Kaap180 Intro to Exercise Science
Kaap180 Intro to Exercise Science PHYS202010
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Training for your rst marathon How would you do it Marathon to Athens Distance 262 miles Time for men 2hr 2 minutes 57 seconds Time for women 2hr 15 minutes 25 seconds Why Why would you choose to do a marathon Adventure challenge Are marathons healthy Hard on your bones knees deplete body of carbohydrates and muscle glycogen but active training and healthy nutrition plan If you accomplish your marathon goal how does the impact or relate to other aspects of your life When How much time do we need to train for a marathon 16 weeks 4 months woman age 1824 years old 6 month plan Which one should we pick Seasonal Environment Hilly cold warm street How should we train for it We should probably run How A few miles to start 2 or 3 times this week to start Walk 26 miles before running 26 miles What should we do when we re not running Eating properly stretch sleeping What if Toe nail falls off Cha ng What about clothing Form tting stay warm Thought Exercises same problem from a different directions Could you do one today 0 Why or why not Could you do all your training the day before 0 Why or why not Could you do all your training the week before 0 Why or why not One month Plan and EXECUTE A marathon is the same as vour nal exam Exercise Science the study of various aspects of physical activity exercise sport and athletic performance that have the common characteristic of physical movement and the adaptations that occur as a result of participation in physical activity and exercise Kinesiology and applied physiology Kinesiology ad Applied Physiology are almost synonymous Kinesiology is a bit broader and includes domains such as physical education and sociology of sport Kinesiology movement Applied Physiology applied function Kinesiology is an interdisciplinary eld focusing on the science of human movement Its four basic elements biochemistry biomechanics motor control and physiology are integrated to allow kinesiology to address a wide variety of ques ons In recent years the eld of kinesiology has evolved toward less emphasis on sport and a much stronger focus on an understand of human movement and the role of physical activity and exercise in health and disease To those ends kinesiologists use tools from molecular biology neuroscience engineering medicine and computer science to work on unique problems in a diverse array of settings that include laboratories hospitals health and wellness centers and eld environments UMASS Amherst the nation39s rst kinesiology Adaptation is central Adaptation changed that occur as an accommodation to or adjustment to 0 Environment Stimuli Stressors The stimuli of interest 0 Physical activity Inactivity Exercise KAAP kinesiology and applied physiology The journal of applied physiology publishes original papers that deal with diverse areas of research in applied physiology especially those papers emphasizing adaptive and integrative mechanisms Adaptive physiology includes inherent adaptations such as those related to development aging and pathophysiological conditions and adaptations to the external environment such as those occurring with exercise microgravity hypoxia hypo and hyperbaric and hypo and hyperthermia conditions Integrative physiology includes horizontal integration across organ systems and vertical integration from molecule to cell to organ In all areas of applied physiology the use of cutting edge techniques including molecular and cellular biology is strongly encouraged ls exercise science all about elite physical performance No elite athletes or performers represent only a small percent of our population so should federal grants support research about jumping 1 centimeter higher Yes studying elite performance high level adaptations and performance in environmental extremes has taught us much of what we know about human physiology Elite physical performance can teach us about physiology and adaptation De nitions Physical activity movement activities of daily living including work and job related activities leisure time activities ad activities performed around the home ExerciseL structured movement process that humans conscious and voluntarily engage in for the purpose of improving tness health and performance What is our discipline The principle function of a discipline is to develop a coherent body of knowledge that describes explains and predicts key phenomena from the domain of interest What is our profession Professions attempt to improve the conditions of society by providing a regulated service in which practice and educational or training programs are developed in the health eld Undergraduate Trainer Exercisespecialist Graduate 0 Physical therapy Physician39s Assistant 0 Occupational therapist Orthotics and prosthetics Medicine Chiropractic Occupational theapy Occupational therapist help people across a lifespan participate in the things they want and need to do through the therapeutic use of everyday activity Common occupational interventions include helping children with disabilities to participate fully in school and social situations Historical contributors to kinesiology Hippocrates 400 BC De nitions amp frameworks health tness amp specialization Objective to understand the importance or unity of operational de nitions and frameworks in organizing knowledge and activites To understand the difference between health and tness and to learn the components of each Why use de nitions and framework 0 Theoretical frameworks and de nitions add structure to a problem or tops 0 Structure helps to provide a common starting point for discussion Health is a state of complete physical mental and social wellObeing and not merely the absence of disease or in rmity World Health Organization 1948 has not been amended since 1948 Biological tness the ability to survive and reproduce Darwinian survival of the ttest the ability to put your genes into the next generation Physical tness a set of attributes or characterizes that people have or achieve that related to the ability to perform physical activity