Level 2 Gym Instructor Manual PDF

Manual Level 2 Certificate in Gym Instructing Version AIQ005803  Introduction Gym instructors provide a key role within health and fitness settings and are considered by many as the ‘face’ of the organisation. Following a successful membersh...

Manual Level 2 Certificate in Gym Instructing Version AIQ005803  Introduction Gym instructors provide a key role within health and fitness settings and are considered by many as the ‘face’ of the organisation. Following a successful membership sale, gym instructors are normally the next person a new customer will interact with, therefore they need to be welcoming and professional, building a positive rapport and making them feel at ease. Gym instructors provide valuable technical input, therefore their knowledge and understanding of how the body reacts to exercise must be strong. This will help them to support client’s with their goals and guide them through positive behaviour change, whilst also ensuring the health and safety of all members is maintained throughout their visit. This manual aims to cover all of these areas in depth, providing you with the knowledge and understanding needed to have a successful career in the health and fitness industry. The manual is broken up into 5 units: 1. Principles of anatomy, physiology and fitness 2. Professionalism and customer care for fitness instructors 3. Health and safety in the fitness environment 4. Conducting client consultations to support positive behaviour change 5. Planning and instructing gym-based exercise Towards the back of the manual, you will find a glossary, which explains any unfamiliar terms you might come across, and a reference list of reputable sources, which identifies where the information contained within has been found. Best of luck with your studies! Active IQ wishes to emphasise that whilst every effort is made to ensure accuracy, the material contained within this document is subject to alteration or amendment in terms of overall policy, financial or other constraints. Reproduction of this publication is prohibited unless authorised by Active IQ Ltd. No part of this document should be published elsewhere or reproduced in any form without prior written permission. Copyright © 2018 Active IQ Ltd. Not for resale 00 Q2CGI Manual Book.indb 2 26/03/2018 10:27  Principles of anatomy, physiology and fitness Aim A basic understanding of anatomy and physiology in relation to exercise is essential foundation knowledge for all fitness professionals. Exercise affects all body systems. An understanding of the benefits of exercise and the demands it places on the body will help with the programming of safe and effective exercise. Learning outcomes At the end of this unit you will: ❯ Understand the skeletal system and the effects of exercise. ❯ Understand the neuromuscular system and the effects of exercise. ❯ Understand the cardiovascular and respiratory systems and the effects of exercise. ❯ Understand how energy is produced in the body and the effects of exercise on energy production. ❯ Understand the structure and function of the digestive system. ❯ Understand health and wellbeing. ❯ Understand the components of fitness and the effects of exercise. Copyright © 2018 Active IQ Ltd. Not for resale 1 00 Q2CGI Manual Book.indb 1 26/03/2018 10:27  Unit Contents Principles of anatomy, physiology and fitness Section 1: The skeletal system.......................................................................................................................................... 3 Section 2: The neuromuscular system............................................................................................................................13 Section 3: Cardiovascular and respiratory systems.......................................................................................................27 Section 4: Energy systems...............................................................................................................................................37 Section 5: The digestive system......................................................................................................................................43 Section 6: Health and wellbeing......................................................................................................................................47 Section 7: Components of fitness and special populations..........................................................................................51 Please see end of manual for Glossary and References 2 Copyright © 2018 Active IQ Ltd. Not for resale 00 Q2CGI Manual Book.indb 2 26/03/2018 10:27  The skeletal system Section 1 Section 1: The skeletal system Without the skeleton, we would be a heap of tissues all over the floor. It makes up almost one fifth of body weight to give us a flexible framework with which to move, protect and support internal and external systems. Structure of the skeleton The skeletal system can be classified as two main structures: Calcified connective tissue that forms most of the adult Bone Bone skeleton. There are around 206 bones in the body and they are connected via a series of different types of joint. Dense, durable, tough fibrous connective tissue that is able Cartilage Bone to withstand compression forces. There are three types of cartilage found in the body, each fulfilling a separate function. Principles of anatomy, physiology and fitness Types of cartilage The three types of cartilage found in the human body are: Hyaline cartilage: This is the tissue that forms the temporary skeleton of the foetus, which is eventually replaced by bone when calcium is deposited. It is found at the end of the long bones that meet to form the synovial joints. Elastic cartilage: This is similar to hyaline cartilage, except that it has more fibres and most of these are made up of elastin as opposed to collagen. Elastic cartilage has the ability to regain and return to its original shape. It is found in the ear, the walls of the Eustachian tube and the epiglottis, which are all places that require a specific shape to be maintained. Fibrocartilage: This cartilage is thicker and stronger than the other types and has limited distribution within the body. It forms various shapes depending on its role and acts like a shock absorber in cartilaginous joints. The skeleton The skeleton is split into two main sections: cranium cranium Axial skeleton cervical clavicle vertebrae scapula sternum humerus Bones that form the humerus thoracic main frame or axis: rib vertebrae The spine, ribs and lumbar vertebrae skull. ulna ilium radius sacrum pubis carpals coccyx Appendicular skeleton metacarpals phalanges ischium femur femur Bones that attach patella to the main frame (the appendages): fibula The upper and lower tibia tibia limbs, the pelvic and shoulder girdles. tarsals metatarsals phalanges Copyright © 2018 Active IQ Ltd. Not for resale 3  Section 1 The skeletal system Classification of bones Bones can be classified according to their formation and shape. Classification Description Examples Long bones Have a greater length than width. Humerus, femur, Consist of a main shaft (diaphysis) and usually two fibula, tibia, ulna, extremities (epiphysis). radius, metacarpals, metatarsals and Principally act as