...11/9/2015 In the experiment we performed in lab last week, our group’s objective was to measure the force output in the unit of Newtons (N) and Electromyography (EMG) output of an isometric hand contraction squeezing a ball in four varying wrist angles. This experiment was created with the intention to help us better understand how muscle force varies when muscle length varies. The title of the experiment is the “Length-Tension Experiment”. The Length-Tension relationship in anatomy refers to how the number of crossbridges depends on the amount of overlap between thick and thin fibers. Optimum amount of overlap will result in the greatest amount of tension. The optimum amount of overlap can be determined by the length of the sacromeres when the muscle is contracted. If the muscles are too stretched when contraction occurs, myosin will pull away from the actin and prevent cross bridge formation. Conversely, if muscles/sacromeres are too short at contraction cannot conduct signal efficiently because the crowded thin filaments disrupt the t-tubule’s arrangement in the myofibers. It is also essential to comprehend the relationship between myosin and actin. Myosin (thick filaments in sacromere) grabs onto actin (thin filaments in sacromere) and pulls, creating tension in the muscle. The contraction is caused by the previously described interaction between actin and myosin, resulting in the thin filaments being pulled closer to the M line of the sacromere, widening the zone of overlap between...
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...Muscle contractions are the reason why the skeleton can be moved. The muscle contraction starts off with a nerve impulse that is sent from the brain or spinal cord to the skeletal muscle to cause a contraction. This nerve impulse is also known as an action potential. The site where the motor neuron connects with the muscle fiber is called the neuromuscular junction. At the sarcolemma, the neuromuscular junction is a chemical synapse that consists of the axon terminals and motor end plate. The action potential travels from the axon, down the motor neuron and into the axon terminals. Calcium channels then open and spend calcium ions into the axon terminals. The entrance of calcium causes synaptic vesicles to release acetylcholine. Acetylcholine...
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...The final results of this experiment showed that the area under the graph of the absolute values of the EMG is nonlinearly proportional to the strength of the muscle contraction. The duration of the burst is equal to the duration of the muscle contraction. The relationship between EMG and muscle force production is often linear but not always. The amount of force a muscle produces when electrically activated by EMG depends on the current state of the muscle. The contraction of muscle fibers in vivo is stimulated by somatic motor neurons. Each somatic motor axon branches to innervate a number of muscle fibers. When a muscle is composed of many motor units, there is fine control of muscle contraction. Muscle fatigue is the decline in ability...
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...1. Without ATP, muscles cannot relax nor contract. During muscle contraction, an ADP and phosphate molecule is attached to the myosin head. The actin myofilaments’s active site are exposed because calcium binds to troponin during contraction. This binding causes the tropomyosin to move out of the way exposing the active site. The phosphate molecule attached to the myosin head is used, as energy, and released after it pulls the myosin head to the active site of the actin myofilament, which forms a bond called a cross-bridge. The connects myosin head uses the energy of the ADP molecule to slide pass the actin myofilament. This is a contraction. ADP is released after. Once released, ATP comes and binds the myosin head, this allows the myosin head...
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...FIS3703 Discuss the sources of energy for muscle contraction Sources of energy for muscle contraction Muscle contraction is dependent on energy supplied by ATP. The majority of this energy is needed to actuate the walk-along mechanism by which the cross-bridges drag the actin filaments, but some energy is also needed for (1) propelling C ions into the sarcoplasmic reticulum from the sarcoplasm after the contraction is over and (2) propelling sodium and potassium ions through the muscle fiber membrane to keep suitable ionic environment for conduction of muscle fiber action potentials The ATP concentration in the muscle fiber is enough to maintain full contraction up to 2 seconds. ADP is formed after it splits from ATP and ADP transports energy from the ATP molecule to the contracting machinery of the muscle fiber. After that, the ADP is rephosphorylated and new ATP is synthesized within a few split seconds which permit the muscle to maintain its contraction. Numerous sources of energy for rephosphorylation exist, the first one being phosphocreatine which transports a high-energy phosphate bond almost the same to the bonds of ATP. Phosphocreatine has a little bit more free energy than that of an ATP molecule. Thus, phosphocreatine is immediately cleaved and the energy released from it results in the combining of a new phosphate ion to ADP to reconstitute the ATP. However, there is not much phosphocreatine in the muscle fiber and thus, the collective energy of the stored...