Cardiorespiratory tness ability of the circulatory and respiratory systems to supply oxygen to skeletal muscles during activity The president39s council on physical tness and sports a study group sponsored by the government of the United States declines to offer a simple de nition of physical tness Instead there is a chart Resilience is an individual39s ability to properly adapt to street and adversity Street and adversity can come in the shape of family or relationship problems health problems or workplace and nancial stressors Individuals demonstrate resilience when they can face dif cult experiences and rise above them with ease People who demonstrate resilience are people with positive emotional They are keen to effectively balance negative emotions with positive ones Health and tness bene t of exercise Exercise Science amp Epidemiology Epidemiology is the study of the determinant occurrence and distribution of health and disease in a de ned population There are course and careers in epidemiology When we do our research we use epidemiology to explain or support the importance of our research problems o X of individuals in Delaware have Diabetes 0 Comparison of disease rates by state or country First epidemiologist Dr John Snow Like a modern crime scene investigator 1854 long cholera outbreak Cause infected public water pump at Broad st Handle removed Not only did this solve the immediate problem of the cholera outbreak but it provided new information about how the disease spreads Exercise Epidemiology Studies Follows health and disease under the in uence of physical activity or sedentary Occupational comparisons Postal clerks compared to mail carries 0 Train drivers compared to walking conductors Fitness vs Mortality Rate 0 A measure of the number of death in a given population per unit of time Morbidity the incidence of ill health ex Obesity diabetes Morbidity rate the number of individuals in poor health during a given time period Consider preventable diseases vs unpreventable Mortality the incidence of death Mortality rate the number of deaths during a given time period Consider preventable death vs unpreventable Comorbidities Comorbidities of obesity include diabetes hypertension high cholesterol sleep apnea Like asking quotWhat is likely to come with obesityquot The existence of a comorbidity DOES NOT PROVE a causeeffect relationship THIS IS VERY IMPORTANT ln statistics and epidemiology relative risk RR is the ratio of the probability of an event occurring for example developing a disease being injured in an exposed group to the probability of the event occurring in a comparison nonexposed group gt1 is increased risk lt1 is reduced risk Some exposures of interest in exercise science 1 Overweight and Obesity 2 Being female or male noncontact Anterior Cruciate Ligament ACL injury 3 Relative risk of falls of people with Parkinson39s disease compared to age matched group RR P event when exposedP event when not exposed The Science in Exercise Science Anecdotal usually by generalizing from an insuf cient amount of evidence Marketing claims the motivation is to sell a product or service often based on internal report that are biased and not peer reviewed Testimonial or endorsement the term quottestimonialquot most commonly applied to the sales pitches attributed to ordinary citizens whereas endorsement usually applies to pitches by celebrities Scienti c evidence appears in scienti c scholarly journals that are peer reviewed by acknowledged scholars Expert opinion scienti c evidence determines who is an quotexpertquot Objectivity in science is a value that informs how science is practiced and how scienti c truths are discovered It is the idea that scientists In attempting to uncover truths about the natural world most aspire to eliminate personal biases a priori commitments emotional involvement Different approaches to research Human model Animal model Tissue and cell cultures Computer modeling Advanced statistical techniques Peer review of manuscripts Authors submit nal raft o manuscript to the most appropriate journal The manuscript describes an experiment 0 Editor selects 2 or 3 experts in the same or a related eld to evaluate the manuscript 0 Editor evaluates the reviews and determines 0 Accept as is rare 0 Revise and resubmit o Reject When the manuscript is accepted it is then published in a peer reviewed journal meaning that it was deemed acceptable by members of the scienti c community Basic research pure or fundamental research that aims to expand the knowledge base without connection to a practical problem the practical application of the new knowledge might be determined later 0 Experiments sought to determine what proteins in muscle produce force Applied research application of the practices of basic science to an immediate practical problem Mechanistic seeks the reason for a change in a physiological system or the reason why it operates as it does Quantitative research 0 Uses a scienti c approach designed or the collection and analysis of numerical data typically obtained from subjects through direct testing or questionnaires Assumes reality is relatively stable uniform measureable and governed by natural laws that allow results to be generalized to a larger population 0 Interpretation is typically based on statistical tests Qualitative Uses extensive observations and interviews that provide nonnumeric data obtained in natural environments Quantitative analysis seeks to interpret phenomena and discover meanings of situations Naturalistic does not attempt to control the context or conditions surrounding the research setting 0 Results are typically categorized into trends and patterns and statistical procedures are rarely used Descriptive describes characteristics about the system population or phenomenon being studied Experimental some experimental condition is applied An experimental variable is manipulation allows conclusions about cause and effect Cross sectional compares two groups of individuals with attributes of interest Longitudinal report changes over a meaningful period of time typically year decades 0 Large sample of people involved 0 A