levers. phalanges. Contain mostly compact bone in their diaphysis. Contain more cancellous bone in their epiphyses. Short bones Normally about as long as they are wide (cube-shaped). Carpals and tarsals. Usually highly cancellous, which gives them strength with reduced weight. Flat bones Thin layer of cancellous bone sandwiched between two Scapula, cranial plate-like layers of compact bone. bones, costals (ribs), Provide protection and large areas for muscle sternum and ilium. attachment. Irregular bones Form very complex shapes and cannot be classified Vertebrae and within the previous groups. calcaneus (heel bone). Sesamoid (‘seed-like’) Develop within particular tendons at a site of Patella (kneecap). considerable friction or tension. Serve to improve leverage and protect the joint from damage. Structure of a long bone Epiphysis: This is the expanded portion located at each end of the bone. It contains the cancellous bone tissue. Articular Epiphysis (hyaline) Diaphysis: This is the shaft of the bone. It contains a cartilage thick layer of compact bone with a hollow centre (the medullary cavity). Epiphyseal plate Epiphyseal plates: These are the growth plates located between the diaphysis and epiphysis that allow the Cancellous former to increase in length until adulthood. (spongy bone) Hyaline cartilage: This covers the end of the bone (the epiphysis), where the bones meet to form joints. Periosteum: A tough, fibrous sheath covering the whole Medullary cavity Diaphysis bone. Compact bone: This is solid and strong to help the long bone withstand weight-bearing stress. Periosteum Cancellous bone: This is spongy bone tissue that contains red marrow. Flat, short and irregular bones Compact bone are formed mainly from cancellous bone. Medullary cavity: This is the hollow tube which runs down the centre of the diaphysis (the marrow cavity). Yellow marrow: This functions for the storage of fat. It is found in the medullary cavity. Red marrow: This functions in the production of Epiphysis various types of blood cell. It is found in cancellous bone tissue. 4 Copyright © 2018 Active IQ Ltd. Not for resale 00 Q2CGI Manual Book.indb 4 26/03/2018 10:27  The skeletal system Section 1 Functions of the skeletal system The skeletal system performs a range of functions. These include: The skeletal bones give the body its basic shape. Shape For example, the skull protects the brain and the ribs Protection protect the heart and lungs. Ligaments, tendons and muscles attach to bones to Attachment create stability and movement. Muscles pull on long bones to create movement, e.g. the Movement tibia and fibula are pulled backwards to flex the knee. Some bones produce red (to carry oxygen) and white (to Production fight infection) blood cells from their marrow. Principles of anatomy, physiology and fitness Bones store important minerals, such as calcium and Storage phosphorus, which support growth and development. Joints in the skeletal system A joint is the junction where two or more bones meet. Joint classification There are three main types of joint, which are classified according to potential range of movement. These include: Joint name Movement range Examples Fibrous. Fixed/immovable. Cranium (skull). Cartilaginous. Slightly moveable. Vertebrae. Synovial. Freely moveable. Ankle, knee, hip, elbow, shoulder, neck and wrist. Structure of synovial joints Joint cavity and space Synovial, freely moveable joints are the most commonly for synovial fluid Articular cartilage found in the human body; each one has the same physical characteristics to allow it to function efficiently. These characteristics are: Hyaline/articular cartilage: This covers the ends of the bones to absorb shock and prevent friction. Ligaments: These connect bone to bone to stabilise joints and align bones. Synovial membrane: This stores and secretes synovial Bursa fluid when required. Synovial fluid: This lubricates the joint during Ligament movement. Joint capsule Joint capsule: This holds all of the properties of the synovial joint in place. Joint cavity: This is the space inside the synovial joint. Tendon Tendons: These connect muscle to bone to create movement. Copyright © 2018 Active IQ Ltd. Not for resale 5  Section 1 The skeletal system A little extra on cartilage, ligaments and tendons Cartilage Cartilage is a dense, durable, tough fibrous connective tissue that is able to withstand compression forces (e.g. when jumping and running). Cartilage does not have a blood supply, so it has limited ability to repair itself. The two main types of cartilage are: Articular/hyaline cartilage. Fibrocartilage. Considerations for exercise Cartilage is dependent on regular activity for health, e.g. release of synovial fluid. Cartilage can be worn or torn, e.g. through overuse, repetitive movement (high-impact) and ageing. Ligaments Ligaments are made of tough, white, non-elastic fibrous tissue which is strung together in a cord or strap-like formation. They can withstand a lot of tension, but prolonged tension (e.g. repetitive incorrect movement patterns) will permanently damage the fibres. Ligaments have four main functions within the body: Attaching and connecting bone to bone in all joints. Enhancing joint stability. Guiding joint motion and alignment. Preventing excessive or unwanted motion in the joint. Tendons Tendons attach muscle to bone across the joint and transmit the force produced by the muscle. They are formed from all the muscle fibres and connective tissue of the muscle. For example, the Achilles tendon attaches the calf muscles to the heel bone and the quadriceps tendon crosses the knee joint and attaches to the tibia. Injury and healing Blood supply is one of the major determinants in the healing process of any injury. Bone and muscle tissue often heal fairly easily and quickly because they have a healthy blood supply. By contrast, ligaments, tendons and cartilage have a poor blood supply and this limits their healing potential and the speed of recovery. Healing is particularly unlikely for cartilage, which has a lower nutrient supply. Fibrocartilage may need surgical removal when torn (e.g. the menisci in the knee). 6 Copyright © 2018 Active IQ Ltd. Not for resale 00 Q2CGI Manual Book.indb 6 26/03/2018 10:27  The skeletal system Section 1 Types of synovial joints There are six main types of synovial joints, each allowing varying degrees and directions of movement: Joint type Example picture Range of motion (ROM), examples and actions Ball-and-socket. ROM: Allows for movement in almost any direction. Examples: The shoulder and hip joint. Actions: Flexion, extension, horizontal flexion and extension, internal (medial) and external (lateral) rotation, circumduction, adduction and abduction. Hinge. ROM: Allows flexion and extension of an appendage. Examples: The knee and elbow joint. Actions: Flexion and extension. Pivot. ROM: Allows rotation around an axis. Examples: In the neck, the atlas (the uppermost cervical vertebra – C1) rotates around the axis (second cervical vertebra – C2). In the forearms, the radius and ulna twist around each other. Principles of anatomy, physiology and fitness Action: Rotation. Saddle. ROM: Allows movement back and forth and side-to-side. Example: The carpometacarpal joint (thumb). Action: Adduction and abduction, flexion and extension. Gliding (plane). ROM: Allows two bones to slide past each other. Examples: The acromioclavicular joint. The mid-carpal and mid-tarsal joints of the wrist and ankle. Action: Elevation and depression of the shoulder girdle. Ellipsoid/condyloid. ROM: Similar to a ball-and-socket joint – it allows the same type of movement but to a lesser magnitude. Example: The metacarpophalangeal joints (knuckles). Action: Flexion, extension, adduction, abduction and circumduction but no rotation. Joint movements Muscles pull on bones to create joint movements. There is specific terminology for describing the different actions of the joints, which is important to understand when exploring the actions of muscles (covered in Section 2). The joint actions are described in the table below: Movement terminology Normal terms Description (general) Flexion. The angle of the joint decreases, or the return from extension (e.g. bending the knee or elbow). Extension. The angle of the joint increases, or the return from flexion (e.g. straightening the elbow or knee). Rotation. A bone rotating on its own long axis – this may be internal or external (e.g. twisting the neck or trunk to the right or left). Abduction. Away from the midline of the body (e.g. taking the leg or arm out to the side). Adduction. Towards the midline of the body (e.g. drawing the leg or arm in towards and across the front of the body). Copyright © 2018 Active IQ Ltd. Not for resale 7 00 Q2CGI Manual Book.indb 7 26/03/2018 10:27  Section 1 The skeletal system Specific terms Description (regional) Horizontal flexion. Moving the upper arm towards the midline of the body in the horizontal plane (e.g. bringing the arms in front of the body – a hugging action). Horizontal Moving the upper arm away from the midline of the body in the horizontal plane extension. (e.g. drawing the arms backward in a horizontal position). Lateral flexion. Bending to the side (e.g. bending the spine or neck to the right or left). Circumduction. A circular or cone-shaped movement that occurs at ball-and-socket joints (e.g. moving the arm in a full circle, like a cricket bowling action). Elevation. Upward movement of the shoulder girdle (e.g. lifting the shoulder girdle towards the ears). Depression. Downward movement of the shoulder girdle (e.g. lowering the shoulder girdle down and further away from the ears). Protraction. Forward movement of the shoulder girdle (e.g. rounding the shoulder girdle forward). Retraction. Backward movement of the shoulder girdle (e.g. squeezing the shoulder blades together). Pronation. Turning the palm of the hand to face downward. This action occurs between the radius and ulna (e.g. turning the palm down). Supination. Turning the palm of the hand to face upward. This action occurs between the radius and ulna (e.g. turning the palm up to hold something in the hand). Dorsiflexion. When the foot moves towards the shin. This action only occurs at the ankle (e.g. lifting the toes towards the knees). Plantarflexion. Moving the foot away from the shin (tiptoe action). This only occurs at the ankle (e.g. pointing the toes away from the knees or rising onto the balls of the feet). Inversion. When the sole of the foot faces the midline (e.g. turning the foot inwards). Eversion. When the sole of the foot faces away from the midline (e.g. turning the foot outwards). The spine The spine plays a vital role in muscle attachment to allow stability and movement, and protection of the spinal cord, which sends important messages to and from the brain. Structure of the spine An adult spine has four natural curves: two convex (thoracic and sacral) and two Figure 1.4 concave (lumbar and cervical). These are formed over time from birth to support Regions of the spine posture and balance during movement. The spine is comprised of 33 irregular bones (vertebrae), which make up the vertebral column. Each region of the spine has a different number of bones and the bones are shaped differently to allow different ranges of motion and absorb various levels of shock, as identified in the diagram below: Cervical: 7 vertebrae 7 Cervical This region allows large movements of rotation, lateral flexion/extension and flexion/extension. The skull sits on top of the atlas bone to enable flexion/extension (nodding the head) and lateral flexion, while the axis bone sits underneath to create a pivot joint with the atlas bone to enable rotation (shaking the head). Thoracic: 12 vertebrae 12 Thoracic This region allows the same movements as the cervical vertebrae but in smaller ranges (upper thoracic bones are limited to flexion and extension). Lumbar: 5 vertebrae 5 Lumbar This region allows the same movements as the cervical and thoracic vertebrae but they are very limited. The lumbar vertebrae are the largest as they absorb the most shock through the spine. Sacral: 5 vertebrae 5 Sacral Coccyx: 4 vertebrae 4 Coccyx The bottom two sections are fused together and allow no movement. (coccygeal) 8 Copyright © 2018 Active IQ Ltd. Not for resale 00 Q2CGI Manual Book.indb 8 26/03/2018 10:27  The skeletal system Section 1 7 Cervical (secondary curve) Neutral spine 12 Thoracic (primary curve) The term ‘neutral spine’ describes the natural, gentle s-shaped spinal position that is formed when each spinal vertebrae is loaded one on top of the other without any uneven deformation of the intervertebral discs (see figure 1.4). When the spine is in this position, the stress on the passive structures (vertebrae and ligaments) is minimal and the risk of strain or injury to5 Lumbar the lower back is (secondary curve) minimised. It is therefore the ideal and essential position to maintain during daily activities and exercise. 5 Sacral (fused) Postural abnormalities 4 Coccygeal (fused) Development of spinal curves Deviations from neutral spine can happen for a number of reasons, including: Sustained poor postures (e.g. driving, excess sitting and desk-based work) that result in changes in opposing muscle length and strength. Exercise or sport imbalances, e.g. a golfer or an exerciser who only trains ‘mirror muscles’, i.e. pectorals and biceps. Age-related conditions, such as osteoporosis. Medical conditions, such as spina bifida and cerebral palsy. Principles of anatomy, physiology and fitness These abnormalities increase stress on the spine and surrounding soft tissue structures, while decreasing the efficiency with which the body moves. It is thought that the normal thoracic and lumbar curves should be approximately 20–45° when in a static neutral position. A minor lateral deviation of the spine is considered fairly normal, but a curve of more than 10° would be considered a scoliosis. The image below shows the difference between optimal posture and some common postural abnormalities. Hyperkyphosis The muscles at the front of the chest (pectorals) and upper back (upper trapezius) are shortened and the muscles of the mid back (rhomboids and lower trapezius) are lengthened. This gives a hunched back appearance. Hyperlordosis The abdominal muscles (rectus abdominis) and trunk stabilising muscles (transversus abdominis) are lengthened and the back extensor muscles (erector spinae) are shortened. This gives a hollow Normal Spine Hyperkyphosis Hyperlordosis Scoliosis back appearance. Scoliosis Scoliosis refers to a sideways or lateral curving of the spine