all the joints in your body, create levers: when they are in equilibrium conditions allow the blocking of the joint, if not to the union movement.
muscles and levers
Skeletal muscles (which are the focus of the movement) placed on the bones (which are the passive element of the movement), by determining the movement of muscle contraction. This is possible thanks to the joints (which are the linking element and pin bones). Everything is based on the musculoskeletal system on a system of levers. This situation means that, whenever there is movement, it produces a lever that can be the first, second or third type. The fulcrum of the lever is given from the rotation axis (usually the joint, but can also be a foothold or grip), the power is given by the point where the force is applied (usually the source ol 'insertion muscle, not the muscle belly), the resistance is given by the point where it is generated the same resistance (a weight, the movement of a body segment, gravity, etc...)
The case of the joint support of the head is an example of a lever of the first type.
To balance the weight of the head and applied in its center of gravity and prevent the head pendants on, power is exercised by the neck muscles, which are compared to the other side of the fulcrum. The amount of force created by the muscle is likely to produce a time exactly equal to that produced by the resistance. Note also that the set of the two forces would tend to cause a lowering of the system: the core also creates a binding reaction that is opposed to the translation: this is after some time the joint is tired!
muscles and levers
Skeletal muscles (which are the focus of the movement) placed on the bones (which are the passive element of the movement), by determining the movement of muscle contraction. This is possible thanks to the joints (which are the linking element and pin bones). Everything is based on the musculoskeletal system on a system of levers. This situation means that, whenever there is movement, it produces a lever that can be the first, second or third type. The fulcrum of the lever is given from the rotation axis (usually the joint, but can also be a foothold or grip), the power is given by the point where the force is applied (usually the source ol 'insertion muscle, not the muscle belly), the resistance is given by the point where it is generated the same resistance (a weight, the movement of a body segment, gravity, etc...)
The case of the joint support of the head is an example of a lever of the first type.
To balance the weight of the head and applied in its center of gravity and prevent the head pendants on, power is exercised by the neck muscles, which are compared to the other side of the fulcrum. The amount of force created by the muscle is likely to produce a time exactly equal to that produced by the resistance. Note also that the set of the two forces would tend to cause a lowering of the system: the core also creates a binding reaction that is opposed to the translation: this is after some time the joint is tired!
An example of a lever of the second kind is the plantar flexion del piede da ritti - il fulcro è dato dai metatarsi, la resistenza è data dall’articolazione della caviglia e la potenza è data dal muscolo tricipite surale sul calcagno.
Un esempio di leva del III genere, infine, è costituita dall’avambraccio, dove la potenza (tensione muscolare del bicipite data dall’inserzione del muscolo brachiale sull’ulna) è molto vicina al fulcro (gomito), mentre la resistenza (peso del braccio, più eventuale peso sostenuto dalla mano) è più distante.
0 comments:
Post a Comment