CHAPTER 2: Anatomy, Posture, and Body Mechanics

00:42:32
https://www.youtube.com/watch?v=SaRqXyxVU5M

Résumé

TLDRIn this educational lecture by Teacher Jeff, the focus is on understanding human anatomy, posture, body mechanics, and ergonomics. Key points include the introduction of ergonomics, the muscle structure and functions, skeletal and muscular system functions, and how they contribute to physical support and stability. The difference between macroscopic and microscopic anatomy is explained, along with the key roles of the skeletal system such as support, protection, and movement. The lecture emphasizes the significance of maintaining good posture and the impacts of stress on posture. Additionally, it discusses biomechanics, particularly differentiating between kinematics and kinetics, and details static and dynamic muscle contractions. The importance of safe lifting techniques and the four stages involved (preparation, lifting, carrying, setting down) are highlighted, along with factors affecting static strength and proper ergonomic practices to minimize workplace injuries.

A retenir

  • 🧍 The human body is a mechanical system obeying physical laws.
  • 🗺️ Anatomy can be macroscopic or microscopic.
  • 💪 Muscles are made up of 45% of total body weight and include skeletal, cardiac, and smooth types.
  • 🦴 The skeleton supports and protects the body, facilitating movement.
  • 🧘 Postural stability (good balance) is crucial for avoiding falls.
  • 🌀 Biomechanics studies movement and includes kinematics and kinetics.
  • 📏 Factors like age, sex, and training affect static strength.
  • 📦 Proper lifting techniques involve preparation, lifting, carrying, and setting down.
  • 🪑 Ergonomic design is essential for workplace health and safety.
  • 🚫 Poor posture can lead to stress and injury.

Chronologie

  • 00:00:00 - 00:05:00

    Teacher Jeff introduces Chapter 2, which covers anatomy, posture, and body mechanics. He outlines six key areas to highlight, including ergonomics, muscle structure, skeletal systems, stability, stress, and lifting techniques. Emphasizing posture as an active process based on reflexes, he stresses the importance of understanding body mechanics for ergonomic applications.

  • 00:05:00 - 00:10:00

    Jeff further elaborates on the concept of anatomy, derived from Greek, meaning the cutting up of a body. Anatomy is divided into macroscopic and microscopic types. Macroscopic anatomy involves large structures, divided into regional, systematic, and surface anatomy. Microscopic anatomy focuses on small structures like cells and tissues. He connects anatomy to ergonomics, discussing measurements and biomechanics, including anthropometric variables like stature and reach.

  • 00:10:00 - 00:15:00

    He explains the human body as a mechanical system, where the skeleton plays an essential role. The skeleton is categorized into axial (head and trunk) and appendicular (limbs and girdles), comprising 206 bones with functions like support, movement, and protection. Jeff describes the ergonomist's role in applying anatomical principles to design ergonomic workplaces to reduce stress and improve performance.

  • 00:15:00 - 00:20:00

    Jeff introduces biomechanics, studying body movement through muscles and bones. It divides into kinematics (describing motion without forces) and kinetics (forces causing motion). Kinematics further splits into linear, angular, and general movements. Kinetics branches into statics (body at rest) and dynamics (motion changes). He transitions to discussing muscle structure, covering skeletal, cardiac, and smooth muscles, focusing on their roles in movement, posture, and blood circulation.

  • 00:20:00 - 00:25:00

    The discussion shifts to the functions of skeletal and muscular systems. Skeletal functions include support, protection, movement, and blood cell production, while muscular functions cover movement and heat production. Jeff emphasizes the integration of bones and muscles in facilitating bodily functions, highlighting the importance of posture, flexibility, and strength in maintaining stability and support in daily activities.

  • 00:25:00 - 00:30:00

    Jeff explores stability and support in professional settings, discussing the significance of ergonomic chairs and posture. Good posture is vital for balance, which can be static or dynamic. The base of support, including feet or other contact points, affects stability, and ergonomic design helps maintain balance. He stresses understanding muscle function, tension, and contraction types, highlighting static (isometric) and dynamic (isotonic) contractions in maintaining posture.

  • 00:30:00 - 00:35:00

    He addresses stress in posture, differentiating between postural stress from poor posture and task-induced stress from repetitive tasks. Both can lead to discomfort and inefficiency in the workplace. Good posture aligns body parts optimally, influencing force exertion and muscle tension. He explains strength types: static, involving constant muscle engagement without movement, and dynamic, with changing muscle tension. Factors affecting strength include age, gender, training, and motivation.

  • 00:35:00 - 00:42:32

    Jeff concludes with lifting techniques, a common cause of injury. He outlines four lifting stages: preparation, lifting, carrying, and setting down, emphasizing planning, body alignment, and rest to avoid injuries. He stresses avoiding twisting, keeping loads close, and utilizing proper handholds and personal protective equipment. Implementing rest breaks and job rotation are crucial to maintain health and motivation in tasks involving frequent or heavy lifting.

Afficher plus

Carte mentale

Mind Map

Questions fréquemment posées

  • What is the main topic of Teacher Jeff's lecture?

    The main topic is about anatomy, posture, and body mechanics with a focus on ergonomics.

  • What are the two types of anatomy discussed?

    The two types are macroscopic and microscopic anatomy.

  • What is the difference between static and dynamic muscle contraction?

    Static muscle contraction involves tension without muscle length change, while dynamic involves tension with muscle shortening or lengthening.

  • How many functions does the skeletal system have?

    The skeletal system has four major functions: support, protection, movement, and homopoiesis.

  • What are the key areas of focus mentioned in the video?

    The key areas of focus include anatomy, posture, body mechanics, muscle structure, skeletal functions, stability, stress, posture, and lifting.

  • How many bones does an adult human have?

    An adult human has 206 bones.

  • What is postural stability?

    Postural stability, or good balance, is the ability to maintain an upright position and is necessary for preventing falls.

  • What are the four stages of lifting?

    The four stages are preparation, lifting, carrying, and setting down.

  • What factors can influence static strength?

    Factors influencing static strength include age, sex, training, motivation, and medical condition.

  • How does posture affect strength?

    Posture influences a person's ability to exert force, affecting the length-tension relationship in muscles.

