Coactivation Rate Contraction

* Electromyogram- Measures electrical activity of muscles at rest and during contraction. These studies measure how well and fast the nerves can send electrical signals.

This is known as constant hypertrophy. This is where either the size or number of muscle filaments increase. This is may be due to the "ATP deficiency theory": ATP stores are drained and the protein content in the working muscles is extremely low. As the athlete recovers between sessions, the body renews the protein in the muscles. During this procedure, the protein content in the muscle surpasses the initial level, bringing about an expansion in muscle fibre size. This is the desired effect of strength training because it has a direct impact on an athlete’s performance. Another physiological adaptation that occurs through training is inter-muscular coordination, this means that there is less of a contraction from the antagonists during these trained movements; making the movement more effective. Additionally, as mentioned by (Fisher, 2011), resistance training can reduce an athlete’s chances of getting injured by strengthening joints, muscles, bones and tendons. As well as this, a neuromuscular response occurs through heavy weight training. This can result in a stronger and more powerful contraction because of the ability to recruit more motor units to take part in the contraction of the muscle. During training, to start with the plan was to also improve the strength of tendons, causing them to grow in diameter and improving their ability to withstand

Resting heart contractions were recorded for thirty seconds until the heart rate was less than 60 beats per minute. A stimulator electrode to be used was set to the following states: Amplitude of 4.00 Volts, a stimulus delay of 50ms, stimulus duration of 10ms, a frequency of 1.0Hz, and a pulse number of 30. The electrode was then placed in direct contact with the heart for 30 seconds at which time the data was observed and recorded.

When exercising, the weight or stress you’ve produced to the muscles can create resistance and then contraction of the muscles can be drawn out. These contractions enable the muscles significantly increase in size. Along with the increase in size is the increase in strength as well. Repeated exercise, coupled with weight bearing activities, hypertrophy, and medical term for increase in muscle size, of the muscles will be evident.

Introduction: According to the “Human Physiology Laboratory Manual “,BIOL 282 ,page 31 , the reason of performing this experiment is to learn how the muscle contraction occurs based on the molecular level and what kind of factors are involved .As a matter of fact, skeletal muscles contain a lot of nuclei because of the cell fusion while being developed and are made of cylindrical cells that have myofibrils. The myofibrils contain sarcomeres and the

The EMG signal that is observed through the placement of electrodes on the skin is closely coupled with the generation of muscle force. In normal conditions, the force-EMG relationship is either linear or the increase in EMG at low force levels is less than proportional (Semmler 2014). However, a different force-EMG relationship was observed following eccentric exercise,

Review Sheet Results 1. Describe how increasing the stimulus frequency affected the force developed by the isolated whole skeletal muscle in this activity. How well did the results compare with your prediction? Your answer: When the stimulus frequency was at the lowest the force was at its lowest level out of all of the experiments. As the stimulus frequency was increased to 130, s/s the force increased slightly but fused tetanus developed at the higher frequency. When the stimulus frequency was increased to the amounts of 146-150 s/s, the force reached a plateau and maximal tetanic tension occurred, where no further increases in force occur from additional stimulus frequency. 2. Indicate what type of force was developed by the isolated skeletal muscle in this activity at the following stimulus frequencies: at 50 stimuli/sec, at 140 stimuli/sec, and above 146 stimuli/sec. Your answer: At 50- Unfused

The further the muscle is stretched the bigger the force it exerts. This is a linear effect.

Regular electrical impulses are sent within the conduction system of the heart prompting contraction (Marieb, 2015). These electrical signals can be identified and documented by the use of an electrocardiography (ECG) machine. In a familiar ECG recording, three waves will occur; The P wave, QRS complex and

The electrocardiogram measures electric activity of the heart and looks at heart rate from different angles using electrodes placed around the body (clavicles, write, calf, ankle) and the charge that travels through this apparatus. Einthoven’s triangle describes the axes at which the heart can be studied based on the placement of the electrodes.

This is because once a contraction has started, the action potential has already fired, stimularing the muscle fibers. Once they

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.

Both of these muscles expand and contract as they have complex structures so it is essential how they do this. The cardiac muscle needs the contractions to occur in order to pump blood out of the atria and into the ventricles and round the circulatory system so the structure of this muscle shows the systole of the heart. The contractions of the skeletal muscle also depend on its structure. The binding and releasing of two strands of sarcomere is how the repeated pattern of contractions occurs. ATP is used to prepare myosin for binding to allow the contractions to happen. The skeletal and cardiac muscle also both has elasticity. The elasticity is used to restore the muscles back to their original lengths which enable them to resume back to their original length once they have contracted and been stretched.

6. Automaticity – ability of heart to beat spontaneously and repetitively without external neurohormonal control. The heart is capable of beating outside the body, given proper laboratory conditions. Automaticity is evidently linked to fluid and electrolyte balance rather than to nervous system control.

An electrocardiogram can be used to record activity during the cardiac process of pumping and returning blood to the body and heart because of the electric current that spreads through the tissue of the heart and to the surface of the body. By