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...Glossary acetylcholinesterase: It is an enzyme that carries out the process of acetylcholine (a neurotransmitter) break-down at the region between two nerve cells (synaptic cleft) so that the impulse gets transmitted from one neuron to another. achalasia cardia: It is also called as cardiospasm and in this case the neuromuscular failure of oesophageal relaxation especially at the lower end with progressive dilatation of the part of the oesophagus above. actin-myosin crossbridging: It is responsible for the force generation and contraction of skeletal muscle. There are certain myosin-binding sites present on actin which undergoes bonding with myosin forming cross-bridges.it is an important step in skeletal muscle contraction. adenine: It is...
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...The strength and conditioning philosophy can be wrapped up in one statement; to train for sport-specific power. The definition of power is: strength x speed= power. Strength training, Olympic weightlifting, sprint speed, agility, plyometrics, flexibility, balance, and core/stability training all need to be performed to achieve maximum sport-specific power. A strong core is necessary to maintain back strength throughout all ranges of motion. Proper posture in the core can significantly increase the force production of the arms and legs and keep the athlete's back strong and healthy throughout all training. This can especially be important in today’s society where kids walk around all day with their shoulders slumped forward to hold a back pack on their shoulders comfortably. Flexibility to comfortably go through the full range of motion with proper technique in all lifting and running drills is also necessary. A good total body flexibility test would be a properly executed overhead squat where the athlete gets all the way down with their hips below their knees. Sprinting, agilities, and plyometrics are all important components of speed training. This is also where the coach can get very sport specific with agility drills and sprinting distances. The weight room is critical to maximize strength, power, and speed training. Lifts such as the deep squat and bench are great for lower and upper body strength and all the Olympic weightlifting will work to maximize speed and power. ...
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...muscular tension first, All muscular tension means is as you go down in the splits position your muscles panic because the position is new territory to them and they think (oh I don’t think this is a good idea, this is going to hurt or injure me) The result is as soon as the fear of pain kicks in or your muscles feel uncomfortable they will contract or tense up with all their might to stop you going any further. You have to admire the little buggers because they are only trying to protect you but the fact is your own muscles deliberately stop you from doing what you want to do. So what’s the answer? It is simple all you have to do is learn to control muscular tension so that you can delay and eventually stop your muscles from contracting. How do you control muscular tension? There are several methods and you will use all of them in the 6 weeks to splits plan. One, Waiting out the tension, This one is great because it is so easy but works like magic. All you have to do is slide into your splits position and keep going until your muscles tense up and act like breaks to stop you going any further. When this happens and it will unless you can already do the splits perfectly and I’m guessing you can’t or you wouldn’t be reading this article, then the solution is easy you simply stay in the same position and do nothing but relax and wait out the tension (by the way the muscular contraction that stops you going any further is know as the stretch reflex). When I say relax I mean you use...
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...uses the stretch shortening cycle to gain height when jumping. There are threes phases that make up the stretch shortening cycle (SSC), the concentric, amortization and eccentric contractions. These three phases refer to muscular contractions, which form the stretch shortening cycle. This lengthening and shortening cycle of muscle actions is fundamental to athletic movement. The initial eccentric phase of contraction involves the muscle lengthening or stretching under tension. This type of contraction is used to decelerate the body. A basic example of this is the running motion, when the athlete makes contact with the ground their centre of gravity drops quickly. The muscles contract and control this sinking motion. The concentric contraction quickly follows the eccentric contraction and involves a rapid shortening of the muscles. The period of time between the beginning of the eccentric contraction and the start of the concentric contraction is known as the amortization phase and is the most important part of a plyometrics exercise. This phase is marked by a very brief period where the muscle is completely stationary which is referred to as an isometric contraction. Sports Motion Injuries (jumping) Jumping is a form of plyometric exercise used to increase power and strength into the muscles. Power and...
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...marketed in therapeutic doses as “Botox”. Initially, it was used to treat neuro-muscular disease with involuntary muscle contraction symptopms. This problem arises from too little inhibitory input to motor neuron, as compared to excitatory input, thus leading to excessive motor neuron activation. Botulinum toxin injection blocks the release of musclecontraction-causing acetycholine at the neuromuscular junctions. The goal is to inject just enough dosage to relieve the troublesome spasmodic contraction, but not enough to eliminate the normal contractions needed for ordinary movement. Botulinum toxin clears away after 3 to 6 months, so the treatment must be repeated. From treating involuntary muscle contraction to fighting wrinkles Botulinum toxin’s potential as a treatment option for cosmetic surgeon was accidentally discovered when the physicians noted the injections used to counter abnormal eye muscle contractions also smoothed the appearance of wrinkles in the treated area! It turns out that frown lines, crow’s feet, and furrowed brows are caused by facial muscles that have become over-activated, or permanently contracted. This is the results of years of performing certain repetitive facial expression. By relaxing these muscles, botulinum toxin temporarily smoothes out these age-related wrinkles. However, as with its therapeutic use to treat muscle spasms, the costly injection of botulinum toxin must be repeated every 3 to 6 months, to maintain the desired...
