Cardiorespiratory System 10-29-07

Notes for readers: * = the dot atop the first letter symbolizing "per unit time".
! = delta symbolizing "change or difference".

Cardio-respiratory System
aka
Cardiovascular
Cardiopulmonary
Aerobic

3 systems within the Cardiorespiratory System:

1. Respiratory system
Sometimes referred to as the pulmonary system- lungs
Involves...
A. movement of O2 & CO2 into/out of the lungs
B. exchange of O2 & CO2 between lungs and blood
O2 moves from the lungs to the blood, CO2 moves from the blood to the lungs
pg. 16 of pkt.

2. Circulatory system
Arteries and veins- carry blood
Involves...
A. transport of O2 & CO2 in blood
B. exchange of O2 & CO2 between blood and muscle
O2 moves from blood to the muscle, CO2 moves from the muscle to the blood

3. Cardiac system
Heart
Involves...
A. the action of the heart that pumps the blood

Respiratory System
Can train it a lot. Makes important gains with training, but it is never the limiting factor in exercise.

Pulmonary Ventilation
1. Rhythmic movement of air into and out of the lungs
Measured via minute ventilation
*Ve = (TV)(F)
= Volume of air expired by the lungs in one minute.
TV= tidal volume= volume of air expired per breath
f= frequency= # of breaths per minute
Rest= 7.51/ min.
MAXendurance= 180/ min.

Smallest functional unit of a lung is the alveoli
Alveoli= terminal sacs in the lungs where gas exchange occurs with the blood
Alveolar Ventilation
O2 moves into the blood
CO2 moves out of the blood

Dead Space
Only place air is exchanged with blood is at the alveoli
Bronchials and trachea are considered dead space= i.e. O2 and blood cannot mix here

Breathing deeply gets air all the way into the lungs to the alveoli. Breathing shallowly keeps the same air in the dead space.

Gas Exchange
Two exchange sites:
1. alveolar- capillary membrane
2. tissue(muscle)- capillary membrane

Diffusion
Due to random movement of molecules, molecules move from areas of high concentration to areas of low concentration.

Random movement is measured via:

Partial Pressure
Because of random movement of molecules, collisions between these molecules are constantly occurring. The # of collisions is equal to the partial pressure (pp).

O2 and CO2 diffuse across the membranes via partial pressure.

CO2 builds up in the muscle
O2 builds up in the blood
causing diffusion via partial pressure.

At Altitude

Anywhere- 20.9% of air is O2
At altitude: less partial pressure, less collisions, less diffusion.
When people come from sea level they breathe abnormally heavily.
The major adaptation of living at altitude is that the body starts producing significantly more red blood cells.

Definition of high altitude is 7500 ft. and higher.
Going from high alt. to low. = within 2-3 days your blood starts getting rid of extra red blood cells. To be competitive you must race within 2-3 days of arriving at sea level.

Lungs/ blood
ppO2 > ppO2

ppCO2 < ppCO2

Muscles/blood

ppO2 < ppO2

ppCO2 > ppCO2

3% of air is CO2

Transport of gases in blood
O2 & CO2 carried in blood in 2 forms:
1. dissolved- into fluid portion- not a lot (5% CO2, 1.5% O2)
2. Chemically bonded to blood
* O2- bonded to hemoglobin (98%)
* CO2 - 65% as bicarbonate

CO2 + H2O > H2CO3 > H+ + HCO3^- > lungs

The body takes in CO2 and H2O then converts them to carbonic acid. The body does not like this so it converts it to H+ & HCO3^- and brings it to the lungs where it turns back to carbonic acid. The body again does not like this so it converts it back to CO2 & H2O and we exhale them.



Pg. 20 of NSCA book

Right side- pulmonary circuit
to and from the lungs
Left side- Systemic Circuit- to and from the muscles
(This is what Tom said but if you look at it, it doesn't make sense)

Heart has its own automatic nervous system
SA node (sino-atrial) is a bundle of nerves that initiates all heart action (pacemaker of the heart) at the atria.
SA > Atria > AV > Ventricles
AV node is a bundle of nerves in the ventricles
R & L Atria and then R & L ventricles contract simultaneously

Pg. 15 of packet

superior vena cava- returning blood from upper body/ head
inferior vena cava- returning blood from lower extremities

Returns to RA
Tricuspid & pulmonary valves are 1 way valves
Capillaries give the O2 to the muscle
diameter gets smaller down to the capillaries. Blood cells move single file in capillaries.

