Learn about how our muscle functioning everyday. And check out the muscle roles!! Simple notes, Simple slides for the beginner person who's attracted to science.
Biomechanics of Tendon, Ligament, Cartilage,, Bone
Wolf's Law
Mechnical Behavior
stress strain curve (Young's Moudulas)
viscoelasticity
time depended and rate depended properties
creep stress relaxation, hyteresis,
Thank You
Extensor mechanism of finger, very easy notes. Referred from cynthia norkin. In this ppt in last two slides u can see the identify the parts. Its like a quiz for candidates who studying this ppt. They can able to know that how well they prepared this topic.
Thank you, From Liki pedia
(A student physiotherapist)
Elbow complex is designed to serve hand.
They provide MOBILITY for Hand in space by apparent shortening and Lengthening of upper extremity.
They provide Stability for skillful and forceful movements
Biomechanics of Tendon, Ligament, Cartilage,, Bone
Wolf's Law
Mechnical Behavior
stress strain curve (Young's Moudulas)
viscoelasticity
time depended and rate depended properties
creep stress relaxation, hyteresis,
Thank You
Extensor mechanism of finger, very easy notes. Referred from cynthia norkin. In this ppt in last two slides u can see the identify the parts. Its like a quiz for candidates who studying this ppt. They can able to know that how well they prepared this topic.
Thank you, From Liki pedia
(A student physiotherapist)
Elbow complex is designed to serve hand.
They provide MOBILITY for Hand in space by apparent shortening and Lengthening of upper extremity.
They provide Stability for skillful and forceful movements
The Dynamic Training Scale empowers Riders to understand Why they do What they do, or When to do that, How to Self-Correct. It is a dynamic system that is repeated through each level of the Horses training, in a multi- dimensional manner
It also works as a Reference Point to know where your Training is at .
Muscle is one of the four primary tissue types of the body, and the body contains three types of muscle tissue: skeletal muscle, cardiac muscle, and smooth muscle.
skeletal, cardiac & smooth Muscles by Thiru Murugan.pptxthiru murugan
Unit III – The Muscular System - Anatomy
Types and structure of muscles
Muscle groups
Alterations in disease
Applications and implications in nursing
Muscle:
Muscle is a soft tissue and it is one of the 4 basic tissues, along with nervous tissue, epithelium, and connective tissue.
Muscles helps in movement, support and protection of internal organs.
Muscles can perform variety of functions
Muscles tissue is made up of cells called “MYOCYTES” or muscle fibers.
There are more than 600 muscles in the human body. A kind of elastic tissue makes up each muscle, which consists of thousands, or tens of thousands, of small muscle fibers.
Types of Muscles: There are 3 main types of muscles
Skeletal muscle
Cardiac muscle
Smooth muscle
Skeletal muscle:
These are having close relationship to the bone or skeleton, so called Skeletal muscles
It present in limbs and related body parts & It form about 40% of body weight.
Under microscope the skeletal muscles fibers shows prominent striations, so called “Striated Muscles” & It is also known as “Voluntary Muscles” (movements are under our control)
Structure of Skeletal muscle:
Muscle fibers shows transverse striations under light microscope so it is called “striated muscles”
The nucleus is located peripherally.
Each skeletal muscle is an organ that consists of numerous cells called muscle fibers.
Each muscle fibers surrounded by “ Endomysium”
Inside each skeletal muscle, muscle fibers are organized into bundles, called fascicles, each fascicle surrounded by perimysium.
The whole muscle is covered by “epimysium”
Each skeletal muscle has three layers: endomysium, perimysium and epimysium
Muscle fibers:
Muscle is composed of many long cylindrical-shaped elongated fibres called muscle fibers
Length varies according to the size and shape of the muscles.
The actual arrangement of the fibres depending on the function of the muscle.
Each muscle fibers covered by a membrane is called the sarcolemma.
