Training+Adaptations+in+Skeletal+Muscle

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**Introduction**  The nature of this adaptation can be summarized using the following principle:  The cell will adapt in a manner that tends to minimize any movement away from **homeostasis**, or resting conditions.  In exercise physiology we refer to the acute changes that occur in a system, organ, or cell during exercise as **responses**. An example is the increase in heart rate that occurs when we jump up from our chair and start jogging.   Cellular adaptations generally involve an increase or decrease in the rate of synthesis of a specific cellular component. All muscle cells are in a constant state of synthesis and degradation. If synthesis rate exceeds degradation rate, an increase in the cellular component occurs. A change in protein synthesis requires a cellular signal. Biologists and physiologists continue to explore the communiction process by which different forms of muscular work induce cellular changes. At the cellular level, there are some theories, but no complete understanding. However, __we do know quite a bit about **what** adaptations do occur__, even if we aren't sure **how** just yet.  //**Contrast Between** // **Maximal Strength** ** & Maximal Endurance** <span style="FONT-SIZE: 12pt; FONT-FAMILY: 'Verdana','sans-serif'"> <span style="FONT-SIZE: 12pt; FONT-FAMILY: 'Verdana','sans-serif'">If we could build a skeletal muscle for the purpose of endurance, what would the recipe be? Since the heart is the supreme endurance muscle, let's look at it first. <span style="FONT-SIZE: 12pt; FONT-FAMILY: 'Verdana','sans-serif'"> <span style="FONT-SIZE: 12pt; FONT-FAMILY: 'Verdana','sans-serif'"> <span style="FONT-SIZE: 12pt; FONT-FAMILY: 'Verdana','sans-serif'">**Characteristics of Fatigue Resistant Muscle Cells** <span style="FONT-SIZE: 12pt; FONT-FAMILY: Symbol; mso-bidi-font-family: Symbol; mso-fareast-font-family: Symbol"> ·  <span style="FONT-SIZE: 12pt; FONT-FAMILY: 'Verdana','sans-serif'">The surrounding network of capillaries is extremely well developed. This characteristic also facililitates even and rapid oxygen distribution to all myocardial cells. <span style="FONT-SIZE: 12pt; FONT-FAMILY: 'Verdana','sans-serif'"> <span style="FONT-SIZE: 12pt; FONT-FAMILY: Symbol; mso-bidi-font-family: Symbol; mso-fareast-font-family: Symbol"> ·  <span style="FONT-SIZE: 12pt; FONT-FAMILY: 'Verdana','sans-serif'">The mitochondrial density of heart cells is extremely high, 20-25% of cell volume in adults. Mitochondria use oxygen to metabolise food and produce ATP. <span style="FONT-SIZE: 12pt; FONT-FAMILY: 'Verdana','sans-serif'"> <span style="FONT-SIZE: 12pt; FONT-FAMILY: 'Verdana','sans-serif'"> <span style="FONT-SIZE: 12pt; FONT-FAMILY: Symbol; mso-bidi-font-family: Symbol; mso-fareast-font-family: Symbol"> ·  <span style="FONT-SIZE: 12pt; FONT-FAMILY: 'Verdana','sans-serif'">The cytoplasmic enzymes responsible for breaking down fatty acid molecules into 2 carbon fragments that can enter the mitochondria are present in high concentrations. <span style="FONT-SIZE: 12pt; FONT-FAMILY: 'Verdana','sans-serif'"> <span style="FONT-SIZE: 12pt; FONT-FAMILY: Symbol; mso-bidi-font-family: Symbol; mso-fareast-font-family: Symbol"> ·  <span style="FONT-SIZE: 12pt; FONT-FAMILY: 'Verdana','sans-serif'">Contractile protein makes up about 60% of cell volume. The ATPase subtype found in heart is slower than that seen in skeletal muscle. Consequently, the rate of force development is slower, although absolute tension/cell