cohort of individuals followed Evidence bases Practice 0 Think of the behavior of a professional 0 All practices decisions made should be based on a minimum amount of supportive research scienti c evidence 0 Health insurance does not cover some practices that do not have an adequate evidence base Biomechanics a sub discipline of exercise science Subdiscipline Newtons Laws Kinematics Kinetics Applications P PWF How is this movement described or quanti ed Strength Speed Endurance Range of motion Accuracy Correctincorrect Successfailure Visual quality dance Pace Metabolic cost HR V02 Place rst second Mechanically o displacement position velocity 0 force 0 amount of work joules or kilojoules 0 power Ef ciency mechanically work metabolic work Biomechanics de ned The study of the human body at rest and in motion using principles and concepts from physics mechanics and engineering Why do we need to study the mechanics of human movement To understand how the human body works To prevent injury To optimize performance and ef ciency rehabiitation and activities of daily living sport and performance occupationa Ef ciency mechanical cost of movement metabolic or physiological cost of movement Law of inertia a body in rest or in motion will continue in that state unless acted upon by a force In the equation fma inertial mass is m which quanti es the body39s resistance to being accelerate a Law of acceleration objects accelerate in force and mass Fma quotforce cause masses to acceleratequot Law of action reaction Acceleration of an object is proportional to the force exerted on it it39s mass For every action there is an opposite and equal reaction Kinematic temporal and spatial components of movement position or displacement veocitydispacement time acceeration velocitytime Kinetics forces during movement forever that cause movement external forces head injury internal force muscle forces bone on bone reaction forces during locomotion Edward Muybridge 18301904 the development of motion capture technology and the kinematic description of movement Kinematic description of movementcamera think cinema High speed motion capture video the details of fast movements can be captured with high speed video Biomechanics of injuries kinematics and chronic injuries 0 Figure shows different patterns of foot strike while running Believed that over pronation and under pronation result in chronic running injuries 0 Over pronation and under pronation refer to the angles of the rearfoot Because we are describing the motion in terms on its position velocity or acceleration the focus is kinematics Kinetics and Kinematics combines Motion capture video provides kinematics 0 Single plane biomechanics only require 1 camera 0 Multiple cameras are required to capture motion in 3D motion is 3D 0 Force plates provide kinetics in 3D Biomechanics of injuries kinetics and an acute injury 0 this is a medal force on the lateral side of the right knee football side tackle to the knee 0 An injury caused by acute not repetitive loading 0 A contact injury 0 Because this example describes the force that caused the injury the focus is kinetics Force Platform or plate Analysis of kinetics Measures Ground reaction forces law of reaction Sensitivity standing barefoot can detect pulse We need isolation from train vibration at the UD campus Ground reaction forces are measured in 3 directions along 3 axes Anteroposterior is in direction of movement in walking and running studies Mediolateral forces are typically small except in cutting maneuvers Basic Landmarks in Gait Analysis walking video Related to Fma A VfVidt An increase the distance and time which decreases the acceleration and decreases the impact force Acceleration A VfVi t A nal velocity initial velocity time Ergonomics Biomechanics applied to the occupational setting and workplace or task de gn Biomechanics of running Stride cycle landmarks 0 Swing phase foot off the ground 0 Support or stance phase foot on the ground 0 Foot strike foot ground contact 0 Toe off foot leaves ground 0 Description of Running Speed 0 Stride length length off one stride 2 steps 0 Stride frequency of strides Speed stride length x Stride frequency 0 One or both can be increased to increase speed Running speed units mstride X stridess meterss Biomechanics of running 0 What are the kinetics forces of the foot strike 0 Rear foot strikers 0 Mid foot strikers 0 With or without shoes 0 With long strides or short strides The force platform provides this information as ground reaction forces Newton39s law of reaction AnteriorPosterior Ground Reaction Force Data 0 These graphs show the ground reaction forces being applied to the runner s center of mass during one stance phase 0 The positive direction force gt 0 is in the anterior direction Negative is in posterior direction 0 Remember that force plates measure forces in three directions 0 Medial lateral o Anterior posterior 0 Vertical Good runners minimize vertical COM displacement Not bouncing up and down too much Minimize the forces for braking and propulsion when running at a constant velocity Braking action results if foot hits ground too far ahead of COM Good runners save energy by minimizing the amount of braking force at foot strike With less braking force Less propulsive force is required to keep a constant velocity Center of pressure measurements Center of pressure the instantaneous point of application of the reaction force vector 0 Some People with diabetes have diabetic neuropathy and cannot sense forces or pain on the soles of their feet 0 Use COP measurements to locate quothot spotsquot of high pressure and design shoes or orthotics optimally Center of pressure and Force vectors 0 Center of pressure data come from a piece of planar material with a matrix of pressure sensors on it Data show how much pressure is being applied to different areas of the surface at different times 0 Force vectors magnitude and direction are shown as arrows The arrowhead of each vector is located where the peak pressure is located at that point in time Biomechanics center of mass Mechanical stability Biomechanics work amp power Work force displacement