[Light]

Not so good.
I think that I've caught a cold. I use to take a shower after I go the the gym and drink a juice or a beer with my friends. Probably I got a cold from this and this week I've been not well.
I had not problem all winter and now this.
Well I plan to run in weekend, I will let you know how its going.

[Holly]

[LuckySmile]

Thats no good, I thought you were feeling better.

[Light]

Holly,
I run (cardio) to burn some of my extra fat. Running is a great way to burn fat but will also deteriorate, consume, some part of the muscular tissue.

Let me give you an example. You probably seen the marathon runners running 26 miles (42 kilometers). You seen how skinny they are, just fiber and no fat? Its due to the extraordinary cardio effort they make, their body is burning the fat and the muscles also.

On the other side, the 100 metres sprinters are all build up and have lean mass. Their effort is also cardio but is way different the marathonists cardio. This is called HITT training and is used if you want to loose fat but keep the muscular tissue.

In a nutshell, if you run in o low tempo for 10-30 minutes you will burn fat and also the muscles. This should be no problem if you are a girl and just want some pounds off. Do not worry about it, run if you can.

LuckySmile, thanx for the good thoughts. Tomorrow I'll be better for sure.

[LuckySmile]

Just a little more detailed if your interested

Muscle Structure and Physiology

Although you might think of a specific muscle, such as the hamstring, as a single unit, skeletal muscle is highly compartmentalized, which makes it well-designed to generate force and produce movement. When looked at as a whole, muscles are comprised of individual cells or fibers embedded in a matrix of collagen. This matrix forms the tendon at either end that connects muscle to bone.

Individual muscle cells are roughly cylindrical in shape and can be as long as two to three centimeters. Most fibers are somewhat oblique to the muscle's line of action. The size and number of fibers (which contributes to the muscle cross-sectional area) determine the peak amount of force that can be generated by a muscle. The speed and range of contraction are related to muscle fiber length.

Muscle cells are densely packed with contractile proteins, energy stores, and signaling mechanisms. Each muscle cell or myofiber contains hundreds or thousands of threadlike structures called myofibrils. Each myofibril contains thousands of actin and myosin microfilaments plus some smaller protein structures (these regulate the organization, length, and activity of the actin and myosin). The organized stacking of actin and myosin creates the stripes that are visible under a microscope and also allows the two components to slide across each other.

Actin looks like two thin strings of beads twisted together. Along the actin filaments are active spots that are strongly attracted to a specific part of myosin. These active spots remain covered when the muscle is relaxed.

Myosin like a thick stalk (looks a bit like broccoli) with cross-bridges and globular heads that are attracted to the active sites on actin. As part of its structure, myosin has an energy source, adenosine triphosphate (ATP), bound on.

When the active spots on actin are uncovered, the myosin globular heads fit into the actin much like spokes fit into a wheel rim. The ATP is hydrolyzed or split to release energy from the chemical bonds (adenosine diphosphate or ADP and inorganic phosphate remain) During this release of energy, the cross-bridges rotate slightly to pull the actin filaments across each other toward the central myosin stalk (much like the oars of a rowboat pull the across the water). The motion of the actin displaces the ADP and phosphate from the myosin cross-bridge.

Muscle Contractions

Muscle contractions are triggered by nerve impulses from the brain. Higher motor nerves carry the signal to the spinal cord, and from there lower motor nerves conduct the impulses directly to muscle fibers. Each muscle fiber maintains an electrical potential difference across its cell membrane, just as a battery creates an electrical potential difference by having different concentrations of ions at its two poles (the + and - signs marked on either end).

The nerve impulses alter the potential difference of muscle cell membranes, allowing positively charged sodium ions to rush in, reversing the charge in a wavelike pattern across the muscle fibers. The change in polarity is carried deeper into the cell by special tubules. The depolarization signal causes certain sacs (known as the sarcoplasmic reticulum) to release calcium, which eventually causes the active spots on the actin to be exposed.

