Stretching & PlyometricsLecture OverviewReview Question #1Review Question #2-3Review Question #4Review Question #5Review Paper & Presentation Due Wednesday December 7Stretching – Is it advised?How is muscle stretch detected?Muscle SpindlesMuscle Spindles (con’t)Slide 12Slide 13Movement ExampleMovement Example (con’t)Golgi Tendon Organs (GTO)Types of Stretching TechniquesResearch Article #1Stretching Basic Science EvidenceSlide 20PlyometricsPlyometrics (continued)Slide 23Plyometrics Coordination RequirementsResearch Article #2Plyometrics Workout IntegrationSlide 27Stretching & PlyometricsDr. MoranEXS 558December 1, 2005Lecture OverviewReview QuestionsReview Paper Brief PowerPoint DemoStretching (partial Ch. 13)Muscle SpindlesGTOType of StretchesMuscular Adaptations to Stretching“Stretching Before Exercise Does Not Reduce the Risk of Local Muscle Injury: A Critical Review of the Clinical and Basic Science Literature”Plyometrics (partial Ch. 12)Scientific Basis“The effects of shoulder plyometric training on propioception and selected muscle preformance characteristics”Workout IntegrationPlyometric Training DesignCTE (Student Volunteer?)Review Question #1What physiological adaptations can be expected from a basketball engaged in a 12 week preseason conditioning program?↑ transformation of type II fibers to a more glycolytic subtype (spectrum)↑ elevations of glycolytic enzymes (e.g. PFK)↑ in maximum blood lactate concentrations↑ [blood lactate] during submax exercise intensitiesImproved buffering capacityReview Question #2-3Which of the following is NOT a method for measuring anaerobic power?(a) Wingate Test(b) Margaria-Palamen Test(c) Sargaent Jump TestWhat is difference between anaerobic power and anaerobic capacity?Anaerobic capacity is the maximum amount of ATP resynthesized during a short duration anaerobic activity and is usually measured by maximal blood lactate levels. Anaerobic power is defined as the maximal capacity to produce to produce ATP via a combination of the ATP-CP and glycolytic systems. It is measured in watts.Review Question #4What is the primary reason for increased central blood volume flow during deep water running?Hydrostatic vascular gradient increases perphiral pressure shunting blood to the central thoracic cavity.This causes _____ increase in cardiac output at rest?(a) 15-20%(b) 20-25%(c) 25-30%(d) 30-35%Review Question #5What is the major differences for an untrained versus trained population that are utilizing a deep water training program? What are the biggest differences in the expected outcomes in these two groups?The relevant research shows that trained runners can use DWR to MAINTAIN but not IMPROVE aerobic capacity for up to 3 weeks, BUT untrained athletes can actually IMPROVE aerobic capacity through a DWR training program.Review Paper & PresentationDue Wednesday December 7Things to Remember - PRESENTATIONPowerpoint: make slides available to classmatesEmail before 5pm on Wednesday to Dr. Moran ORBring on a JumpDrivePresentation should be at least 15 minutes long with 5 minutes for questionsEach class member will ask at least one question following presentationEach class member will also evaluate each presentation in a # of categories and offer constructive criticismSome Key Points – PAPERTitle Page – don’t forget thisAvoid paragraph after paragraph of summarizing research articles. A CRITICAL review forces you to synthesize material not just regurgitateAvoid statement:In 2004 Moran’s study on….First sentence of paragraph should explain that entire paragraph. Scientific writing should be simple and easy for the reader to followBrief PowerPoint DEMOStretching – Is it advised?Does stretching before exercise reduce injury rates?How does stretching increase flexibility?No basic science articles have directly examined the effect of stretching on injury preventionMany believe stretching to improve ROMImproved performanceReduced Injuries?“Stretching-Induced Strength Deficit”: preexercise stretching may compromise the ability of a muscle to maximally contract.How is muscle stretch detected?Muscle PropioceptorsGolgi Tendon Organs (GTO)Muscle SpindlesThese are all sensory neural fibers that relay information about musculotendon stretch to the upper CNSMuscle SpindlesThese structures let other neurons know about the LENGTH and VELOCITY of muscle fibersScattered among muscle fibers in large quantitiesBetween regular skeletal muscle fibers (extrafusal)Within each spindle – specialized muscle fibersIntrafusal: attached to either extrafusal fibers or tendionous ligaments, so that when extrafusal fibers change length the intrafusal fibers are stretched or shortenedBag Fibers: refers to distribution of nuclei in fiberStaticDynamicChain Fibers: refers to distribution of nuclei in fiberThese fibers are myelinated with diameters ranging from 12-20 μm (AP velocity of 120 m/s)Central region can not contract b/c contain few actin or myosin filamentsNerve endings are wrapped around this central portionMuscle Spindles (con’t)Two types of sensory endingsPrimary (Ia): in all intrafusal fibersSecondary (II): seen in chain fibers and static bag fibers, but NOT dynamic bag fibersIntrafusal Fibers controlled by γ-motor neuronsExtrafusal fibers controlled by α–motor neuronsSensory Input to CNSInnervation to muscle fibersMuscle Spindles (con’t)Muscle Spindles (con’t)Your arm is bent at the elbow with your palm up when someone suddenly places a weight in your handMuscle Stretch (biceps brachi): this stretches the muscle spindlesThis sends a signal to the CNS which stimulates the α–motor neuronsMuscle force increased in biceps to overcome forearm drop and stabilize weightMovement ExampleMovement Example (con’t)γ-motor neurons excite the intramusal fibersPrestretch  increases sensitivity to muscle length changesUnique system because the “GAIN” of system can be altered through innervationCo-activationγ-motor neurons are also contracted when α–motor neurons are stimulated to contract extrafusal fibersThis increases muscle force productionIntegral to the field of motor controlGolgi Tendon Organs (GTO)Located proximal to the tendon fibers attachment to the muscle