Muscle Fatigue Essay

The movement of protons would no longer be controlled by the carrier protein embedded within the inner membrane of the mitochondria. Normally, the ATP synthase is able to use the potential energy contained in the protons passing through it to produce ATP, but as was explained in the previous question, protons would no longer be passing through the synthase. Uncontrolled movement of this kind would mean any energy release would be uncontrolled as well, and therefore

For needed energy, a molecule of glucose is broken down through a process called glycolysis to form 2 ATP’s. The by-product is lactic acid. During intense, anaerobic muscle activity, anaerobic hydrolysis occurs. The Cori Cycle is activated to recycle the accumulated lactic acid back into useable energy. The lactic acid travels through the bloodstream to the oxygen-rich liver and is converted back to glucose by a process called gluconeogenesis. The glucose is then returned to the muscle to resupply it with energy. This conversion process uses up 6 ATP’s to make 2 ATP’s for the muscle to reuse. This creates a net loss of 4 ATP’s. The Cori cycle is meant to be a temporary shift of energy production from the oxygen-depleted muscles to the liver.

Muscular hypertrophy occurs through anaerobic training and also causes an increase in lactate tolerance since the lactate produced is less concentrated enabling athletes to tolerate increased amounts. The greater extent of muscular hypertrophy and therefore lactate tolerance in males compared to females is evident in the greater number of attacking efforts performed by them whilst on field. During the 20 minutes of the game spent on field, males performed 88.5 attacking skills (approximately 4.43 maximal efforts per minute), while females performed 76.4 attacking skills (3.82 per minute) (Appendix 2). Due to insufficient recovery of CP, the anaerobic glycolysis system would have been dominant for these efforts. Males can tolerate more lactate hence perform more efforts. Furthermore, males had a higher average of 15.40 seconds in the speed endurance test compared to 17.19 seconds for females, indicating that males have greater lactate tolerance due to developed anaerobic adaptations including muscular hypertrophy (Appendix 1). As men have a greater lactate tolerance, they can work at higher anaerobic intensities for longer durations, therefore perform more maximal efforts such as repetitively

This activity is the critical driving force of muscle contraction. The stream of action potentials along the muscle fiber surface is terminated as Acetylcholine at the neuromuscular junction is broken down by acetyl cholinesterase. The release of Calcium ions is ceased. The action of the myosin molecule heads is obstructed because of the change in the configuration of troponin and tropomyosin due to the absence of calcium ions. This will eventually cause the contraction to be ceased. Together with these physical processes, an external stretching force such as gravity pulls the muscle back to its normal length.

Muscle fatigue is defined as a decrease in the maximum force generating capacity of a muscle (3). Muscle force and fatigability are correlated to muscle mass, muscle fiber type, and motor unit recruitment. Muscle fibers consume stored energy and generate force by contracting. If a muscle depletes its fuel supply faster than they can be replenished by metabolism, then fatigue occurs. The purpose of this study was to determine the time to fatigue to 50% of maximum clench force for both dominant and non-dominant arms, and then determine differences between male and female. Recent literature has suggested that there are sex differences in muscle fatigability, however the physiological mechanisms are not entirely understood. In general, men have

activities as it can create a large amount of ATP but does not do so very quickly. This happens in

In recent years, interest has sparked the health industry to research protein consumption after exercise to optimise muscle growth. Muscle Protein Synthesis (MPS) is not only an appealing topic for bodybuilders, it is also beneficial to those over 60 years of age who may have experienced muscle mass loss over time. A decrease in muscle mass does not only lead to a decrease in overall strength but also makes daily movement severely painful, leading to a poor quality of life. All individuals can benefit from increasing muscle protein synthesis via an increased protein intake after resistance training. This will aid in maintaining muscle mass, strength and overall health (Wolfe, 2012).

Muscle fatigue can occur for a number of reasons, but it often happens due to intensive exercises. Placing a large amount of strain on your muscle for extended periods of time can cause it to weaken. During muscle fatigue, the muscle fails to produce enough force. Therefore, things like running and walking become difficult to do and should be put on the back burner until the muscle has a chance to heal and rest. In order to promote healing and reduce pain in your muscle, there are a number of herbal remedies that you can use.

The Cori cycle is a metabolic pathway where lactic acid is made anaerobic glycolysis in the muscle and then travels to the liver where it is converted to glucose and then goes back to the muscle and is made back into lactate. (Wikipedia, 2007) When muscle activity occurs epinephrine is released by the brain. Epinephrine stimulates glycogen breakdown in the muscles as well as the liver. Muscle activity causes stored ATP (Adenosine triphosphate) to be used quickly and more ATP must be created by the breakdown of glycogen. In anaerobic conditions glucose is converted to pyruvate and then to lactic acid. The lactic acid then travels though the blood stream to the liver. In the liver lactate is converted back to pyruvate and then back to glucose. Once it has converted back to glucose it can be returned to the muscle for energy. (Ophardt, 2003)

Ideally, take 2-3 minutes rest after еvеrу set. Dоn't concentrate оn specific parts оf thе body, make іt а whоlе body workout оr уоu саn assign specific days tо work оut оn thе specific parts оf thе body.

complete citric acid cycle which will release a total of 38 ATP molecules. Aconitase removes a water

one) of ATP. This happens in the mitochondria of muscle cells; the increase of size and quantity will

Carbohydrate, in the form of glucose, is the preferred fuel for working muscles. It is particularly important during high intensity activity but whatever exercise is performed some carbohydrate will be used. Glucose is stored in the muscles and liver as a substance known as glycogen and is rapidly converted back to glucose when is it required. The capacity for glycogen storage is limited - a 70kg individual has glycogen reserves of approximately 400g. Once these stores have been used, the ability to perform exercise is reduced.

During prolonged activity, muscles show a decline in ability to respond to stimulation with optimal levels of contractile activity; this is a phenomena denoted as muscle fatigue (MF) (1). The causes of MF are not yet understood, however there are many observations of associations between metabolic and biochemical factors with MF. In order for force to be generated by muscles, calcium ions which are released from the sarcoplasmic reticulum bind to troponin. The new troponin-Ca2+ complex cause’s tropomyosin to change shape, exposing the binding site on actin. Myosin then binds to actin, causing cross bridge tilting, and generating contraction (1).

The intensity of work is still high, being around 85 – 95% of one’s max heart rate. Its main energy fuel being Carbohydrates, (such as breads, potatoes, sugars & pasta), however its fatiguing factor is gaining Lactic Acid. This is because the end product of Glycolysis is Pyruvic acid – without oxygen – Pyruvic acid will turn into Lactic Acid, which further causes fatigue in the muscles. However, when one’s heart rate is increased, oxygen is delivered around the body faster which results in the removal of Lactic Acid & reduction in blood pooling. This process usually occurs at 60 – 65% of someone’s max heart rate. This Energy System is best used for 200 m sprints, 100 m swims & within a team sport with repeat maximal efforts with insufficient recovery of Creatine