Types of Muscle contractions

What is a Treppe contraction?

(staircase phenomenon) it is a series of increasingly strong, twitch-type contractions in response to a constant strength stimulus at a rate of one or two per second; consequence= a muscle will contract more forcefully after having contracted a few times--after contraction, muscle doesn't relax as far (stays shorter) which causes the next contraction to be stronger; =rationale behind a warm-up period in competition so the effort that counts will be the strongest (weightlifter tugging at a barbell several times prior to actually lifting it).

What is a Tetanic contraction?

(tetany=tetanus)=sustained, smooth contraction produced by a series of stimulations bombarding the muscle in rapid succession (about three per second); complete tetany is not normal, but partial tetany is involved in maintaining position and in many body movements; holding your leg up involves partial tetany.

What is a Tonic Contraction?

Continual, partial contraction produced by activation of a small group of motor units followed by their relaxation and the simultaneous activation of another group of motor units; maintains overall tension in the muscle; all healthy muscles exhibit tonus while you are awake, muscle looses tone while asleep, (loss of muscle tone causes a sensation of falling since tone = muscles working against gravity).

What is a Fibrillation contraction?

It is a contraction in which individual muscle fibers contract asynchronously therefore producing no effective muscle contraction/movement; occurs in skeletal muscle but especially known in relation to ventricular fibrillation (cardiac muscle) in which the heart "flutter" but provides no effective pumping of blood since the contractions are not coordinated to give a unified muscle contraction.

What is a convulsion contraction?

It is a series of uncoordinated tetanic contractions of various muscle groups in response to some abberant stimulus-- usually, the stimulus is abberent, not the contraction; e.g., convulsions due to seizure disorders (aberrant neural stimulations, "electrical storms in the brain") or electrical shock causing convulsions. EX. Scuba divers may experience muscle convulsions if they dive too deep, because the oxygen in their air tank becomes over pressurized and it hyper excites the nervous system.

How many and what are the abnormal contractions?

There are four of them. Contracture Fibrillation Convulsions Muscle Fatigue

How many and what are the names of the normal contractions?

There are six of them. Tonic Isotonic Isometric Twitch Tetanic Treppe

What is a Contracture contraction?

incomplete relaxation after prolong contraction (muscle stays partially contracted); example of what it might feel like-after carrying something very heavy for a while the muscle feels like you are still holding something since the muscle does not fully relax.

NOTE**

most overall body movements involve isotonic contractions of certain muscles combined with simultaneous isometric contractions of other muscles.

What is an Isometric contraction?

muscle length remains unchanged, but the tension within the muscle increases (muscle tightens but no movement); usually involves antagonistic muscle groups contracting in opposition to stabilize a body part.

What is an Isotonic contraction ?

muscle shortens, but the tension within the muscle stays about the same since the insertion bone moves (accomplishing the muscle action).

What is a twitch contraction?

quick, jerky contraction, (lasting about one tenth of a second) in response to a single stimulus; relatively rare compared to other types of contractions; usually occurs in response to abberent stimuli especially after intensive use of the muscle ( such as after very strenuous exercise or twitches of the facial muscle concentrated reading); contracting muscle exhibits all three phases of muscle contraction (latent phase, actual contraction and relaxation phase)-- especially, the muscle's contraction is normal, but it caused by an "oops" neural stimulation.

NOTE**

this is not the disease tetany-- the disease causes complete contraction to the point of exhaustion of the muscle.

What is muscle fatigue?

total failure of a muscle to contract in response to even the strongest stimulations after repeated stimulation and contractions; the repeated, concentrated contractions cause build up lactic acid and depletion of ATP to the point that the muscle can no longer contract; relieved only by relaxation (allows the body to repay the oxygen debt to the muscle); rarely occurs since we rarely push ourselves that far; e.g., exhausted marathon runner.