The cytoplasm of a muscle fiber is called Sarcoplasm
In sarcoplasm there are many mitochondria and bundles of fine longitudinal thread like part is called “myofibrils”
Microscopic structure of myofibrils:
A myofibril (also known as a muscle fibril or sarcostyle) is a basic rod-like part of a muscle cell.
Muscles are composed of tubular cells called myocytes, known as muscle fibres in striated muscle, and these cells in turn contain many chains of myofibrils.
They are created during embryonic development in a process known as myogenesis.
Under light microscope each myofibril consist of 2 bands:
Light band or “I” Band and Dark band or “A” Band
The alternating pattern of these bands results in the striated appearance of skeletal muscle.
Light band or “I” Band:
The I-bands (isotropic in polarized light) appear light in color.
I band divided into 2 portions by a narrow dark line called “Z” line or “Z” Disc.
This “Z” line is formed by protein which does not permit the light.
The part in between 2 “Z” lines called “sarc
Describes the overview of the skeletal muscles, its description, functons, and properties. It also inccludes the gross organization of the skeletal system.
Report Back from SGO 2024: What’s the Latest in Cervical Cancer?bkling
Are you curious about what’s new in cervical cancer research or unsure what the findings mean? Join Dr. Emily Ko, a gynecologic oncologist at Penn Medicine, to learn about the latest updates from the Society of Gynecologic Oncology (SGO) 2024 Annual Meeting on Women’s Cancer. Dr. Ko will discuss what the research presented at the conference means for you and answer your questions about the new developments.
These simplified slides by Dr. Sidra Arshad present an overview of the non-respiratory functions of the respiratory tract.
Learning objectives:
1. Enlist the non-respiratory functions of the respiratory tract
2. Briefly explain how these functions are carried out
3. Discuss the significance of dead space
4. Differentiate between minute ventilation and alveolar ventilation
5. Describe the cough and sneeze reflexes
Study Resources:
1. Chapter 39, Guyton and Hall Textbook of Medical Physiology, 14th edition
2. Chapter 34, Ganong’s Review of Medical Physiology, 26th edition
3. Chapter 17, Human Physiology by Lauralee Sherwood, 9th edition
4. Non-respiratory functions of the lungs https://academic.oup.com/bjaed/article/13/3/98/278874
- Video recording of this lecture in English language: https://youtu.be/lK81BzxMqdo
- Video recording of this lecture in Arabic language: https://youtu.be/Ve4P0COk9OI
- Link to download the book free: https://nephrotube.blogspot.com/p/nephrotube-nephrology-books.html
- Link to NephroTube website: www.NephroTube.com
- Link to NephroTube social media accounts: https://nephrotube.blogspot.com/p/join-nephrotube-on-social-media.html
Explore natural remedies for syphilis treatment in Singapore. Discover alternative therapies, herbal remedies, and lifestyle changes that may complement conventional treatments. Learn about holistic approaches to managing syphilis symptoms and supporting overall health.
The prostate is an exocrine gland of the male mammalian reproductive system
It is a walnut-sized gland that forms part of the male reproductive system and is located in front of the rectum and just below the urinary bladder
Function is to store and secrete a clear, slightly alkaline fluid that constitutes 10-30% of the volume of the seminal fluid that along with the spermatozoa, constitutes semen
A healthy human prostate measures (4cm-vertical, by 3cm-horizontal, 2cm ant-post ).
It surrounds the urethra just below the urinary bladder. It has anterior, median, posterior and two lateral lobes
It’s work is regulated by androgens which are responsible for male sex characteristics
Generalised disease of the prostate due to hormonal derangement which leads to non malignant enlargement of the gland (increase in the number of epithelial cells and stromal tissue)to cause compression of the urethra leading to symptoms (LUTS
micro teaching on communication m.sc nursing.pdfAnurag Sharma
Microteaching is a unique model of practice teaching. It is a viable instrument for the. desired change in the teaching behavior or the behavior potential which, in specified types of real. classroom situations, tends to facilitate the achievement of specified types of objectives.