which often occurs simultaneously with a laterally altered pelvic position and/or uneven shoulder girdle position. A spinal bend to the left side is often compensated for elsewhere in the spine with a bend to the right side or vice versa. Alterations in muscle length will occur throughout the body to control and stabilise this spinal position. Something extra It is not uncommon for posture to alter during pregnancy. The growing baby causes the abdominal muscles to lengthen and weaken and the extra weight can cause alterations to the position of the pelvis, leading to a hyperlordotic posture. Other postural deviations may also present. For example, scoliosis can develop following childbirth as a result of the mother carrying the child on their hip to one side, which may cause a lateral deviation to the spine. Hyperkyphosis can develop from holding and cradling the baby. Copyright © 2018 Active IQ Ltd. Not for resale 9 00 Q2CGI Manual Book.indb 9 26/03/2018 10:27  Section 1 The skeletal system The lifecycle of the skeletal system Something extra The basic shape and size of an individual’s skeleton is genetically Human infants are born with determined, but their final shape is influenced greatly by the about 270 bones, some of environment in which they develop. Environmental influences include which fuse together as the body mechanical factors, such as muscle forces acting on the developing develops. By the time we reach bone, and metabolic factors, such as the supply of nutrients to the adulthood, we have 206 bones. skeleton. Bone development In a fully developed skeleton, bone contains both living and non-living tissue. Ossification Ossification is the process by which bone is formed in the body from the activity of osteoblasts and osteoclasts with the addition of minerals and salts. Calcium compounds must be present for ossification to take place. Osteoblasts take calcium compounds from the blood and deposit them in the bone. The living tissues are the blood vessels, nerves, collagen and bone cells, including: Osteoblasts Cells that deposit calcium to help form bone. Osteoclasts Cells that help to eat away old bone. Osteocytes Mature osteoblasts that have ended their bone-forming role. Stages of bone growth Foetal stage In the foetus, most of the skeleton is made up of cartilage: a tough, flexible connective tissue containing no minerals or salts. As the foetus grows, osteoblasts and osteoclasts slowly replace cartilage cells and ossification begins. Many of the bones have been at least partly formed (ossified) by the time we are born. Birth to adulthood In long bones, the growth and elongation (lengthening) continue from birth through adolescence. Bone lengthening is achieved through the activity of two cartilage plates (called epiphyseal plates) located between the shaft (the diaphysis) and the heads (epiphyses) of the bones. The epiphyseal plates expand, forming new cells and enabling the diaphysis to lengthen. The length of the diaphysis increases at both ends and the heads of the bone move progressively apart. As growth continues, the thickness of the epiphyseal plates gradually decreases and the bone lengthening process ends. Different bones stop lengthening at different ages, but ossification is fully complete between the ages of 18 and 30. During this lengthening period, the stresses of physical activity result in the strengthening of bone tissue. Bone thickness and strength must be continually maintained. Old bone must be replaced by new bone to maintain strength and mass. Adulthood to later life Calcium is progressively lost from the bones as the skeleton ages; this happens earlier in women. Loss of calcium and bone mass can lead to osteoporosis. Osteoporosis increases the risk of fractures and is responsible for loss of height and changes in posture (hunched back) in senior years. 10 Copyright © 2018 Active IQ Ltd. Not for resale 00 Q2CGI Manual Book.indb 10 26/03/2018 10:27  The skeletal system Section 1 Factors affecting bone formation Bone development and health are influenced by a number of factors, including: Nutrition. Exposure to sunlight. Hormonal secretions. Physical activity and exercise. Nutrition A nutritious diet is essential for bone health; the mineral, calcium, is especially important. Calcium-rich foods include dairy products (e.g. milk and cheese), oily fish (e.g. sardines) and green vegetables (e.g. spinach and kale). Bone health can be compromised by excessive intake of caffeine, alcohol and carbonated drinks, as these inhibit the absorption of calcium. Sunlight Exposing the skin to the ultraviolet portion of sunlight is favourable to bone development because the skin can produce vitamin D when exposed to such radiation. Vitamin D is necessary for the proper absorption of calcium in the small intestine. If calcium is poorly absorbed, the Principles of anatomy, physiology and fitness bone matrix will be deficient in calcium and the bones are likely to be deformed or very weak. Hormonal secretions Hormones produced by the endocrine system have a significant role to play in bone development and growth. The growth hormone secreted by the pituitary gland is responsible for general development in childhood and adolescence (bone reformation in adulthood is driven by testosterone and oestrogen). Short-term effects and long-term benefits of exercise on the skeletal system Short-term, Long-term benefits immediate effects Increased secretion of synovial fluid in joints, Increased bone density and bone strength. which reduces wear-and-tear. Increased joint stability due to stronger Increase in blood flow and nutrients to bones ligaments and tendons. and joints. Improved posture. Muscles pull on bones to increase ROM. Improved cartilage health. Increased ROM, leading to improved flexibility. Reduced risk of osteoporosis (brittle bone disease). Reduced risk of fractures. Copyright © 2018 Active IQ Ltd. Not for resale 11 00 Q2CGI Manual Book.indb 11 26/03/2018 10:27  END OF SECTION Revision activities Answer the following questions and make notes to revise this section. ❯ What are the two main structures that make up the skeleton? ❯ List the bones found in the axial skeleton. ❯ List the bones found in the appendicular skeleton. ❯ Give an example of a long, short, irregular, flat and sesamoid bone. ❯ What is the name of the structure found at the end of long bones, which prevents friction and absorbs shock? ❯ Where are red and white blood cells produced? ❯ List the functions of the skeletal system. ❯ What are the three main joint types? ❯ List the characteristics of a synovial joint. ❯ Which structure joins bone to bone? ❯ Which structure joins muscle to bone? ❯ Where would you find a hinge joint? ❯ What movements are possible at a hinge joint? ❯ Where would you find a ball-and-socket joint? ❯ What movements are possible at a ball-and-socket joint? ❯ List the five sections of the vertebral column and identify how many vertebrae are in each. ❯ Describe hyperlordosis. ❯ Describe hyperkyphosis. ❯ Describe scoliosis. ❯ What is the difference between an osteoblast and an osteoclast? ❯ What are the long-term benefits of exercise of the skeletal system? 