diameter is the same. <span style="FONT-SIZE: 12pt; FONT-FAMILY: 'Verdana','sans-serif'"> <span style="FONT-SIZE: 12pt; FONT-FAMILY: 'Verdana','sans-serif'"> <span style="FONT-SIZE: 12pt; FONT-FAMILY: Symbol; mso-bidi-font-family: Symbol; mso-fareast-font-family: Symbol"> ·  <span style="FONT-SIZE: 12pt; FONT-FAMILY: 'Verdana','sans-serif'">Heart lactate dehydrogenase, the enzyme that converts pyruvate to lactic acid competes poorly with pyruvate dehydrogenase. This contributes to the very low lactate production in heart cells despite high metabolic flux. <span style="FONT-SIZE: 12pt; FONT-FAMILY: 'Verdana','sans-serif'"> <span style="FONT-SIZE: 12pt; FONT-FAMILY: 'Verdana','sans-serif'">So, heart cells display almost zero fatiguability due to the tremendous capacity they have to receive and consume oxygen. Fatigue resistance is traded for anaerobic capacity. This is why the heart has little tolerance for oxygen deprivation, or a heart attack. If we want to build a skeletal muscle that is highly fatigue resistant, it must resemble heart muscle in its basic features. <span style="FONT-SIZE: 12pt; FONT-FAMILY: 'Verdana','sans-serif'"> Now let's build a muscle that is optimized for brief efforts and maximum force production. Here are the characteristics needed. <span style="FONT-SIZE: 12pt; FONT-FAMILY: 'Verdana','sans-serif'"> <span style="FONT-SIZE: 12pt; FONT-FAMILY: 'Verdana','sans-serif'"> <span style="FONT-SIZE: 12pt; FONT-FAMILY: 'Verdana','sans-serif'">**Characteristics of** <span style="FONT-SIZE: 12pt; FONT-FAMILY: 'Verdana','sans-serif'">**Maximal Strength Muscle Cells** <span style="FONT-SIZE: 12pt; FONT-FAMILY: Symbol; mso-bidi-font-family: Symbol; mso-fareast-font-family: Symbol"> ·  <span style="FONT-SIZE: 12pt; FONT-FAMILY: 'Verdana','sans-serif'">Each muscle cell should contain a high volume of contractile protein. Since oxygen diffusion is not a concern, making the cell diameter larger will help it hold more contractile protein (actin and myosin). <span style="FONT-SIZE: 12pt; FONT-FAMILY: Symbol; mso-bidi-font-family: Symbol; mso-fareast-font-family: Symbol"> ·  <span style="FONT-SIZE: 12pt; FONT-FAMILY: 'Verdana','sans-serif'">To make more room for actin and myosin, mitochondrial density should be minimized to that necessary to maintain resting cell function. <span style="FONT-SIZE: 12pt; FONT-FAMILY: Symbol; mso-bidi-font-family: Symbol; mso-fareast-font-family: Symbol"> ·  <span style="FONT-SIZE: 12pt; FONT-FAMILY: 'Verdana','sans-serif'">Since fat can only be metabolized aerobically, high levels of fat cleaving enzymes in the cytosol are also unnecessary. <span style="FONT-SIZE: 12pt; FONT-FAMILY: Symbol; mso-bidi-font-family: Symbol; mso-fareast-font-family: Symbol"> ·  <span style="FONT-SIZE: 12pt; FONT-FAMILY: 'Verdana','sans-serif'">The capacity for anaerobic glycolysis should be high to allow brief but high capacity energy production without oxygen. The capacity for lactic acid production should be high. <span style="FONT-SIZE: 12pt; FONT-FAMILY: 'Verdana','sans-serif'"> //What you should notice is that these two lists are exactly opposite. __The optimal muscle for endurance CAN NEVER be maximally strong__. And __the muscle fiber that produces the most force CANNOT be optimally developed for endurance__ as well. The two conditions are mutually exclusive. This is one of the most important concepts to understand when designing a training program.