the 1975 Major League All-Star Game pre-game workout in Milwaukee,
WI, Baseball Hall of Fame pitcher, Tom Seaver, approached me
and started explaining the forces with which he pitched. He said
two energy masses originated in the back of his legs and moved
up to his buttocks where they combined and traveled up his back
to his throwing shoulder from where it flowed along his arm and
exploded out his fingertips. Tom's proprioceptive analysis provided
an entertaining image. However, muscles come in different sizes,
shapes, attachment locations and muscle fiber to motor nerve
ratios. Different muscle fiber types have different metabolic
processes and nutrient sources. Therefore, before pitchers make
pitching artistic, it is a science.
humans have about two hundred and fifty million muscle fibers.
Muscle fibers contain hundreds of myofibrils. Myofibrils contain
hundreds of alternating bands of actin and myosin filaments.
b. Actin Filaments
filaments resemble intertwined pearl strands with thin tropomyosin
protein filaments wrapped around them. Vesicles at tropomyosin
filament ends store troponin. Troponin enzymatically inhibits
muscle contraction. Light passes through actin filament bands
isotropically. Therefore, researchers call actin filament bands,
filaments resemble straight line layers fused together into thick
strips with numerous paddle-like myosin cross-bridge appendages
arising everywhere. Adenosine Tri-Phosphate (ATP) molecules attach
to every cross-bridge tip. Light passes through myosin filament
bands anisotropically. Therefore, researchers call myosin filament
and three phosphates combine to make up ATP molecules. When two
ATP molecule terminal phosphates separate, they release heat
energy and one inorganic phosphate (Pi) and leave adenosine di-phosphate
Ill 14.4: Adenosine Tri-Phosphate (ATP)
connective tissue lines bisect actin filament I-bands. These
connective tissue lines separate contractile units. Therefore,
researchers call these connective tissue lines, Z-lines after
zwischen, the German word for between. Sarcoplasmic reticulum
nervous tissue networks surround myofibrils. At Z-lines, these
nervous tissue networks have outer vesicles that store calcium.
Calcium stimulates muscle contraction. Therefore, a contractile
unit contains a one-half actin filament I-band, a whole myosin
filament A-band and another one-half actin filament I-band.
Sliding Filament Theory explains how muscles contract. During
contractile unit relaxation, troponin inhibits actin filament
movement towards the myosin filaments. However, ten sequential
events causes muscle contraction (tension).
1. Motor nerve impulses strike muscle fiber motor end plates.
2. Motor end plate activations release acetylcholine into sarcoplasmic
reticulum nervous tissue networks.
3. Sarcoplasmic reticulum nervous tissue network activations
4. Calcium neutralizes troponin.
5. Actin filament I-bands slide over myosin filament A-bands.
6. Actomyosin complexes release ATPase.
7. ATPases severe high energy bonds between two terminal phosphate
8. Severed terminal phosphate component high energy bonds produce
adenosine di-phosphate (ADP), an inorganic phosphate (Pi) and
9. Heat energy tilts myosin cross-bridges away from actin filament
10. Actin filament I-bands slide over flattened myosin cross-bridges.
muscle fibers resynthesize sufficient ATP molecules to resupply
depleted myosin cross-bridges, then myosin cross-bridges straighten
and return actin filaments to relaxation status. Simultaneously,
calcium returns to their storage vesicles and troponin again
inhibits actin filament affinity with myosin filaments.
g. Three Muscle
muscle fiber types serve our wide movement requirements.
1. Fight or flight emergencies require muscle fibers with high
2. Until metabolic processes become fully operational situations
require muscle fibers with medium intensity movements.
3. After metabolic processes operate efficiently situations require
muscle fibers with low intensity movements.