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Sous-titres
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Défilement automatique:
  • 00:00:01
    hi welcome to
  • 00:00:03
    i educator this is teacher jeff
  • 00:00:06
    i'm an educator and an engineer by
  • 00:00:09
    profession
  • 00:00:10
    and today we will discuss chapter two
  • 00:00:14
    and chapter 2 is all about anatomy
  • 00:00:17
    posture and body mechanics
  • 00:00:20
    now in this chapter there are six key
  • 00:00:24
    areas that i want to highlight today
  • 00:00:27
    first is the introduction to ergonomics
  • 00:00:31
    second the muscle structure and
  • 00:00:34
    functions third functions of the
  • 00:00:37
    skeletal
  • 00:00:38
    and muscular systems fourth
  • 00:00:42
    stability and support fifth
  • 00:00:45
    stress and posture and finally
  • 00:00:49
    we have lifting now according to
  • 00:00:52
    hd denison 1935
  • 00:00:56
    pasture is an active process and
  • 00:00:59
    is the result of a great number of
  • 00:01:01
    reflexes
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    many of which have its sony character
  • 00:01:06
    now it is easy to overlook the fact
  • 00:01:10
    that the human body is a mechanical
  • 00:01:13
    system
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    that obeys physical laws many of our
  • 00:01:17
    postural and balance control mechanisms
  • 00:01:21
    essential for even the most basic
  • 00:01:24
    activities
  • 00:01:25
    operate outside of conscious awareness
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    only when these mechanisms break down
  • 00:01:32
    are we reminded of our physical
  • 00:01:35
    limitations
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    an understanding of these limitations
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    is fundamental to practically
  • 00:01:43
    all applications of ergonomics
  • 00:01:46
    now what is meant by anatomy
  • 00:01:49
    anatomy comes from the greek words anna
  • 00:01:53
    which means up and so me which means
  • 00:01:56
    a cutting therefore etymologically
  • 00:02:00
    speaking
  • 00:02:01
    anatomy means the cutting up of a body
  • 00:02:05
    or simply dissection it is
  • 00:02:08
    the art of dissecting or artificially
  • 00:02:12
    separating the different parts of any
  • 00:02:15
    organized body to discover their
  • 00:02:18
    situation
  • 00:02:19
    structure and economy
  • 00:02:22
    now there are two types of anatomy
  • 00:02:25
    the first is macroscopy
  • 00:02:28
    and the second is microscopic
  • 00:02:32
    anatomy when we say macroscopic
  • 00:02:35
    anatomy this is the study of
  • 00:02:38
    large body structures it is
  • 00:02:42
    composed of three types first we have
  • 00:02:45
    the original
  • 00:02:47
    second we have systemic or systematic
  • 00:02:51
    and third we have surface anatomy
  • 00:02:55
    when there is a regional anatomy this
  • 00:02:57
    refers
  • 00:02:58
    to all structures in one particular
  • 00:03:02
    region when this is systematic
  • 00:03:05
    anatomy it refers to system
  • 00:03:08
    by system and lastly when this is
  • 00:03:12
    surface
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    anatomy it is the study of internal
  • 00:03:17
    body structures on the other hand
  • 00:03:20
    if we see microscopic anatomy
  • 00:03:24
    this is the study of very small
  • 00:03:27
    structures
  • 00:03:28
    that cannot be seen on the naked
  • 00:03:32
    eye or with the naked eye microscopic
  • 00:03:35
    anatomy is composed
  • 00:03:37
    of two types first is cytology and
  • 00:03:41
    second
  • 00:03:42
    is histology now as you can see on the
  • 00:03:45
    sample pictures
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    the difference between the two is that
  • 00:03:50
    if we say
  • 00:03:50
    cytology it is the study of
  • 00:03:53
    body cells on the other hand histology
  • 00:03:57
    is the study of
  • 00:03:59
    body tissues now physical ergonomics
  • 00:04:02
    is concerned with human anatomy
  • 00:04:06
    and human anatomy involves anthropometry
  • 00:04:10
    and biomechanics as they relate to
  • 00:04:13
    physical activities
  • 00:04:15
    if we see anthropometry this is the
  • 00:04:17
    measurements
  • 00:04:18
    of the human body and when we see
  • 00:04:21
    biomechanics
  • 00:04:23
    this is the signs of movement
  • 00:04:26
    of a living body including how muscles
  • 00:04:30
    bones tendons and ligaments
  • 00:04:33
    work together to produce movement
  • 00:04:36
    now the basic anthropometric variables
  • 00:04:40
    include forward reach
  • 00:04:43
    it also include includes stature
  • 00:04:47
    eye height elbow height
  • 00:04:50
    we have knee height forearm hand length
  • 00:04:55
    hand length and breath and we also have
  • 00:04:58
    foot length and breath now the human
  • 00:05:02
    body is
  • 00:05:03
    a mechanical system which obeys
  • 00:05:07
    physical loss design to perform
  • 00:05:10
    a variety of functions in
  • 00:05:13
    daily life the skeleton plays
  • 00:05:16
    an integral role in the body as well
  • 00:05:19
    all other parts are attached directly
  • 00:05:23
    or indirectly and there are two types or
  • 00:05:27
    three parts rather of skeleton
  • 00:05:29
    first we have the actual and second is
  • 00:05:32
    the
  • 00:05:33
    appendicular now before discussing into
  • 00:05:36
    that
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    let's discuss first the first bullet
  • 00:05:40
    which is
  • 00:05:41
    the human body is a mechanical system
  • 00:05:44
    now what do we mean by this it means
  • 00:05:47
    that the human body
  • 00:05:48
    is a biological machine made of body
  • 00:05:52
    systems
  • 00:05:53
    or group of organs that worked together
  • 00:05:57
    to produce and sustain life
  • 00:06:00
    and when we say the skeleton plays an
  • 00:06:03