Anti ulcer drugs and their Advance pharmacology ||
Anti-ulcer drugs are medications used to prevent and treat ulcers in the stomach and upper part of the small intestine (duodenal ulcers). These ulcers are often caused by an imbalance between stomach acid and the mucosal lining, which protects the stomach lining.
||Scope: Overview of various classes of anti-ulcer drugs, their mechanisms of action, indications, side effects, and clinical considerations.
Tom Selleck Health: A Comprehensive Look at the Iconic Actor’s Wellness Journeygreendigital
Tom Selleck, an enduring figure in Hollywood. has captivated audiences for decades with his rugged charm, iconic moustache. and memorable roles in television and film. From his breakout role as Thomas Magnum in Magnum P.I. to his current portrayal of Frank Reagan in Blue Bloods. Selleck's career has spanned over 50 years. But beyond his professional achievements. fans have often been curious about Tom Selleck Health. especially as he has aged in the public eye.
Follow us on: Pinterest
Introduction
Many have been interested in Tom Selleck health. not only because of his enduring presence on screen but also because of the challenges. and lifestyle choices he has faced and made over the years. This article delves into the various aspects of Tom Selleck health. exploring his fitness regimen, diet, mental health. and the challenges he has encountered as he ages. We'll look at how he maintains his well-being. the health issues he has faced, and his approach to ageing .
Early Life and Career
Childhood and Athletic Beginnings
Tom Selleck was born on January 29, 1945, in Detroit, Michigan, and grew up in Sherman Oaks, California. From an early age, he was involved in sports, particularly basketball. which played a significant role in his physical development. His athletic pursuits continued into college. where he attended the University of Southern California (USC) on a basketball scholarship. This early involvement in sports laid a strong foundation for his physical health and disciplined lifestyle.
Transition to Acting
Selleck's transition from an athlete to an actor came with its physical demands. His first significant role in "Magnum P.I." required him to perform various stunts and maintain a fit appearance. This role, which he played from 1980 to 1988. necessitated a rigorous fitness routine to meet the show's demands. setting the stage for his long-term commitment to health and wellness.
Fitness Regimen
Workout Routine
Tom Selleck health and fitness regimen has evolved. adapting to his changing roles and age. During his "Magnum, P.I." days. Selleck's workouts were intense and focused on building and maintaining muscle mass. His routine included weightlifting, cardiovascular exercises. and specific training for the stunts he performed on the show.
Selleck adjusted his fitness routine as he aged to suit his body's needs. Today, his workouts focus on maintaining flexibility, strength, and cardiovascular health. He incorporates low-impact exercises such as swimming, walking, and light weightlifting. This balanced approach helps him stay fit without putting undue strain on his joints and muscles.
Importance of Flexibility and Mobility
In recent years, Selleck has emphasized the importance of flexibility and mobility in his fitness regimen. Understanding the natural decline in muscle mass and joint flexibility with age. he includes stretching and yoga in his routine. These practices help prevent injuries, improve posture, and maintain mobilit
New Directions in Targeted Therapeutic Approaches for Older Adults With Mantl...i3 Health
i3 Health is pleased to make the speaker slides from this activity available for use as a non-accredited self-study or teaching resource.
This slide deck presented by Dr. Kami Maddocks, Professor-Clinical in the Division of Hematology and
Associate Division Director for Ambulatory Operations
The Ohio State University Comprehensive Cancer Center, will provide insight into new directions in targeted therapeutic approaches for older adults with mantle cell lymphoma.