12 Copyright © 2018 Active IQ Ltd. Not for resale 00 Q2CGI Manual Book.indb 12 26/03/2018 10:27  The neuromuscular system Section 2 Section 2: The neuromuscular system All of the internal and external muscles in the body and the nerves serving them make up the neuromuscular system. Every movement your body makes requires communication between the brain and muscles, some of which you don’t even have to think about, such as your digestive muscles breaking down ingested food. The muscular system There are over 600 muscles in the body, making up around 40% of a person’s total weight. The bones and joints create the framework of levers (bones) and pivots (joints) which give the body the potential to move, but this framework cannot move on its own. It is the contraction and relaxation of muscles that bring about movement. The muscular system produces a continuous and wide-ranging number of actions, such as bodily movements (e.g. walking and jumping) and the powering of internal processes (e.g. contraction of the heart muscle and focussing of the eye). KEY Principles of anatomy, physiology and fitness Types of muscle tissue POINT There are three types of muscle tissue and each one has a different Contraction of the heart function. The three types are: is controlled by the sinoatrial node (SAN). Cardiac muscle (myocardium), e.g. the heart. The set rhythm of the Smooth muscle, e.g. the walls of the small intestine. heart (on average, Skeletal muscle (striated), e.g. the hamstrings or triceps. 72bpm at rest) is called autorhythmicity. Copyright © 2018 Active IQ Ltd. Not for resale 13 00 Q2CGI Manual Book.indb 13 26/03/2018 10:27  Section 2 The neuromuscular system The table below describes the key characteristics of the different types of muscle tissue: Cardiac Smooth Skeletal Control Involuntary, not under Involuntary, not under conscious Voluntary, under conscious conscious control (autonomic control (autonomic nervous control (somatic nervous nervous system). system). system). Appearance Striated (striped or streaked). Smooth, spindle-shaped. Striated (striped or streaked). Location The heart, to ensure The digestive system, to break Biceps, triceps, quadriceps, examples continuous rhythmic beating down ingested food and drink. etc. to create bodily and function in order to push oxygen movement. Some muscles around the body. The walls of blood vessels, to contract to stabilise the control the volume of blood flow. body and prevent unwanted movement. Characteristics of muscle tissue Muscle tissue has four key characteristics: Contractility Ability to shorten. Extensibility Ability to stretch and lengthen. Elasticity Ability to return to its original size and shape. Excitability Ability to respond to stimuli from the nervous system. The heart contracts to pump blood and relaxes to fill with blood. The skeletal muscles work in pairs and contract and relax to create movement of the skeleton. Muscle contraction occurs in response to different stimuli, such as neurotransmitters and hormones. Skeletal muscle is controlled by the somatic nervous system. Smooth muscle is controlled by the autonomic nervous system. Contraction of the heart is controlled by the SAN. Muscle is elastic; it can stretch and then recoil to its original shape. Skeletal muscle is like an elastic band; if the muscle is pulled too far it can tear. Skeletal muscle Skeletal muscles make the human body move. They sit just underneath the skin, shortening and lengthening by pulling on bones; this is normally achieved using a tendon to pull them in different directions. Structure of a skeletal muscle Something extra Each bundle of individual muscle fibres (fasciculi) is wrapped in connective tissue called perimysium, and each single fibre The main constituents of skeletal muscle are: within the bundle is wrapped in connective tissue called 70% water. endomysium. 23% protein, e.g. actin and myosin Inside the individual fibres, there are smaller myofibrils and (elastin) and connective tissue (collagen). within each myofibril are strands of myofilaments (actin and 7% minerals (e.g. calcium, potassium myosin). It is the action of myosin and actin working together and phosphorus) and substrates (e.g. that brings about movement. glycogen, glucose and fatty acids). The numerous fibres and connective tissues continue throughout the length of the muscle. Layers of connective tissue converge to form tendons, which are strong, inelastic and strap-like. The tendon attaches to the periosteum, which is the sheath that surrounds the bone. 14 Copyright © 2018 Active IQ Ltd. Not for resale 00 Q2CGI Manual Book.indb 14 26/03/2018 10:27  The neuromuscular system Section 2 To summarise: Whole muscle is wrapped in epimysium. Bundles of fibres, or fasciculi, are wrapped in perimysium. Single muscle fibres are wrapped in endomysium. Myofibrils are located inside single fibres. Principles of anatomy, physiology and fitness Myofilaments – myosin and actin ‒ are located inside sarcomeres. Sliding filament theory The sliding filament theory was proposed by Huxley in 1954 to explain the contraction of skeletal muscle. The theory states that the Muscle fibre myofilaments, actin (a thin protein strand) and myosin (a thick protein strand) slide over each other, creating a shortening of the sarcomere (the contractile units in the muscle where myosin and actin are found), which causes the shortening or lengthening of the entire muscle. The myofilaments do not decrease in length themselves. This proposed action is accomplished by the unique structure of the protein, myosin. Myofibril The myosin filaments are shaped like golf clubs and form cross bridges with the actin Actin filament filaments. Each myosin molecule (there Myosin filament are many) has two projecting heads. These heads attach to the actin filaments and pull them in closer. Stimulus from the nervous system and the release of adenosine triphosphate (ATP) – the high-energy molecule stored on the myosin head – provide the impetus for the SARCOMERE IS RELAXED head to ‘nod’ in what is termed the ‘power stroke’. It is this nodding action which ‘slides’ the thin actin filaments over the thick myosin filaments. The myosin head then binds with another ATP molecule, causing it to detach from the actin-binding site, which is known as the ‘recovery SARCOMERE IS CONTRACTED stroke’. It is then able to attach to the next binding site and perform the same routine. Copyright © 2018 Active IQ Ltd. Not for resale 15 00 Q2CGI Manual Book.indb 15 26/03/2018 10:27  The neuromuscular system Section 2 Location of skeletal muscles The main anterior and posterior skeletal muscles are shown below: Upper Upper Middle Trapezius Trapezius Deltoids Trapezius Pectoralis Lower Triceps Major Biceps Trapezius Brachii Brachii External Latissimus and Dorsi Erector Internal Spinae Gluteus Obliques Maximus Rectus Iliopsoas – Abdominis Hip Flexors Hamstrings Hip Abductors Hip Quadriceps Principles of anatomy, physiology and fitness Adductors Gastrocnemius Soleus Tibialis Anterior Muscle actions and movement When standing upright and erect, a range of skeletal muscles are in a state of continuous tone or tension. Muscles are contracting, resisting the force of gravity and preventing the body from falling to the floor. For example, the muscles in the neck keep your head upright to prevent it from dropping to the front, back or side. Skeletal muscles with a postural role typically have a higher proportion of slow twitch fibres. How skeletal