2. TOPICS OF DISCUSSION
• Types of Muscles
• Muscle Structure and Function
• Types of Muscle Contractions
• The muscle/nerve interaction (motor unit)
• Muscle Memory
• Muscle Training Principals
• Stretching
• Connective Tissue (tendon/ligament) structure
and function
3. Types of Muscles
• Three types of muscle in the body
• Cardiac
– Involuntary
– Highly resistant to fatigue – contracts and relaxes more
than 100,000 x per day without tiring
– Can get stronger and bigger with exercise
• Smooth
– Involuntary
– Found in the walls of various organs and tubes in the body:
blood vessels, GI tract, airways etc.
• Skeletal
– Voluntary – focus for yoga
4. Muscle Physiology
• Study of muscle function
• Muscles are tailored for force generation and
movement
• Muscle is a bundle of fibers covered by
connective tissue
• Muscles make up 45% of adult’s body weight.
• Most abundant tissue in the body
• Muscle rely on the breakdown of food to produce
energy for contraction. Certain minerals are also
important in the contraction of muscles
5.
6. Muscle Origin and Insertion
• All muscles pass over a joint. In some cases a
muscle will pass over two joints
• The muscle is contacted on each end to the bone
by a strong connective tissue known as a tendon.
• Origin – is the more proximal attachment and is
the area of the greatest concentration of muscle
fibers
• Insertion – is the opposite or more distal end. At
this end the muscle thins out.
7. Types of Muscle Fibers
• Type I (slow twitch) these fibers are more suited
for endurance type activities, have a high
resistance to fatigue, dominant in postural
muscles
• Type II (fast twitch) these fibers are more suited
for explosive activity (sprinting, jumping), rapid
contraction of muscles, easily fatigued
• Three subclasses under Type II are classified as
intermediates
8. Example of different fiber types
A chicken breast represents type II muscle fibers. They are white
in appearance. A chicken flaps its wings violently for short
periods of time throughout the day. The chicken leg represents
type I muscle fibers. They are red. A chicken walks around all
day which requires a level of endurance.
9. Muscle Innervation
• Muscles are penetrated by blood vessels, which
supply nutrients to the muscle cells and carry
away waste products
• These blood vessels are know as your capillaries
• Muscles are also penetrated by nerves from the
central nervous system
• Motor nerves cause the muscle to contract
• Sensory nerves allows the muscle to sense
changes in the surrounding environment
10. Muscle Contraction
• The motor unit is the fundamental unit of muscle
contraction
• The motor unit consists of the nerve cell, its axon with
branches and the muscle fibers that it innervates.
• The number of motor units in different muscles
depends on whether fine movement or gross
movement is required
• Examples: the thumb – requires strength and fine
motor movement so each motor unit is composed of
only a few muscle fibers. The thigh which requires
generating power to jump the motor unit is
compoased of thousands of fibers
13. Types of Muscle Contraction
• Concentric – the muscle shortens to generate
force and overcome resistance
• Eccentric – the muscle lengthens to overcome an
external force on the muscle
• Isometric – the muscle is activated, but instead of
shortening or lengthening, it is held at a fixed
length. The muscle force matches the load
• Passive stretching – the muscle is lengthened in a
passive state.
14. Muscle Roles
• Mover or agonist – is the main muscle that
contracts to produce movement
• Prime mover – the main muscle which is
responsible for causing joint movement
• Assistant mover – assists the prime mover
• Antagonist – opposes the agonist. Causes
extension of the muscle
• Stabilizer – support the agonist
15. Muscle Tone
• Muscle movement is under voluntary control – muscle
tone refers the unconscious nerves impulses coming to
the muscle to keep it in a partially contracted state.
• This is a positive adaptation to exercise
• Even in full relaxation there is always a low level of
muscle tone or firmness
• Tone that is different in two antagonist muscles causes
the joint to deviate from its normal position and this
causes a postural defect.
• Hypotonia = flaccidity
• Hypertonia = spasticity
16. Muscle Memory
• Definition – adaptation of muscles over a period of
time to perform a new movement or action
• When a movement – yoga pose – is repeated over time
the muscles involved learn the task (termed motor
learning) and can repeat it without conscious effort.
• When a yoga pose is learned there is a change in brain
and muscle circuitry.
• Example: newborns lack muscle memory such as
crawling, scooting or walking; the muscles become
accustomed to these activities by active learning and
later practice with trial and error
17. Stretching
• Flexibility – is usually described as the range of
motion for a specific joint. Flexibility involves
the joint capsule, the surrounding muscles,
and the connective tissue
• To improve flexibility stretching techniques are
employed.
• Stretching can be passive, active (dynamic) or
use of reciprocal inhibition.
