, 1999)
Diagram taken from NBA Power Conditioning Page 136 Rim Jumps

21. Trunk Rotational Twist with Medicine Ball Standing
Sitting on Physio-ball or Floor
Sit-up with medicine ball toss
Bilateral Straight Leg Raise
Eccentric Phase of the Rotational Trunk Twist
Concentric Phase of the Rotational Trunk Twist
Eccentric Phase of the Rotational Trunk Twist

22. Conclusion
Prior to performing plyometric exercises the athlete should have a good foundation of core strength and proprioception.
Plyometric exercise, when performed correctly, can be a great tool during the rehabilitation process.
Plyometric exercise used in conjunction with other forms of strength training provides a greater benefit than plyometric exercises used alone.

23. References
Luttgens, Kathryn, Deutsch, Helga, and Hamilton, Nancy Kinesiology –Scientific Basis of Human Motion, 8th Ed. Madison, Wisconsin: Brown & Benchmark..
Chu, Donald Jumping Into Plyometrics, 2nd Ed. Champaign, Illinois: Human Kinetics.
Chu, Donald Plyometrics in Sports Injury Rehabilitation and Training. Athletic Therapy Today. Vol.4, Num. 3. Pages 7-11.
Harris, R.T., and Dudley, Gary Essentials of Strength Training and Conditioning, 2nd Ed. Champaign, Illinois, Human Kinetics.
Riewald, Scott Energy Storage in Muscle. NSCA’s Performance Training Journal. Vol. 2 , Num.2 Pages 8-9.
Kutz, Matthew R Theoretical and Practical Issues for Plyometric Training. NSCA’s Performance Training Journal. Vol. 2, Num. 2. Pages
Swanik, Buz C, Swanik, Kathleen A Plyometrics in Rehabilitating the Lower Extremity. Athletic Therapy Today. Vol. 4, Num. 3 Pages 16-22,
Handzel, Tracey M Core Training For Improved Performance. NSCA’s Performance Training Journal. Vol. 2, Num. 6. Pages

24. Living well is the best revenge
Thank You
Living well is the best revenge
George Herbert