// <span style="FONT-SIZE: 12pt; FONT-FAMILY: 'Verdana','sans-serif'"> <span style="FONT-SIZE: 12pt; FONT-FAMILY: 'Verdana','sans-serif'"> <span style="FONT-SIZE: 12pt; FONT-FAMILY: 'Verdana','sans-serif'"> <span style="FONT-SIZE: 12pt; FONT-FAMILY: Symbol; mso-bidi-font-family: Symbol; mso-fareast-font-family: Symbol"> ·  <span style="FONT-SIZE: 12pt; FONT-FAMILY: 'Verdana','sans-serif'">There are identifiable proteins in the muscle that contribute to its ability to produce high force at high rates (Strength and Power). <span style="FONT-SIZE: 12pt; FONT-FAMILY: 'Verdana','sans-serif'"> <span style="FONT-SIZE: 12pt; FONT-FAMILY: Symbol; mso-bidi-font-family: Symbol; mso-fareast-font-family: Symbol"> ·  <span style="FONT-SIZE: 12pt; FONT-FAMILY: 'Verdana','sans-serif'">There are also identifiable proteins and structural characteristics that confer high fatigue resistance (Endurance). <span style="FONT-SIZE: 12pt; FONT-FAMILY: 'Verdana','sans-serif'"> <span style="FONT-SIZE: 12pt; FONT-FAMILY: 'Verdana','sans-serif'"> <span style="FONT-SIZE: 12pt; FONT-FAMILY: Symbol; mso-bidi-font-family: Symbol; mso-fareast-font-family: Symbol"> ·  <span style="FONT-SIZE: 12pt; FONT-FAMILY: 'Verdana','sans-serif'">There is no identifiable specific protein or structure that confers the quality <span style="FONT-SIZE: 12pt; FONT-FAMILY: 'Verdana','sans-serif'"> "Strength-Endurance". When we train for strength-endurance, what we are really <span style="FONT-SIZE: 12pt; FONT-FAMILY: 'Verdana','sans-serif'"> doing is training in a way that fails to <span style="FONT-SIZE: 12pt; FONT-FAMILY: 'Verdana','sans-serif'"> stimulate either strength or endurance <span style="FONT-SIZE: 12pt; FONT-FAMILY: 'Verdana','sans-serif'"> adaptations optimally. An example of this <span style="FONT-SIZE: 12pt; FONT-FAMILY: 'Verdana','sans-serif'"> "best of neither worlds" approach is circuit <span style="FONT-SIZE: 12pt; FONT-FAMILY: 'Verdana','sans-serif'"> training. <span style="FONT-SIZE: 12pt; FONT-FAMILY: 'Verdana','sans-serif'"> <span style="FONT-SIZE: 12pt; FONT-FAMILY: 'Verdana','sans-serif'"> <span style="FONT-SIZE: 12pt; FONT-FAMILY: 'Verdana','sans-serif'">As a coach/athlete, your success begins with your ability to accurately understand the muscular demands of your sport. Then, a training program can be designed that will result in muscular development suited to the combination of strength and endurance that your sport requires. <span style="FONT-SIZE: 12pt; FONT-FAMILY: 'Verdana','sans-serif'"> <span style="FONT-SIZE: 12pt; FONT-FAMILY: 'Verdana','sans-serif'"> <span style="FONT-SIZE: 12pt; FONT-FAMILY: 'Verdana','sans-serif'"> <span style="FONT-SIZE: 12pt; FONT-FAMILY: 'Verdana','sans-serif'"> <span style="FONT-SIZE: 12pt; FONT-FAMILY: 'Verdana','sans-serif'"> <span style="FONT-SIZE: 12pt; FONT-FAMILY: 'Verdana','sans-serif'"> <span style="FONT-SIZE: 12pt; FONT-FAMILY: 'Verdana','sans-serif'"> <span style="FONT-SIZE: 12pt; FONT-FAMILY: 'Verdana','sans-serif'">Essential Knowledge - Exercise Physiology <span style="FONT-SIZE: 12pt; FONT-FAMILY: 'Verdana','sans-serif'"> <span style="FONT-SIZE: 12pt; FONT-FAMILY: 'Verdana','sans-serif'">Muscle – Skeletal Muscle – 40% body weight (males) <span style="FONT-SIZE: 12pt; FONT-FAMILY: 'Verdana','sans-serif'"> - 33% body weight (females). <span style="FONT-SIZE: 12pt; FONT-FAMILY: 'Verdana','sans-serif'"> <span style="FONT-SIZE: 12pt; FONT-FAMILY: 'Verdana','sans-serif'">Not all muscle is the same. Bundles of fibres (cells). <span style="FONT-SIZE: 12pt; FONT-FAMILY: 'Verdana','sans-serif'">Born with a certain pre-disposition. <span style="FONT-SIZE: 12pt; FONT-FAMILY: 'Verdana','sans-serif'"> <span style="FONT-SIZE: 12pt; FONT-FAMILY: 