18. What Really Stretches?
• Stretching involves pulling the muscle fibers away
from one another in order to increase length, but
this length is limited.
• A braking mechanism is necessary to avoid the
muscle fibers from severing entirely.
• Several braking mechanisms are in place to
prevent injury when stretching. These include the
ligaments, the tendons, the connective tissue
surrounding the muscle, and the muscle spindles
19. Methods of Stretching
• Passive stretching – the lengthened muscle does not
contract. A position is attained which causes a tension
in the muscles. The position is held for 15 seconds to
longer
• Dynamic stretching (active and ballistic)
• Active – moving the limb through its full ROM and
repeating several times.
• Ballisitc – rapid bouncing at the end-range of motion –
increased risk of injury
• PNF – proprioceptor neuromsuclar faciliation. The
muscle to stretch or its antagonist is contracted and
then relaxed
20. Muscle Spindle
• Special sensory receptors in the muscle which
detect changes in the length of the muscle
• Know as stretch reflex
• A protective mechanism to protect muscle fibers
from overstretching and becoming injured
• You can overcome or trick the muscle spindle by
bouncing when stretching. This is not
recommended because it can lead to injury of the
muscle being stretched
21.
22. Muscle Tightness
• Tightness is an increased tension either passive
or active in the muscle.
• Passive tension is a shortening of the muscle
through postural adaptation or scarring
• Active tension is a spasm or contraction of the
muscle. The cause of spasm is not well
understood. Could result from an underlying
medical condition.
• Tightness limits range of motion and can create
muscle imbalance
23. STRETCHING ADAPTATION
• How do we become more flexible?
• The muscle adapts to repeated stretching tow
ways
• Increased length of the muscle which causes a
reduction in tension
• Increased stretch tolerance (ability to
withstand more stretching force)
24. Muscle Cramps/Spasms
• Sudden involuntary contract of a muscle or
group of muscles
• Painful, but does not cause long-term injury
• Proposed causes
• Electrolyte depletion
• Dehydration
• Muscle fatigue
25. Muscle Adaptation
• Muscles adapt to the stress placed upon them
• If the stress is positive the muscles will respond by
changing their makeup depending upon the particular
type of stress applied
• Overload principle – the stress must be of sufficient
magnitude and time for adaptation to occur –
hypertrophy (grow larger)
• Specificity – muscle adapt specifically to the nature of
the stress
• Reversibility – muscle will atrophy when not used
• Individual differences
26. Core Muscle Concepts of Yoga
• Increase strength – associated with general
health benefits i.e. increased life expectancy,
psychological benefits, prevention of illness,
decreased disability
• Increased flexibility – improved joint range of
motion, enhanced power. Increased suppleness.
• Increased stability – improved balance and
neuromuscular control, injury prevention, and
treatment for injuries
27. TENDON FUNCTION
• Attach muscle to bone
• Have a mechanical function: transferring muscle
contraction into joint movement
• Transmit forces from muscle to bone
• Tendon is stiffer than muscle, but less than bone. It is 15x
stronger than a ligament
• It acts as a buffer to less the concentrations of stresses on
the muscle with the movement of the bone.
• Stores and releases energy making movement more
efficient
• Dissipates energy thus protecting the muscle and bone
from injury
29. TENDON INJURIES
• Because of its critical role in the mechanical
movement of the body and buffering the
tremendous stresses developed with muscle
contraction and movement of the bone, the
tendon is particularly susceptible to injury and
these injuries can be highly debilitating.
• Roughly 1 in 10 people will be afflicted with
Achilles tendinopathy (tendon pain with
damage or inflammation)
30. LIGAMENTS
• Several ligaments are associated with each
joint.
• Attach bone to bone
• Primary function is joint stability
• Ensure that when movement occurs the bones
do not separate and a full and even pressure is
maintained between the two bones in contact
31. Illustration of a Ligament Stretching
A ligament is functional
when stretched and non-
functional when compressed
When a ligament is stretched
tension develops, if the
stretch is held the tension is
diminished, while the length
is maintained
Slow stretching results in low
tension.
32. Ligament and Tendon Adaptation
• Increase size (hypertropy)
• Increase strength
• Increase in collagen (more protein)
• Improved metabolism
• Immobilization/aging results in weaker and
thinner (atrophy) tissue
• Less crimping
• Reduced protein synthesis
• Increased susceptibility to injury.
33. Proprioception and Kinesthetic
Awareness
• Proprioception – sense of joint location
• Kinesthetic awareness – knowing how your
body is moving through space
• Improving kinesthetic awareness through yoga
• Many of the yoga poses promote kinesthetic
awareness
• Closing the eyes during yoga asana help
develop this awareness