KIN 122 1st Edition Lecture 3Measurement• Direct measure (laboratory test): measuring the exact thing you are trying to assess • Indirect measure (field test): measuring something else as a measure of the thing you are trying to assessWhat is fitness?• A set of attributes that people have or achieve that relates to the ability to perform physical activity • Remember: NOT a behaviorA characteristic of a personTwo types:Skill-related fitnessHealth-related fitness1. Skill-related: Ability to perform specific skills required to take part in various activities and sports2. Health-related: Focused on areas that relate to our overall health status and our ability to perform daily tasks and activitiesHealth-related fitness1. Cardiorespiratory fitness2. Body composition3. Musculoskeletal fitnessMuscular strengthMuscular enduranceFlexibilityCardiorespiratory fitness (CRF)• The ability of the body’s circulatory(heart, blood vessels) and respiratory systems (lungs) to supply fuel during sustained moderate to vigorous activities • Often reflected and measured as oxygen consumption (maximal/submaximal)These notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.Oxygen consumption • Rate of oxygen utilization during exercise• Reflects:The capacity of the cardiorespiratory system to transport oxygen to the working musclesThe utilization of oxygen by the muscles during exercise • Fick equation:VO2 = CO x A-VO2Cardiac output (CO) = amount of blood leaving the heart per minuteArterial-venous O2 difference (A-VO2) = Difference in oxygen content between the arterial blood (↑oxygen) and the venous blood (↓oxygen)CO= HR x SVHeart Rate (HR) = # of beats/minStroke Volume (SV) = amount of blood heart pumps with each beatHow to measure CRF?• Maximal O2 consumption (VO2max)Maximum capacity of the body to transport and use oxygen during exerciseMeasured directly or indirectlyDirect: maximal graded exercise testIndirect: submaximal test, field testMaximal graded exercise test• “Gold standard” for measuring fitness• Gradual increase in intensity to point of exhaustion • Commonly conducted on a bike, treadmill, arm ergometer• Hooked up to metabolic cart to analyze inspired/ expired air to determine oxygen consumption• Peak = When intensity increases, oxygen consumption levels offSubmaximal exercise tests• Exercise at a moderate intensity and use equations to estimate VO2max• Equations use HR, workload, age, sex• Commonly use bike, treadmill, step test• Key assumption: Steady-state HR at each exercise intensityLinear relationship between heart rate, oxygen uptake and workloadField tests• Measure time it takes to walk/run specific distance • Examples: 9-12 minute run test1.5 mile run/walk“beep test”CRF and exercise training• Exercise training results in ...More effecient oxygen delivery/consumptionHeart delivers oxygen-rich blood more efficiently to the muscles Muscles use oxygen more efficiently VO2 = CO x A-VO2– Ability to sustain continuous aerobic activities• What types of activities promote CRF?Running, biking, swimming, any type of aerobic activityCRF and aerobic exercise• ~15% increase in VO2max with training • Strong genetic component to increase (~75%) • Benefits of improved CRF:Improved functioning and enduranceReduced risk for chronic diseases and death Body composition• Relative amount of body fat vs. lean body tissue (fat free mass)Fat Free Mass: muscle, bone, water, skin and blood• Often expressed as percent body fatMeasuring body composition• Laboratory tests (direct):Hydrostatic weighing Air displacement plethysmography (Bod Pod)Dual-energy X-Ray absorptiometry (DXA)• Field Methods (indirect):Skinfold methodBioelectrical impedance • Use standard equations to calculate body composition based on measured values• Field Methods (indirect):Anthropometric measures• Waist circumference • Body mass index (BMI)• BMI = kg/m2• Waist-to-hip ratio Why is body composition important?• Unhealthy body composition associated with increased risk of diseaseOverweight/Obesity – CVD, hypertension, type 2 diabetes, osteoarthritis, certain cancers Underweight – cystic fibrosis, physiological dysfunctionBody composition and exercise training• Improved body composition profile:Reduce percent body fatIncrease fat free massImprove bone mineral densityImprove anthropometric measuresMuscular fitness• 3 Components: Muscular StrengthMuscular EnduranceFlexibilityMuscular fiber types• Slow-twitch (red)Smaller fibersFatigue-resistanceLow force capacityAssociated with endurance or aerobic activities• Fast-twitch (white)Larger fibers FatigableHigh force capacityCapable of more powerful but shorter contractions• The percent of fast-twitch and slow-twitch fibers largely genetically determined• Most people roughly 50/50• Ratio not related to health, but related to performanceMuscle contraction• Voluntary contraction controlled by Central Nervous System (CNS)• Tension generated by muscles fibers• Contraction can be static or dynamic• Muscle may lengthen, shorten or remain the same length Contraction types• Static – isometric contractionresistance is immovablemuscle stays the same length while producing force• Dynamic –isotonic contractionvisible joint movement Muscles are shortening or lengthening while producing forceEccentric – muscle lengthensConcentric – muscle shortensMuscular strength• Ability of the muscles to develop maximal force • How much we can lift, push or pull in a single all-out effort• Power: Amount of work performed in a given time• Ability to exert strength and power limited by central nervous system (CNS)Factor influencing strength• Muscle mass activated • Type of fiber activated (I vs. II)• Number and sizeof motor units activatedMotor unit: single motor neuron and the muscle fibers it innervates• Frequency at which action potentials are sent to muscle fibersDefinitions related to strength• Strength Training: all types of exercise devoted to increasing muscular strength and size• Hypertrophy: Increase in muscle size as a result of trainingResult of increased volume of muscle fibers Atrophy: Shrinking of the musclesResults from inactivity, lack of use, immobilization, diseaseStrength assessment• No single test to measure overall muscular strength or endurance –