    integral role
  • 00:06:04
    in the body you need to take note that
  • 00:06:07
    skeletal system
  • 00:06:09
    is composed of bones and cartilages
  • 00:06:13
    and there are two types of skeleton as
  • 00:06:16
    mentioned earlier
  • 00:06:17
    we have the actual and we have
  • 00:06:20
    appendicular
  • 00:06:21
    the difference between the two is that
  • 00:06:24
    when we say actual
  • 00:06:25
    it consists of the bones of the head
  • 00:06:28
    and trunk and when we say appendicular
  • 00:06:32
    it consists of the bones within the
  • 00:06:35
    limbs
  • 00:06:36
    as well as supporting pectoral and
  • 00:06:38
    pelvic
  • 00:06:39
    girdles now take note that there are 206
  • 00:06:44
    bones in an adult human body
  • 00:06:47
    and the place at which two bones are
  • 00:06:50
    fitted
  • 00:06:50
    together is called the joint or
  • 00:06:53
    the articulation joints are supported by
  • 00:06:58
    cartilages and reinforced with
  • 00:07:01
    ligaments now the functions of skeletal
  • 00:07:04
    system
  • 00:07:04
    are mechanical support movement
  • 00:07:08
    protection blood cell production
  • 00:07:12
    calcium storage endocrine regulation
  • 00:07:16
    and this being said what is then the
  • 00:07:18
    function of
  • 00:07:19
    an ergonomist now the function of an
  • 00:07:22
    ergonomist
  • 00:07:23
    is to use the principles of anatomy
  • 00:07:27
    and biomechanics to design the working
  • 00:07:30
    environment in order to minimize
  • 00:07:33
    induced stress preserve health and
  • 00:07:37
    improve performance now in the earliest
  • 00:07:40
    part
  • 00:07:40
    of the presentation we discussed that
  • 00:07:43
    anatomy
  • 00:07:44
    is associated with two disciplines
  • 00:07:48
    especially in terms of ergonomics
  • 00:07:51
    and these disciplines are anthropometry
  • 00:07:54
    and biomechanics
  • 00:07:56
    and we learn that anthropometry is the
  • 00:07:59
    measurement
  • 00:07:59
    of the human body at this point
  • 00:08:03
    we will try to dive deeper about what
  • 00:08:06
    biomechanics is and what the two major
  • 00:08:10
    parts of biomechanics
  • 00:08:12
    are if we say biomechanics it is the
  • 00:08:15
    signs
  • 00:08:16
    of movement of a living body including
  • 00:08:19
    how
  • 00:08:20
    muscles bones tendons and ligaments
  • 00:08:24
    work together to produce movement
  • 00:08:27
    biomechanics is divided into two
  • 00:08:30
    major parts first we have kinematics
  • 00:08:34
    and second we have kinetics when there
  • 00:08:37
    is a kinematics
  • 00:08:38
    it describes the motion of a body
  • 00:08:42
    without reference to the forces causing
  • 00:08:45
    it
  • 00:08:46
    it also examines how when
  • 00:08:49
    and where a body moves movement
  • 00:08:52
    may be linear angular or a combination
  • 00:08:56
    of
  • 00:08:56
    both or what we call general
  • 00:09:00
    on the other hand if we say kinetics
  • 00:09:03
    it examines the causes of motion
  • 00:09:06
    the internal and external forces that
  • 00:09:10
    cause
  • 00:09:10
    motion or cause a body to remain at rest
  • 00:09:14
    and the interactions between these
  • 00:09:17
    forces
  • 00:09:18
    and there are two branches of kinetics
  • 00:09:21
    first we have statics and second
  • 00:09:24
    we have dynamics
  • 00:09:27
    as mentioned earlier there are
  • 00:09:30
    [Music]
  • 00:09:31
    three different types of kinematics we
  • 00:09:36
    have
  • 00:09:36
    linear angular and general
  • 00:09:40
    now the difference between the three is
  • 00:09:42
    that
  • 00:09:43
    when using linear kinematic this is the
  • 00:09:46
    movement
  • 00:09:47
    of a body in a straight line
  • 00:09:50
    or along a straight pathway
  • 00:09:54
    and releasing angular this is when
  • 00:09:57
    a body or part of a body moves
  • 00:10:00
    in a circle or part of a circle about a
  • 00:10:04
    point
  • 00:10:05
    and when we say general this is a
  • 00:10:08
    combination
  • 00:10:09
    of linear and angular motion
  • 00:10:13
    and next we have kinetics like
  • 00:10:16
    mentioned earlier kinetics is divided
  • 00:10:19
    into
  • 00:10:20
    two types we have statics and we also
  • 00:10:23
    have
  • 00:10:23
    dynamics and the difference between the
  • 00:10:26
    two
  • 00:10:26
    is that when this is statics it refers
  • 00:10:30
    to a situation where the body or object
  • 00:10:34
    remains at rest or is moving at a
  • 00:10:37
    constant speed
  • 00:10:38
    in a state of equilibrium equilibrium
  • 00:10:42
    is a balanced state in which there is no
  • 00:10:46
    acceleration on the other hand dynamics
  • 00:10:50
    deals with the changes in motion
  • 00:10:54
    brought on by the unbalanced forces
  • 00:10:58
    now the second key area that i'm gonna
  • 00:11:00
    be discussing today
  • 00:11:02
    that would be muscle structure and
  • 00:11:04
    function
  • 00:11:06
    okay when we say muscle structure and
  • 00:11:08
    function
  • 00:11:09
    take note that muscles make up to 45
  • 00:11:14
    of the total body weight human body
  • 00:11:17
    consists of more than
  • 00:11:19
    600 muscles and there are
  • 00:11:22
    also three classifications of muscles
  • 00:11:26
    we have skeletal muscles we have cardiac
  • 00:11:29
    muscles
  • 00:11:30
    and we also have smooth muscles
  • 00:11:34
    whether it is skeletal muscles these are
  • 00:11:36
    connected to the bones
  • 00:11:38
    and provide the forces and movement
  • 00:11:41
    needed to carry out
  • 00:11:43
    external tasks on the other hand
  • 00:11:46
    we have cardiac muscle
  • 00:11:49
    cardiac muscles are integral parts of
  • 00:11:52
    the heart
  • 00:11:53
    and help it to pump out the blood for
  • 00:11:57
    circulation and the last classification
  • 00:12:01
    of muscle
  • 00:12:01
    is called smooth muscles smooth muscles
  • 00:12:05
    are connected
  • 00:12:06
