Proprioceptive Neuromuscular FacilitationExercise and the Musculoskeletal SystemPages 267-270 and 431-439TermsMuscular strength. What is it?Muscular endurance. What is it?AdaptationsN e u r a l f i r s tC o n t r a c t i l e , s e c o n dNeural AdaptationsWhat neural changes occur with training that contribute to an increase in muscle strength?Neural AdaptationsRecruitment of additional MU (IIb or Fast Twitch B)Increase rate of MU stimulationEnhance synchronization of MU firingNeural dis-inhibition (ignoring GTO)Neural dis-inhibitionGolgi tendon organs inhibit continued contractionMuscle AdaptationsWhat muscular changes occur with training that contribute to strength grains?What is hypertrophy?What contributes to muscle hypertrophy?Does one fiber type hypertrophy more than another?Muscular AdaptationsCell Hypertrophy or Cell Hyperplasia?Muscle cell hypertrophy accounts for 95-100% of overall muscle hypertrophyThe remainder is the result of hyperplasia Strength and Endurance TrainingSome studies show combined aerobic endurance and strength training may limit strength gains.Other studies show no effectOnce aerobic training reaches a plateau, strength training can improve time to exhaustion.Progressive Resistance Principle of OverloadMilo of CrotonaMilo of Crotona, Greek athlete, lived about the end of the 6th century B.C. He was six times crowned at the Olympic Games and six times at the Pythian for wrestling, and was famous throughout the civilized world for his feats of strength - such as carrying an ox on his shoulders through the stadium at Olympia. In his native city he was much honored, and he commanded the army which defeated the people of Sybaris in 511.The traditional account of his death is often used to point a moral: he found a tree which some woodcutters had partially split with a wedge, and attempted to rend it asunder; but the wedge fell out and the tree closed on his hand, imprisoning him until wolves came and devoured him. His name became proverbial for personal strength.Encyclopaedia BritannicaStrength Training PrinciplesIntensityFrequencyDurationRepsSetsRestDiscussionWhat are the general recommendations for the following resistance training programs: strength, power, hypertrophy and endurance. [Kraemer and Koziris, 1992]Why are there differences in these programs? Think physiological.What is plyometric training? What gained from plyometric training?Strength ProgramHeavy resistance (< 6-RM)Moderate to long rest periods (> 2 min)Moderate to high number of sets (4-10 and 1-3) for primary exercisesWhy so much time in between?Power ProgramSpeed overload increases neural stimulation and minimizes the slowing effects of hypertrophy High resistance (< 10 RM) that is varied over time; rarely more than 5 reps per set.Moderate to long rest periods (> 2 min.)Moderate to high number of sets (4-10 and 1-3)Plyometric exercisesPower Program - PlyometricsPlyometric PhysiologyPlyometric LoadingWhat is it? Eccentric contraction followed by a fast, explosive concentric contraction What’s the physiology behind it?Stretch-shortening cyclegreater or quicker fiber recruitment with help from muscle spindlesElastic energyHypertrophy ProgramGreater volume and varietyModerate to high intensity (12-20 RM)Less rest (less than 90 sec.)High total number of sets per muscle group (> 3)UnprovenGreat size and number of type I fibersEndurance ProgramLow intensity (12-20 RM)Moderate rest depending on number of reps (2-3 min or 30-60 sec.)Moderate sets (2-3)Toning?Summary TableDiscussionPeriodizationLoad Period (Hypertrophy)2-3 months with microcycles or day to day variationsRecovery Period (Endurance)2-3 weeksPeak Period (Strength)Same length as load cycleConditioning Period (Power)WeeksPeriodizationPeriodizationNo advantage to untrainedNo clear advantage to trainedMyth BustersMuscle size (hypertrophy) is not a synonym for muscle strengthMuscle size (hypertrophy) does not necessarily lead to inflexibilityEndurance programs (high reps) are not effective for weight lossMuscle tissue has only a slightly higher “metabolism” than fat tissueResistance TrainingIsometricIsotonic or DynamicIsokineticIsometric TrainingIs isometric training effective?What are its limitations?What are its advantages?Isotonic TrainingConcentric and eccentric muscle contractionsExamples of isotonic exercisesFree WeightsMachinesVariable resistanceEccentricIsotonic Free WeightsWhat are the advantages?What are the disadvantages?Isotonic MachinesWhat are the advantages?What are the disadvantages?Variable ResistanceVariable ResistanceWhat are the advantages?What are the disadvantages?Eccentric LoadingIsokineticSpeed kept constant with “accomodating resistance”What are the advantages?What are the disadvantages?ComparisonGender DifferencesDISCUSSIONIn what ways does the principle of specificity apply to resistance training?Is strength re-grained faster than the initial gains?SPECIFICITYIntensity of contractionSpeed of contractionMuscle groupType of contractionSpecificity & Functional TrainingFunctional TrainingMuscle Group SpecificityType of exercise matters even in the same muscle groups ReversibilityReturn of strength after periods of inactivity FlexibilityStreching/FlexibilityF = 3-7 days a weekI = stretchingT = 15-60 sec., 1-3 setsFlexibilityCan decrease or increase the risk of injury.Training for FlexibilityStatic stretchingPrevents muscle spindles from shortening the muscleDynamic stretchingMay activate muscle spindles which produce muscle shorteningTraining for FlexibilityProprioceptive Neuromuscular FacilitationContract muscle to stimulate GTOGTO cause muscle to relaxStretch relaxed muscle furtherThe Impact of Stretching on Sports Injury Risk: A Systematic Review of the LiteratureTHACKER, S. B., J. GILCHRIST, D. F. STROUP, and C. D. KIMSEY, JR. Med. Sci. Sports Exerc., Vol. 36, No. 3, pp. 371-378, 2004.Impact of Stretching on Sports InjuryLittle evidence of link between flexibility and injury rateLack of flexibility does not account for many muscles injuries the occur w/i a normal range of motionImbalance in flexibility may increase injury riskStretching may increase performance or it may decrease performanceImpact of Stretching on Sports Injury“There is not sufficient evidence to endorse or discontinue routine stretching before or after exercise to prevent injury among competitive or recreational athletes.” “Further research, especially well-conducted randomized controlled trials, is urgently needed to