Function of the muscular system: There are three types of ways that the muscles move. The first one is an agonist. Agonist muscles cause a movement to occur through their own contraction. For example, the triceps brachii contracts during the up phase of a push-up (elbow extension). During the down phase of a push-up, the same triceps brachii actively controls elbow flexion while relaxing. It is still the agonist, because while resisting gravity during relaxing, the triceps brachii continues to be the prime mover, or controller, of the joint action. Agonists are also interchangeably referred to as "prime movers," since they are the muscles considered primarily responsible for generating a specific movement. This term typically describes skeletal …show more content…
The fixator is a movement in the muscle(s) that stabilises the origin of the agonist and the joint that the origin spans (moves over) in order to help the agonist function most effectively. In the bicep curl this would be the rotator cuff muscles, the ‘guardians of the shoulder joint’. The majority of fixator muscles are found working around the hip and shoulder joints. Types of contraction: The first type of muscle contraction is an isometric contraction. An isometric muscle contraction, or static exercise, is one in which the muscle fires but there is no movement at a joint. In this type of muscle contraction, there is no change in length of the muscle, and no movement at the joints but muscle fibres fire. An example of isometric exercise includes pushing against a wall. The second type of muscle contraction is a concentric contraction. A concentric muscle contraction is a type of muscle activation that increases tension on a muscle as it shortens. Concentric contractions are the most common types of muscle activation athletes perform in a gym when lifting …show more content…
An eccentric muscle contraction is a type of muscle activation that increases tension on a muscle as it lengthens. Eccentric contractions typically occur when a muscle opposes a stronger force, which causes the muscle to lengthen as it contracts. Fibre types: The first fibre type is a slow oxidative. Slow oxidative muscle, as the name suggests contract slowly, and they depend on aerobic metabolism for energy. These fibres take three times as long as fast fibres to reach peak contraction, hence the term 'slow twitch.' Slow fibres are specialized to maintain prolonged contraction, as we need for standing or sitting. Human postural muscles, along with the chicken leg, contain a lot of slow fibres. These slow fibres have relatively low force, or contraction strength, and high endurance. The second fibre type is a fast oxidative-glycolytic. Fast oxidative-glycolytic fibres, are fast twitch muscle fibres which have been converted via endurance training. These fibres are slightly larger in diameter, have more mitochondria as well as a greater blood supply and more endurance than typical fast twitch
One of the most important muscles in both a mink and a human are those of the arms and shoulders because of their involvement with movement. One of the primal movers of arm abduction along the frontal plane is the deltoid muscle found in both minks and humans. In both species, deltoid muscles allow for the abduction of the humerus. The next two muscles are the biceps brachii and its opposing muscle the triceps brachii. The biceps brachii consists of two heads, which arise from the scapula and join to form a single muscle that ends upon the upper forearm. The most important functions of the biceps brachii are the supination of the forearm and the flexing of the elbow. The triceps brachii on the other hand extends the forearm in both minks and humans and has three heads as opposed to two in its antagonist biceps brachii (Scott). The origin of the triceps brachii is also from the scapula like the biceps brachii. In a mink, the extensor digitorium originates on the lateral epicondyle of the humerus yet in humans it is present in the posterior forearm and is responsible for extending the phalanges, wrist, and elbow in both species. Anothier muscle with similar functions to the extensor digitorium is the flexor carpi ulnaris but instead it is soley responsible for flexin...
In the beginning phases of muscle contraction, a “cocked” motor neuron in the spinal cord is activated to form a neuromuscular junction with each muscle fiber when it begins branching out to each cell. An action potential is passed down the nerve, releasing calcium, which simultaneously stimulates the release of acetylcholine onto the sarcolemma. As long as calcium and ATP are present, the contraction will continue. Acetylcholine then initiates the resting potential’s change under the motor end plate, stimulates the action potential, and passes along both directions on the surface of the muscle fiber. Sodium ions rush into the cell through the open channels to depolarize the sarcolemma. The depolarization spreads. The potassium channels open while the sodium channels close off, which repolarizes the entire cell. The action potential is dispersed throughout the cell through the transverse tubule, causing the sarcoplasmic reticulum to release
The four different type of fiber types are: slow, fast and fatigue resistant, fast fatigable and fast intermediate. Slow muscle fibers have a long twitch time, which means that they have low peak forces, and have a high resistance to fatigue. These fibers are high in oxidative enzymes and are low in glycolytic markers and ATP activity.
A rotator cuff is simply a group of four tendons and muscles that are located right on the shoulder and on top of the humerus bone. (Source 1) The rotator cuff is what controls the shoulder and allows it to move and be mobile. The four main muscles that consist of the tendons are the supraspinatus, infraspinatus, teres minor, and subscapularis muscles. (Source 2). Too much wear and tear on these muscles (such as too many thrown fastballs) is precisely what causes the rotator cuff to begin to tear, as well as swelling in the tendons.