STATEMENT OF NEED
Mantle cell lymphoma (MCL) is a rare, aggressive B-cell non-Hodgkin lymphoma (NHL) accounting for 5% to 7% of all lymphomas. Its prognosis ranges from indolent disease that does not require treatment for years to very aggressive disease, which is associated with poor survival (Silkenstedt et al, 2021). Typically, MCL is diagnosed at advanced stage and in older patients who cannot tolerate intensive therapy (NCCN, 2022). Although recent advances have slightly increased remission rates, recurrence and relapse remain very common, leading to a median overall survival between 3 and 6 years (LLS, 2021). Though there are several effective options, progress is still needed towards establishing an accepted frontline approach for MCL (Castellino et al, 2022). Treatment selection and management of MCL are complicated by the heterogeneity of prognosis, advanced age and comorbidities of patients, and lack of an established standard approach for treatment, making it vital that clinicians be familiar with the latest research and advances in this area. In this activity chaired by Michael Wang, MD, Professor in the Department of Lymphoma & Myeloma at MD Anderson Cancer Center, expert faculty will discuss prognostic factors informing treatment, the promising results of recent trials in new therapeutic approaches, and the implications of treatment resistance in therapeutic selection for MCL.
Target Audience
Hematology/oncology fellows, attending faculty, and other health care professionals involved in the treatment of patients with mantle cell lymphoma (MCL).
Learning Objectives
1.) Identify clinical and biological prognostic factors that can guide treatment decision making for older adults with MCL
2.) Evaluate emerging data on targeted therapeutic approaches for treatment-naive and relapsed/refractory MCL and their applicability to older adults
3.) Assess mechanisms of resistance to targeted therapies for MCL and their implications for treatment selection
Factory Supply Best Quality Pmk Oil CAS 28578–16–7 PMK Powder in Stockrebeccabio
Factory Supply Best Quality Pmk Oil CAS 28578–16–7 PMK Powder in Stock
Telegram: bmksupplier
signal: +85264872720
threema: TUD4A6YC
You can contact me on Telegram or Threema
Communicate promptly and reply
Free of customs clearance, Double Clearance 100% pass delivery to USA, Canada, Spain, Germany, Netherland, Poland, Italy, Sweden, UK, Czech Republic, Australia, Mexico, Russia, Ukraine, Kazakhstan.Door to door service
Hot Selling Organic intermediates
Title: Sense of Smell
Presenter: Dr. Faiza, Assistant Professor of Physiology
Qualifications:
MBBS (Best Graduate, AIMC Lahore)
FCPS Physiology
ICMT, CHPE, DHPE (STMU)
MPH (GC University, Faisalabad)
MBA (Virtual University of Pakistan)
Learning Objectives:
Describe the primary categories of smells and the concept of odor blindness.
Explain the structure and location of the olfactory membrane and mucosa, including the types and roles of cells involved in olfaction.
Describe the pathway and mechanisms of olfactory signal transmission from the olfactory receptors to the brain.
Illustrate the biochemical cascade triggered by odorant binding to olfactory receptors, including the role of G-proteins and second messengers in generating an action potential.
Identify different types of olfactory disorders such as anosmia, hyposmia, hyperosmia, and dysosmia, including their potential causes.
Key Topics:
Olfactory Genes:
3% of the human genome accounts for olfactory genes.
400 genes for odorant receptors.
Olfactory Membrane:
Located in the superior part of the nasal cavity.
Medially: Folds downward along the superior septum.
Laterally: Folds over the superior turbinate and upper surface of the middle turbinate.
Total surface area: 5-10 square centimeters.
Olfactory Mucosa:
Olfactory Cells: Bipolar nerve cells derived from the CNS (100 million), with 4-25 olfactory cilia per cell.
Sustentacular Cells: Produce mucus and maintain ionic and molecular environment.
Basal Cells: Replace worn-out olfactory cells with an average lifespan of 1-2 months.
Bowman’s Gland: Secretes mucus.
Stimulation of Olfactory Cells:
Odorant dissolves in mucus and attaches to receptors on olfactory cilia.
Involves a cascade effect through G-proteins and second messengers, leading to depolarization and action potential generation in the olfactory nerve.
Quality of a Good Odorant:
Small (3-20 Carbon atoms), volatile, water-soluble, and lipid-soluble.
Facilitated by odorant-binding proteins in mucus.
Membrane Potential and Action Potential:
Resting membrane potential: -55mV.