Power worktime Power Force velocity Pressure of a iud water or air Pressure FA P uid pgh Where p mV Exercise Physiology overview of physiological systems Applied physiology adaptive and integrative mechanisms Adaptive physiology Inherent adaptations such as those related to development again and pathophysiological conditions and adaptations to the eternal environment such as those occurring with exercise microgravity hypoxia hypobaric and hyperbaric and hypothermic and hyperthermia conditions Integrative physiology includes horizontal integration across organ systems and vertical integration from molecule to cell to organ Integration of systems Nervous system Primary function control systems of the body Primary component neuron nerve cell Responds to acute challenges of the body Very rapid milliseconds Clinical topics multiple sclerosis Parkinson39s disease carpal tunnel syndrome Sport performance coordination speed strength power movement skill Muscular System Primary function provide movement Primary component muscle cell muscle ber Muscle is the most metabolically active organ in the body 3 types of muscle 0 Skeletal 0 Cardiac 0 Smooth Clinical consideration muscle injury muscular dystrophy sarcopoenia 0 Sport consideration endurance speed strength power Skeletal system 0 Primary function structural framework of the body protects underlying organs and tissues provide a lever system for movement serves as a storage area for minerals Primary component minerals and cells bone Clinical consideration osteoporosis stress fracture bone loss in microgravity Cardiovascular system Primary function transport oxygen nutrients hormones and electrolytes Primary components heart blood vessels blood Clinical considerations cardiovascular disease leading cause of death in the US Sport consideration cardiac output in a predictor of performance in endurance sports Integrated Systems the delivery of nutrients from the digestive system by the cardiovascular system to the skeletal system Urina ry system Primary functions elimination of waste products regulation of uid volume electrolytes composition and pH Primary component kidney Clinical consideration hypertension can be in uenced by increasing the amount of uid removed by the kidneys Sport consideration performance at altitude performance in heat involved in regulatory responses to heat stress Pulmonary system Primary functionsL moving air into and out of the lungs regulation of acid base balance Primary component lung Clinical consideration CO poisoning tissue damage due to smoking high altitude pulmonary edema Sport consideration factor during exercise due to the ability to exhale carbon dioxide and regulate blood pH levels extract oxygen Very high surface area is accomplished by the structure of the alveoli and the extensive ca pilla rization Digestive system Primary function transfer nutrients and water from the food we consume into the body Primary component gastrointestinal tract Sport consideration gastric emptying rate of carbohydrate is best when its concentration is 6 glucose is a common source of carbohydrate in sports drinks a 10 carbohydrate concentration slows the emptying rate Transit time and absorption rates Endorine system Primary function control and regulation of physiological function and systems of the body Primary components endocrine glands secrete horomones to bloodstream insulin secreted by pancrease and regulates carbohydrate and fat metabolism Immune system Primary function regulating the susceptibility to severity of and recovery from infection abnormal tissue growth and illness Primary components physical mechanical chemical blood and cellular factors Clinical Considerations Exercise with compromised immune function Overtraining and higher rate of Upper respiratory tract infections Chronic in ammation Sport consideration Physical activity and regular exercise may improve the ability of the body to maintain health and reduce the risk for certain disease conditions Energy System Primary function provide energy during rest and exercise Primary component enzymes and energy sources within the cells Sports consideration energy production is critical for successful performance in athletic events of various intensities and duration Some training adaptations involve increases in key enzymes What are the bene ts of integrative thought when addressing health problems Health problems are complex and complete solutions often require knowledge about Multiple systems and how they work together horizontal integrative physiology And an understanding of mechanisms function and behavior at multiple levels or scales of observation molecule cell tissue organ behavior This vertical integration The Nervous System The endocrine system hormones and nervous system electrical are the two controllers of the body The nervous system is the faster controller Within the nervous system we will focus only on the motor and sensory aspects of movement Consider important clinical problems Delayed development of movement in a child Paralysis following stroke or spinal cord injury Parkinson39s disease Mobility limitations following traumatic brain injury TBI Consider interesting sport topics Neural determinants of Strength Speed Power Balance Coordination Dexterity OOOOOO Nervous System 0 Peripheral Nervous System PNS o Receptors 0 Motor Nerves o Sensory Nerves Central Nervous System CNS 0 Spinal Cord 0 Brain Afferent sensory pathways receiving information sensory feedback towards spinal cord from periphery or towards brain from spinal cord Efferent motor pathways motor drive towards effectors muscles Synapse Neuromuscularjunction is a synapse When an action potential arrives at the presynaptic terminal from the nerve axon neurotransmitter acetylcholine Ach is released Ach diffuses across the synapse to the muscle ber membrane and a muscle ber action potential is generated Synapses also form connections between neurons How is the control of muscle bers organized Muscle bers are controlled in sets 0 The sets are stimulated by an electrical impulse action potential from a neuron A single neuron and all the bers it innervates is a motor