Sport and Exercise Physiology Muscles Muscle Types 1. Smooth Muscle – – Involuntary muscles – not under direct conscious control Walls of blood vessels, internal organs (GIT) 2. Cardiac Muscle – – Heart only – not under conscious control Controls itself 3. Skeletal or Striated Muscle – – – – Under conscious control Attached to and move the skeleton Make up the Musculoskeletal System Can you name a few?? Definition • Muscle is a contractile tissue which brings about movements. • Muscles can be regarded as motors of the body. BASIC PROPERTIES • IRRITABILITY: – Sensitive to stimuli • CONTRACTILITY: – When stimulated, the contracts lengthwise leading to its shortening • EXTENSIBILITY: – Once stimuli removed, the muscle fibers return to their original length. • ELASTICITY: – Muscle assumes a desired shape. The Musculoskeletal System Activity • In Groups discuss what muscles you think equestrian athletes use: LO 2 & 3 The Musculoskeletal System http://www.shapesense.com/fitness-exercise/muscle-anatomy/ Muscle Actions Types of Muscle Action Isometric – Muscle exerts force without changing length – Pulling against immovable object – Postural muscles Dynamic (isotonic) – Concentric Muscle shortens during force production – Eccentric Muscle produces force but length increases Associated with muscle fiber injury and soreness Muscle Actions Isometric and Isotonic Muscle Actions Eccentric / Concentric • Somebody perform a squat: – What is happening on the way down? – What is happening on the way up? • Somebody perform a press-up: – What is happening on the way down? – What is happening on the way up? Summary of Muscle Actions LO 1 Types of Muscle Contractions Dynamic exercise = change in muscle length creating joint movements. Rhythmic cycles of contraction and relaxation •concentric •eccentric LO 1 Types of Muscle Contractions Isometric (static) exercise = constant muscle length and increased tension – Joint angles do not change. Discuss in pairs what type of contractions occur when you ride. Anatomy of Skeletal Muscles Muscle Contractions Now in pairs yourvideo answers to prepare Watch the discuss following & answer thefor a Kahoot quiz questions provided Go to www.kahoot.it Muscle Fibre Contractions • α-motor neuron connects with numerous muscle fibers • Excitation – Contraction Coupling (1-3) • Role of Calcium Ions (45) • Myosin Cross Bridge formation and the sliding filament theory (6) • Adenosine Triphosphate (ATP) is needed to power this process – broken down by enzyme ATPase • Muscle Relaxation (7-9) LO 1 Muscle Fibre Types • Two types different speeds of shortening and ability to generate maximum force Type of Muscle Fibre Speed AVG % in to reach Muscles peak tension Forms of Myosin ATPase Sacroplasmic α – reticulum (SR) motor Development neuron Aerobic Endurance Type of Activity Type I 110ms 50% Slow form Low Innerva tes ≤300 muscle fibers High lowintensity Type IIa – 25% Type IIx – 25% Type IIc – 1-3% Fast form High Innerva tes ≥300 muscle fibers Low = Anaerobic High – intensity Type II 50ms (Type IIa, Type IIx and Type IIc) Recruitment of Muscle Fibres • Principle of orderly recruitment: Motor units are ranked e.g muscle with 200 motor units = number 1200 – very fine contraction recruits No1 only, as contraction increases 2,3,4,5etc = recruited • Skeletal Muscle contraction goes through progressive recruitment Type I Type IIa Type IIx Fibre types and success in sport • In Groups discuss which type of muscle fibre would be best for the following Sports areas (as allocated) a. b. c. d. Team Sports Endurance Sports Sprints Strength and Power Sports • Feedback to the class your thoughts LO 2 What about Equestrian??? Testing Muscle Strength • Isometric Testing: – Tests strength at a particular angle of the joint. – Determines parameters – maximal force, maximal torque and rate of force development (RFD). – Poor relationships between isometric (static) and dynamic performance – Uses tensiometers, strain gauges and force transducers. • Isoinertial Testing – Uses external weights – Dynamic contractions are tested – Limitation = great motor control required to lift weights – increase the risk of injury – Maximal Concentric Strength is measured – Uses test involving a low number of repetitions – typically 1-3 repetition maximum (RM) – 1RM regularly used Testing Muscle Endurance • Isoinertial Testing – Subject’s own body mass provides the resistance. – Uses tests such as Curl-up, Press-up and Chip-up – Athlete’s perform as many of these exercises as possible Aerobic Vs Anaerobic Training Effects O Aerobic 2 • Type I fibres increase in size and number • Within the Muscles Fibres: 1. red in colour (high myoglobin content) – increase myoglobin by 75-80% 2. surrounded by many capillaries – increases by up to 15% 3. numerous mitochondria – increase by 15% 4. low glycogen content (they also metabolize fatty acids and proteins, which are broken down into the acetyl CoA that enters the Krebs cycle) LO 1 O2 Anaerobic • Type IIa and Type IIx increase in size and number • Within the Muscles Fibres: 1. 2. 3. 4. Whiter in color (low myoglobin) surrounded by few capillaries relatively few mitochondria high glycogen content (they have a ready supply of glucose for glycolysis) Effects of Resistance Training • Strength – increases 25-100%!!!???? • Hypertrophy – Transient Hypertrophy – Immediate increase in muscle size after exercise– goes within hours of exercise – Chronic Hypertrophy – increase in size from long-term resistance training = structural changes in the muscle. Results in: • In increases in size to individual muscles fibres = fibre hypertrophy • Increase in number of muscle fibres = fibre Hyperplasia • Training disrupts the sarcomere Z-lines resulting in fibre protein remodelling (Shepstone et al 2005) LO 3 Resistance Training • Considerations: – What major muscle groups need training – What type of training should be used to achieve the desired outcome – What energy system should be stressed – What are the primary sites of concern for injury prevention – Numbers of sets for each exercise – Rest periods between sets and exercises – The amount of resistance, repetitions and velocity of the movement. LO 3 Resistance Training • Strength – – – – Involves repetitions of concentric and eccentric actions Large muscles groups – smaller muscle groups stress first High-intensity exercises are done before low intensity exercises When athlete can perform current workload at or above the desired number of reps – increase load by 2-10% – Focuses more on Eccentric contractions • Hypertrophy or power – Uses the same principles but athlete works at a higher 1RM % and performs increased amounts of sets and/or works at a faster pace • Endurance – Uses the same principles but uses a light load (weight), increased repetitions and works at a slow pace LO 3 Next Week – Respiratory System • Before then in two groups: • Group 1 – Investigate what the Conducting zone of the lungs is and what it is made up of? • Group 2 – Investigate what the Respiratory zone of the lungs is and what it is made up of? You will report this back to the class next week!!