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KINE 1020 SEM 2.doc

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Kinesiology & Health Science
KINE 1020
Hernan Humana

KINE 1020 Jan 4th 2012TOPIC 4Factors Impacting muscle health and fitness A Why muscle strength is importantHealth and fitnessPerformance RelatedSportGreater power speed and balanceReduce demand on Cardiovascular system JobOccupational requirementreduce risk of injuryProductivityHealth Related Lower Risk of Functional limitations avoiding injuriesinfirmityPredictor of advanced age disability Lower Risk of Chronic Diseases improved blood sugar control Prevent slow down osteoporosis Increase metabolic Rate Psychological Health improve self image Emergencies Muscle Fiber types for Sport Performances Type I fibres endurance activities slow Long distance runners need more muscle fibres Type II fibres strength and power activities fast Sprint runners need less muscle fibresOccupational Requirement Physical Ability test in firefighters Some jobs require a certain type of physical fitness in order to qualify HealthRelated Lowering the risk of Functional Limitations Maintaining or improving muscular strength later in life reduces the percentage of functional limitations by over 50 for both men and women Muscle Strength as a Predictor of old age Used grip strength predictor of functional limitations later on in lifeHigher percentage of people who had a lower strength a functional limitationPeople with greater muscle strength during midlife are at a lower risk of becoming disabled bc of their greater reserve of strength regardless of chronic conditions that may developB Muscle Strength Across the LifespanMuscle Performance Measures Childhood to Young Adult 618yrs Static Strength Grip strength pull strength Dynamic Strength flexed knee sit ups Muscular Endurance Flexed arm hang Fairly linear increase in strength from 6 to 18 For the most part males have more strength power and endurance then females especially when they hit puberty Girls will start to plateauTraining will gain power and strength If you stop you will still have some strength and if you continue to train again the rate of increase in strength will be better Muscle Performance Measures aging After age of 30 strength begins to decreaseIf you do strength training you will have more strength and it will decrease at a lower rate after age of 30Decreasing muscle strength with Aging Sarcopenia is the loss of muscle mass and strength due to aging process12 muscle massyr past 50yrs of age loss of strength varies and may be greater PrevalenceImpacts 1025 of the population under 70rs of age an about 40 above 80yrs of ageBy 80yrs a loss of 3040 of the muscle fibres hypoplasia loss of muscles fibres ofmuscle containing Type II muscle fibre Concerns Risk of functional limitationsJan 6th 2012Sarcopenia Loss of muscle size is a result of Programmed Cell death ApoptosisCharacterized by DNA fragmentation Nuclear condensation leading to formation of apoptotic bodies these are engulfed by macrophages but do not induce an inflammatory responseDNA Fragmentation DNA Fragmentation Fractor Enzymes DFF 40 degrades the DNADNA Fragmentation Fractor Eat out muscle cells DFF 45 Doesnt allow the DFF 40 to occur It inhibits DFF 40 does not allow it to be active Caspase3 important part in DNA fragmentation Key regulators Nuclear Condensation or Disassembly StagesUncondensedRing Necklace Collapse Disassembly AIF ApoptosisInducing Factor occurs at the Ring Decreasing Muscle Strength with AgingPotential Causes of Sarcopenia Still being identifiedI Activation of apoptotic pathways caspases enzymes that breakdown and degrade proteins an DNA and AIFMOST IMPORTANTII Loss of hormone adaptations decreases in testosterone and growth hormoneIII Loss of Neurological influences selective loss of Type II motor units resulting in cluster of Type I muscle fibre with age Apoptotic Pathways Leading to Programme Cell DeathCapase Dependent Processes Inactive ActiveProcaspases CaspasesDNA ProteinInitiator Caspases Caspase 8 10 Effector CaspasesCaspase 9 Caspase 3Caspase 12 Caspase 6 7Activation This is what Procaspases need to be activatedIncreased Calcium in muscleleaky sarcoplasmic reticulum Caspase 12 perhaps 8 and 10 Increased Reactive Oxygen Species ROS from mitochondria caspase 8 10 Released Cytochrome c from leaky mitochondria when its leaky cytochrome c will leak out of the mitochondria damages the muscle Apaf1ATP Apoptosome caspase 9Bax and Bcl2 regulate cytochc releaseBax promotes and increases leakage of Cytochrome C not a good thingBcl2 will slow down the leak of Cytochrome C which slows down the Apoptosome a good thingActivation of proteolytic pathways proteases enzymes that breakdown and degrade proteins byI CaspaseDependenta Ionic Imbalance accumulation of intracellular calcium sodium hydrogen loss of potassiumb Oxidative stress accumulation of reactive oxygen species ROS which are considered damagingc Mitochondria dysfunction a decline in ATP levels increase in Oxygen free radicals membrane leakageII CaspaseIndependent nuclear condensation a Mitochondria dysfunction apoptosis including factor AIF resulting in nuclear condensation and DNA fragmentation AIF is the primary agent for reducing nuclear condensation
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