Cardiac System

Cardiac Output (*Q) aka (CO)
Amount of blood pumped from either ventricle per minute.

*Q = (SV)(HR)

SV = stroke volume= amount of blood pumped per beat

HR= heart rate= # of beats per minute

All of these are trainable

Stroke Volume is significantly raised at all levels (rest- max training)
*Q significantly rises
HR lowers
SV is single best indicator of aerobic shape= ability of the heart to pump blood per beat.

Resting SV of in-shape person= Max SV of untrained
Maximal heart rate never changes- is genetically and age determined
220-age= x (predicted HRmax) +/- 11 bpm (margin of error) (has nothing to do with aerobic level but is sport specific)

Specificity of Training is Going to significantly change this



A person obtains maximal SV during sub maximal exercise levels.

*Q = SV x HR
*Qmax = SVmax x HRmax

*VO2 max- max oxygen consumption
single best indicator of aerobic shape

*VO2 max determines what HR your client needs to work out at.

*VO2 = (*Q) (a-vO2 !max) (where != difference)



a-vO2 ! is the difference between O2 at point A & B.

Anaerobic Threshold-very adaptable
aka
lactate threshold
ventilatory
OBLA-onset of blood lactate accumulation



Pg. 17
Non-invasive way to identify
Lactate threshold

You want to run @ your lactic threshold during a race.
Train over anaerobic threshold to be able to bypass it.

Chronic Adaptations of Resistance Training 10-15-07

1 week from today is test 2. 63 questions, MC, TF, Calculation MC
Central and Peripheral nervous system including today's lecture.

Periodization of Training
The foundation f all muscle fitness is muscle endurance.
Power 3-5 sets, 2-3 reps @ 30-60% of 1RM. RI: 5min.
Strength 4-8 sets, 1-8 reps, RI > 3 min
Hypertrophy 3-6 sets, 8-12 reps, RI 30-90 sec.
Endurance 3-5 sets, 12-20 reps, RI <60>There are two types of Periodization:

Traditional, linear, Classical: Long periods of time spent in each stage from Endurance to Power.

Non-linear, undulated: One day of hypertrophy, the next of endurance, the next power, etc. in a randomized fashion. This type is best for a maintenance program after traditional conditioning because in order to even to a higher stage you must have the foundation.

How do you know when to go from one stage to another? Depends on the person. Must test them and then gradually move them up a few workouts at a time.

Pg. 14 Periodization Phases

General: Circuit training, working on technique, learning lots of different exercises
Specific: Much more specific to sport
Pre-Comp: The "pre-game" phase
Main Comp: Maintenance, week to week performance


Chronic Adaptations to Resistance Training

Acute vs. Chronic
Short term long term

> Feeling of pumped limbs > Definition of muscles
> raised heart rate > Ability to do the exercise well
> increase blood flow to worked muscles > lower resting heart rate
Assuming a well designed, consistent program of at least 16 weeks.

1. Muscle Endurance
a) hypertrophy- your existing muscle cells get bigger by creating more sarcomeres. Vast majority of muscle is gained via hypertrophy (99%).
b) Hyperplasia (plasia= #) - creating additional muscle cells. A muscle divides itself because it cannot withstand any more sarcomeres. There are very few cases of this. Mostly found in bodybuilders who abuse anabolic steroids because they can work out more frequently. The amount of training that it would take to get hyperplasia is not within human ability. All studies done on animals.

2. Capillary Density Changes
An untrained muscle containing two capillaries.
A resistance trained muscle. Bigger muscle, capillary density decreases though total # of capillaries stays the same.
Aerobically trained muscle. Body creates additional capillaries for increased oxygen. When you stop training, you lose these.

3. Body Composition Changes.
Fat vs. Fat-free mass
A) two-component model
Fat Mass (FM)-average for college aged: Males: 15%, Females 25%
Fat Free Mass (FFM) - Males: 85%, Females: 75%
FFM *Mineral (bone) 7% * Water 72% * Protein (muscle) 21%

Unfortunately, no differences in people are taken into account. These numbers fixed assumptions that the whole field of body composition is founded on.
It is a useless measure because you cannot even perform the test if you have consumed alcohol within 48 hrs. worked out aggressively just prior, or have eaten just prior.