muscles create movement To create specific movement of the joints, the following has to happen: Muscles receive a message from the brain to shorten. Muscles exert a force and pull on the bones. As one muscle contracts and shortens, it works in pairs with an opposing muscle, which relaxes and lengthens. Example of Origins and insertions an origin and insertion- O – Anterior Each muscle has a start and end point known as the origin and biceps brachii surface of insertion. scapula Origin The muscle attachment site on a bone(s) that serves as a relatively fixed, motionless anchor point. This end is called the origin of a muscle and is described as the proximal attachment, i.e. the one nearest to the centre midline of the body. Muscles I – Radius may have more than one origin, e.g. quadriceps (four) and triceps (three). Copyright © 2018 Active IQ Ltd. Not for resale 17 00 Q2CGI Manual Book.indb 17 26/03/2018 10:27  Section 2 The neuromuscular system Insertion The end of the muscle attached to the bone that usually moves during contraction is called the muscle insertion. The insertion is described as the distal attachment, i.e. the one furthest away from the centre midline. Muscles usually have a single insertion. Types of muscle contractions Muscles work and contract in different ways. They can contract and shorten, contract and lengthen or contract and stay the same length, with no movement occurring. A number of terms are used to help distinguish between these different types of muscular activity: Isotonic Muscles move under tension by either shortening or lengthening. These terms are known as: Concentric contraction: the muscle shortens under tension, i.e. the insertion moves towards the origin, for example the curling/upward phase of the bicep curl. Eccentric contraction: the muscle lengthens under tension, i.e. the insertion moves away from the origin, for example the straightening/downward phase of the bicep curl. Isometric The muscle remains the same length under tension, for example, holding a squat at the bottom of the movement. KEY POINTS Concentric During the eccentric phase contraction Eccentric of an exercise (e.g. the contraction lowering phase of a bicep curl), the working muscle still has to contract in order to control the movement, otherwise the triceps muscle would fire into action and potentially injure the elbow joint due to the strain placed upon it. Roles of different muscles during movement Efficient human movement is dependent on the coordinated activity of whole groups of muscles and will involve varying combinations of different muscle actions happening simultaneously. During any movement, different muscles can be working in the following ways: Agonist or prime mover: This is the muscle(s) that contracts and causes a desired action, e.g. the biceps brachii contracts during a bicep curl or the quadriceps contract during a leg extension. Antagonist: This is the opposing muscle(s) to the agonist that is relatively relaxed, e.g. the triceps brachii during a bicep curl or the hamstrings during a leg extension. Synergist: This is the muscle(s) that contracts to assist or modify the movement of the prime mover, e.g. during hip extension the hamstrings act as synergists for the gluteus maximus. Fixators: These are the muscles that contract to stabilise the part of the body that remains fixed, e.g. shoulder girdle muscles stabilise the scapula to allow for efficient movement at the shoulder joint when the arm moves. 18 Copyright © 2018 Active IQ Ltd. Not for resale 00 Q2CGI Manual Book.indb 18 26/03/2018 10:27  The neuromuscular system Section 2 Joint movements caused by concentric contractions When specific muscles contract and shorten (concentric muscle work) they pull on bones to create an action or movement at the joints they cross. The table below identifies the different joint actions and movements that are brought about when specific muscles contract and shorten (concentric muscle work) while working in the role of a prime mover. Muscle Location Origin Insertion Primary concentric actions (start point) (end point) Deltoids. Shoulder. Clavicle and upper Upper Abduction, flexion and extension, scapula. humerus. horizontal flexion and extension and internal and external rotation of the shoulder joint. Biceps brachii. Front of the Anterior surface of Upper radius. Flexion of the elbow and supination upper arm. the scapula. of the forearm. Triceps brachii. Back of the Posterior upper Upper ulna. Extension of the elbow. upper arm. humerus and the scapula. Latissimus Sides of the Lower seven Anterior upper Adduction, extension and internal dorsi. back. thoracic vertebrae, humerus. rotation of the shoulder joint. inferior angle Principles of anatomy, physiology and fitness of the scapula, thoracolumbar fascia and the iliac crest. Trapezius. Upper back. Base of skull and Lateral Elevation, retraction and depression spinous processes clavicle and of the shoulder girdle; extension, of C7-T12. upper surface lateral flexion and rotation of the of the scapula. neck. Rhomboids. Mid-back. Spinous processes Medial border Retraction and elevation of the of C7-T5. of the scapula. scapula. Pectoralis Chest. Medial clavicle Upper Flexion, horizontal flexion, adduction major. and sternum. humerus. and internal rotation of the shoulder joint. Erector spinae. Either side of Sacrum, ilium, ribs Ribs, Extension and lateral flexion of the spine. and vertebrae. vertebrae and spine. base of the skull. Rectus Along the centre Pubis. Cartilage of Flexion and lateral flexion of abdominis. of the abdomen. 5th–7th ribs the spine and tilting the pelvis and base of posteriorly. the sternum. Internal Sides of the Iliac crest and Lower three Rotation and lateral flexion of the obliques. abdomen, thoracolumbar ribs, pubic spine. deeper to fascia. crest and external the fascial obliques. connection to the linea alba. External Sides of the Outer surface of Iliac crest, Rotation and lateral flexion of the obliques. abdomen, closer the 5th–12th ribs. the pubis and spine. to the surface – the fascial superficial. connection to the linea alba. Copyright © 2018 Active IQ Ltd. Not for resale 19 00 Q2CGI Manual Book.indb 19 26/03/2018 10:27  Section 2 The neuromuscular system Muscle Location Origin Insertion Primary concentric actions (start point) (end point) Transversus Abdomen. Iliac crest, Pubis and Compressing and supporting the abdominis. thoracolumbar fascial abdominal contents. Deep stabiliser fascia and lower connection to of the spine. six ribs. the linea alba. Diaphragm. Beneath the Base of the Central Drawing the central diaphragmatic ribcage. sternum, inner tendon of the tendon downwards and increasing surface of the diaphragm. volume of the thorax. lower six ribs and the upper three lumbar vertebrae. Intercostals. Between ribs. Inferior border of Superior Elevate the ribs to aid inspiration the ribs and costal border of the and draw the ribs down to aid cartilages. rib below. expiration. Hip flexors. Through the Iliac fossa and all Lesser Flexion and external rotation of the pelvis and onto lumbar vertebrae. trochanter of hip. the femur. the femur. Gluteus Bottom ‒ Coccyx, sacrum Upper femur Extension, external rotation and maximus. buttocks. and iliac crest. and iliotibial abduction of the hip. band (ITB). Abductor group. Outside of the Outer surface of Upper femur Abduction of the hip. upper thigh/hip. the ilium. and upper Gluteus medius tibia (via the and minimus. ITB). Adductor group. Inner thigh. The pubis and Upper, mid Adduction and internal rotation of ischium. and lower the hip. femur. Quadriceps Front of the Anterior inferior Anterior, upper Flexion of the hip and extension of group. thigh. iliac spine (AIIS) tibia via the the knee. and the femur. patella. Hamstrings Back of the Ischium and Head of the Extension of the hip, flexion of group. thigh. posterior surface fibula and the knee and tilting the pelvis of the femur. upper, medial posteriorly. surface of the tibia. Gastrocnemius. Calf. Posterior, lower Calcaneus. Plantarflexion of the ankle and femur. flexion of the knee. Soleus. Calf. Upper, posterior Calcaneus. Plantarflexion of the ankle. tibia. Tibialis anterior. Front of the Lateral, upper 1st metatarsal Dorsiflexion and inversion of the lower leg. tibia. and medial ankle. tarsal. 