    to internal organs such as stomach
  • 00:12:10
    intestines blood vessels etc
  • 00:12:14
    and the next key area that i'm gonna be
  • 00:12:17
    discussing to you today that would be
  • 00:12:19
    functions of skeletal and muscular
  • 00:12:23
    system now there are four major
  • 00:12:26
    functions of skeletal
  • 00:12:28
    system these are support
  • 00:12:31
    protection movements and homo prices
  • 00:12:36
    when we say support the most apparent
  • 00:12:40
    functions of the skeletal system are the
  • 00:12:43
    growth
  • 00:12:43
    functions those visible by
  • 00:12:46
    observations simply by looking at a
  • 00:12:50
    person
  • 00:12:51
    you can actually see how the bones
  • 00:12:53
    support
  • 00:12:55
    facilitate movement and protect the
  • 00:12:58
    human body
  • 00:12:59
    just as the steel beams of a building
  • 00:13:02
    provide a scaffold to support its weight
  • 00:13:06
    the bones and the cartilage of your
  • 00:13:08
    skeletal system
  • 00:13:10
    compose the scaffold that supports
  • 00:13:13
    the rest of your body without the
  • 00:13:15
    skeletal system
  • 00:13:17
    you would be a limb mass of organs
  • 00:13:20
    muscles and skin now
  • 00:13:23
    the other function of skeletal system is
  • 00:13:26
    called
  • 00:13:27
    protection bones also protect
  • 00:13:30
    internal organs from injury
  • 00:13:33
    by covering or surrounding them for
  • 00:13:36
    example
  • 00:13:37
    your rims protect your lungs and heart
  • 00:13:42
    the bones of your vertebral column or
  • 00:13:44
    spine
  • 00:13:45
    protect your spinal cord and the bones
  • 00:13:48
    of your cranium is called
  • 00:13:51
    protect your brain okay
  • 00:13:54
    another function that we have is
  • 00:13:57
    movement
  • 00:13:58
    function bones also facilitate
  • 00:14:01
    movement by serving as points of
  • 00:14:04
    attachment for your muscles
  • 00:14:06
    while some bones only serve as a support
  • 00:14:09
    for the muscles
  • 00:14:11
    others also transmit the forces produced
  • 00:14:14
    when your muscles
  • 00:14:15
    contract from a mechanical point of view
  • 00:14:19
    bones act as levers and joints serve as
  • 00:14:22
    fulcrums unless a muscle spans a joint
  • 00:14:26
    or contracts
  • 00:14:28
    a bone is not going to move
  • 00:14:31
    and the last function of skeletal system
  • 00:14:34
    is called homophosis the process of
  • 00:14:37
    homopoisons takes place
  • 00:14:40
    in the red bone marrow which is a soft
  • 00:14:43
    network of reticular connective tissue
  • 00:14:47
    that borders on white blood capillaries
  • 00:14:50
    called sinocytes here certain bones
  • 00:14:54
    produce
  • 00:14:54
    red blood cells in their mario
  • 00:14:58
    on the other hand we have muscular
  • 00:15:01
    system
  • 00:15:02
    remember that our muscles play a vital
  • 00:15:05
    part
  • 00:15:06
    in every function of the body the now
  • 00:15:09
    the muscular system is made up of
  • 00:15:12
    600 muscles and these include
  • 00:15:15
    three muscle types we have smooth
  • 00:15:19
    skeletal and cardiac
  • 00:15:22
    and the first function of muscular
  • 00:15:24
    system is
  • 00:15:26
    mobility it produces movement of
  • 00:15:29
    the body or body parts when using
  • 00:15:32
    mobility
  • 00:15:33
    your skeletal muscles are responsible
  • 00:15:36
    for
  • 00:15:36
    the movements you make skeletal muscles
  • 00:15:39
    are
  • 00:15:40
    attached to your bones and partly
  • 00:15:42
    controlled by the central
  • 00:15:44
    nervous system your skeletal muscles
  • 00:15:48
    also control posture which happens to be
  • 00:15:52
    the second function of your muscular
  • 00:15:55
    system
  • 00:15:56
    take note that flexibility and strength
  • 00:15:59
    are keys to maintaining proper posture
  • 00:16:03
    stiff neck muscles weak back muscles
  • 00:16:06
    or side hip muscles can throw off
  • 00:16:10
    your alignment poor posture can affect
  • 00:16:13
    parts of your body and lead to joint
  • 00:16:16
    pain and weaker muscles these parts
  • 00:16:19
    include your shoulders
  • 00:16:21
    your spines your hips and
  • 00:16:24
    your knees and the last function of
  • 00:16:28
    muscular system
  • 00:16:30
    is heat production muscle cell
  • 00:16:33
    produce heat as a byproduct
  • 00:16:36
    and are important mechanisms for
  • 00:16:39
    maintaining body temperature
  • 00:16:43
    okay so these are the functions of your
  • 00:16:46
    skeletal
  • 00:16:47
    and muscular systems and just a brief
  • 00:16:49
    recap
  • 00:16:50
    your skeletal system has four functions
  • 00:16:54
    you have support protection movement
  • 00:16:57
    and homo process and on the other hand
  • 00:17:00
    your muscular system is composed of
  • 00:17:03
    three
  • 00:17:04
    functions you have
  • 00:17:07
    movement posture and heat
  • 00:17:10
    production okay this is an example
  • 00:17:13
    of your skeletal system and this is
  • 00:17:17
    also your muscular system
  • 00:17:21
    okay the next key area that i'm gonna be
  • 00:17:24
    highlighting today
  • 00:17:26
    that would be stability and support
  • 00:17:29
    now we cannot deny the fact that people
  • 00:17:32
    spend one third of their professional
  • 00:17:35
    lives
  • 00:17:36
    sitting on their word chairs anyone who
  • 00:17:39
    performs
  • 00:17:40
    shellus or repetitive tasks in the
  • 00:17:43
    workplace
  • 00:17:44
    needs a chair that will provide them
  • 00:17:47
    with proper
  • 00:17:48
    support now the chairs that we should be
  • 00:17:51
    using can be adapted to any working
  • 00:17:54
    situation
  • 00:17:56
    and provide excellent stability and
  • 00:17:58
    support
  • 00:17:59
    yet they should not restrict freedom
  • 00:18:02
    of movement now when we say stability
  • 00:18:06
    and support
  • 00:18:07
    a stable posture can be maintained
  • 00:18:11