Essential Fat (minimum needed just to survive): Male: 5% Female 8%
Minimal Fat (you need to be considered healthy): Male 5% Female 15%

Optimal Health Male: 10-25% Female: 18-32%
Obese: Male: >25% Female >32%
Average College age: Male: 15% Female 25%
Being obese you run the risk of heart attack, stroke, etc.
Must be more concerned about blood profile than % of body fat.
However, Resistance training increases FFM and decreases FM.

b) Bone mineral Density (BMD)
Must resistance train very aggressively and very intensely w/ pliometric component
80% of people with osteoporosis are females
Walking is useless for increasing BMD unless you walk with a weighted vest.

4. Neural Factors
Action Potentials travel faster
Brain learns quickest path the send messages
Nerve ends get bigger- larger surface area to associate with muscle
Brain learns to keep agonist and antagonist muscles firing correctly, at the right time, separated during activities.
Brain learns how to override safety mechanisms to be able to go to the next level. However, it's a lot easier to hurt yourself.

5. Force Velocity Curve.
Resistance training moves the curve up and to the right.

6. VO2 Max changes
Two groups of untrained people who start out with about the same VO2 Maxes.
G1: Circuit training
(15 weeks- 3 x per week)
G2: Bike training
(15 weeks- 3 x per week)
G1: VO2 Max increased by 20%
G2: Men- 4% VO2 Max increase, Women- 8% increase

7. Effects on CP and food stuffs availability
22% CP storage increase
This also has to do with diet
Creatine is only stored in animals- vegetarians and vegans will have trouble with weight training
Well trained muscles can store 18% more ATP
No difference in blood glucose or muscle triglyceride storage.
Mitochondria density decreases even though total # stays the same (because muscle gets bigger)
Because of this, aerobic workouts will suffer

8. Hormonal Changes.
AAS: Anabolic androgenic steroids (Ana: increase synthesis of protein, make more muscle; bolic: tissue building; androgenic: begin man)

4 major AAS in humans:
Testosterone
Insulin
Growth hormone
Insulin like growth factor
All of these work together. You don't get the full effect of any one of these without the rest.

Design a resistance program that causes the body to make more of these naturally.
Anabolic Hormone increased
1. Large muscle group exercise
deadlift, power cleans, squats
Put in even just a couple of big muscles- gluts, quads
Hormones are not site specific. They flow through the whole body regardless of what large muscle you are using. They will affect your other muscles you work out as well.
2. Heavy Resistance
85-95% of 1 RM 2-6 reps
3. Moderate to High Volumes
Multiple sets on lots and lots of muscles
4. Short rest interval 30-60 sec.

9) Cardio respiratory changes
Heart- changes the structure of your heart
Cardiac hypertrophy.
The volume of left ventricles increases with aerobic training (low resting heart rate), doesn't beat as often because it shoots out a lot more blood per beat.
Max Stroke Volume for untrained people = resting stroke volume for trained people
In resistance training, the left ventricle hypertrophies- muscles contract and collapse arteries and veins while resistance training, so the heart must contract harder.
Resting heart rate- slightly lower than an out of shape person.
Blood pressure: acute- rises (a lot), chronic- decreases resting blood pressure
Resistance training is good even for high blood pressure patients.
Best way is aerobic but resistance training is also a good way.

10) Reaction/ Contraction Times Change
You can decrease reaction time with specific training.

11) Increase Size and Strength of Tendons and ligaments
Ligaments- bone to bone connection
Tendons- muscle to bone connection
Most improvement during hypertrophy

12) Injury Prevention
Never proven a relationship because we can't test on humans
Don't know if this is a cause and effect relationship but we know there is a positive correlation.

13) Flexibility
Increases it if you practice through a full range of motion

14) Motor Performance
Jump- vertical, horizontal
Ladders
40 yard dash

Resistance Training for Women
1984- Women allowed to run the marathon for the 1st time.
Train a male and female in the exact same ways in resistance except in pregnancy. The muscles respond exactly the same. Men are just larger.

Contraindications for Pregnancy
No supine exercises after 1st trimester
Weight of uterus on vena cava-decreased blood flow
Small muscle groups-NO large, NO valsalva maneuver
No exercises that increase the risk of abdominal trauma
Focus on breathing
Automatic- Must get doctor's approval

Resistance Training for Pre-pubescent kids
NSCA is the leader in resistance training methods for kids.