20 Copyright © 2018 Active IQ Ltd. Not for resale 00 Q2CGI Manual Book.indb 20 26/03/2018 10:27  The neuromuscular system Section 2 The nervous system All internal communication and coordination is the responsibility Something extra of the nervous system. Its primary role is to maintain a constant balance of the internal environment, known as homeostasis. It is estimated that if you could join every It achieves this with the help of the brain and a huge, complex nerve end to end, it would stretch around network of electrical nerves and chemical messages that run the world two-and-a-half times. throughout the body. How the nervous system functions To sum up the role of the nervous system, it is quite simply to: 1. Gather information (sensation). 2. Analyse the gathered information (integration). 3. Respond appropriately to the information (response). Sensation Integration Response Sensation Principles of anatomy, physiology and fitness The nervous system gathers information about the internal and external environment. BARORECEPTORS: Detect changes in blood pressure. A vast array of sensors throughout the PROPRIOCEPTORS: Detect changes in muscle length body (including the eyes, ears and internal and tension. proprioceptors) gather information about CHEMORECEPTORS: Detect changes in chemicals, the internal environment (e.g. carbon e.g. taste, smell. dioxide levels in the blood) and the external THERMORECEPTORS: Detect changes in temperature. environment (e.g. air temperature and space available). Integration (interpretation and analysis) The nervous system interprets and analyses the information gathered from the sensors and decides on the most appropriate action. Many of these ‘decisions’ are automatic (involuntary) without conscious control, e.g. digestion. Others are consciously controlled, e.g. voluntary muscle action. Response The nervous system responds to the information analysed by initiating an appropriate reaction. Responses may include muscle contraction to perform a movement or lift a weight, or glandular secretion. The nervous system works closely with the endocrine system, which is responsible for releasing hormones (chemicals) to maintain homeostasis. Structure of the nervous system The nervous system consists of two primary divisions: Central nervous Peripheral nervous system (CNS) system (PNS) Central nervous system (CNS) The CNS is the control base for the whole nervous system. All nerve impulses that stimulate muscles to contract and create movement of the body originate from the CNS. The CNS is comprised of the brain and the spinal cord. Copyright © 2018 Active IQ Ltd. Not for resale 21 00 Q2CGI Manual Book.indb 21 26/03/2018 10:27  Section 2 The neuromuscular system The brain Cerebrum The largest and most superior aspect. This takes up most of the space in the skull. Cerebellum The smaller part; it is inferior to the cerebrum and posterior to the brain stem. The cerebellum acts as a memory bank for all learnt skills. The cerebellum is mainly responsible for controlling the group action of muscles. It communicates and works harmoniously with the cerebrum. Diencephalon Thalamus and hypothalamus. Brain stem Medulla oblongata, midbrain and pons – the stalk-like component at the inferior aspect of the brain. The lower portion is a continuation of the spinal cord. The spinal cord consists of cervical, thoracic, lumbar and sacral segments, named according to the portions of the vertebral column through which they pass. The spinal cord is the communication link between the brain and the peripheral nervous system (PNS). It integrates incoming information and produces responses via reflex mechanisms (reflex arc). Peripheral nervous system (PNS) The PNS consists of all the branches of nerves that lie outside the spinal cord. Its role is to transport messages through its network of nerve cells, to and from the CNS. The peripheral nervous system subdivides into the: Somatic system which controls voluntary (conscious) movement of the skeletal muscles, e.g. standing, walking and lifting a weight. Autonomic system which controls involuntary functions, e.g. digestion and heart rate. Neurons Neurons (also called nerve cells) are responsible for transmitting electrical messages. Spinal nerves are divided into motor and sensory neurons. These carry messages to the CNS from the sensory organs. Sensory nerves arrive on the posterior side of the spinal cord from a Sensory variety of sensory receptors spread throughout the body. For example, sensory receptors in the muscles are called proprioceptors; these relay neurons information concerning the position of the body to the CNS, and this in turn helps improve movement efficiency and reduce the risk of injury by preventing overstretching. These transmit impulses from the CNS to muscles and glands with specific instructions, such as causing muscles to contract and glands to Motor secrete hormones. neurons These exit on the anterior side of the spinal cord. 22 Copyright © 2018 Active IQ Ltd. Not for resale 00 Q2CGI Manual Book.indb 22 26/03/2018 10:27  The neuromuscular system Section 2 Structure of a neuron An individual neuron consists of: Principles of anatomy, physiology and fitness The cell body which directs the activities of the neuron. Something extra The nucleus, which stores the cell’s genetic information, The brain has over 100 billion neurons and i.e. DNA. In simple terms, it tells the cell ‘what to do’. the body contains millions. Neurons are Dendrites, which pick up impulses and transmit these to highly specialised in terms of structure, the cell body. function and the way in which they link The axon, which transmits messages away from the cell together to communicate. body. The myelin sheath, which insulates the axon to speed up the transport of messages. The combined work of the muscular and nervous systems Without the nervous system, bodily movement would not occur as muscles quite simply would not know what to do. To lift a weight, for example: The eyes gather information (estimate how heavy the weight is and where and how it is positioned). This information is sent to the CNS to be processed. The brain sends information on how to position the body, which muscles to contract and the number of motor units to recruit to perform the lift. Once they are stimulated to contract, the muscles pull on