Phosphagenic (FTP) Muscle Fibers
high intensity muscle fibers must resynthesize ATP without external
resources. They cannot wait for muscle glycogen or muscle triglyceride
metabolism. They cannot wait for oxygen transport. Researchers
name these muscle fibers, Fast Twitch I. Because these muscle
fibers resynthesize ATP with a coupled biochemical phosphogenic
action, I call these muscle fibers, Fast Twitch Phosphagenic
(FTP) muscle fibers.
Twitch Phosphogenic muscle fiber contractions break Adenosine
Tri-Phosphate (FTP) down to Adenosine Di-Phosphate (ADP), an
inorganic phosphate (Pi) and heat energy. Phospho-creatin (PC)
forms when heat energy combines creatine (C) with inorganic phosphates
(Pi). Adenosine Tri-Phosphate (ATP) resynthesizes when heat energy
combines Adenosine Di-Phosphate with an inorganic phosphate (Pi).
Twitch Phosphogenic (FTP) muscle fibers require special biochemical
enzymes. FTP muscle fibers store very little phospho-creatine
(PC). Consequently, FTP muscle fibers intensely respond for about
ten seconds. FTP muscle fibers require about two minutes to recover.
Athletes cannot voluntarily activate FTP muscle fibers. Only
extremely emotional circumstances activate FTP muscle fibers.
However, during the 1968 Mexico City Olympics, longjumper Bob
Beaman may have tapped into his FTP system when he set the world
record by two feet.
Glycolytic (FTG) Muscle Fibers
term medium intensity muscle fibers must resynthesize ATP without
oxygen. They cannot wait for oxygen transport. Researchers name
these muscle fibers, Fast Twitch II. Fast-Twitch Glycolytic (FTG)
muscle fibers metabolize glucose (C6H12O6) to resynthesize adenosine tri-phosphate
(ATP). Because these muscle fibers metabolize muscle glycogen
to resynthesize ATP, I call these muscle fibers, Fast Twitch
Glycolytic (FTG) muscle fibers.
Twitch Glycolytic muscle fiber glycolysis requires twelve separate,
sequential biochemical reactions that do not require oxygen.
Therefore, FTG muscle fibers are immediately available for medium
intensity activities. However, glycolysis' waste product is lactic
acid (2C3H6O3). When lactic acid accumulations
reach about two and one-half ounces, FTG muscle systems cannot
properly operate. Athletes feel as though they are moving in
slow motion. Anaerobic means 'without oxygen. ' FTG muscle fibers
operate during anaerobic activities.
Oxidative (STO) Muscle Fibers
term low intensity muscle fibers resynthesize ATP with oxygen.
They require oxygen transport. Researchers name these muscle
fibers, Slow Twitch. Because slow twitch muscle fibers require
oxygen to metabolize muscle glycogen and muscle triglycerides,
I call these muscle fibers, Slow-Twitch Oxidative (STO). Slow-Twitch
Oxidative (STO) muscle fibers metabolize the basic food cells
glucose and lipids (C16H32O2) to resynthesize ATP molecules. STO
muscle fibers metabolize FTG's lactic acid.
muscle fibers contain mitachondria. Mitachondria are subcellular
structures of elaborate membrane systems that contain numerous
enzymes to accelerate metabolism and ATP resynthesis. However,
mitachondria require oxygen. Consequently, before STO muscle
fibers can properly operate, the oxygen transport system must
supply oxygen to mitachondrion. The oxygen transport system takes
about two minutes to get up to speed. After the oxygen transport
system supplies sufficient oxygen for metabolism and ATP resynthesis
to sustain muscle contraction, STO muscle fibers effectively
operate for long time periods.
the oxygen transport system gets up to speed, athletes have almost
inexhaustible ATP resynthesis sources. Highly trained marathon
runners can sustain oxygen transport equal to ATP resynthesis
at approximately eighty percent of their maximum running intensity.
Only dehydrated blood volumes limit performances. Aerobic means
'with oxygen. ' Athletes activate STO muscle systems for aerobic
activities. The waste products of STO muscle systems are carbon-dioxide
(CO2) and water (H2O).
plants photosynthesize the sun's light energy into chemical energy.