4 Contraindications
Never let them lift with wrist in hyper extended position
No heavy lifting especially overhead
Must be highly supervised
Low weight/ high reps
No competition
No valsalva maneuver
Technique- large muscle group- balance, coordination, symmetry

5 Good Things for kids
1. Increased strength- no hypertrophy, it’s coordination
(Ability to lift heavier weights)
2. Decreased risk of injury
3. Increased motor performance- coordination
4. Improves self image
5. Increased coachability- how to take direction

Steroid Abuse in Adults
This will not improve performance in anything if you are not resistance training in conjunction with taking these steroids.
Decreased FM, Increase FFM
Does nothing for VO2 max

Bad- side effects
Connective tissue damage
When you get big fast- tendons don’t keep up
Blood profile gets worse- increased risk of stroke, heart attack
Increased risk of cancer- liver, kidney failure
Increased body and facial hair
Male pattern baldness
Acne
Premature closer of growth plates
Decreased reproductive capabilities- testes shut down production- testicular atrophy
Increased rage
Increased sense of wellbeing (invincibility, immortality)
Increased libido
Irregular sleep patterns

Resistance Training Principles 10-8-07

Designing Resistance Training Programs

Improve Muscle Fitness

4 Principles (for any exercise but these are most related to Resistance Training)

1. Overload Principle
In order for a muscle to make improvements you must stress it above and beyond the level it is accustomed to.
Ways to overload a muscle:
Change frequency of workouts
Change exercises
Change weight lifted up or down
Change # of reps, sets
Change rest periods- these are important- always carry a watch

2. Progressive Overload Principle
Once your body acclimates to the overload, introduce a new and harder overload.

3. Arrangement of exercises (most specific to resistance training)
Sequence of exercises
Largest muscle groups first to smallest last
Why? If you fatigue the "helper" muscles you won't be able to lift enough to get a work out for your bigger muscles.
Large-----Small
Core-----Auxiliary
Structural----Body part
Multi-joint----single joint
For beginners: alternate body parts (upper then lower, back to upper, in same workout)
Super setting- for every exercise, the next exercise is the complete opposite exercise (e.g. crunches then back extensions)
For beginners: this is good because there is a built in rest time (to walk from one machine to the other)
Major benefit: symmetry- 50% of musculoskeletal injuries are due to muscle imbalances.
2nd most common reason people visit the doctor- low back pain.


4. Specificity of training
To improve your performance in x sport, you must train with exercises specific to the sport.
Cross Training is great for general conditioning but bad for excelling at individual sports.


Establish Their Goals: Needs Analysis

Part of the client assessment

Look at components of activity:

1. Types of muscular fitness
What does the Little Old Lady (LOL) need?: Endurance, strength, balance
What does the College Volleyball Athlete (CVA) need?: explosiveness, strength, hypertrophy, endurance (they are built on each other)

2. Energy systems
LOL: Older adults eat less, so they don‘t get everything they need; increase their protein intake (glycolic, aerobic)
CVA: ATP-CP System

3. Muscle Groups
LOL: All of them
CVA: All of them

4. Movement Patterns
LOL: Step ups
CVA: Vertical jump

5. Muscle Contraction Type
LOL: Eccentric & Concentric
CVA: Explosive eccentric & concentric

6. Primary injury site
LOL: Low back pain, knees, hips
CVA: None, what is the most common injury in this group? Ankles, knees, low back.

Muscular Fitness Assessment

Specific to client, gender, age, goals, etc.

1. Assess Muscular fitness leveL
LOL: Senior Fitness- Use chair sits, etc. There are many senior fitness books around. Leslie Crants uses these. There is a tremendous amount of research on senior fitness.
CVA: Vertical jump- find norms for Division 1 Female volley ball
Test every part of muscle fitness under what level they need to get to. This test is a 1RM test on every exercise.

2. Compare scores to the norms

3. Identify weaknesses
30% is low normal (I actually missed exactly what he said here. Someone please confirm this #. Thanks)

4. Address weaknesses via appropriate program design
See pg. 10 of packet
Must stress individuality of program. Must take into consideration recovery, diet, sleep, etc.
2nd half pg. 24 of packet
A great book to read is Designing Resistance Training Programs by Fleck and Kraemer

Overload Principle

How much weight should you be lifting???

