Static Dynamic Isometric Isotonic Isokinetic Constant External Resistance Variable Resistance Plyometrics Muscle Contraction Static contractions The muscle tension or force exerted against an external load is equal to or weaker than the external force ID: 921340
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Slide1
Muscles Part II
Slide2MUSCLE CONTRACTIONS
Static
Dynamic
Isometric
Isotonic
Isokinetic
Constant External Resistance
Variable Resistance
Plyometrics
Slide3Muscle Contraction
Static contractions
The muscle tension or force exerted against an external load is equal to or weaker than the external force
No visible movement occursDynamic
ContractionsInternal & external forces are unbalancedExternal force (gravity, weight of object) is not equal to the internal force (produced by athlete’s muscle)
Generates movement
Slide4Isometric
Static
Means
“Same Length”Work = force x distanceSince no movement occurs, no work occurs
Instead measured by the rate of tension & duration that tension lasts+ Causes hypertrophy- Strength gains are specific to
joint angleThis is called Specificity
Slide5Isokinetic
Means “same speed
”
Resistance is changed so speed of movement can be maintained - Requires
specialized equipment +/- Trains single joint movements+/- Strength gains are specific to the training velocity
SpecificityUsed primarily in rehabilitative settings+ Safe way to train muscles
+ Muscles can be isolated
Slide6Isotonic
Means “same tension
”
+ Mimics real life movements- Difficult
to achieve “same tension” through entire ROMBeginning & end of ROM achieve less tension than middleTwo Phases:Concentric:
Muscle shortens as it moves through range of motionMoves against gravitational force (overcomes it)Eccentric:Muscle lengthens as it moves through range of motion
Moves with gravitational force (resists it)
Slide7Types of Isotonic Exercise
Constant External Resistance
Free weights, body weight exercises, medicine ball,
etc
Enough resistance provided in parts of movement and not enough in other partsSelection of weight is critical - Often training doesn’t occur at ends of ROM
Result: appearance of joints that can’t be straightened+ May mimic “real world” movements more
+ Increase activation of stabilizing muscles
Slide8Types of Isotonic Exercise
Variable
Resistance
Exercise
Machines that utilize cams and/or pulleys, elastic bands/tubing, etc
Automatically changes the resistive force throughout the ROM
+ Good for novice, older and/or recreational athletes+ Help control motion
- Do not promote muscle coordination or balance
Slide9Types of Isotonic Exercise
Plyometric (
AKA: Jump
Training or Stretch-Shortening Cycling)
Trains muscle to reach maximal force in shortest possible time (power) Amortization Phase: amount of time it
takes muscle to change direction from “stretch” to “shorten” Ideally this should be as short as possible
Places high stress on muscles, connective tissue & jointsRequires foundation of physical fitness Intensity, repetitions & sets should be carefully prescribed
Slide10Training Muscle
Trainable Factors
Fiber diameter
Hypertrophy
Atrophy
Coordination of muscle fibersNerve impulse frequencyElasticity of muscle & tendonsEnergy stores of muscle & liver
# of capillariesNon-Trainable Factors
Number of fibers
HyperplasiaFiber Type
Slide11Creating Movement
Muscle attaches to bone via tendons
Origin of muscle on non-moving bone
Insertion of muscle on the moving bone
Motor neuron signals contractionMuscle shortens and pulls on boneMovement occurs about a jointInsertion moves towards
origin
Slide12Muscle Teamwork
When one muscle contracts, another must relax
Agonist (prime mover) creates desired movement
Antagonist opposes the desired movement
When agonist contracts, antagonist must relaxAgonists & antagonists are typically on opposite sides of jointsExample:Biceps
brachii & Triceps brachii
Slide13Muscle Teamwork
Synergist:
A muscle that surrounds the joint being moved
Aids the prime mover in creating desired movement
On same side of joint as the prime moverEx: Gluteus maximus & Gluteus
medius extend thighFixator or Stabilizer:A muscle that contracts with no significant movement to maintain a posture or fixate a joint
Ex: Erector spinae during a push-up
Slide14Muscle Groups
Gluteal Group
Gluteus Maximus
Gluteus Medius
Gluteus Minimus
Slide15Muscle Groups
Quadriceps Group
Rectus
femorisVastus
lateralisVastus intermedius
Vastus medialis
Slide16Muscle Groups
Hamstring Group
Biceps
femoris
SemitendinosusSemimembranosus
Slide17Muscle Groups
Abdominals
Rectus
abdominis
External obliqueInternal obliqueTransverse abdominis
Slide18Muscle Groups
Erector
Spinae
Iliocoastalis Longissimus
Spinalis