Action potential frequency in the olfactory nerve increases with odorant strength.
Adaptation Towards the Sense of Smell:
Rapid adaptation within the first second, with further slow adaptation.
Psychological adaptation greater than receptor adaptation, involving feedback inhibition from the central nervous system.
Primary Sensations of Smell:
Camphoraceous, Musky, Floral, Pepperminty, Ethereal, Pungent, Putrid.
Odor Detection Threshold:
Examples: Hydrogen sulfide (0.0005 ppm), Methyl-mercaptan (0.002 ppm).
Some toxic substances are odorless at lethal concentrations.
Characteristics of Smell:
Odor blindness for single substances due to lack of appropriate receptor protein.
Behavioral and emotional influences of smell.
Transmission of Olfactory Signals:
From olfactory cells to glomeruli in the olfactory bulb, involving lateral inhibition.
Primitive, less old, and new olfactory systems with different path
Couples presenting to the infertility clinic- Do they really have infertility...Sujoy Dasgupta
Dr Sujoy Dasgupta presented the study on "Couples presenting to the infertility clinic- Do they really have infertility? – The unexplored stories of non-consummation" in the 13th Congress of the Asia Pacific Initiative on Reproduction (ASPIRE 2024) at Manila on 24 May, 2024.
Surgical Site Infections, pathophysiology, and prevention.pptx
Muscular System (Our Muscle)
1. MUSCULAR SYSTEM
OBJECTIVE:
•Identify
the basic behavioral
properties of the
musculotendinous unit
•Structure
of skeletal muscle
•Change
in muscle length with
tension development
•Factors
affecting muscular
force generation
1
2. BEHAVIORAL PROPERTIES OF THE
MUSCULOTENDINOUS UNIT
Four behavioral properties of muscle tissue:
Extensibility
Elasticity
Irritability
The ability to develop tension
These properties are common to all muscle,
including the cardiac, smooth, & skeletal muscle
of human beings.
2
3. Extensibility & Elasticity
The properties of extensibility & elasticity are
common to many biological tissues.
Extensibility – the ability to be stretched or to
increase in length.
Elasticity – the ability to return to normal length
after a stretch.
Muscle’s elasticity returns it to normal resting
length following a stretch & provides for the
smooth transmission of tension from muscle to
bone.
3
4. Two major components of the elastic behavior of muscle:
Parallel elastic component (PEC)
Passive elastic property of muscle derived from the
muscle membranes.
Series elastic component (SEC)
Passive elastic property of muscle derived from the
tendons.
Act as a spring to store elastic energy (EE) when a
tensed muscle is stretched.
Contractile component
Muscle property enabling tension development by
stimulated muscle fibers.
Membranes & tendons are respectively parallel to &
in series (or in line) with the muscle fibers.
4
6. The elasticity of human skeletal muscle is believed
to be due primarily to the SEC.
When a tensed muscle is stretched, the SEC
causes an elastic recoil effect
The stretch promotes subsequent forceful
shortening of the muscle
This pattern of eccentric contraction followed
immediately by concentric contraction is known
as the stretch-shortening cycle.
This phenomenon contributes to effective
development of concentric muscular force in
many sport activities.
6
7. The stretch-shortening cycle also promotes
storage & use of elastic energy (EE) during
running, particularly with the alternating eccentric
& concentric tension present in the gastrocnemius.
Both SEC & PEC have a viscous property that
enable muscle to stretch & recoil in a timedependent fashion.
When static stretch of a muscle group is maintained over
time, the muscle progressively lengthens, increasing joint
range of motion
After a group has been stretched, it does not recoil to
resting length immediately, but shortens gradually over time
7
10. Irritability & the Ability to Develop Tension
Irritability- The ability to respond to a stimulus.
Stimuli affecting muscles are either:
Electrochemical – action potential from the
attaching nerve.
Mechanical – an external blow to a portion of a
muscle.