FITT Principle is for Aerobic exercise programs

FIRMS is for Resistance training programs

Frequency: how many days per week you work the SAME muscle group. Minimum for ACSM is 2-3 times per week for the average American. Max: 48-72 hours rest between workouts.

Intensity: This is the foundation for reps, sets, and frequency

Reps: Consecutive movements (intimately related to intensity)

Muscle Group: This assessment should be done based on the same muscle group x times per week.

Sets: Groups of reps

Split Routine: aggressive (working out 9 times per week) Called 3 + 1.
M T W R F S S
am Chest/tri back/biceps chest/tri back/biceps chest/tri back/bi OFF
pm lower body OFF lower OFF lower OFF OFF

Middle of pg. 10 of packet

FIRMS is missing Rest periods- these are critical, they are specific to your goals, based on energy systems.

X RM (X= 1-20)
Repetitions Maximum
The heaviest weight that an individual can lift x # of times through a full range of motion and with proper technique (and with no assistance-not true in some situations).
Drives # of sets, reps, weight, and rest period.

When you tell people that strength and endurance are different, most people will say they want a little of both strength and endurance. Hypertrophy bridges the gap between them, not only with muscles but also the connective tissue. If you were to go straight from training for endurance to training for strength, not only would your muscles not be ready, but you would be much more likely to damage connective tissues, ie tendons.

How do you tell if you are tired? If you don't get within 3 inches of your normal vertical jump, you are tired and should stop.

How much weight should you use?
Must know 1 RM first.

There is a relationship between 1 RM and every other RM.
If 1 RM = 200lbs. on the leg press
3 x 12 RM= 140 lbs. (70% of your 1 RM)
20 RM = 100lbs. See table on pg.12 of packet. Memorize.
Test Sub-maximal RM for out of shape people
50lbs. = 8 RM estimate 1 RM
50/0.8 = 62.5lbs.
(Quick hint: if going from higher RM toward 1 RM, divide lbs. by %; when going from 1 RM to another RM, multiply lbs. by %)

The first part of any program is a base of endurance training.
12-20 reps this is a range of 70-50% of your 1RM weight which translates to 44-31 lbs.
#'s will differ slightly between tables. Beyond 20RM the relationship falls apart. After 10RM it isn't as great as the relationship from 1-10RM. And the table is only really good for large muscle groups like
Squat
Bench press
Lat pull down
Best for people who have some experience in resistance training. (Intermediate to advanced)
For a beginner, after testing their 1 RM you can design a program of progressive overload:
Week 1: 3x 12 @ 60lbs.
Week 2: 3x13 @ 60
Week 3 3x14 @ 60
Week 4: 3x 12 @ 65-70lbs.

The good thing about a program like this is that you don't have to be there to tell them to do this. It is self explanatory. However, every muscle will progress differently. Must have 1 RM for all major exercises/muscle groups and progress each according to its own time schedule.
ACSM guide for the General out of Shape American (1998)
1 set of 8-12 to RM 2-3 days a week. For an out of shape person, this is equivalent to 3 sets. This works until they are in any type of good condition at all.


Pg. 13 Periodization
A concept first developed in the Eastern Block Countries 1950's. Didn't catch on here until 1970's with Track and Field coaches.

Break up long term goal into short term goals. Build on top of muscle endurance and going up from there.




Pg. 14 Macrocycle -set a year training program
To turn Strength to power= pliometrics
To turn strength to endurance= interval training programs (H-L intensity over and over)
During Maintenance Period:
Frequency should Decrease
Intensity should Increase
Duration should Decrease
For more information on Periodization, look for recent books by Tudor Bompa.



ISOMETRIC TRAINING

100% MVC
Maximal Vollentary Contraction
5 contractions
6 seconds
>or = 30 is best to increase isometric strength.
Training at a specific joint angle has a + or - 20 degree carry over. Thus if you were to train isometrically at 90 degree joint angle, you would actually be strengthening a range from 70-110 degrees.


ISOKINEIC TRAINING
3 sets
8-15 reps
Machine moves from 0-300 degrees/sec.
Research shows that people should train at moderate speeds (179 degrees/sec) because training at x speed carries over to the speeds above and below. Closest you can get to isokinetic contractions without expensive machines is swimming.

