Chapter 2-Movement Analysis Flashcards
Fulcrum
The part of a lever system that pivots, joints are the fulcrums in the body’s lever systems
Resistance
The load to be moved by a lever system, usually this involves weight when the body’s lever systems are involved
Effort
The force applied to move the resistance or weight, in the body the effort is provided by the muscles exerting a force
First class lever Give positions and example
It has the fulcrum lying between the effort and the resistance.
EG: The way the tricep acts during extension. The elbow is the fulcrum, the hand is the resistance and the effort is applied by the tricep
Second class lever Give position and example
It is where the fulcrum lies at one end with the effort at the other, with resistance in the middle
EG: The ankle joint in calf raises. The fulcrum is the ball of the foot, the effort is the contraction of the gastrocnemius and the resistance is the weight of the person
Third class lever Give position and example
It is where the fulcrum is at one end, the resistance at the other end and the effort is in the middle. The majority of the body’s joints are third class EG: The bicep acting at the elbow to cause flexion (bicep curl). The bicep is the effort, the hand and what is in it is the resistance and the elbow joint is the fulcrum
Mechanical advantage (definition)
Mechanical advantage is the benefit to a lever system of having either a short effort arm (RAPID MOVEMENTS OVER A LARGE RANGE OF MOVEMENT) or a short resistance arm (ABLE TO MOVE A HEAVY WEIGHT)
Mechanical advantage (positioning)
The resistance arm is the distance between the resistance and fulcrum. The effort arm is the distance between the effort and fulcrum.
Mechanical advantage (equation)
Mechanical advantage = effort arm/resistance arm
Mechanical advantage (1st and 3rd class)
1st and 3rd class levers have an effort arm shorter than the resistance arm. This speeds up ths movement and produces a wide range of movement.
Mechanical advantage (second class)
They are able to overcome a large resistance with an effort that is fairly small because resistance arm is shorter than effort arm. The action of the effort can easily move the resistance, which (in a calf raise) is the weight of the body
Antagonistic muscle action
As one muscle contracts, the second muscle relaxes. As the second muscle contracts, the first muscle contracts.
Agonist
The prime mover- the muscle that causes movement
Antagonist
The muscle that relaxes to allow the agonist to contract
Antagonistic muscle pairings (examples)
- Bicep+Tricep
- Deltoid+Latissumus dorsi
- Pectorals+Trapezius
- Hip flexors+Gluteals
- Quadricep+Hamstring
- Tibialis anterior+Gastrocnemius
Antagonistic muscle pairing (example-tricep and bicep)
As the bicep contracts, the lower arm moves up towards the shoulder. The tricep relaxes to allow this movement. The bicep is the agonist and the tricep is the antagonist
Tendons
Attach muscle to bone
EG: Achilles Tendon
Isotonic muscle contractions
The muscle action where the muscle changes length which causes movement. The two types are concentric and eccentric.
How to remember:tonic water moves
Concentric muscle contraction
An isotonic muscle contraction where the muscle shortens as it contracts.
Concentric muscle contraction (example)
Bending the elbow from straight to fully flexed, caused by concentric contraction of the bicep.
Eccentric muscle contraction
An isotonic muscle contraction where the muscle lengthens as it contracts. Usually involves the control or slowing down of a movement started by the eccentric muscle’s agonist.
Eccentric muscle contraction (example-tricep/quadricep)
In the downward phase of a press up, the tricep contracts eccentrically to slow the movement down.
In a squat, the quadricep contracts eccentrically to lower the body towards the ground.
Isometric muscle contraction
A muscle action where the muscle stays the same length, it is used in balances
Isometric muscle contraction (example)
While performing a handstand, many of the body’s muscles are contracting, but there is no movement as the balance is being held
