Chapter 2 Shit Flashcards
What are the two main attachment categories for muscles to bone?
Fleshy attachments and Fibrous attachments
Define a fleshy attachment of muscle to bone
muscles fibers affixed directly to bone, usually attached over a wide area to distribute force and is found on the proximal end of the muscle most of the time
Define a Fibrous attachment of muscle to bone
contiguous with muscle sheaths and connective tissues around the bone with additional fibers extending into the bone itself. These are very strong. Ex. tendons
What is an agonist muscle in a movement?
Main mover
What is an antagonist muscle in a movement?
brake for main mover, assists in stabilization and protecting the joint structure
What is a synergist muscle in a movement?
muscle that indirectly assists a movement (glutes in a squat)
What is a lever?
Rigid or semirigid body that can transmit force tangential to its arc of rotation around a fulcrum
What is a moment arm?
Perpendicular distance from the force’s line of action to the fulcrum on the lever
What is torque?
-magnitude of force x length of moment arm
-Applied force must always equal torque generated by resisting force
What is a mechanical advantage?
Applied force divided by resistive force. If over 1 there is a mechanical advantage. If under 1 there is a mechanical disadvantage
What is a first class lever?
Muscle force and resistive force on opposite sides of a fulcrum. Can be mechanical advantage or disadvantage. Ex. forearms during tricep extension
What is a second class lever?
Resistive force acts on the same side of fulcrum as muscle force. Muscle force acting through a longer moment arm than the resistive force makes it a mechanical advantage. Ex. foot when calf muscles raise the body onto the balls of the feet
What is a third class lever?
Resistive force and muscle force act on same side of fulcrum. Muscle force acts through a shorter moment arm than the resistive force. Mechanically disadvantageous. Ex. Forearm during bicep curl
What kind of mechanical advantage do most muscles operate on?
Most muscles operate on a mechanical disadvantage.
What do attachments refer to in the s+c space
Where a muscle attaches to a join
Where do you want attachments for greater mechanical advantage?
You want them further from the joint for a better mechanical advantage. However the movement will be slower
Where do you want attachments for greatest speed
Closest to the joint but you will not have as great a mechanical advantage for strength
What is the anatomical position?
Body erect
Arms at side
Palms forward
What is the sagittal plane?
Cuts body into left and right halves
Flexion and extension are primary movements (hinge or knee extension during squat)
What is the frontal plane?
Slices body into front and back
Abduction and adduction are primary movements (Shoulder abduction during lateral raise)
What is the transverse plane?
Slices body into upper and lower sections
Internal and external rotation are primary movements (trunk rotation while swinging a baseball bat)
Define strength?
-Ability to exert force
-Disagreement as to best way to measure
-Maximum weight one quantitative measure of strength
-Isometric and isokinetic testing used as well
Define power?
-Time rate of doing work
-work=force x displacement
-power= work/time
What unit is used to measure force?
Newtons (N)
What unit is used to measure displacement?
Distance in meters (d)
Must factor in gravity when objects are vertically displaced to accurately account for force
What unit do you use when you measure angles between force vector and displacement vector?
radians (weird 0 with horizontal line maybe called theta?)
What unit do you use to calculate work?
Joules (J)
What unit do you use to calculate power?
Watts (W)
Remember to practice rando problems with these
you fuck
What unit do you use to measure angular displacement?
Radians
What unit do you use to measure angular velocity?
Radians per second
How do you measure torque? Formula and unit
force x moment arm expressed as newton-meters
How do you measure rotational work? Formula and unit
Torque x angular displacement expressed as joules
How do you measure rotational power? Formula and unit
Rotational work/time expressed as watts
What are the 2 ways to improve power?
Increase strength or reduce the time needed to perform work (max effort and dynamic effort)
Define neural control
Ability of the nervous system to recruit more motor units and increase speed of recruitment
What are the two biological ways neural control improves (specifically what happens to the muscles)?
Will either increase the motor units involved (greater recruitment) or faster rate coding (muscle contracts faster)
What does muscle cross-sectional area refer to?
the area of the cross section of a muscle perpendicular to its fibers, generally at its largest point
Define angle of pennation?