unit The motor unit is referred to as the 39 nal common pathway39 of control because there is no further division of control When an action potential reaches the muscle bers they all contract together Typical Motor Neuron Soma cell body contains nucleus receives input through dendrites Axon carries nerve impulses to terminal bers which in a motor unit are connected to muscle bers at a synapse Control of muscle bers Muscle bers are controlled in sets 0 The sets are stimulated by an electrical impulse action potential from a neuron A single neuron and all the bers it innervates is a motor unit Motor unit A motor neuron and all the bers it innervates Two control mechanisms at the motor unit level 1 Recruitment Increases and decreases in the number of motor units involved in a task causes increases and decreases in muscular force 2 Rate coding If the ring rate number of action potentials per second of a neuron increases or decreases this causes increases and decreases in muscular force Increasing then decreasing drive from brain for increase and decrease in force Motor neurons recruited in order of size Rate coding is the increase and decrease in MU ring rate vertical lines are action potentials How do we maintain balance during normal movement 0 Strategy Cognitive depends heavily on experience 0 Control posture Automatic and preparatory in uenced by practice 0 Control of purposive activity voluntary depends heavily on practice What controls movement of speed Strength is not the most important factor There is not a strong correlation between these variables Segmental Control Mechanisms 0 These are control mechanisms or pathways that operate at the level of the spinal segment Spinal re exes contribute much to the control of movement Involuntary control Simpli ed control no input from brain Rapid control short distance for neural conduction Stretch Re ex Unexpected stretch of muscle spindle Re ex Responses to Painful Stimuli Also segmental control bc it exists at the spinal segment You perceive the pain after you39ve responded The exion re ex or the exion withdrawal response 0 Touch hot iron 0 Step on tack Response too fast to be voluntary Flexion Withdrawal and Crossed Extension Re ex Pay attention to the and signs They indicate excitation or inhibition respectively Right side excite exors and inhibit extensors Left side excite extensors and inhibit exors Throwing as a model of fast movement 0 Rapid elbow extension Triceps agonist extends biceps antagonist prevents movement Nervous System Sensory Nervous System 0 Peripheral Nervous System PNS o Receptors 0 Motor Nerves o Sensory Nerves Central Nervous System 0 Spinal Cord 0 Brain Sensory lnput Interaction between performer and environment Require integration of sensory information and motor activity Vision Golgi tendon organs Muscle spindles Joint receptors Cutaneous receptors Vestibular system OOOOOO Afferent sensory pathways receiving information sensory feedback towards spinal cord from periphery or towards brain from spinal cord Efferent motor pathways motor drive towards effectors muscles Position Sense Proprioception is the detection of information about the movement and orientation of your body space Kinesthetic sense is the sensation of movement Proprioceptors are the sensory organs that are related to position sense The textbook also calls these kinesthetic receptors Visual and Postural Sway control of your body s center of mass location changes when you close your eyes This demonstrates the role of vision in postural control or postural sway Four Sensory Organs 1 2 3 4 Golgi tendon organ GTO detects tension force in muscle tendon organ Inhibits motor neuron In series with muscle bers Muscle spindle detects changes in length of muscle Lie in parallel to muscle bers Joint receptors detect joint positive Most sensitive near the end of a joint range of motion Vestibular apparatus canals that are lled with uid respond to accelerations of the head Golgi Tendon Organ Sensory organs that detects tension force in a muscle tendon unit Sends afferent feedback to the spinal segments In the leg GTO in the Achilles tendon is located where the muscle meets the tendon Protective inhibits muscles contraction in situations of excessive load Muscle spindle stretch re ex and postural control at the ankle joint Vestibular Apparatus amp Newton39s Laws Focus on the three semicircular canals and recall the coordinate system in biomechanics vertical anterior posterior mediolateral Law of inertial the canals are lled with a uid that has inertia Law of acceleration when the head accelerates the canals accelerate but you can think of the uid as lagging behind Like how you move while standing in a bus The uid bends hair cells in the canals and these cells convert the bending force to electrical impulses understood by the nervous system One hair cell in the vestibular apparatus The hair cell is the sensory neuron in vestibular apparatus When uid passes over the hair cells they bend and this causes electrical impulses to be sent to the central nervous system Basic Concepts of the Musculoskeletal System Tendon connects muscle to bone Ligament connect bone to bone in joints Soft tissue a term that refers to nonbody tissues like tendon ligament and muscle Connective tissue tendons and ligaments are different connective tissues 3 types of muscle cells 1 Cardiac muscle cell 2 Skeletal muscle cell 3 Smooth muscle cell Layers of muscle Muscle group joint system Muscle Fascicle Muscle ber bercel Surrounded by endomyisum Myo bril Sarcomere Actin thin Myosin thick Cell biology some organelles Organelle a structure within a cell such as a nucleus mitochondrion or chloroplast that performs a speci c function We will discuss the circled organelles throughout the semester Intracellular within the cell Extracellular outside of the cell Muscle cells are multinucleated What is a nucleus 0 Organelle that contains genetic material 0 What does it do 0 Controls activities of the cell through genetic expression Myo bril and sa rcomere A muscle cell contains hundreds or thousands of myo brils Sarcomeres contain the contractile proteins and are repeating units