Issues

Sorry guys, I'm having some weird technical issues with Blogger right now. Hold tight on the graphs for Monday's notes. I'll keep working on it.

Fast and Slow Twitch 10-1-07

Three Ways A Muscle Generates Force or Tension

1. Isometrically- (Latin- Iso: same, metric: length) muscle generates force or tension w/ no change in length. Isometric endurance and strength is critical to every day life. IE posture muscles work isometrically to keep you in an upright position. Another example is performing the Iron Cross on the rings. Another example of an isometric workout is to stay in the pushup position without performing the pushup. Your abs and triceps are engaged but not lengthening or contracting.

2. Isotonically- (Latin- Iso: same, tonic: tension- this is an inaccurate term) muscle generates force while either shortening or lengthening.
A. Concentric- muscle generates force or tension while shortening
B. Eccentric- muscle generates force or tension while lengthening. Vast majority or DOMS is related to eccentric exercise.
Reason why Isotonic is inaccurate: Torque (T)= Force (F) x Distance (d_ )
(where d_ = distance perpendicular)

T90* = (10 lbs.)(16 in.)= 160 in. lbs.
Where d is the distance from the axis of rotation (joint) to the center of gravity of the resistance (weight).

T140*= (10 lbs.)(14 in.)=140 in. lbs.
NOT the same tension throughout the full range of motion. NSCA does not use the term Isotonic. They use any combination of the following: Dynamic Constant External Resistance (DCER, DR, CDER, CER)

Any difference, from other people, in where your bicep inserts on your radius determines differences in lifting capabilities. This is genetically determined. The difference can be as small as .5 mm but translate into a large difference in lifting capabilities. This determines the “Sticking Point” also. (See pg. 69 of NSCA book). The average sticking point for bench press is about 4 inches off the chest.

STICKING POINT: Aside from the definition on pg. 69 of the NSCA book, according to Physiological Aspects of Sport Training and Performance by Jay Hoffman, Sticking Point refers to the joint angle position of the contraction in which the muscle is the weakest.

3. Isokinetically- (Latin- Iso: same, kinetic: speed/motion) A near maximal effort at a constant speed throughout an entire range of motion (ROM). Only way to do this type of exercise accurately is with an expensive machine often found in physical therapy labs. Mostly used in rehab. (Cybex, Kintron, Med-X machines) These machines keep the speed of motion constant but change the resistance. The machine gives less resistance at your weakest point, and most resistance at your strongest. This is called Accommodation Resistance. This machine is primarily used in physical training facilities because it shuts down when you stop pushing and it gives you a read out.

Theories of the causes of DOMS (Delayed Onset of Muscle Soreness)

1. SPASM theory:
When you work out a muscle aggressively, you have micro-muscle spasms you don’t feel. This happens naturally. These spasms push the muscles against arteries and veins collapsing them. Support for this theory is that stretching and massage helps decrease DOMS.

2. TEAR theory:
When you exercise a muscle, you actually destroy the muscles in order to build them back up. In order to heal these tears, your body uses enzymes. The by-products of this repair process of the enzymes are said to create discomfort in the muscles causing DOMS.

3. LACTATE ACCUMULATION theory:
Muscle produces lactate & H+ ions. This CANNOT be a reason for DOMS because even with rest recovery, it still only takes 2 hrs. for these to be cleared from the muscle. This theory has been disproved.

4. CONNECTIVE TISSUE DAMAGE theory:
This theory has the most credibility. Damage associated with eccentric movements to connective tissue. (See pg. 5 of NSCA book). Every muscle structure is separated by connective tissue. All the connective tissue comes together & connects to the bone (as a tendon). Hydroxyproline is a by-product of connective tissue damage. This means you can use it as a marker of damage to the joints. Hydroxyproline has been shown to be most present in the body around 2 days after exercise, the same time DOMS sets in.

In one study, Tom had to perform very aggressive negative (eccentric) resistance training. They had him do 90% of his 1 RM as many times as he could but only the eccentric portion of the exercise. The highest concentration of hydroxyproline in his urine was at 48 hrs. after the testing was done.

Three of these theories contribute to do with DOMS.

Your endurance and strength significantly decrease during DOMS. It is suggested not to work out aggressively during this time.

You should NOT get DOMS every time you work out. This is a sign of over training.

MOTOR UNIT: A motor unit nerve and all the muscle fibers it innervates.