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...Glycerinated Muscle Introduction Muscles are a fibrous bundle of tissues that contract to produce movement in the body. There are three different types of muscles, cardiac, skeletal, and smooth. Though these three different types of muscles serve slightly different purposes, they function very similarly. The main components of muscles are muscle fibers, myosin, actin, and a few more. Muscle contractions works primary off of the interaction between the proteins, actin and myosin. Troponin and tropomyosin work to regulate the contraction. Purpose The purpose of this lab was to learn about glycerinated muscle systems and how contraction works in relation to it. Materials Glycerinated muscle. 0.25% ATP in distilled...
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...Activity 1: Muscle Twitch and the Latent Period Muscles have different functions in our body. They maintain body temperature by contracting, and they use the energy stored in the body, which later is transformed into heat. For muscles to contract, they must be stimulated by motor neurons; these motor neurons meats at the neuromuscular junction. When the nerve impulses reach the neuromuscular junctions voltage –regulated calcium channels open and allow calcium to enter the axon; the ca2+ inside cause’s vesicles to fuse with an axonal membrane causing it to release ACH via exocytosis. The ACH then binds to its receptors in the sarcolemma and causes an action potential in the muscle. Binding of ACH to its receptor opens chemically gated channels;...
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...resistance training that may keep people from living healthier lives. To clarify, resistance training, as defined by wikipedia, is a “physical exercise that specializes in the use of resistance to induce muscular contraction which builds the strength, anaerobic endurance, and size of skeletal muscles”. Resistance training has numerous benefits, all of which are helpful in maintaining a fit physique, lowering body fat, and reducing the chance of problematic medical diseases. The first and least vital benefit of resistance training is its impact on the body’s natural physique. The best part about this is its simplicity: resistance to muscle contraction causes the muscles to break down which then allows for them to be rebuilt even stronger. This explanation however does not cover the vast and ever changing methods which can be used to achieve this muscle break down. Furthermore, it is apparent that any method will yield positive results for the user as long as it is done in a way that demotes injury. If one were to tailor fit a certain method to match their muscle gaining goals then they should see even grater results, possible even in less time. Most people can successfully associate weight lifting with building muscle, but forget that the energy for building muscle must come from somewhere. Thankfully this happens to be the body's fat stores,so when working out it will lower one's body fat percent during the recovery period. Which provides another fantastic reason for the...
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...muscular contraction. It is similar to explosive strength and involves a large proportion of fast twitch muscle fibres and the ability to recruit as many motor units as quickly as possible. Power is produced through the skeletal muscles. Although skeletal muscle cells come in different shapes and sizes the main structure of a skeletal muscle cell remains the same. The Epimysium protects the muscle from friction against other muscles and bones. It also continues at the end of the muscle to form (along with...
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...BTEC 90 Credit/Extended Diploma in Public Services Unit 5 Physical Preparation, Health and Lifestyle for the Public Services Learner Resource Pack Introduction The human body is a very complex piece of machinery. It is made up of many different systems that work together to allow us to take part in a wide range of sports and everyday activities. It is important that anyone working with clients in the sport and exercise industry has a good understanding of how each of these systems works and copes with the stresses of exercise. This unit will explore the structure and the functions of the skeletal, muscular, cardiovascular and respiratory systems and how each of them is affected by exercise. It will also focus on the energy systems and their role in sport and exercise performance. Section One - The Structure and Function of The Skeletal System and How it Responds to Exercise Part 1.1: The structure of the skeleton system The skeleton provides us with a complex framework of bones, joints and cartilage without which we could not stand upright or move. It consists of 206 bones which can be divided into the axial and appendicular skeleton. The axial and appendicular skeleton The axial skeleton provides the supportive structure of the skeleton and is made up of the skull, vertebral column, sternum and ribs. The appendicular skeleton is made up of the upper limbs, shoulder girdle, lower limbs and hip girdle and provides...
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