within all muscle Steps of Muscle contraction 1 Action potential electrical impulse travels along axon to neuromuscular junction electrical 2 A neurotransmitter called acetylcholine Ach is released and it diffuses across the synapse to the muscle ber membrane passive process about 1 min 3 When the Ach binds to receptors on the muscle membrane the process becomes electrical again and an action potential travels along infoldings of the muscle ber membrane ttubules towards the interior of the muscle ber where the contractile proteins are 4 Calcium is released and this causes a protein to move out of the way so that actin and myosin can bind These connections are called crossbridges 5 The power stroke happens involving the energy supplier ATP The myosin head changes shape and pulls actin proteins closer together Z lines are pulled towards each other and force is produced 6 When the calcium from step 4 is taken away repackaged the process stops The contractile proteins relax The muscle relaxes This is the neuromuscularjunction This is a speci c type of synapse the part of a nerve cell that allows one cell to communicate to another 0 A Synapse is a structure that involves the presynaptic nerve terminal and the post synaptic membrane It is a type of connection Contractile proteins in muscle ATP is the only energy source Actin and myosin contractile proteins Myosin heads pull actin laments The unit between Z lines is a sarcomere Muscle twitch characteristics 0 Muscle twitch muscle response to a single stimulus Biomechanics of muscle force Determinants of muscle force production 0 Consider muscles of the forearm and grip strength 0 Muscle size 0 Physiological cross sectional area 0 Forearm girth a gross eld measure 0 MRI a speci c clinical or research tool 0 Fiber type c Number of active cross bridges Muscle Force Length relationship Resting length is the muscle length at which a muscle or muscles produces its greatest force The mechanistic explanation is at the level of the cross bridges between actin and myosin proteins Muscle Force Velocity relationship Maximal lifts are very slow and you can throw a light object very fast These two tasks occur at different places on the force velocity relationship below 0 Velocity contractions eccentric generate the greatest force 0 The formation and release of cross bridges takes time At slow shortening velocities more cross bridges are formed at one time than at fast shortening velocities The amount of force produced by a muscle depends on the number of cross bridges formed 0 Power training can improve your forcevelocity relationship The post training curve shows he same force can be moved with greater velocity or that more force can be moved at the same velocity upward shift This would occur due to increases in fast twitch ber type speci cally due to an increase in the myosin heavy chain isoforms that have higher velocities Myosin lsoforms A protein isoform is any of several different forms of the same protein 0 There are multiple isoforms of myosin and some differ by their rate of quotturn overquot in cross bridge cycling fast vs slow Together with energy enzymes in the muscle ber the myosin isoform is what determines whether a muscle ber is slow or fast twitch Training can alter the amount of different myosin isoforms you have This is the reductionist mechanistic explanation for getting faster 0 Note there are also contributi09ns rom the nervous system to speed and power motor control system Power Force x velocity The shortening velocity of muscle bers determines the velocity of muscle bers determines the velocity ofjoint movements triceps shortening causes elbow extension in throwing Shortening velocity of muscle bers are determined by ber type slow twitch vs fast twitch or by myosin heavy chain isoforms at a more reduced level reductionist Many athletes want power and therefore want fast shortening velocities Summary 0 The forcelength and forcevelocity relationships are two properties of muscle 0 These mechanical properties have a physiological basis at the level of the cross bridges between actin and myosin Chronic power training can cause myosin heads to change to the faster isoforms of the fast twitch muscle ber Muscle damage and delayed onset muscle soreness DOMS Muscle pain and stiffness that usually peaks around 2436 hours after the exercise Accompanied by temporary loss of strength andor performance 0 Best treatment seems to be muscular activity 0 There is evidence that ibuprofen is counterproductive to the process of gaining strength DOMS Exaggerated by eccentric contractions Damage to muscle bers 0 Not caused by lactic acid The picture shows the research model of forced biceps lengthening exercise Subject resists experimenter pulls lever DOMS zline steaming Electron micrographs show structural damage at the level of the sarcomere When the highly organized zlines become disrupted this is called zline streaming The next two slides show normal and damaged muscle tissue DOMS elevated creatine kinase in blood 0 With the disruption of muscle bers a high amount of creatine kinase CK is found in the blood Creatine kinase is an enzyme involved in rapid production of ATP from Creatine Phosphate It belongs in the muscle cells not the blood Creatine kinase is also higher in the blood following a heart attack damage to the myocardium Creatine kinase release was pronounced only after the rst session of eccentric exercise This is interpreted as a protective effect of the rst bout of exercise the repeated bout effect Summary 0 A gradual progression into resistance exercise training will prevent soreness Repeated bout effect if you get sore after 1 bout of eccentric exercise you are less likely to be as sore after the next bout o If you cause muscle damage before competition your performance will suffer Basic concepts of the musculoskeletal system Functions of bone skeletal system 0 Provides support for weight bearing activities 0 Protect internal organs 0 Skull brain 0 Ribs lungs and heart 0 Provides structure that facilitate our movement 0 Bones rigid links between joints levers 0 Sites for muscle attachment 0 Storage of essential