the bones and create appropriate movement of the joints, through the sliding action of the myofilaments (myosin and actin). This, in effect, is the neuromuscular system at work. Motor unit recruitment and the ‘all or none’ law KEY A motor unit consists of a single motor neuron and all POINT the muscle fibres it innervates (activates). A single motor neuron may be responsible for innervating thousands of The ‘all or none’ law applies to individual muscle fibres, depending on its location and function. motor units, not the entire muscle. Only the This concept is known as the innervation ratio. muscle fibres stimulated by the motor unit(s) recruited will contract. When an impulse is sent down a neuron, all the muscle fibres within that motor unit are innervated. The motor unit activates all of its fibres or none at all. This is known as the ‘all or none’ law. Copyright © 2018 Active IQ Ltd. Not for resale 23 00 Q2CGI Manual Book.indb 23 26/03/2018 10:27  Section 2 The neuromuscular system Number and size of motor units The number and size of motor units in specific areas of the body depend Innervation of Skeletal Muscle on their role and function. Axon of motor neuron Muscles responsible for strength and large force generation, such as the quadriceps and gluteals, tend to have motor units with a larger Skeletal muscle fibres innervation ratio e.g. 1:2000. Muscles involved in finer, intricate Muscle fibre nucleus movement, such as the fingers, tend to have a much lower innervation ratio e.g. 1:50. The hands, for example, have a lot of small motor units and these supply Neuromuscular junctions fewer fibres to enable finer, more intricate movement, e.g. playing a musical instrument or using a computer. The legs and muscles involved in maintaining posture have fewer motor neurons, but these are larger and supply more muscle fibres. Maintaining posture and movement of the legs to walk, kick, run and jump is less intricate than the movement of the hands. A motor unit is typically made up of one type of muscle fibre (slow or fast twitch) spread throughout the muscle: For tasks requiring less effort, smaller neurons controlling slow twitch fibres are recruited. For tasks requiring more effort, larger neurons controlling fast twitch fibres are recruited. Neuromuscular sensory organs There are different muscle sense organs that form part of the autonomic nervous system: Joint receptors are found in the ligaments and joint capsule. They inform the brain about the position of the joint. Muscle spindles are found in the muscle belly and inform the brain about the length of a surrounding muscle fibre ‒ this helps to prevent overstretching and resultant damage. Golgi tendon organs (GTOs) are found in the tendons and tell the brain how much tension a muscle is under. In extreme cases, where the muscle cannot withstand the amount of tension, the GTOs will cause the muscle to relax to avoid injury. The lifecycle of the neuromuscular system Early years This is the period of most significant growth for all of the body’s systems, including the neuromuscular system. Over this period, neural pathways (motor connections) increase rapidly in number to develop specific movement patterns and motor skills, such as coordination and balance. Postural and stabilising muscles also grow very quickly to progress a newborn baby from not having the ability to hold any body part upright, to having head control and being able to sit up on their own, and eventually walking within the first 12–18 months of life. The two main factors that influence the rate of neuromuscular development in early years are: Genetics: Each individual has a genetic potential for maximum growth, which is shaped by the genes passed on by our parents and grandparents. Environment: Opportunities to support neuromuscular development, or restrictions that could hinder it, strongly affect the potential for neuromuscular development in early years. For example, a child that spends more time taking part in physical activity, especially if it has a particular focus on developing motor skills, will be much more likely to fulfil their genetic potential for growth than a child that is restricted to a more sedentary lifestyle. Muscle, as a percentage of body mass, increases from about 42% to 54% in boys between the ages of 5 and 11; in girls, it increases from about 40% to 45% between the ages of 5 and 13 and thereafter declines (Malina et al., 2004). 24 Copyright © 2018 Active IQ Ltd. Not for resale 00 Q2CGI Manual Book.indb 24 26/03/2018 10:27  The neuromuscular system Section 2 Pubescent period Up until puberty, neuromuscular development is fairly similar between girls and boys ‒ this changes dramatically during adolescence. The growth of new neural pathways slows down significantly in both sexes, however the growth of muscle tissue (hypertrophy) increases at a much higher rate in boys than girls. This is due to a surge in sex hormones (testosterone in boys and oestrogen in girls); testosterone primarily stimulates muscle and bone growth in males, whereas in females, oestrogen stimulates increases in bone, muscle and female specific fat tissue in preparation for bearing children. Adulthood and later years It is commonly accepted that we continue to grow in different ways until our mid-20s, with many individuals finishing their development even earlier. The neuromuscular system is the same; neural pathways and muscular growth that aren’t related to exercise come to a halt around the age of 25. If we continue to challenge the neuromuscular system, there is the potential for further growth beyond our mid-20s. One of the effects of ageing on the nervous system is the loss of neurons. By the age of 30, the brain begins to lose thousands of neurons each day. The cerebral cortex can lose as much as 45% of its cells and the brain can weigh 7% less than in the prime of our lives. In conjunction with the loss of neurons comes a decreased capacity to send nerve impulses to and from the brain. Because of this, the processing of information slows down. Additionally, the voluntary motor movements slow down. Loss of cells from the motor system occurs during the normal ageing process, leading to a reduction in the Principles of anatomy, physiology and fitness complement of motor neurons and muscle fibres. The latter age-related decrease in muscle mass has been termed ‘sarcopenia’ and is often combined with the detrimental effects of a sedentary lifestyle in older adults. Clear evidence of this ageing effect is seen when voluntary or stimulated muscle strength is compared across the adult lifespan, with a steady decline of approximately 1–2% per year occurring after the sixth decade (Vandervoort, 2002). Short-term effects and long-term benefits of exercise on the neuromuscular system Short-term, Long-term benefits immediate effects Increased muscle temperature. Increased muscular endurance/hypertrophy/ Increased muscle pliability (ability to stretch strength (depending on the intensity of further). training). Increased power output from muscles. Increased stores of glycogen and creatine phosphate in muscle. Increased nerve-to-muscle link. Increase in contractile proteins, actin and Increased recruitment of muscle fibres. myosin. Increased basal metabolic rate (ability to burn calories at rest). Improved posture.