Muscle
stimulus
Develop tension
• The ability to develop tension is the one behavioral characteristic
unique to muscle tissue.
• Development of tension = contraction (eccentric or concentric)
10
11. STRUCTURAL ORGANIZATION OF
SKELETAL MUSCLE
Approximately 434 muscles in the human body (4045% of the body weight of most adult).
About 75 muscle pairs are responsible for body
movements & posture, with the remainder involved
in activities such as eye control & swallowing.
11
12. Structure of Skeletal Muscle (muscle fiber)
Epimysium
Bone Epimysium
Perimysium
Endomysium
Tendon
(b)
Perimysium Fascicle
(a)
Muscle fiber
in middle of
a fascicle
Blood vessel
Fascicle
(wrapped by perimysium)
Endomysium
(between individual
muscle fibers)
Muscle fiber
(single muscle
cell)
12
13. Epimysium
The outermost layer that surround the entire
muscle.
Perimysium
Connective tissue surround individual bundles of
muscle fibers (inward from the epimysium).
Fascicle
Individual bundle of muscle fibers.
Endomysium
Connective tissue surrounded for each muscle fiber
within the fasciculus.
13
14. Sarcolemma
◦ The cell membrane surrounding the muscle fiber cell.
Myofibrils
◦ Numerous threadlike structure that contain the
contractile proteins (protein filaments)
Myosin – thick filaments composed of the protein.
Actin – thin filaments composed primarily of the
protein.
Sarcoplasmic reticulum
◦ The storage sites for calcium, which plays an
important role in muscular contraction.
Sarcomeres
◦ Myofibrils further subdivided into individual segments.
14
15. Small part of one myofibril enlarged to
show the myofilaments
responsible for the banding pattern. Each
sarcomere extends from
one Z disc to the next (basic structural unit of
muscle fiber).
Enlargement of one sarcomere
(sectioned lengthwise). Notice the
myosin heads on the thick filaments.
M line
Bisect each sarcomere (middle)
A band
Contain thick, rough myosin filament, each of
which is surrounded by thin, smooth actin
filaments
I band
Contain only thin actin filaments
Z lines (disc)
Attachment of thin actin filaments
H zones
Center of A bands, contain only thick myosin
15
16. Part of a skeletal
muscle fiber (cell)
A band
I band
Z disc
Myofibril
I band
H zone
Z disc
M line
Sarcolemma
Sarcolemma
Triad:
• T tubule
• Terminal
cisternae
of the SR (2)
Tubules of
the SR
Myofibrils
Mitochondria
16
Figure 9.5
17. Motor Units
Composed of a single motor neuron & all fibers
innervated by it.
Typically, there is only 1 end plate per fiber.
A single mammalian motor unit may contain from
less than 100 to nearly 2000 fibers, depending on
the type of movements the muscle executes.
Movements that are precisely controlled (eyes, fingers) produced
by motor units with small numbers of fibers
Gross, forceful movements (gastrocnemius) result of the activity
of large motor units
17
18. Spinal cord
Motor Motor
unit 1 unit 2
Axon terminals at
neuromuscular junctions
Nerve
Motor neuron
cell body
Motor
Muscle
Motor end
plate
neuron
axon
Muscle
fibers
Axons of motor neurons extend from the spinal cord to the
muscle. There each axon divides into a number of axon
terminals that form neuromuscular junctions with muscle
fibers scattered throughout the muscle.
18
Figure 9.13a
19. Fiber Types
Slow twitch fiber (ST)
◦ A fiber that reaches peak tension relatively
slowly.
Fast twitch fiber (FT)
◦ A fiber that reaches peak tension relatively
quickly.