minerals 0 Calcium and phosphorus Bone Marrow 0 Makes red blood cells 0 Makes white blood cells part of the body s immune system Cellular level 3 types of bone cells in bone remodeling and ongoing turnover Osteocyte a mature bone cell Osteoblast cell bone formations Osteoclast cell responsible for bone resorption Calcium is important throughout the body When the body is in need of calcium osteoclasts breakdown bone to release calcium into the blood This is resorption Bone spongy and compact Spongy bone cancellous trabecular has trabeculae a lattice meshwork of boney rods 0 Compact bone cortical or dense bone Femur why are the ends bigger Pressure Force Area 0 Large surface area spreads forces 0 More spongy bone in big ends spongy 1015 times more exible Thin layer of compact bone covers spongy Soft tissues at the knee Cartilage 0 Flexible connective tissue 0 Reduces friction between bones allows them to glide o Absorbs shock o Menisci bands of cartilage Ligaments connective tissue that connects bone to bone Tendons connect muscle to bone Avulsion fracture excessive force of bone on muscle breaks off a piece of bone where the muscle is attached Reducing bonebone friction at the knee 0 Large ends and high surface area Cartilage on bone ends reduced friction Synovial uid reduced friction o Femur in thigh to tibia in leg Lifespan changes in musculoskeletal system Viscosity a uid39s resistance to flow 0 High viscosity oil molasses 0 Low viscosity water Decrease in viscosity of synovial joint uid with increase in age The patella provides mechanical advantage that increases joint torque b changing the angle at which the quadriceps muscles pull on the tibia Energy or muscular work Energy system 0 Primary function provided energy during rest and exercise 0 Primary components enzymes and energy sources within the cells 0 Signi cance energy production is critical for successful performance in athletic events and activities of daily living ADLs of various intensities and durations Metabolism Metabolism is the set of life sustaining chemical transformations within the cells of living organisms These enzymecatalyzed reactions allow organisms to grow and reproduce maintain their structures and respond to their environments Energy metabolism 0 Goal make energy for muscular contraction movement 0 The universal energy supplier is adenosine triphosphate ATP Macronutrients 0 Fat carbohydrate and protein 0 Don t provide energy directly 0 They are all converted to ATP which provided the energy Immediate energy ATP 0 Some ATP is stored in muscle and ready to use immediately 0 It is converted to energy without oxygen Anaerobic Breaking the chemical bond in ATP releases energy 0 This process is catalyzed by an enzyme called myo brillar ATPase ATP l ADP Pi heat energy Fast energy creatine phosphate Creatine Phosphate PCr is also stored in muscle 0 Break bonds in creatine phosphate PCr provides energy to reassemble ATP from ADP and available Phosphate P 0 Then the ATP is used for muscular work PCr ADP l creatine kinase ATP creatine Short term energy glycolysis Goal is to make ATP from Glucose Most glucose is stored as glycogen in the muscle quotmuscle glycogenquot and liver 0 Glycogenolysis rst converts glycogen to glucose Anaerobic Glycolysis provided 2 ATP and byproducts that enter the other aerobic energy pathways in the mitochondria krebs These aerobic pathways provide more ATP Anaerobic and Aerobic pathways in Glycolysis Follow the glucose o It enters the cell from the blood and anaerobic glycolysis provides 2 ATP 0 When pyruvate a byproduct enters the mitochondrion 36 ATP are provided by an aerobic pathway uses oxygen This pathway takes longer but with more yield 0 See the oxygen 02 molecule on the hemoglobin Hb in the blood 0 Some pyruvate becomes lactate Lactate production is related to that burning sensation in high power anaerobic exercise lactic acid Glycolysis lactate is a byproduct and a fuel 0 Bad lactate hydrogen ions H is lactic acid 0 You ve felt the burning sensation 0 Muscle contraction is impaired by H Lactic acid is not the cause of delayed onset muscle soreness Good lactate is an energy source for other metabolic pathways and tissues Lactic Acid as a fuel Lactate provides energy and material for gluconeogenesis conversion of lactate to glycogen in liver Lactate is the preferred fuel source for the heart liver kidneys and perhaps slow twitch muscle bers These tissues use lactic acid made during exercise forfueL Long term energy oxidative metabolism 2 Aerobic processes both require oxygen and occur in the mitochondria 1 Krebs cycle yields 4 ATP per glucose 2 Electron transport chain ETC yield 32 ATP per glucose Sum is 36 ATP Fat metabolism Evolutionarily we store fat for a reason energy supply during food shortage Fat stored in adipose tissue Fat cells adipocytes o Largest storage form of energy in body Mostly subcutaneous under skin some visceral surrounding organs Adipocytes comprised of triglycerides Triglyceride is converted to free fatty acids FFA Free Fatty Acid enters Beta Oxidative pathway highest ATP yield but slowest 1 Available ATP is immediate not much of it though 2 Creatine Phosphate can provide energy to reassemble ATP fastseconds not much ATP produced 3 Glucose supplied glycolysis and then oxidative metabolism results in 2 ATP anaerobic and 36 ATP through Krebs and ETC aerobic short term energy 4 Free Fatty Acids Beta Oxidation provide a lot of input to Krebs and ETC 460 ATP made long term energy Histochemistry ber typing with ATPase stain Histology the study of the microscopic structure of cells and tissues Histochemistry combining histology and chemistry to study the microscopic structure of cells and tissues Glycolytic capacity and oxidative capacity are related to energy pathways and determined by the amount of enzymes for these chemical reactions Contraction speed is determined by the type of myosin head that is in the muscle ber Different types are also called different isoforms Myoglobin protein that carries oxygen in muscle white meat vs dark meat in a chicken In the blood oxygen is carried by the hemoglobin Hb molecule In the muscle it is