By combining green plants' chemical energies with carbon-dioxide
(CO2) and water (H2O), green plants manufacture
four basic food molecules. Cellulose, protein, glucose and lipids
are the four basic food molecules. Indigestible cellulose helps
digestive processes. Proteins form enzymes and filaments. FTG
and STO muscle systems metabolize glucose to resynthesize ATP.
STO muscle systems metabolize lipids to resynthesize ATP. Green
plants eliminate oxygen.
plants and humans form a biological energy cycle. Green plants
consume carbon-dioxide and water. Green plants manufacture food
molecules and eliminate oxygen. Humans consume food molecules
and oxygen. Humans eliminate carbon-dioxide and water. Green
plants consume carbon-dioxide and water, and so on, and so on
and so on.
Biological Energy Cycle
||food + O2
|CO2 + H2O
well-defined finite structures, actin and myosin filaments would
meaninglessly quiver. Therefore, connective tissues form well-defined
finite structures within which contractile units, myofibrils,
muscle fibers and muscles operate. Myofibril z-lines join with
endomysium connective tissues. Endomysium connective tissues
surround individual muscle fibers. Perimysium connective tissues
surround selective muscle fiber bundles (fasciculi). Epimysium
connective tissues surround entire muscles. Endomysial, perimysial
and epimysial connective tissue intertwine at muscle fiber ends
to form tendons. Tendons attach muscles to bones. Connective
tissues provide muscle contraction stability.
myofibril force theory states, "Without regard for percentages
of contractile units operating, myofibrils generate the same
force." Myofibrils achieve maximum lengths when zero percent
of contractile units operate. Myofibrils achieve minimum lengths
when one hundred percent of contractile units operate. If athletes
did not exert identical forces without regard for percentages
of contractile units operating, they could not lower weights
they just raised. When activities require specific joint angles,
myofibrils match contractile unit contraction percentages to
specific joint angles. Myofibril number determines strength differences.
k. Three Kinesiological
athletes grab weights with one hand from waist high tables and
raise them to shoulder heights, Kinesiologists label the joint
action, concentric. Concentric means something has a common
center with something else, like concentric circles. When athletes
grab weights with one hand from waist high tables, but cannot
raise them, Kinesiologists label the joint action, isometric.
Isometric means the same length. When athletes lower weights
from shoulder heights to waist high tables, Kinesiologists label
the joint action, eccentric. Eccentric means deviating
from the center.
all three joint actions, athletes contracted biceps brachii muscles.
Biceps brachii muscles attach across elbow joints. The three
joint actions differ in whether elbow joint angles decrease,
remain the same or increase.
isometric and eccentric refer to three muscle contraction types.
In the three examples, the same muscles operate. Muscles apply
force only when contractile units shorten maximum resting lengths.
Muscles contract in only one way, not three. Therefore, these
names are without meaning.
phenomenon actually refers to changing joint angles. Names assigned
to phenomenon should describe the phenomenon. Therefore, the
following names describe the three joint actions.
concentric muscle contractions, the joint angles across which
contracting muscles operate decrease. The Greek word for less
is 'meion' and the Greek word for angle is 'angkylos.' Mioanglos properly describes the joint action. Therefore, Mioanglos
Joint Action means that the joint angles across which contracting
muscles operate decrease.
isometric muscle contractions, the joint angles across which
contracting muscles operate remain the same. The Greek word for
equal is 'isos' and the Greek word for angle is 'angkylos.' Isoanglos properly describes the joint action. Therefore, Isoanglos
Joint Action means that the joint angles across which contracting
muscles operate remain the same.
eccentric muscle contractions, the joint angles across which
contracting muscles operate increase. The Greek word for more
is 'pleion' and the Greek word for angle is 'angkylos.' Plioanglos properly describes the joint action. Therefore, Plioanglos
Joint Action means that the joint angles across which contracting
muscles operate increase.