◦ Fast-twitch Oxidative Glycolytic
◦ Fast-twitch Glycolytic
19
20. SKELETAL MUSCLE FIBER CHARACTERISTICS
CHARACTERISTIC
TYPE 1
SLOWTWITCH
OXIDATIVE
(SO)
TYPE IIA
FAST-TWITCH
OXIDATIVE
GLYCOLYTIC
(FOG)
TYPE IIB
FASTTWITCH
GLYCOLYTIC
(FG)
Contraction speed
Slow
Fast
Fast
Fatigue rate
Slow
Intermediate
fast
Diameter
Small
Intermediate
Large
ATPase concentration
Low
High
High
Mitochondrial concentration
High
High
Low
Glycolytic enzyme
concentration
Low
Intermediate
High
20
22. Fiber Architecture
Two categories of muscle fiber
arrangement
◦ Parallel fiber arrangement
Pattern of fibers within a
muscle in which the fibers
are roughly parallel to the
longitudinal axis of the
muscle.
E.g. sartorius, rectus
abdominis, biceps brachii.
22
23. Pennate fiber arrangement
Pattern of fibers within a
muscle with short fibers
attaching to one or more
tendons (lie at an angle).
E.g. tibialis posterior,
rectus femoris, deltoids
23
24. SKELETAL MUSCLE FUNCTION
When an activated muscle develops tension, the
amount of tension present is constant throughout
the length of the muscle, & at the sites of the
musculotendinous attachments to bone.
The tensile force (stretching force) developed by
the muscle pulls on the attached bones & create
torque at the joints crossed by the muscle.
24
25. Torque (Tm ) produced
by a muscle at the
joint center of
rotation is the product
of muscle force ( Fm )
& muscle moment arm
( d⊥ ).
25
26. The torque exerted
by the biceps brachii
(Fb) must counteract
the torques created
by the force
developed in the
triceps brachii (Ft),
the weight of the
forearm & hand
(wtf), & the weight
of the shot held in
the hand (wts).
26
27. Recruitment of motor units
The CNS exerts an elaborate system of control that
enables:
◦ Matching of the speed & magnitude of muscle
contraction to the requirements of the movement
so that:
Smooth, delicate, & precise movements can be
executed.
Slow twitch (ST) motor units generally have low
thresholds & are relatively easy to activate.
Fast twitch (FT) motor units are supplied by nerves
more difficult to activate.
27
28. Change in Muscle Length with Tension
Development
When muscular tension produces a torque larger than
the resistive torque at a joint, the muscle shortens,
causing a change in the angle at the joint.
Type of contraction;
◦ Concentric
◦ Eccentric
◦ Isometric
28
29. Concentric
Eccentric
Isometric
Contraction involving shortening of muscle
Resulting joint movement is in the same direction
as the net torque generated by the muscle.
A single muscle fiber is capable of shortening to
approximately one-half of its normal resting
length.
29
30. Concentric
Eccentric
Isometric
When opposing joint torque exceeds that
produced by tension in a muscle, the muscle
lengthens.
When a muscle lengthens as it is being stimulated
to develop tension.
The direction of joint motion is opposite that of
the net muscle torque.
The eccentric tension acts as a braking
mechanism to control movement speed.
E.g. without the presence of eccentric tension in
muscles, the forearms, hand, & weight would drop
uncontrolled because of the force of gravity.
30
31. Concentric
Eccentric
Isometric
Muscular tension is developed but no change in
muscle length.
Opposing torque at the joint crossed by the
muscle is equal to the torque produced by the
muscle (with zero net torque present),
◦ Muscle length remains unchanged & no
movement occurs at the joint.
31
34. Agonist
Prime mover.
When a muscle contracts & causes movement of a
body segment at a joint.
E.g.
◦ During the elbow flexion phase of a forearm
curl, the brachialis & the biceps brachii act as
the primary agonist, with the
brachioradialis, extensor carpi radialis longus, &
pronator teres serving as assistant agonist.
34
35. Antagonist
Muscle with actions opposite those of the agonist
act.
Opposers by developing eccentric tension at the
same time that the agonists are causing movement.
Agonists & antagonists are typically positioned on
opposite sides of a joint.
E.g.
◦ During elbow flexion when the brachialis & the
biceps brachii are primary agonists, the triceps
could act as antagonists by developing resistive
tension.