'Verdana','sans-serif'"> <span style="FONT-SIZE: 12pt; FONT-FAMILY: 'Verdana','sans-serif'"> //<span style="FONT-SIZE: 12pt; FONT-FAMILY: 'Verdana','sans-serif'">White //<span style="FONT-SIZE: 12pt; FONT-FAMILY: 'Verdana','sans-serif'"> (No Oxygen Required) <span style="FONT-SIZE: 12pt; FONT-FAMILY: 'Verdana','sans-serif'">Size is Important. Bigger Muscle = more strength. <span style="FONT-SIZE: 12pt; FONT-FAMILY: 'Verdana','sans-serif'"> <span style="FONT-SIZE: 12pt; FONT-FAMILY: 'Verdana','sans-serif'"> <span style="FONT-SIZE: 12pt; FONT-FAMILY: 'Verdana','sans-serif'"> //<span style="FONT-SIZE: 12pt; FONT-FAMILY: 'Verdana','sans-serif'">Grey //<span style="FONT-SIZE: 12pt; FONT-FAMILY: 'Verdana','sans-serif'"> ( Minimal Oxygen Required ) <span style="FONT-SIZE: 12pt; FONT-FAMILY: 'Verdana','sans-serif'">Explosive strength. Sprinter, High Jump <span style="FONT-SIZE: 12pt; FONT-FAMILY: 'Verdana','sans-serif'"> <span style="FONT-SIZE: 12pt; FONT-FAMILY: 'Verdana','sans-serif'"> <span style="FONT-SIZE: 12pt; FONT-FAMILY: 'Verdana','sans-serif'">because they are full of haemoglobin (oxygen in the blood) <span style="FONT-SIZE: 12pt; FONT-FAMILY: 'Verdana','sans-serif'">These muscle cells need oxygen. <span style="FONT-SIZE: 12pt; FONT-FAMILY: 'Verdana','sans-serif'">This means longer than 90secs <span style="FONT-SIZE: 12pt; FONT-FAMILY: 'Verdana','sans-serif'">Oxygen + Carbon (Sugar) = Energy <span style="FONT-SIZE: 12pt; FONT-FAMILY: 'Verdana','sans-serif'">O**2** + C = CO**2 (Exhale)** <span style="FONT-SIZE: 12pt; FONT-FAMILY: 'Verdana','sans-serif'"> <span style="FONT-SIZE: 12pt; FONT-FAMILY: 'Verdana','sans-serif'"> <span style="FONT-SIZE: 12pt; FONT-FAMILY: 'Verdana','sans-serif'">So which type of muscle fibre do we need to train for : - <span style="FONT-SIZE: 12pt; FONT-FAMILY: 'Verdana','sans-serif'">Triathlon Road Cyclist Rugby/League <span style="FONT-SIZE: 12pt; FONT-FAMILY: 'Verdana','sans-serif'">Shot Put Weightlifter Netball <span style="FONT-SIZE: 12pt; FONT-FAMILY: 'Verdana','sans-serif'">400m runner Rower Soccer
 * __<span style="FONT-SIZE: 12pt; FONT-FAMILY: 'Verdana','sans-serif'; mso-bidi-font-family: Gautami">Training Adaptations in Skeletal <span style="FONT-SIZE: 12pt; FONT-FAMILY: 'Verdana','sans-serif'"> Muscle __<span style="FONT-SIZE: 12pt; FONT-FAMILY: 'Verdana','sans-serif'; mso-bidi-font-family: Gautami"> **
 * <span style="FONT-SIZE: 12pt; FONT-FAMILY: 'Verdana','sans-serif'">Adaptability **<span style="FONT-SIZE: 12pt; FONT-FAMILY: 'Verdana','sans-serif'"> is a fundamental characteristic of skeletal muscle (and the body in general).
 * <span style="FONT-SIZE: 12pt; FONT-FAMILY: 'Verdana','sans-serif'">Long term changes that occur **<span style="FONT-SIZE: 12pt; FONT-FAMILY: 'Verdana','sans-serif'"> as a result of repeated bouts of exercise(Training), are called **__adaptations__**.
 * //__Three Points to Remember:__//**
 * __Exercise Physilogy__**
 * __<span style="FONT-SIZE: 12pt; FONT-FAMILY: 'Verdana','sans-serif'">Types of Muscle Fibre __**
 * //__<span style="FONT-SIZE: 12pt; FONT-FAMILY: 'Verdana','sans-serif'">Fast Twitch I __//**<span style="FONT-SIZE: 12pt; FONT-FAMILY: 'Verdana','sans-serif'"> = Strength
 * //__<span style="FONT-SIZE: 12pt; FONT-FAMILY: 'Verdana','sans-serif'">Fast Twitch II __//**<span style="FONT-SIZE: 12pt; FONT-FAMILY: 'Verdana','sans-serif'"> = Power / Speed
 * //__<span style="FONT-SIZE: 12pt; FONT-FAMILY: 'Verdana','sans-serif'">Slow Twitch __//**<span style="FONT-SIZE: 12pt; FONT-FAMILY: 'Verdana','sans-serif'"> = Endurance – //Red//