How does collagen healing differ with ligament grafts?
- necrosis- inflamation and granulation tissue for about 2 weeks with native cells lost by endo of week one and migration of synovial cells into collagen superstructures
- revascularization- 8 weeks from patellar fat pad and synovium
- cellular proliferation- 12 weeks as collagen content increases
- remodeling 12 weeks and beyond
- by week 26 it is usally pretty normal
What did Nardone’s 1998 study find regarding order of muscle recruitment?
- concentric and isometrics tend to recruite type I tonics
2. eccentrics recruite type II phasics
What is the stretch shortening cycle?
- refers to a priming of a volitional movement by an antagonistic contraction
- this loads the agonist connective tissues
- preloaded tissue allows for a reduction in contraction rate and an increase in fiber recruitement and liberation of kenetic energy from preloaded tissues
What are the phases of the stretch shortening cycle?
- eccentric phases sets and preloads the muscle fibers and connective tissues with prestretch
- prestrech stimulates the muscle spindles to bias A-alpha motor activation and places kinetic energy in the connective tissues
- ammoritation where you transition from eccetnric to concentric phase
- recoil of concentric phase
What is the sequence of events from Alpha motor AP to onset of muscle tension?
- AP travels down axon
- AP moves along the t-tubules
- Ca++ released from sarcoplasmic reticulum
- cross bridge formation
- stretching of series elastic tissue of muscle
How does the stretch shortening cycle increase force production?
- prestretch of SEC allows for more energy transfer to the bone
- prestretch creates a relatively shorter contractile unit so the muscle can contract slower concentrically allowing for recruitment of a greater number of motor units
What are the benefits of eccentrics for collagen repair?
- decreased metabolic demand while providing max stretch to collagen
- good for over tendonopathy
What are the benefits of eccentrics with dynamic stabilization?
trains a hypermobile joint to eccentrically prevent entering into the pathological range
How does muscle EMG activity change with increasing work loads?
Less EMG activity with ECW compared to CCW possibly due to fewer motor untis or a shift towards phasic with larger motor units and less electrical activity
How does intramuscular fluid pressures change with DOMS?
- ECW has an increase in intramuscular fluid pressure, but concentric doesn’t
- pressure changes usually resolve with 8 minutes
- 48 hours later fluid pressure has doubled and is consistent with onset of pain.
Teague’s 1995 study demonstrated what changes in DOMS with variations in rest time and why is this important?
Rest time between sets did not effect DOMs indicating limited metabolic involvement with DOMs
What did warren’s study in 1993 demonstrate regarding DOMs?
The number of reps has a greater impact on DOMs that peak torque forces
How is protien synthesis effected when eccentrics are take to the point of tissue damage?
- protein synthesis is not elevated for at least 48 hours
2. may not return to normal levels for about 14 days
How would you dose resistence targeting DOMS?
5 sets of CCW at 50% of 1 RM
What intramuscular chemical changes occur with ECW to suggest tissue damage?
- 50 fold plasma creatine phosphokinase
- creatine kinase
- glutamic-oxalotic transaminase
How does tissue response to ECW change between workouts
- repeating the exercises 1-10 weeks later and you have faster recovery time
- limited change in chemical markers for tissue damage
How does gender impact DOMs?
- women demostrate a greater tolerance for eccentric work
2. women show less enzymatic response to ECW
What vitiams seem to improve recovery rate of muscle?
Vitiam C
-500 mg 21 days prior to eccentric work outs and seven days after demonstrates improved rate of recovery of strength
How often should ECW be performed?
- tissue repair: start with one set per day and increase to 2-3 seter per day
- high end plyos 1-2x week
What are the four models of pathology?
- biomechanical
- neurophysiologic
- biochemical
- psycological
What are the different types of human contractile tissue?
- smooth muscle
- striated muscle
- cardiac muscle
What systems control visceral function?
autonomic and hormonal
What two fiber types make up 90-95% of the skeletal muscle?
- type I tonic
2. type II phasic
How do the metabolic processes differ with type I and II muscle fibers
- type I uses aerobic energy and oxygen
2. type II- anerobic and carbohydrates