35
36. Stabilizers
Stabilizing a portion of the body against a
particular force.
◦ The force may be internal, from tension in other
muscles, or external, such as the weight of an
object being lifted.
E.g.
◦ The rhomboids act as stabilizers by developing
tension to stabilize the scapulae against the pull
of the tow rope during water skiing, or on tugof-war event.
36
37. Neutralizer
Neutralizers muscle prevent unwanted accessory
actions that normally occur when agonists develop
concentric tension.
E.g.
◦ When the biceps brachii develops concentric
tension, it produces both flexion at the elbow &
supination of the forearm. If only elbow flexion
is desired, the pronator teres act as a
neutralizer to counteract the supination of the
forearm.
Performance of human movements typically
involves the cooperative actions of many muscle
groups acting sequentially & in concert.
37
38. Factors Affecting Muscular Force
Generation
The magnitude of the force generated by muscle
is also related to:
Velocity of muscle shortening
Length of the muscle when it is stimulated
Period of time since the muscle received a
stimulus
Factors affecting:
Force-Velocity relationship
Length-Tension Relationship
Electromechanical Delay (EMD)
38
39. Force-Velocity Relationship for muscle tissue
When the resistance (force) is negligible, muscle
contracts with maximal velocity.
As the load progressively increases, concentric contraction
velocity slows to zero at isometric maximum.
As the load increases further, the muscle lengthens
eccentrically.
Maximall
y
activated
muscle
FVR does NOT imply that it is impossible to move a
heavy resistance at a fast speed.
The stronger a muscle, the greater the magnitude of
maximum isometric tension
FVR also does NOT imply that it is impossible to move
a light load at a slow speed.
39
40. Length-Tension Relationship
The total tension present in a stretched muscle is
the sum of the active tension provided by the
muscle fibers & the passive tension provided by
the tendons & muscle membranes.
Total tension = active tension (muscle fibers) + passive tension (tendons &
muscle membranes)
Within the human body, force generation capability
increases when the muscle is lightly stretched.
Parallel-fibered muscles produce maximum tensions at just
over resting length.
Pennate-fibered muscles generate maximum tension at
between 120% & 130% of resting length.
This phenomenon is due to the contribution of the elastic
components of muscle (primarily the SEC), which add to
the tension present in the muscle when the muscle is
stretched.
40
41. Electromechanical Delay (EMD)
When a muscle is stimulated, a brief period of time
elapse before the muscle begins to develop tension.
ED- time between the arrival of neural stimulus and
tension development by the muscle
41
42. EMD where the period of time is believed to be needed
for the contractile component of the muscle to stretch
the SEC.
During this time, muscle laxity is eliminated.
Once the SEC is sufficiently stretched, tension
development proceeds.
Researchers have found shorter EMDs produced by
muscles with high percentages of FT fibers as compared
to muscles with high percentages of ST fibers.
42
43. Muscular Strength, Power & Endurance
Muscular Strength
The maximum amount of force a muscle can
produce in a single effort
Muscular Power
The product of muscular force and the
velocity of muscle shortening
Muscular Endurance
The ability of a muscle to exert a sub-maximal
force repeatedly over time
43
44. What is the effect of muscle temperature (warm up) ?
The speeds of nerve and muscle functions increase.
Normal body temperature
Elevated body temperature
velocity
With warm-up, there is
a shift to the right in
the force-velocity
curve, with higher
maximum isometric
tension and higher
maximum velocity of
shortening possible at a
given load.
force
44
45. Common Muscle Injuries
Strains - overstretching of muscle tissue
Contusions - compressive forces sustained during impacts
Cramps - electrolytes imbalance, deficiencies in calcium & magnesium,
dehydration
Delayed-Onset Muscle Soreness (DOMS)
◦ occurs after some period of time following
unaccustomed exercise.
◦ arises 24 – 72 hours after participation in a long or
strenuous bout of exercise.
45