    only if the various body parts
  • 00:18:14
    are supported and maintained in an
  • 00:18:17
    appropriate relation to the base of
  • 00:18:20
    support such as the feet or the squat
  • 00:18:24
    of the feet now what do we mean by this
  • 00:18:28
    take note the postural stability
  • 00:18:31
    is also known as good balance
  • 00:18:34
    and remember the postural stability is
  • 00:18:37
    the ability
  • 00:18:38
    to maintain an upright position
  • 00:18:42
    without postural stability or good
  • 00:18:44
    balance
  • 00:18:45
    we make ourselves prone to false
  • 00:18:48
    and potential injuries postural
  • 00:18:52
    stability
  • 00:18:52
    comes in two forms we have static
  • 00:18:56
    postural stability and second we have
  • 00:18:59
    dynamic postural stability the
  • 00:19:02
    difference between the two
  • 00:19:04
    is that static postural stability is
  • 00:19:07
    when you are standing
  • 00:19:09
    and not moving on the other hand
  • 00:19:13
    dynamic postural stability is when you
  • 00:19:15
    are
  • 00:19:16
    moving or doing specific movements
  • 00:19:20
    though you may not realize it and pretty
  • 00:19:23
    sure you are
  • 00:19:24
    doing or the other right now even when
  • 00:19:27
    you are sitting down
  • 00:19:28
    watching this video you are doing some
  • 00:19:31
    form of
  • 00:19:32
    postural stability on the other hand
  • 00:19:36
    the size of the base of support
  • 00:19:39
    determines the stability and posture
  • 00:19:43
    now if we say base of support or bos
  • 00:19:47
    it refers to the area beneath
  • 00:19:50
    an object or a person that includes
  • 00:19:54
    every point of contact that the object
  • 00:19:57
    or person
  • 00:19:58
    makes with a supporting surface these
  • 00:20:01
    points of contact may be the body parts
  • 00:20:04
    for example
  • 00:20:06
    the feet or in the hands or they may
  • 00:20:09
    include
  • 00:20:09
    things like crutches or the chair
  • 00:20:12
    a person is sitting in now the base of
  • 00:20:15
    support is an important
  • 00:20:17
    concept to an individual's
  • 00:20:20
    ability to balance as balance
  • 00:20:24
    is defined as the ability to maintain
  • 00:20:27
    the line of gravity within the base of
  • 00:20:31
    support and also it is
  • 00:20:34
    important to provide sufficient space
  • 00:20:38
    around standing operators and plenty of
  • 00:20:41
    room
  • 00:20:42
    for the feet to avoid losses of
  • 00:20:45
    balance okay so the next
  • 00:20:49
    um we have some aspects of muscle
  • 00:20:52
    functions and the first aspect of muscle
  • 00:20:55
    function
  • 00:20:56
    the function of skeletal muscle is to
  • 00:20:59
    exert
  • 00:21:00
    tension between the body points
  • 00:21:03
    to which they are attached now what do
  • 00:21:06
    we mean by this
  • 00:21:07
    we need to take note that these body
  • 00:21:10
    points
  • 00:21:11
    refer to your tendons where our muscles
  • 00:21:14
    are attached
  • 00:21:16
    to and these tendons maintain our muscle
  • 00:21:20
    under constant level of stretch called
  • 00:21:23
    the resting
  • 00:21:24
    length also tension is exerted
  • 00:21:29
    when a muscle changes from its resting
  • 00:21:32
    to its active state in response to
  • 00:21:36
    impulses
  • 00:21:37
    from the central nervous system
  • 00:21:40
    this means that if we tend to move our
  • 00:21:43
    muscles
  • 00:21:44
    from static state or stationary
  • 00:21:47
    to dynamic state or moving it is
  • 00:21:50
    then that tension is being exerted
  • 00:21:54
    because our muscles are just responding
  • 00:21:58
    to the impulses from the central
  • 00:22:01
    nervous system and the last aspect of
  • 00:22:04
    muscle function
  • 00:22:05
    we have muscle contraction
  • 00:22:09
    the physiological active state of the
  • 00:22:11
    muscle
  • 00:22:12
    rather than its physiological shortening
  • 00:22:16
    now what we mean about this is that
  • 00:22:19
    muscle contraction
  • 00:22:20
    is the activation of tension generating
  • 00:22:24
    sites within muscle fibers in physiology
  • 00:22:28
    muscle contraction does not necessarily
  • 00:22:31
    mean
  • 00:22:32
    muscle shortening because
  • 00:22:35
    it can be produced without changes in
  • 00:22:38
    muscle length
  • 00:22:39
    such as when holding a heavy book or
  • 00:22:43
    a dumbbell at the same position
  • 00:22:46
    and aside from that the termination of
  • 00:22:48
    muscle contraction
  • 00:22:50
    is followed by muscle relaxation
  • 00:22:53
    which is a return of the muscle fibers
  • 00:22:56
    to their low tension generating state
  • 00:23:00
    now there are two types of muscle
  • 00:23:02
    contraction
  • 00:23:04
    we have the static or isometric
  • 00:23:07
    contraction
  • 00:23:08
    and the second is dynamic or
  • 00:23:11
    isotonic contraction take note that
  • 00:23:15
    muscle contractions can be described
  • 00:23:18
    based on two variables first we have the
  • 00:23:21
    length
  • 00:23:22
    and second we have tension now
  • 00:23:25
    a muscle contraction is described as
  • 00:23:28
    static or isometric
  • 00:23:30
    if the muscle tension changes but
  • 00:23:34
    the muscle length remains the same again
  • 00:23:37
    i would like to reiterate a muscle
  • 00:23:40
    contraction
  • 00:23:41
    is described as static or isometric
  • 00:23:45
    if and only if the muscle tensions
  • 00:23:48
    changes but the muscle length remains
  • 00:23:52
    the same as you can see in the sample
  • 00:23:55
    image
  • 00:23:56
    the muscle contracts but does not change
  • 00:23:59
    length so technically speaking there is
  • 00:24:03
    no
  • 00:24:04
    movement in contrary a muscle
  • 00:24:07
    contraction
  • 00:24:08
    is described as dynamic or isotonic
  • 00:24:12
    if muscle tension remains the same
  • 00:24:15
    throughout the contraction
  • 00:24:19