l. Motor Nerve
nerve cells accompany blood vessels under endomysial connective
tissues to individual muscle fibers. Nerve cells have one nucleus,
several dendrites, one axon and one synaptic knob. Motor nerve
cells have indented myelin sheaths surrounding their axons. Myelin
sheaths protect against unwanted electrical disturbances and
accelerate nerve impulse conduction velocities. When stimulated,
sodium molecules enter nerve cell bodies and change the electrical
polarity. At eleven millivolt polarity, nerve cells send their
nerve impulses down their axons to their synaptic knobs. Non-myelinated
axons conduct nerve impulses at between thirteen and twenty-two
miles per hour. Myelinated axons conduct nerve impulses at between
one hundred and thirty-five and two hundred and twenty-five miles
nerve synaptic knobs attach to muscle fibers at motor end plates.
Synaptic knobs contain mitachondria. Mitachondria resynthesize
acetylcholine. Acetylcholine stimulates sarcoplasmic reticulum
tubule and vesicle networks.
m. Motor Units
four hundred and twenty thousand motor nerves supply approximately
two hundred and fifty million muscle fibers. However, motor nerves
do not innervate the same number of muscle fibers. Fine control
motor nerves, like eye muscles, innervate only about twenty-five
muscle fibers. Moderate control motor nerves, like hand muscles,
innervate about four hundred muscle fibers. Gross control motor
nerves, like lower leg muscles, innervate about two thousand
muscle fibers. Motor units consist of one motor nerve and its
n. Motor Unit
Contraction and Relaxation Sequences
have specific motor unit contraction and relaxation sequences.
Simple motor skills, like bicycle riding, have simple motor unit
contraction and relaxation sequences. Complicated motor skills,
like baseball pitching, require complicated motor unit contraction
and relaxation sequences. Complex motor skills require more perfect
practice of its motor unit contraction and relaxation sequence.
thousands of perfect motor unit contraction and relaxation sequence
practices, athletes' central nervous systems permanently align
their protoplasmic nerve tissues. Researchers label these permanent
specific protoplasmically aligned central nervous system tissues,
engrams. During competitions, superior athletes automatically
activate engrams. Therefore, athletes must practice activities'
motor unit contraction and relaxation sequence perfectly.
injure muscles in different ways. When athletes improperly apply
force, they strain mal-aligned muscles. When athletes vigorously
increase motion ranges, they tear connective tissues. When athletes
generate high velocity limb movements beyond physiological deceleration
limits, muscle tissues tear. Improper motor unit contraction
and relaxation sequence programming tears muscle tissues.
Force Applications Injuries
force application injuries occur most commonly. Pitcher injuries
usually result from improper force application techniques. Biomechanists
and kinesiologists have the professional responsibility to determine
the proper force application techniques for all physical activities.
Unfortunately, they have failed to meet their obligations.
ranges of motion injuries occur because coaches train athletes
to avoid ranges of motion injuries. Coaches routinely recommend
'stretching' exercises. They claim stretching exercises increase flexibility. Stretching exercises apparently increase
ranges of motion about specific joints. However, stretching exercises
do not increase myofibril lengths. Stretching exercises trains
athletes to use fewer contractile units to maintain specific
joint stabilities. When fewer contractile units contract, myofibril
lengths increase. However, contractile units, myofibrils and
muscle fibers do not stretch, they are finite length tissues.
touches provide an interesting example. Toe touches increase
athletes' knees-locked toe touch range of motion. However, they
did not stretch their 'hamstring' muscles. Biceps femoris' long
head, semimembranosis and semitendinosis muscles (hamstring muscles)
stabilize hips and torsos during toe touches. Therefore, they
cannot stretch when contracting. Actually, because athletes use
fewer myofibril contractile units to stabilize their hips and
toe touches, their myofibrils are longer.
prevent high velocity deceleration muscle injuries, the cerebellum
regulates these velocities. The cerebellum restricts limb velocities
below deceleration capacities. However, during emotional competitions,
athletes sometimes exceed deceleration capacities.