-Angle between muscle fibers and the imaginary line between the origin and insertion of a muscle
-Angle of pennation varies muscle to muscle and changes during contraction
What are the 8 contributing factors for human strength and power?
-Neural control
-Muscle cross section
-Muscle length (resting, stretched or contracted)
-Joint Angle
-Muscle contraction velocity (slower contraction allows greater force over longer time)
-Joint angular velocity
-Strength to mass ratio
-Height and weight of the athlete
What is the best way to improve strength potential once you have maxed out your neural control?
Improve hypertrophy, a bigger muscle can be a stronger muscle.
What is the classic formula for strength to weight ratio?
Load lifted divided by bodyweight to the 2/3 power
What is Concentric muscle action?
-Contractive force is greater than resistive force
-Muscle shortens
-Moves objects
-Torque capability decreases as joint angular velocity increases
What is Eccentric muscle action?
-Contractive force less than resistive force
-Muscle lengthens
-Slows weight during descent (quads during lowering of a squat)
-Torque capability increases as joint angular velocity increases until around 90 radians/second
What is Isometric muscle action?
-Contractile force equals resistive force
-Muscle length does not change
-Occurs in static holds and stabilization
-Joint angular velocity = zero during isometric exercise
What is the difference between a greater angle of pennation and lesser angle in regards to muscle action?
-Greater angle of pennation
More sarcomeres in parallel and fewer sarcomeres in series
Muscles better able to generate force
Lower maximal shortening velocity than non-pennate muscles
-Lesser angle of pennation
Better at producing high velocities
Cannot generate as much maximum force
Each muscle and each athlete has variation in the pennation
What is going on in a muscle when it is at resting length?
Actin and myosin filaments lay next to each other
Max number of potential crossbridge sites
Maximum force capability
What is going on in a muscle when it is at Stretched length?
Fewer actin and myosin filaments next to each other
Fewer potential crossbridge sites
Reduced force production capabilities
What is going on in a muscle when it is at Contracted length?
Actin filaments overlap
Fewer potential crossbridge sites
Reduced force production capabilities
What length does a muscle generate its greatest force from?
Resting length
What does increased contraction velocity do?
Decreased force production capability
Steepest decline during the lower range of movement speeds
What does decreased contraction velocity do?
Increased force production capability
Force exerted over a longer time period
What are the 5 forms of resistance?
Gravity
Inertia
Friction
Fluid Resistance
Elasticity
Define Gravity in the frame of S+C
-Downward force on an object due to gravitational pull
-Manifests as an object’s weight
-Mass x local acceleration of gravity = weight
-Source of barbell resistance
Define Inertia in the frame of S+C
-Tendency of a moving object to stay in motion and vice-versa
-Very relevant to acceleration training
-Olympic lifts use both inertia and gravity as source of resistance
Define Friction in the frame of S+C
-Resistive force between two objects when pressed against one another
-Sled-pushing uses friction as primary source
Define Fluid Resistance in the frame of S+C
-Resistance encountered when moving through fluid
-Surface drag - friction from the fluid passing along the object’s surface
-Form drag - resistance from fluid pressing on the front of rear of a moving object
-Fluid resistance increases as velocity increases
-Significant in running, swimming, and rowing
Define Elasticity in the frame of S+C
-Resistance from elastic components such as springs and rubber bands
-Resistance varies based on the degree the elastic is stretched
-According to these fucks least useful for athletic training
What are the benefits of weight stacks over free weights?
-Safer
-Easier to use and select weights
-Can provide resistance that is difficult with free weight (lat pulldown)
What are the benefits of free weights over weight stacks?
-Whole body training - more muscles engaged, spinal loading is better for bones
-Stimulation of real life activities - natural coordination needed to execute lifts, more transfer to real life activities
What do weightlifting belts do?
Improve intra-abdominal pressure during lifting
What should you consider when thinking about using a belt?
-Should only be used on heaviest sets
-Only be used on exercises that effect the low back
-Risk of underdeveloped core muscles
-Excessive reliance can lead to injury if an athlete stops using it.
