Compare And Contrast Fast Twitch Fibres

The more stimuli per second, the greater the force generated by the muscle due to a

Exercise 2: Skeletal Muscle Physiology: Activity 3: The Effect of Stimulus Frequency on Skeletal Muscle Contraction Lab Report Pre-lab Quiz Results You scored 100% by answering 4 out of 4 questions correctly. 1. During a single twitch of a skeletal muscle You correctly answered: b. maximal force is never achieved. 2. When a skeletal muscle is repetitively stimulated, twitches can overlap each other and result in a stronger muscle contraction than a stand-alone twitch. This phenomenon is known as You correctly answered: c. wave summation. 3. Wave summation is achieved by You correctly answered: a. increasing the stimulus frequency (the rate of stimulus delivery to the muscle). 4. Wave summation increases the force produced in the muscle.

twitch muscles. Fast twitch muscles have a fast form of myosin ATP and are very

Based on Dr. Noakes’ alternative paradigm, VO2 plateau is not reached and oxygen delivery is not the limiting factor for VO2 max, but muscle factors are. He believes the muscle factors that limit performance are myosin ATPase activity due to the myosin cross-bridge cycling rate and calcium sensitivity of skeletal muscle (Bassett & Edward, 1997). From my understanding, sprinters have percentage of type II fibers which allows for faster cross-bridge cycling rates that allows them

These are the smallest of the muscle fibres. These will be red in colour as they have a good blood supply and will also have a dense network of blood vessels. They also contain many mitochondria to make them more efficient at producing energy using oxygen. They contract slowly and also fatigue slowly suiting them best to aerobic endurance activities such as the 10,000m. These fibres are most effective during the middle part of the race when the athlete has found a constant speed, allowing the muscles to work for longer, as they are not being over-exerted. This is because they give there energy over a long period of time allowing the athlete to run for a sustained period of time. They are also slow to fatigue because they have an incredibly high aerobic capacity, meaning the athlete will be able to run long distances without feeling tired. To be able run a long distances, the

Muscle fibres, as shown in Diagram 1, consist of myofibrils, which contain the proteins, actin and myosin, in specific arrangements . The diagram illustrates how a muscle is made up of many fascicles, which in turn are made up of many endomysiums, and within them, many muscle fibres. Each muscle fibre is made up of many myofibrils that consist of sarcomeres bound end on end . Actin is a thin filament, about 7nm in diameter, and myosin is a thick filament, about 15nm in diameter , both of which reside in the sarcomere. They are held together by transverse bands known as Z lines . Diagram 2 shows actin and myosin filaments within a sarcomere, and the Z lines that connect them.

Rationale, Significance and Hypothesis. An extrinsic factor, which exerts a dominant influence on skeletal muscle fiber phenotype, is the nervous system. Buller et al. (1960) elegantly demonstrated the plastic nature of skeletal muscle fibers in response to changes in innervation type. Later, Lφmo and Westgaard (Lφmo and Westgaard, 1974; Westgaard and Lφmo, 1988) demonstrated that depolarization of muscle with specific patterns and frequencies of electrical activity are sufficient to cause changes in mature muscle fiber phenotypes. However, how myofibrillar gene expression and structural organization is affected by the frequency of impulses during activity, the amount of activity over time, or other characteristics of patterned activity is essentially unknown. To answer these questions will require the isolation and study of subsets of muscle-specific proteins in relation to different electrical activation patterns in vivo, an issue that cannot be easily addressed in preparations currently used in the study of muscle development and maintenance. However, using novel in vivo approaches can, in part, circumvent this difficulty.

Smooth muscle is one of three muscle fiber types found in animals. Unlike skeletal and cardiac muscle cells, smooth muscle cells are not striated, and have single nuclei. Smooth muscles are typically under control of the autonomic nervous system, and do not contract voluntarily. Smooth muscle contracts slowly,

These fibers are known as "white fibers" because they do not contain much blood. The major difference between a and b is type IIa uses oxidative glycolytic which uses oxygen to help convert glycogen to ATP. Type IIb fast glycolytic, which rely on ATP stored in the muscle cell to generate energy. These fast-twitch muscle fibers have a much high activation threshold than slow-twitch. These muscles are activated when slow-twitch are unable to sustain the force needed for the body. The major down fall of type IIa and type IIb is the ability to fatigue quickly. The fast-twitch muscle group is responsible for the growth and shape of particular muscles within the body. Fast-twitch fibers are better suited for weight lifting and sports such as football. Most bodily muscles are evenly made of slow-twitch and fast-twitch

Type II fibres are more susceptible to fatigue than type I fibres because, to begin with type II fibres have smaller and fewer mitochondrion unlike type I fibres that have more and larger mitochondrion, which in return results in greater oxidative enzyme activity, greater utilization of oxygen and will have a greater fatigue resistance compared to fast twitch fibres. Secondly, type II fibres have a lower myoglobin concentration which hinders its ability to store and facilitate oxygen diffusion which will cause type II fibres to fatigue more faster. Another factor is that type I fibres have a much smaller muscle fibre diameter, which means there is a smaller diffusion distance allowing for oxygen to be used faster since it doesn’t have to travel to far, unlike the large type II fibres. The last factor that causes for a large fatigue index being associated with a high percentage of fast twitch fibres is that type I fibres

Kathryn North, a neurologist and geneticist, sequenced the ACTN3 gene. North found that one variation she named the “X variant” of ACTN3, instructed muscles to produce less alpha-actinin-3, a protein North suspects is directly related to muscle performance. Furthermore North observed an “R variant” of ACTN3, which tells special “fast-twitch muscle fibers” to produce AA3 along side other muscles. Following this logic North deduces that runners with one or more copies of the X variant should preform substantially worse than runners with one or more copies of the R

A few examples of some activities that primarily uses type 1 muscle fibers or slow twitch muscle fibers would be long distance running, long distance cycling or a cross-country skiing. Typically those who are involved in these kind of activities are very lean, have low body fat and very little muscle mass. If one wanted to train their body to perform better at these kinds of activities they should be doing long interval aerobic training. A couple examples of some activities that primarily uses type 2a muscle fibers or fast twitch muscle fibers would be swimming or boxing. Typically those who are involved in these kind of activities are lean and have more muscle mass than those who are involved in activities like long distance running, long

Muscular endurance is very important for people playing sports and who have to sustain an activity for long periods of time. Muscular endurance is determined by how well your slow twitch muscle fibers are developed. In case your wondering what slow twitch muscle fibers are, I will explain. There are generally two types of muscle fibers in your body, slow twitch and fast twitch. Slow twitch muscle fibers cannot exert as much force as fast twitch, but can sustain an effort over a much greater period of time. Fast twitch muscle fibers can exert a great amount of force but for a very limited amount of time. Therefore, slow twitch equals endurance, while fast twitch equals strength.

The age-related loss of muscle power is more rapid than the parallel loss of muscle strength which in turn is more rapid than the loss of muscle mass. Patients with sarcopenia manifested a reduction in the number of both type I/slow-twitch

incredibly high contractile strength and endurance. While smooth muscle tissue has the form of thin