1. chapter 9
Plyometrics

2. Plyometrics
= Quick movement of eccentric activity rapidly followed by a burst of concentric activity to produce a powerful movement
Purpose: increase power of movements Plio = more Metric = measure

3. Figure 9.1

4. Mechanical Components
Muscle lengthening increases elastic tension of noncontractile tissue  stored elastic (potential) energy.
If immediately followed by a rapid concentric contraction, release of elastic energy contributes to total muscle output.

5. Neurological Components
Muscle stretch (eccentric lengthening) stimulates the muscle spindle to create a reflex shortening (concentric).
Movement must occur rapidly for the stretch reflex to occur.

6. Influential Factors Strength Flexibility Speed of movement
Efficiency of movement (coordination)

7. Plyometric Phases: Stretch-Shortening Cycle
1. Eccentric phase
Muscle lengthens to take up slack and stretch elastic components.
“Sets” the muscle.
Stores potential energy as elastic energy.
Muscle spindle responds to a rapid stretch and accommodates to a slow stretch.
Best with rapid eccentric movement in a partial range of motion.
(continued)

8. Plyometric Phases: Stretch-Shortening Cycle (continued)
2. Amortization phase
Must immediately follow the eccentric phase
= Time it takes to transfer from eccentric to concentric motion
Too much time: potential energy absorbed and dispersed, and spindle reflex overridden by cognitive functions
(continued)

9. Plyometric Phases: Stretch-Shortening Cycle (continued)
3. Concentric phase
Stretch reflex causes increased muscle activity.
Stored (potential) energy is released to increase output.
The combined result is greater muscle performance.

10. Pre-Plyometric Considerations
Plyometrics is used in therex near the end of the program.
Used with patients returning to power-based sports: basketball, volleyball, gymnastics, track and field, softball, baseball, skating, swimming, soccer, football
Serve as a bridge between therex and sport-specific activities

11. Plyometric Program Design
Mode of training: based on body part
Lower-body plyometrics
Jumps in place
Standing jumps
Multiple hops and jumps
Bounds
Box drills
Depth jumps
(continued)

12. Plyometric Program Design (continued)
Upper-body plyometrics
Medicine-ball throws
Medicine-ball catches
Push-ups
Trunk plyometrics
Medicine-ball sit-ups
Plyometric sit-ups
(continued)

13. Plyometric Program Design (continued)
Intensity: stress of the activity
Volume:
Lower extremity: number of foot contacts
Upper extremity: reps and sets or number of throws
Beginner: /session
Intermediate: /session
Advanced: /session
Recovery: between reps = 5-10 s; between sets = 2-3 min
Frequency: once a week to three times a week (QW – TIW)

14. Program Considerations
Age: <16 years
Weight: >220 pounds
Competitive level
Surface: not too hard, not too soft
Footwear: stable yet absorbing
Progression: allow for overload adaptations
Goals based on individual needs

15. Precautions Time: early in the session Delayed-onset muscle soreness
Proper supervision
Depth jumps
Max = 48 in.
Range = 16 to 42 in.
Norm = 30 to 32 in. (if >220 lb, range = 20 to 30 in.)
Contraindications
Acute inflammation
Post-op
Instability

16. Exercise Progression Beginning stages
Double-leg takeoffs
Increasing difficulty levels dependent on athletic level, learning aptitude
With increased mastery, amplitude increases
Consistent emphasis
Coordination
Correct movement and motor patterns

17. Exercise Techniques Landing exercises Stabilization jumps
To teach proper foot strike
Use of ankle, knee, and hip to absorb shock
Correct body alignment
Stabilization jumps
To reinforce correct landing technique
Raise levels of eccentric and stabilization strength
Same as landing exercises, but landing position is held 5 s before next jump
(continued)

18. Exercise Techniques (continued)
Jumping up
To teach takeoff action and arm use
For jump on box: Emphasize arm swing, Jump up with leg tuck
In-place bouncing movements
For quick reaction off ground and vertical displacement
Tuck jump, scissors jump, increasing vertical jump
(continued)

19. Exercise Techniques (continued)
Short jumps
To teach horizontal displacement of center of gravity
Two-foot takeoffs  multiple-step takeoffs, power skipping
Long jumps
To add more horizontal velocity
Leg bounding, bounding hops

20. Exercise Techniques (continued)
Shock jumps
To raise explosive power to highest levels
Impose high neural demand
Advanced form of training—require a large training base
Jump boxes, rebound hurdles

21. Equipment Boxes: 16 in. to 48 in. (non-slip surfaces on floor, boxes)
Cones
Hurdles
Medicine balls
Other equipment

22. Precautions Increase one factor q 3 d, especially in early phases.
Provide constructive cues to correct performance.
Avoid pain and swelling.
Understand tissue integrity: Be alert to progression tolerance.
Understand patient’s confidence level.

23. Figure 9.4

24. Figure 9.6a1

25. Figure 9.6a2 25

26. Figure 9.6b1

27. Figure 9.6b2 27

28. Figure 9.6b3 28

29. Figure 9.7a1

30. Figure 9.7a2 30

31. Figure 9.7b1

32. Figure 9.7b2 32

33. Figure 9.7c1

34. Figure 9.7c2 34

35. Figure 9.8a1

36. Figure 9.8a2 36

37. Figure 9.8a3 37

38. Figure 9.8b1

39. Figure 9.8b2 39

40. Figure 9.8b3 40

41. Figure 9.9a1

42. Figure 9.9a2 42

43. Figure 9.9b1

44. Figure 9.9b2 44

45. Figure 9.9b3 45

46. Figure 9.10a1

47. Figure 9.10a2 47

48. Figure 9.10b

49. Figure 9.11a1

50. Figure 9.11a2 50

51. Figure 9.11b1

52. Figure 9.11b2 52

53. Figure 9.13a

54. Figure 9.13b