carried by myogobin Mb Recruitment of muscle bers by force level 0 The recruitment of muscle tissue into a task occurs at the level of the motor unit 0 Small motor unit recruited rst slow twitch bers small action potential 0 Large motor unit recruited seconds fast twitch bers large action potential Ultra endurance exercise alters muscle substrate use from blood glucose and muscle glycogen towards the use of fat as energy on a relatively short timescale Mechanism upregulation of genes that increased key energy enzymes and creation of new capillaries These short term adaptations are processes of glucose sparing and increased fat use Summary of Energy 0 ATP is the only source of energy at the actinmyosin cross bridge site of contraction Fast energy systems work without oxygen but produce few ATP There are few steps in the chemical reactions 0 Slow energy systems use oxygen and produce a lot of ATP There are many steps in the chemical reactions Cardiovascular System Physiology Signi cance of this unit Epidemiology cardiovascular diseases are the leading cause of death worldwide o It is largely preventable through modi able lifestyle factors healthy eating exercise and avoidance of smoking tobacco The American Heart Association is a great resource for information on cardiovascular health and pathology Circulation provides 0 Energy substrate for muscle 0 Oxygen 0 Blood Glucose 0 And other stuff Circulation removes 0 Carbon dioxide 0 Lactate note this can also be a fuel when brought to other tissues Cardiovascular System Components 1 Heart 2 Blood vessels 3 Blood The heart 0 Heart composed of cardiac muscle myocardium 0 Supported by mostly aerobic energy systems 0 Highly fatigue resistant 36792000 contractions in a year at 70 bpm o Requires oxygen heart attack deprived oxygen damaged tissues why asprin Has 4 chambers o 2 atria left and right smaller 0 2 ventricles left and right larger 0 Has two valves that separate chambers and control direction of blood ow no backwash Is a muscle with its own blood supply 0 Myocardiumheart muscle 0 Has its own nervous system to coordinate the contractions Top to bottom atria to ventricles o Pacemaker cells generate electrical impulses to initiate the heart39s contractions Arteries and veins Arterial circuit carries oxygenated blood Venous circuit returns deoxygenated blood to the heart Capillary bed 0 The branching of veins and arties into ne small diameter capillaries is the strategy that increases surface area for exchange of substances across membranes Capillary beds support our organs 0 Skeletal muscle 0 Lungs 0 Brain 0 Kidneys Pulmonary circuit between heart and lungs Systemic circuit to organs Pathway of circulation 1 Deoxygenated blood returns from body to heart 2 Heart sends some blood to lungs to get rid of carbon dioxide and pick up oxygen Oxygenated blood returns to the heart Heart sends oxygenated blood to body to support systems Oxygen dropped off at capillary beds in different tissuesorgans Deoxygenated blood returns to the heart at step 1 P P PPquot Blood pressure BP 0 Blood Pressure BP 0 Peripheral resistance to blood flow 0 Sphygmomanometer 2 components 0 Systolic highest pressure blood ejected from ventricles o Diastolic lowest pressure blood owing into ventricles Why is high blood pressure bad 0 Excess or chronic strain on the heart and vasculature Why is low blood pressure bad 0 Insufficient delivery of bloodsyncope fainting Responses to exercise 0 Acute immediate during a run heart rate goes up 0 Transient short lasting after run heart rate returns to resting value 0 Chronic long lasting After 6 weeks of running heart rate might be lower Cardiac Output 0 HR x SV The volume of blood pumped per minute It is one limiting factor during exercise It is trainable It is affected by pathology 1 Heart Rate beatsmin a Resting heart rate b Heart rate increases with exercise 2 Stroke volume SV a Volume pumped per beat b Depends on i Left ventricle size ii Forcefulness of heart contraction systole Acute Cardiac Output response to exercise 0 Heart rate goes up Max heart rate 220age o Mechanism in response to hormones and sympathetic nervous system activity and norepinephrine pacemaker cells increase the heart rate 0 Stroke volume goes up perhaps up to about 150200 mlbeat depending on the size of the heart and the person s activity background 0 Mechanism norepinephrine from sympathetic nerve bers causes stronger contractions of the myocardium The stronger contraction results in more blood being ejected from the heart 0 Norepinephrine acts as a hormone and neurotransmitter Here it acts as a hormone Integrated systems nervous system endocrine system cardiovascular system What is Angina Angina is chest pain or discomfort that occurs if an area of your heart muscle doesn39t get enough oxygenrich blood Angina may feel like pressure or squeezing in your chest The pain also can occur in your shoulders arms neck jaw or back Angina pain may even feel like indigestion Angina isn39t a disease it39s a symptom of an underlying heart problem Angina usually is a symptom of coronary heart disease What is heart failure 0 Heart failure is a condition in which the heart can39t pump enough blood to meet the body s needs In some cases the heart can39t ll with enough blood In other cases the heart can39t pump blood to the rest of body with enough force Some people have both problems What is cardiac rehabilitation Cardiac rehabilitation is a mechanically supervised program that helps improve the health and wellbeing of people who have heart problems Blood ow distribution 0 Send blood to where most needed during exercise 0 Away from digestive system 0 Towards muscles 0 Part of the mechanism 0 Vasoconstriction contraction of smooth muscle in arteriolar walls Reduce flow to area 0 Vasodilation relaxation of smooth muscle that increases arteriolar diameter and increases ow Sports medicine Sudden cardiac death in athletes rare 0 Left ventricular hypertrophy LVH occurs as a training response Left ventricular wall thickness Hypertrophic cardiomyopathy but sometimes ventricular hypertrophy is pathologic
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