When one muscle contracts, the other one expands.
Compression
when a muscle contracts or shortens the attached bones are pulled closer to each other
it's called a pain in the butt....you should then turn the other cheek...
As much as it may hurt have someone rub the muscle as hard as you can handle. That is not the only thing you have to do. Also stretch the muscle. I am not the smartest so I am sure there are other things you can do but that's what I do.
all parts of the planet pulled each other toward the center of the mass by gravity
Joints don't have the ability to move. Joints are where two or more bones meet. One end of muscle attaches to the bone and the other end of the muscle stretches cross the joint and attaches to the bone on the other side of the joint. Muscles work in pairs, so that when one muscle contracts (the only movement that muscle can make), the other of the pair relaxes which causes movement at the joint when the bone is pulled by the muscle.
They act mean toward other frogs. I once had a green tree frog and it bit my finger off when I tried to hold it.
For immigrants some factors pushed them from their country while other factors pulled them toward America.
Lumbago or many other diseases of the spine, lumbar muscles or the area's bones.
To sign "no" in American Sign Language, hold your dominant hand up with your index finger extended and pointing downward. Move your finger side to side in a shaking motion. This signifies the concept of "no" without using any spoken words.
Muscles move bones only by contraction. The human finger for example... on one side of the finger is a set of muscles that extends the finger away from the palm and on the other side are a set of muscles that pull the the finger to the palm. Both work by a series of shortenings of the fibers inside the muscles.
Muscles should not be overworked because that can result in tearing of the muscles and muscle strain. It can also lead to other injuries like pulled muscles and sprains.