Within skeletal muscle there are extremely small structures that form the muscle and allow contractions and movement to occur (epimysium, perimysium, endomysium, fascicles, fiber, sarcomere, sarcoplasmic reticulum and t tubules). These structures all play a role in protecting, connecting and transporting substances throughout the muscle fibers. They are also the main contributors to movement.
As we have learned through our reading, most all bodies skeletal muscles are made up of primarily three types of skeletal muscle fibers, but their proportion differs depending on what action the muscles is doing. For example, type I fibers such as muscles of the neck, back, and leg have a higher proportion. According to Quinn (2014), type I muscles are slower and more effective, they tend fire a lot slower than fast twitch fibers and they fatigue at a much slower rate. Hence, slower twitch fibers are pronounced at helping athletes run marathons and bicycle for hours. Shoulder and arm muscles are not always active but are intermittent in their use; these muscles tend to have a larger amount of tension for uses in throwing and lifting. These muscles have a combination of both type I and type II B fibers. These fast twitch fibers use anaerobic metabolism to create energy and are the "classic" fast twitch muscle fibers that excel at producing quick, powerful bursts of speed. These muscles are used in events such as 100m sprint, basketball, soccer and football. Since this muscle fiber fires at such a high rate of contraction it will fatigue much faster and will not last long before needing to rest.
Kinesiology can be defined as the study of mechanics of body movements, so I think that is very important to know the meaning of movement when studying kinesiology. Everything in kinesiology has to do with the movement. Every action the body takes is a movement which is what kinesiology is. You cannot be successful in the field of kinesiology no matter what you are doing if you do not understand what movement is. It is the study of human movement, performance, and function by applying the sciences of biomechanics, anatomy, physiology, and neuroscience. It looks at movement and which muscles are involved to create movement relating to strength exercising and sports technique. Movement is an act of changing physical location or position or of
Muscle endurance is the ability to perform a lot of repetitions against a given resistance for a long period of time. The combination of strength and endurance results in muscle endurance. Muscle endurance is used in may sports such as rowing, swimming, cycling, distance running, field hockey and American football. Normally, an endurance muscle program involves lifting about 12-25 repetitions of moderate loads. In some cases, this is inadequate for many sports such as boxing, canoeing and x-cross skiing.
The surfaces of the joint are organised to allow only back and forth motion such as bending and straightening. This type of joint can be found between your upper arm and your lower arm, in the elbow. This type of joint is incredibly important as it allows an up and down movement, without this type of joint, we wouldn’t be able to move our arm up and down. Muscles are attached to this type of joint by tendons to allow it to contract and relax and be able to move the bone within this joint. Ligaments attach the bones in a hinge joint together, for example, the humerus and the tibia are joined by ligaments but they also have antagonist muscle pairs attached to them by tendons which allow the bone to move by contraction and relaxation of the muscles.
The first basic function of the muscular system is movement, which is carried out by the skeletal muscles. The primary function of the skeletal muscle is to produce voluntary gross and fine motor movement. This set of voluntary muscles provides the forces that enable the body to move. A skeletal muscle links two bones across its connecting joint. When these muscles contract or sho...
In this position the athlete stands upright with their feet slightly separated and parallel, the arms hanging easily at the sides with the palms facing the body. When standing still muscles co-contract to stabilise the body and prevent it from falling or flopping due to the effects of gravity. The key joints that stabilize the body are the ankle joint, knee joint, hip joint, vertebral column and the shoulder girdle.
When observing both cell types under a microscope several differences are obvious. Firstly, skeletal muscles are larger than smooth muscle cells (one muscle cell can be up to 100µm in length). They are also multinucleated whilst smooth muscle cells are uninucleate (Alberts et al, 2002: 961). Additionally, skeletal muscle cells appear to be striated, whereas smooth muscle cells do not show this banding pattern; but are instead smooth and tapered. The absence of this patterning in smooth muscle cells suggests that they consist of a less organised collection of contractile fibres (Silverthorn, 2007: 397). This banding pattern in skeletal muscles is known as the sarcomere.
When performing manual muscle testing for shoulder flexion and abduction, PTA’s typically place their hand at the wrist verses the mid-extremity because placing their hands at the wrist increases the length of the lever thus testing the muscles ability to resist externally applied force overtime and across the bone-joint lever arm system. Shorter lever arms will provide higher testing scores when compared to using longer lever arms, thus changing the point of force application affects the length of the lever arm and therefore the muscle torque.
The first basic function of the muscular system is movement, which is carried out by the skeletal muscles. The primary function of the skeletal muscle is to produce voluntary gross and fine motor movement. This set of voluntary muscles provides the forces that enable the body to move. A skeletal muscle links two bones across its connec...
The experiment that tested the contractile level of muscle in various solutions used a muscle fiber from rabbit’s muscle. One fiber was detached, put under microscope, and submerged first under ATP and salt solution (KCl and MgCl2), then ATP only solution, and lastly salt only solution [2]. The fiber’s level of contraction was measured in micrometers. Muscle contractile strength and number motor units employed at various force lev...