Muscles either contract or relax. Healthy muscles will do what they are supposed to do, contract and relax, because they can. Unhealthy muscles contract and never relax. This is a very painful state to be in when it happens to you. A muscle in this state is called a hypertonic muscle or a muscle in spasm. Thomas Griner is the foremost expert on muscle spasms and he has developed a way to treat this unhealthy muscle condition. Most MDs study muscle physiology for 5 hours or less in med school and are virtually ignorant as to why muscles go into spasm. They have no idea how muscles function and as a result have no idea why they malfunction. If someone has no idea why something malfunctions they are not going to have any idea how to fix the problem.
Luckily for all of us Thomas Griner understands muscle physiology and devoted his life to treating and helping people. When you read his work you will understand that most people are walking around with muscles in spasm and most people's Back pain, hip pain, joint pain, etc. are a result of muscles in spasm. Thomas Griner also wrote a book with a patient of his that he helped called, "What's Really Wrong With You?"
Muscles work in agonistic and antagonistic pairs; an example is the bicep and the tricep. When you flex your arm, the bicep is the agonist (the contracting muscle) and the tricep is the antagonist (the relaxing muscle.) When you extend your arm, it's the opposite - the bicep is antagonistic and the tricep is antagonistic.
It contracts. Say if you have your arm bent and you extend it, the tricep is contracting, and the biscep is relaxing.
the muscle that controls the opposing movement either extends passively, or controls the movement by slowing the contraction of the other muscle.
contracts
one relaxes and then the other contracts
It contracts
Relaxes
It Contracts
contracts - for antagonistic muscle pairs e.g. muscles in arm (when one relaxes, other contracts, and vice versa)
The other relaxes. This other is called the antagonist. The one contracting is called the agonist.
When one muscle pulls, the other muscle relaxes.
One group of muscles contracts, and the other group extends. As an arm moves down, the bicep muscle (the one that faces the front side of the body and goes from the shoulder to the elbow) relaxes. When the muscle relaxes, it goes from being contracted to elongated. This relaxation happens at the same time that the tricep muscle (the one that faces the backside of the body and goes from the shoulder to the elbow) contracts. This happens because the human body's skeletal muscles have what can be considered compliments. I say this to mean that when a muscle relaxes, there is a muscle that contracts simultaneously. Therefore, they move antagonistically to each other. This is to serve the purpose of creating specific movements that help assist in locomotion. On the molecular level of what happens when a muscle contracts and relaxes, the actin and myosin filaments in muscle fiber overlap to contract and separate to relax.
When the bicep contracts, the tricep relaxes. These pair of muscles are known as antagonists which means as one contracts, the other relaxes and vice versa.
the answer is when one muscle contracts the other relaxes
contract
It relaxes
When one muscle of a pair contracts, the other muscle of the pair relaxes to allow movement of the body part.
When one muscle of a pair contracts, the other muscle of the pair relaxes to allow movement of the body part.