4. Motor Unit
Contraction and Relaxation Sequence Injuries
muscles powerfully contract while opposing (antagonist) muscles
are contracting, antagonist muscle fibers tear. Tearing 'hamstring'
muscles is a good example. When athletes mis-program their sprinting
motor unit contraction and relaxation sequence, they tear their
biceps femoris muscles' short head. When the central nervous
system sends contraction signals to muscles, they also send inhibitory
signals to their antagonist muscles. However, the biceps femoris
muscle's short head receives its inhibitory signal from a different
sensory nerve than the other 'hamstring' muscles. Consequently,
the biceps femoris muscles' short head inhibitory signal arrives
late and the powerful antagonistic muscle contraction tears the
biceps femoris muscles' short head.
body builders pose, they co-contract antagonistic muscles. For
example, they contract biceps brachii and triceps brachii muscles
simultaneously without injury. These co-contractions occur without
meaningful joint actions. These are co-contractions without joint
actions. However, co-contractions with joint actions tear muscles.
The biceps femoris muscles' short head and plantaris muscle are
tears require rehabilitation. When improper force application
techniques tear muscles, athletes must learn proper force application
techniques. Until athletes can perform proper force application
techniques without tearing injured muscles, they should use cold-induced
vaso-dilation. Cold-induced vaso-dilation means pack injured
regions with ice. Athletes conform gallon zip-locked plactic
bags filled with crushed ice around injured regions directly
coldness initially vaso-constricts effected blood vessels and
reduces blood flow. Blood flow deprivation causes effected muscles
to emit pain signals for oxygen deprivation (hyperemia). Oxygen-deprived
muscle cells eventually die. However, reactive hyperemia prevents
oxygen-deprived muscle cell deaths. Reactive hyperemia vaso-dilates
blood vessels serving oxygen-deprived muscle cells. Vaso-dilation
floods injured muscle cells with healing blood. Therefore, throughout
rehabilitations, injured athletes should use cold-induced vaso-dilation.
the October 1, 1907 American Journal of Physiology, Warren P.
Lombard and F. M. Abbott published, "The Mechanical Effects
Produced by the Contraction of Individual Muscles of the Thigh
of the Frog. " Lombard and Abbott sought to explain how
the muscles on the front and back of the thigh contracted simultaneously
when humans stood up from sitting positions. They analyzed the
actions of twenty-two muscles of the thigh and hip. They offered
lever and pulley explanations. Kinesiologists accepted their
theory and called it, 'Lombard's Paradox.'
frogs do not have hips. The 'quadriceps' muscles, vastus lateralis,
vastus intermedialis and vastus medialis, straighten the knee
joint, but the 'hamstring' muscles, biceps femoris' long head,
semimembranosis and semitendinosis, straighten the hip joint.
The biceps femoris' short head does also straightens the hip
joint. When people stand up from sitting, they first bend forward
at their waists. To bend forward at their waists, they use their
'hamstring' muscles to stabilize their hips. Then, they use their
'quadriceps' muscles to straighten their knees. The concurrent
muscle actions cause the simultaneous 'hamstring' and 'quadriceps'
limbo dancers move under low bars with their hips thrust forward
and thorax and heads leaning way back, they straighten their
bodies without straightening their hip joints. Pregnant women
stand up from sitting without straightening their hip joints.
Both keep their thorax and heads backward and use the muscles
that bend the hip forward to remain upward.
can do similarly. First, stand up from the front edge of a chair
with your thorax and head leaning forward. You will find that
the 'hamstring' and 'quadriceps' muscles contract simultaneously.
Second, stand up from the front edge of a chair with your thorax
and head leaning backwards. You will find that only the 'hamstring'
muscles contract. Therefore, when people stand up from sitting
with their thorax and head leaning forward, co-contraction with
joint action does not occur, but at very controlled velocities.