Fig. 3

Each muscle fiber only has one motor nerve that innervates it. For subtle movements you recruit motor nerves that innervate less muscle fibers. For big/explosive movements you recruit motor nerves that innervate a lot of muscle fibers.
Repetition of training makes the body more efficient at this.

SKELETAL MUSCLE FIBER TYPE CHARACTERISTICS (9 characteristics)

1. Three types of skeletal muscle
* Slow twitch: ST, red, type I, slow oxidative (so)
* Fast twitch a: FT a, pink, type IIa, fast oxidative Glycolitic (FOG)
* fast twitch b: FT b, white, type II b, fast glycolitic (FG)

Different muscles have completely different % of fast/slow twitch fibers. To have your fast/slow twitch analyzed, a biopsy is taken from a muscle and studied under a microscope. The three different fiber types are counted separately and divided by the total number of fibers under the microscope. Unfortunately, these % have no use. This is because depth into muscle, proximity to tendons, and other factors influence how many fast twitch and slow twitch fibers there will be.

Not only does the same muscle vary within itself, but each muscle differs greatly from one another in amount of slow/fast twitch fibers they contain. Posture muscles are composed of mainly slow twitch muscles (60% ST, 40% FT). The triceps is 60% FT, 40% ST.

The average American has 50% ST, 25% FT a, and 25% FT b.

2. Energy Pathway Potential

ST: Oxidative (High oxidative capacity, low glycolitic capacity)

FTa: Aerobic & Anaerobic (High oxidative capacity, high glycolitic capacity). Starts mimicing
ST and FTb if you have a great training program. This is why you don't train resistance

athletes aggresively in aerobic sports.

FTb: Anaerobic (Low oxidative capacity, high glycolitic capacity.

Slow Twitch
Stores 3 x more muscle triglycerides (because it uses the oxidative system it can use fat)
stores same amount of muscle glycogen
better suited for aerobic system

Fast Twitch
Enzymes used by the CP-ATP system are 3 x more active
Stores same amount of muscle glycogen
better suited for anaerobic system

3. Speed of Contraction

FT contracts faster. FT can contract in 1/3 the time of a ST. This is because the energy system it uses is faster but also because the motor nerves that innervate FT fibers are thicker. The brain can send a message faster down larger diameter nerves. This means you must not only train the muscle but also the nervous system. The nerves make a muscle ST or FT, not the muscle itself necessarily.

4. Force of Contraction
FT can generate a more forceful contraction. Motor nerves that innervate FT innervate more muscle fibers. Specificity of Training: to be explosive you must teach the muscles with explosive exercise. To be a high duration low intensity athlete, you must train with low intensity and high duration exercise.

5. Force-Velocity Curve
Graph. We are at our strongest at 0 movement (isometric resistance). Our ability to generate force decreases with velocity (speed of movement).
Graph. The graph of the trained person moves up and to the right from an untrained person. At the same velocity, a trained person can produce 15% more force than the untrained person. At the same force, a trained person's speed can increase 85% above the untrained person's.

6. Recruitment
High intensity low duration: body prefers to use FT. Low intensity high duration: body prefers to use ST.

7. Distribution in Athletes
Vertical jump is a good indication of fast twitch muscle fibers. Athletes who excel at low intensity high duration sports probably have a lot more slow twitch fibers and therefore may not excel in high intensity low duration sports. Eg Flo Joe who excelled at sprinting but could not excel at running long distances due to the great difference in FT to ST muscle fibers in her body.

8. Heredity
We are born with a certain number of FT and ST muscle fibers. These #s cannot be changed. They are determined by genetics: 99.9% genetically determined in males, 92.2% genetically determined in females.

9. Fatigability

Slow Twitch
6 Reasons why they fatigue
1. Muscle glycogen depletion
2. Liver (and thus blood glucose) glycogen depletion
(Hypoglycemia)
3. Dehydration
4. Electrolyte loss (especially in excessive heat-sweating electrolytes)
5. Increased core body temperature
6. Boredom

Fast Twitch
Fatigues faster because of its energy system
1. Fatiguing by-products (H+)
Must train athletes to use anaerobic Glyc. System and deal with high levels of H+. To be able to metabolize them faster and work at partial recovery (tolerated and clear faster).

http://www.brianmac.co.uk/muscle.htm