Muscle Strength and Endurance

1. 7 Muscle Strength and Endurance

2. Facilitation in Proprioceptive Neuromuscular Facilitation Tactile (hand on part) Auditory (verbal cues) Oculomotor (patient seeing where body part is going by moving segment through ROM prior to exercise) Proprioceptive (quick stretch before PNF movement)

3. Proprioceptive Neuromuscular Facilitation Movement Patterns

4. Proprioceptive Neuromuscular Facilitation Patterns of movement Principles of application For flexibility: hold-relax, contract-relax, slow reversal-hold-relax For strengthening: repeated contractions, rhythmic initiation, slow reversal, slow reversal-hold, rhythmic stabilization

5. strength: maximum force a muscle or muscle group can exert – 1RM power: strength applied over a distance for a specific amount of time endurance: muscle or muscle group’s ability to perform repeated contrac-tions against a less-than-maximal load for a prolonged time or sustain an isometric contraction

6. Muscle Strength and Endurance Continuum: high intensity, low reps vs. low intensity, high reps Strength: ≥90% of 1RM, 3-9 reps Both strength and endurance: 70-90% of 1 RM, 6-12 reps Endurance: ≤70% of 1 RM, 20+ reps Sets Depends on goal

7. Relationship Between Muscle Strength and Endurance

8. Recovery Following Fatigue

9. Implications of Recovery in Therapeutic Exercise 30 sec to 1 min between isotonic sets 2-4 min recovery if using isokinetic machines 1 min between isometric sets Factors influencing number of repetitions-pain tolerance, phase of healing, demand of patient after return to competition

10. kinetic chain: a series of rigid arms linked by movable joints; a mechanical description of the body

11. open kinetic chain activities: motions in which the distal segment of an extremity moves freely in space closed kinetic chain activities: motions in which the distal segment of an extremity is weight bearing and the body moves over the hand or foot

12. Open and Closed Kinetic Chain Activities Open: high-velocity motions; any link can move independently of the others; NWB; small forces-large velocities Closed: less shear stress on joints; no link in the chain can move independently; all are affected by 1 movement segment; WB; large forces but small velocities (continued)

13. Open and Closed Kinetic Chain Activities Functional activities include a combination Other joints within the chain must be included in the program The function of one joint impacts the function of other joints within the kinetic chain; not elusive

14. Static Muscle Activity Isometric Tension produced in muscle without a change in the muscle’s length Advantages Disadvantages

15. Dynamic Muscle Activity A change in muscle’s position Isotonic: change in length Concentric- shortening; takes more NRG to perform; Fig 7.23 Eccentric- lengthening; can produce 30% more force than a concentric; greater chance of delayed-onset muscle soreness Isokinetic: velocity maintained, but force varies through range of motion

16. Evaluating Muscle Strength Manual muscle test Grip or pinch dynamometers Isokinetic equipment Free weights or weight machines

17. 5 = 100%, Normal 4 = 75%, Good 3 = 50%, Fair 2 = 25%, Poor 1 = 10%, Trace 0 = 0%, Zero Manual Muscle Test

18. Gradations of Muscle Activity Passive ROM Active assistive ROM Active ROM Resisted ROM

19. Strength Equipment Manual resistance Body weight Rubber tubing and bands Free weights Isotonic machines Isokinetic machines Others: Nautilus, etc.

20. Strengthening Principles Begin strength exercises soon in therapeutic program. Justification for any exercise is required. Avoid using many exercises to accomplish the same thing. Address patient’s specific needs. Progression is individually determined.

21. SNAP Principle S = Specific exercises N = No pain A = Attainable goals P = Progressive overload Stands for primary concerns in the establishment of any strengthening program

22. SAID Principle Specific Adaptations to Imposed Demands A muscle will adapt and perform according to the demands placed on it High loads, low reps: strength Low loads, high reps: endurance Exercises should mimic sport stresses

23. Progression of Overload Many different systems exist (DeLorme, Oxford, DAPRE). All produce overload gradually to optimally stress the muscle. Regularly evaluate strength to determine if increase should be made. Overload must be present in therapeutic exercise program to produce strength gains.

24. Muscle Structure

25. Motor Unit

26. Filament Arrangement

27. Sarcomere

28. Changes in Sarcomere Length

29. Sliding Filament Theory Sliding Filament Theory Sarcoplasmic reticulum – releases Ca Troponin and tropomyosin – Proteins along the actin Myosin cross bridges bind to the actinwith the help of tropomyosin

30. Neuromuscular Physiology Neural pathways - afferent vs efferent All-or-none law Resting potential Action potential

31. Physiological Properties of Skeletal Muscle Irritability - Contractility - Viscosity -

32. Physiological Properties of Skeletal Muscle Extensibility and elasticity - Contracture - Fatigue - Summation -

33. Slow-Twitch Muscle Fibers Type I fiber Slow oxidative fiber Darker in color 110 ms to reach peak tension Slower-acting ATPase Greater quantity of mitochondria, myoglobin, and glycogen stores For prolonged, sustained aerobic activity

34. Fast-Twitch Muscle Fibers Type II fibers Fast oxidative fiber Lighter in color Reach maximum tension 50 ms after stimulation Faster-acting ATPase More extensive and efficient sarcoplasmic reticulum For brief, intense anaerobic activity

35. Force Production Joint angle - JH Length-tension - SD Muscle size and fiber arrangement - AB

36. Force Production Speed of contraction - AH Number and type of muscle fibers - JH