    now if the muscle length shortens
  • 00:24:22
    then the contraction is called
  • 00:24:25
    concentric
  • 00:24:26
    on the other hand if the muscle length
  • 00:24:29
    lengthens then the contraction is called
  • 00:24:33
    e-centric now as you can see on the
  • 00:24:35
    sample
  • 00:24:36
    image presented this is an example
  • 00:24:39
    of dynamic or isotonic contraction
  • 00:24:44
    for the bicep side it is an example of
  • 00:24:46
    isotonic
  • 00:24:48
    concentric contraction concentric
  • 00:24:51
    because as you can notice the muscle
  • 00:24:54
    length
  • 00:24:55
    shortens okay and next
  • 00:24:58
    key area that we're gonna be discussing
  • 00:25:01
    right now
  • 00:25:02
    that would be stress or posture
  • 00:25:05
    now we all know that stress is a feeling
  • 00:25:09
    of emotional or physical tension
  • 00:25:12
    right it can come from any event
  • 00:25:16
    or thought that makes us feel nervous
  • 00:25:19
    angry or even frustrated in short
  • 00:25:23
    this is our body's reaction to a
  • 00:25:26
    challenge
  • 00:25:27
    or demand when we say postural stress
  • 00:25:31
    it refers to the mechanical load
  • 00:25:34
    on body by virtue of its posture
  • 00:25:38
    or the average orientation of the body
  • 00:25:41
    parts
  • 00:25:42
    with respect to each other over time
  • 00:25:45
    in other words it refers to bodily
  • 00:25:48
    stress
  • 00:25:49
    as a result of poor posture repetitive
  • 00:25:53
    movements
  • 00:25:54
    or prolonged time in the same positions
  • 00:25:58
    now as you can see on the sample figure
  • 00:26:01
    the man is having a slumps posture
  • 00:26:04
    he is slumping downward which can
  • 00:26:06
    contribute
  • 00:26:07
    to stable syndrome
  • 00:26:10
    now there these are another examples of
  • 00:26:14
    postural stress okay as you can see
  • 00:26:18
    each of them is in different
  • 00:26:20
    workstations
  • 00:26:22
    and as you can notice each of them is
  • 00:26:25
    clearly
  • 00:26:25
    uncomfortable with a workstation
  • 00:26:28
    resulting to poor
  • 00:26:29
    and inefficient posture
  • 00:26:32
    this usually happens whenever the chairs
  • 00:26:35
    and tables
  • 00:26:36
    we are using are not ergonomically
  • 00:26:39
    designed
  • 00:26:41
    on the other hand if we say task induced
  • 00:26:44
    stress
  • 00:26:45
    it refers to the results
  • 00:26:49
    from the performance of the task itself
  • 00:26:52
    for example
  • 00:26:54
    repetitive movement of wrist or
  • 00:26:57
    fingers now we cannot deny the fact that
  • 00:27:00
    there are
  • 00:27:00
    certain jobs that are really demanding
  • 00:27:03
    and jobs like these can contribute to
  • 00:27:06
    employees stress
  • 00:27:08
    and so for this matter coping is an
  • 00:27:11
    important
  • 00:27:12
    aspect of the operator's stress
  • 00:27:15
    in fact operators use a variety of
  • 00:27:18
    techniques
  • 00:27:19
    in dealing with potentially stressful
  • 00:27:22
    task demand
  • 00:27:24
    as you can see on the sample pictures
  • 00:27:26
    presented
  • 00:27:29
    these are examples of task induced
  • 00:27:31
    stress
  • 00:27:32
    as these drugs show repetitive movement
  • 00:27:36
    of wrists or fingers all right so these
  • 00:27:39
    are
  • 00:27:40
    the difference between pastoral stress
  • 00:27:43
    and task induced stress and so for this
  • 00:27:47
    matter
  • 00:27:48
    if we say posture it is defined
  • 00:27:51
    as the orientation of the body
  • 00:27:54
    and its part in relation to each
  • 00:27:58
    other it has also considerable
  • 00:28:01
    influence on a person's ability to exert
  • 00:28:05
    force and lastly it affects the length
  • 00:28:09
    tension relationship now examples
  • 00:28:13
    of posture as you can see in the sample
  • 00:28:16
    figures it is poor posture
  • 00:28:19
    if you have forward hands flat back
  • 00:28:23
    sway back rounded shoulders
  • 00:28:26
    and weak abdominal muscles therefore
  • 00:28:30
    having a good posture means having a
  • 00:28:33
    balanced
  • 00:28:35
    upright posture
  • 00:28:38
    and next we have strength and strength
  • 00:28:41
    is divided
  • 00:28:42
    into two types we have static or
  • 00:28:45
    isometric strength and second we have
  • 00:28:49
    dynamic or isotonic strength now if we
  • 00:28:52
    say static strength
  • 00:28:54
    this refers to the maximum study force
  • 00:28:57
    or
  • 00:28:58
    torque which an individual can exert
  • 00:29:01
    in static exertion of short duration
  • 00:29:05
    which is three to five seconds
  • 00:29:08
    this is also known as the maximum
  • 00:29:11
    voluntary
  • 00:29:12
    contraction or mvc
  • 00:29:15
    in short this is a contraction of
  • 00:29:18
    a particular muscle for an extended
  • 00:29:22
    period of time simply put a static
  • 00:29:25
    strength
  • 00:29:26
    is one that involves muscle engagement
  • 00:29:29
    without movement okay
  • 00:29:32
    the static strength the following are
  • 00:29:35
    the factors
  • 00:29:36
    that influence strength or
  • 00:29:39
    the influence static strength and the
  • 00:29:42
    first
  • 00:29:43
    factor which influences
  • 00:29:46
    static strength is what we call the age
  • 00:29:50
    now how come age is considered
  • 00:29:53
    as one of the factors that influences
  • 00:29:56
    strength now age is one of the factors
  • 00:29:59
    that
  • 00:30:00
    influences static strength because
  • 00:30:03
    strength decreases with age
  • 00:30:07
    next we have sex or gender
  • 00:30:10
    sex or gender influences static strength
  • 00:30:14
    in a way that females on average
  • 00:30:17
    have less muscular strength compared to
  • 00:30:21
    males
  • 00:30:22
    also training influences strength
  • 00:30:26
    since training can improve muscular
  • 00:30:29
    strength
  • 00:30:30
    motivation on the other hand is one
