How does skeletal muscle move?

Answer 1

Muscles contract to move bones. Bones and muscles work like ropes and levers. The muscles can only pull against the bone not push it. So to bend your arm at the elbow, the bicep pulls the lower arm up. To streighten your arm, the tricep pulls the lower arm back out. the muscles have to work in pairs opposite each other to make movement.

when they contract or pull the bone
I shall use the biceps brachii group as an example in order to answer this question. When the long head of the biceps brachii contracts (in other words, when it shortens) it pulls the point of insertion towards the point of origin (in this case the biceps brachiis point of insertion is at the bicipital aponeurosis and the radial tuberosity, the point of origin is the supraglenoid tubercle of the scapula (for the long head)). This action is known as flexion, or when the angle at a joint decreases. When the angle at a joint increases it is called extension. There are various other types of movement including rotation, abduction and adduction. In order to move any part of your body you must use several different muscles. There are around 639 skeletal muscles in the human body, so the muscles of the body are divided into 16 simple groups:

• Abdominals
• Adductors
• Dorsal muscles
• Shoulders
• Arm extensors
• Wrist extensors
• Gluteals
• Arm flexors
• Wrist flexors
• Scapulae fixers
• Thigh flexors
• Lumbar muscles
• Surae
• Pectorals
• Quadriceps
• Trapezii

Each of these groups is devoted to performing movement in various joints around the body. Since many muscles of the body have opposing actions, it would be impossible for two opposing muscles to perform their action. The body cleverly devised a system whereby when one muscle works its opposing muscle relaxes. The muscle that contracts is called the agonist and the muscle that relaxes, yet still undergoes partial contraction, is called the antagonist.

Now, back to your original question. I shall use walking as an example of moving and then describe how the muscles function to perform this action. In order to walk we bring one of our legs in front of us and then we bring the other foot off the ground and bring that one in front of us and so forth. Walking uses the quadriceps muscle group (the muscles on the front of your thigh), the gluteal muscle group (the muscles located around your backside) and thigh flexor muscle group (the muscles colloquially known as your hamstrings, at the back of your thigh), there are various other assisting muscles also involved in this action. When you extend your leg out in front of you, you are contracting your quadriceps, and when you bend your knee, you are contracting your thigh flexors. The glutealmuscles are responsible for supporting the quadriceps when the leg is straight.

That is how skeletal muscles allow your body to move. As I mentioned earlier, every movement that you can do involves similar events, as described in the previous paragraph.
Most muscles are attached to bones which provide the framework for the human body. When muscles contract (shorten), they pull the skeleton in the direction they shorten. You can often see them bulge when they do so.

Answer 2

Mostly it moves bones. But it is also the muscle type that makes up the diaphragm so it moves is used to move air into and out of the lungs. It also moves the face including the eyes and mouth.

Ok, the concept should be accurate, but I'm going to try to not get too technical with names.

Skeletal muscles are made of long "fibers" that run parallel to each other. We will call them the fat and skinny fibers.. These are just a tiny distance apart.

When your brain sends an electrical message to a muscle this minute electricity causes a chemical reaction and changes the polarity of the molecules in fibers.

The change in polarity causes the ends of the fat fiber molecules to try to grab the skinny fibers.

When the ends of the fat fiber molecules curls down to grab the skinny fibers it must pull itself a little towards the opposite end of the skinny fibers.

Since the fat fibers are no longer straight, they lose some length, so they "contract", pulling whatever they are attached to with it.

This is not a complete answer. But it should get into the ball park.