  • 00:30:33
    factor
  • 00:30:34
    which influences strength since under
  • 00:30:37
    highly
  • 00:30:38
    motivated condition a person can
  • 00:30:41
    improve strength and finally
  • 00:30:44
    medical condition influences strength
  • 00:30:47
    since illness time of the day
  • 00:30:51
    sleep deprivation and nutrition
  • 00:30:54
    can diminish your strength alright so
  • 00:30:58
    these
  • 00:30:58
    are the factors that influence
  • 00:31:01
    static strength on the other hand we
  • 00:31:04
    have
  • 00:31:05
    dynamic strength and when we say dynamic
  • 00:31:08
    strength
  • 00:31:09
    and like static strength it is difficult
  • 00:31:12
    to define
  • 00:31:13
    due to the following factors absolute
  • 00:31:16
    acceleration velocity
  • 00:31:20
    impulse movement jerk effects on force
  • 00:31:24
    exerted by a muscle and muscle length
  • 00:31:27
    changes with joint motion
  • 00:31:31
    strength can be measured under two
  • 00:31:34
    conditions
  • 00:31:35
    first we have constant velocity or iso
  • 00:31:39
    velocity
  • 00:31:40
    using isokinetic devices just like
  • 00:31:43
    as you can see on the sample image and
  • 00:31:46
    the second
  • 00:31:47
    way to measure dynamic strength though
  • 00:31:50
    would be through
  • 00:31:51
    constant force or isotonic where force
  • 00:31:54
    is
  • 00:31:55
    kept constant okay that ends
  • 00:31:58
    our discussion for the posture
  • 00:32:03
    key area okay the next key area that i'm
  • 00:32:06
    gonna be highlighting to you today
  • 00:32:09
    that would be lifting
  • 00:32:12
    and this is the final and the last key
  • 00:32:15
    area
  • 00:32:16
    for today's lesson now lifting heavy
  • 00:32:19
    items
  • 00:32:20
    is one of the leading causes of injury
  • 00:32:24
    in the workplace now in 2001
  • 00:32:28
    the bureau of labor statistics in united
  • 00:32:31
    states
  • 00:32:32
    reported that over 36 percent
  • 00:32:36
    again over 36 of
  • 00:32:39
    injuries involving missed workdays
  • 00:32:43
    where the result of shoulder and back
  • 00:32:46
    injuries the biggest factors of these
  • 00:32:50
    injuries are over exertion and
  • 00:32:53
    cumulative trauma when employees
  • 00:32:56
    use smart lifting practices
  • 00:33:00
    and work in their power zone they are
  • 00:33:02
    less likely to suffer
  • 00:33:04
    back sprains muscle pulls wrist
  • 00:33:07
    injuries elbow injuries
  • 00:33:10
    spinal injuries and other injuries
  • 00:33:14
    caused by lifting heavy objects now
  • 00:33:17
    let's
  • 00:33:18
    go ahead and take a look at our lifting
  • 00:33:22
    principles
  • 00:33:23
    now as you can see on the slides there
  • 00:33:26
    are four stages
  • 00:33:27
    in lifting first we have preparation
  • 00:33:31
    second we have lifting third we have
  • 00:33:34
    carrying and lastly we have
  • 00:33:38
    setting down now when we say uh
  • 00:33:41
    lifting when we say preparation rather
  • 00:33:44
    this is the first stage in lifting and
  • 00:33:47
    before lifting or carrying you should
  • 00:33:50
    plan out your
  • 00:33:52
    lift first you should think about
  • 00:33:55
    how heavy or awkward is the load
  • 00:33:58
    with this we should ask ourselves
  • 00:34:02
    should we use mechanical means like
  • 00:34:05
    hand trucks or another person to help us
  • 00:34:09
    with this left or is it possible to
  • 00:34:12
    break the load
  • 00:34:13
    into smaller parts next
  • 00:34:17
    we should also think about where we are
  • 00:34:20
    going with the load and so we ask
  • 00:34:23
    ourselves
  • 00:34:24
    is the path clear of obstructions
  • 00:34:28
    slippery areas overhangs
  • 00:34:31
    stairs and other and even services
  • 00:34:35
    are there closed doors that need to be
  • 00:34:38
    opened and lastly we should also
  • 00:34:41
    think about if there are adequate
  • 00:34:44
    handholds on the loan and so for this
  • 00:34:47
    matter
  • 00:34:48
    we should be asking ourselves do we need
  • 00:34:51
    gloves
  • 00:34:52
    or other personal protective equipment
  • 00:34:57
    can we place the load in a container
  • 00:34:59
    with better handholds
  • 00:35:01
    or should another person help us with
  • 00:35:04
    the loan
  • 00:35:05
    okay this is all preparation
  • 00:35:09
    after having prepared
  • 00:35:13
    the next stage that would be lifting
  • 00:35:17
    before lifting the material or the load
  • 00:35:20
    itself
  • 00:35:21
    we need to get as close to the load as
  • 00:35:24
    possible
  • 00:35:25
    we need to keep our elbows and arms
  • 00:35:28
    close to our
  • 00:35:29
    body also we need to keep our back shape
  • 00:35:33
    during the lift by tightening the
  • 00:35:35
    stomach muscles
  • 00:35:37
    bending at the knees keeping the load
  • 00:35:40
    close
  • 00:35:41
    and centered in front of us and looking
  • 00:35:45
    up and ahead we should get a good
  • 00:35:47
    handhold
  • 00:35:48
    and do not twist while lifting we should
  • 00:35:51
    not jerk
  • 00:35:52
    and instead we should use a smooth
  • 00:35:55
    motion
  • 00:35:55
    while lifting and lastly if the load is
  • 00:35:59
    too heavy to allow this
  • 00:36:01
    we should find someone else or we should
  • 00:36:03
    find
  • 00:36:04
    someone maybe a co-worker or a
  • 00:36:07
    co-employee
  • 00:36:08
    to help us with the lift so after
  • 00:36:11
    preparing
  • 00:36:13
    after lifting now it's time for you to
  • 00:36:16
    carry the material or load
  • 00:36:19
    and this is going to be the third stage
  • 00:36:22
    of
  • 00:36:23
    lifting and it is called carrying in
  • 00:36:26
    carrying the material or load
  • 00:36:28
    we have some important pointers
  • 00:36:32
    to remember first
  • 00:36:35
    do not twist or turn the body
  • 00:36:38
    instead move your feet to turn
  • 00:36:41
    and second your hips shoulders
  • 00:36:45
    toes and knees should stay facing the
  • 00:36:49
    same
  • 00:36:50
    direction and next
  • 00:36:53
    keep the load as close to your body as
  • 00:36:56
    possible
  • 00:36:57
    with your elbows close to your side
  • 00:37:00
    and lastly if you feel fatigued
  • 00:37:04
    you need to set the load down and rest
  • 00:37:07
    for a few minutes
  • 00:37:09
    do not let yourself get so fatigued that
  • 00:37:12
    you cannot perform
  • 00:37:13
    proper setting down and lifting
  • 00:37:16
    technique
  • 00:37:16
    for your rest okay and the last stage
  • 00:37:21
    in lifting we have what we call
  • 00:37:24
    setting down in setting down we need to
  • 00:37:27
    set
  • 00:37:28
    the load in the same way we picked it up
  • 00:37:31
    but in the reverse order when we say
  • 00:37:34
    reverse order
  • 00:37:35
    the first thing you need to do is to
  • 00:37:37
    bend at the knees
  • 00:37:39
    not the hips keep your head up
  • 00:37:42
    your stomach muscles tight and do not
  • 00:37:46
    twist your body
  • 00:37:47
    keep the load as close to the body as
  • 00:37:49
    possible and finally
  • 00:37:51
    wait until the load is secure to release
  • 00:37:54
    your
  • 00:37:55
    handhold and we also have
  • 00:37:59
    important things to remember in lifting
  • 00:38:03
    first use mechanical means
  • 00:38:06
    when using mechanical means these are
  • 00:38:09
    hand tracks
  • 00:38:10
    push cards etc when possible
  • 00:38:13
    for every heavier or awkward loads
  • 00:38:17
    remember to obtain training and
  • 00:38:20
    authorization first before using a
  • 00:38:24
    forklift okay the second thing to
  • 00:38:27
    remember
  • 00:38:28
    it is easier and safer to push
  • 00:38:32
    than pull okay just like as you can see
  • 00:38:35
    on the sample pictures next
  • 00:38:39
    we need to keep loads as close to the
  • 00:38:42
    body as possible
  • 00:38:43
    and we should not be twisting while
  • 00:38:46
    lifting
  • 00:38:47
    carrying or setting down a load nose
  • 00:38:51
    shoulders hips and toes should all be
  • 00:38:54
    facing the same
  • 00:38:55
    direction just like as you can see on
  • 00:38:58
    the sample
  • 00:38:59
    pictures again the wrong way of doing
  • 00:39:02
    this
  • 00:39:02
    would be uh twisting your body okay that
  • 00:39:05
    should not be the proper way
  • 00:39:08
    and the next thing to remember minimize
  • 00:39:12
    reaching next we have as a general rule
  • 00:39:16
    bend at the knees not on the hips so
  • 00:39:19
    the red one the red ones are the wrong
  • 00:39:23
    way
  • 00:39:23
    of lifting and the green ones are the
  • 00:39:26
    correct
  • 00:39:27
    way of lifting just like as you can see
  • 00:39:30
    on
  • 00:39:31
    the sample pictures and
  • 00:39:34
    next we have get help when needed
  • 00:39:37
    we should not lift or carry things
  • 00:39:40
    you don't feel comfortable with no
  • 00:39:42
    matter how light
  • 00:39:44
    the load okay we should always ask for
  • 00:39:47
    help to our colleagues co-workers or
  • 00:39:51
    co-employees okay next thing to remember
  • 00:39:55
    we should plan ahead for all parts of
  • 00:39:58
    the lift
  • 00:39:59
    lifting carrying and setting down
  • 00:40:03
    just like as you can see on the sample
  • 00:40:06
    images and next important
  • 00:40:10
    thing to remember we need to try to
  • 00:40:12
    utilize
  • 00:40:13
    proper hand holds while lifting
  • 00:40:16
    if an item does not have a good handhold
  • 00:40:20
    then we should think of ways to remedy
  • 00:40:22
    this such as
  • 00:40:24
    placing the item in a container with
  • 00:40:27
    good handholds
  • 00:40:28
    creating a safe and proper handhold with
  • 00:40:31
    an
  • 00:40:32
    appropriate tool etc okay
  • 00:40:35
    example pictures these are samples
  • 00:40:38
    of materials which have handholds
  • 00:40:42
    and the next important thing to remember
  • 00:40:46
    in lifting we should use personal
  • 00:40:48
    protective
  • 00:40:49
    equipment or ppe where needed such as
  • 00:40:53
    gloves with good grip and sealed
  • 00:40:56
    boots where appropriate or you can also
  • 00:40:59
    make use
  • 00:41:00
    of a helmet or an eye protector
  • 00:41:04
    okay or or an eye shield
  • 00:41:07
    and next we have implement rest breaks
  • 00:41:11
    and job rotation
  • 00:41:13
    for frequent and or heavy lifting this
  • 00:41:16
    should be
  • 00:41:17
    properly implemented by the organization
  • 00:41:21
    because
  • 00:41:22
    if we do not provide rest breaks or job
  • 00:41:25
    relations to our
  • 00:41:26
    employee then chances are our employees
  • 00:41:30
    will get
  • 00:41:31
    demotivated okay so that results to
  • 00:41:35
    absenteeism okay next important thing to
  • 00:41:38
    remember
  • 00:41:39
    we should place items to be lifted
  • 00:41:43
    within the power zone the power zone is
  • 00:41:46
    close to the body between the mid thigh
  • 00:41:50
    and mid chest as you can see on the
  • 00:41:53
    picture
  • 00:41:53
    so you have there a danger zone
  • 00:41:57
    power zone and danger zone so as you can
  • 00:42:00
    notice
  • 00:42:01
    your power zone is located between the
  • 00:42:04
    mid thigh
  • 00:42:05
    and your mid chest of the person doing
  • 00:42:08
    the lifting
  • 00:42:09
    this is actually the area where the arms
  • 00:42:12
    and back
  • 00:42:13
    can lift the most with the least amount
  • 00:42:16
    of
  • 00:42:17
    effort all right i think that's a good
  • 00:42:20
    place to stop
  • 00:42:21
    if you like this video please don't
  • 00:42:23
    forget to subscribe
  • 00:42:25
    and hit the bell button for the latest
  • 00:42:28
    updates thank you
Tags
  • Anatomy
  • Ergonomics
  • Posture
  • Body Mechanics
  • Muscle Structure
  • Skeletal System
  • Biomechanics
  • Lifting Techniques
  • Stability
  • Strength