As noted above, then, during muscle contraction, actin combines with myosin and ATP to produce force (movement), ADP, and inorganic phosphate. The calcium must be pumped back into the sacs (ATP is again split to provide the energy to do this) before the actin will disconnect from the myosin, allowing the muscle fiber to relax again. Otherwise, as in rigor mortis, actin and myosin interact to form a very stiff, permanent connection. This entire complex coupling and decoupling process repeats as often as 100 times per second.

(By the way, the manner in which energy is generated in the muscle cell—mainly by burning or oxidizing glucose, fatty acids, and/or creatine phosphate and ATP—will be discussed in detail in another article. The mysteries and myths of sports nutrition should be cleared up for you then.)

When muscles contract or shorten, energy is dissipated, causing a build up of heat, water, and carbon dioxide in the tissue. During heavy continuous exercise, not enough oxygen is available to prevent the formation and build up of lactic acid, which results in aching, heavy limbs. In addition, if heat is allowed to increase within the muscle, performance will go down.

Muscle Fiber Types

You've probably heard terms like fast-twitch and slow-twitch muscles discussed with regard to athletes who are good in certain events (such as the 100-meter sprint versus a 40-kilometer race). The three major types of muscle fibers have been identified through laboratory techniques used in staining fibers for viewing under a microscope.

Slow muscle fibers, the most distinct type are also known as Type I fibers. They are red (because they are fed by many capillaries), have long twitch times, low peak force, and high resistance to fatigue. They have a high mitochondrial content that are especially good at burning fatty acids for energy during long-distance events. In biochemical terms, these fibers have high levels of oxidative enzymes, low levels of glycolytic markers, and little ATPase activity (the enzyme used to split ATP for energy).

Fast muscle fibers are white, store high levels of glycogen and ATP for energy, and show fast contraction times. Fast muscle fibers are further divided into two groups: intermediate fatigue-resistant or fast oxidative glycolytic (Type IIa) and fast fatiguable or fast glycolytic (Type IIb). The Type IIa fibers can maintain their force production even after a large number of contractions. These fibers tend to be rich in oxidative (fat-burning) and glycolytic (carbohydrate-burning) enzymes as well as ATPase activity. The Type IIb fibers show very fast contraction and very large force production but cannot sustain this effort for more than a few contractions without rest. These fibers rely on ATPase and glycolytic activity rather than oxidative enzymes for energy.

As a side note, muscle fiber type may also play a role in some disease, such as diabetes and obesity. Researchers have discovered that patients with diabetes and/or who are obese tend to have mainly Type IIb fibers. With regular exercise, these patients show improvement in glucose control and better weight control (versus with dietary changes alone). Whether these patients are genetically predispositioned to have predominantly Type IIb fibers (which in turn contribute to the development of diabetes and to weight gain) or whether their disease causes the muscle fibers to switch to Type IIb is under study.

Applying This Knowledge to Training

If your eyes glazed over back there, you might want to take the time to read it through again when you're all done here. Understanding this basic muscle biology will help you understand the rationale for various training recommendations. At this point, though, you should recognize that your training will alter:

muscle mass, the amount of actin and myosin that form cross-bridges within each muscle fiber;

muscle efficiency, through the faster and stronger transmission of nerve impulses throughout muscle fibers and improved coordination; and

muscle metabolism, by targeting a specific fiber type, depending on whether you want to improve endurance, strength, or both.

Hypertrophy

Hypertrophy, an increase in mass or girth of a muscle, is the most widely recognized result of regular exercise. It is also the slowest result of training (it can take as along as two months for actual hypertrophy to begin). You may think that you are growing new muscle cells, but you are mainly enlarging individual fibers (in fact, hypertrophy refers only to an increase in size; when cells multiply in number, this is called hyperplasia). The number of fibers and their propensity to enlarge in response to training is dictated mainly by your genes. Additional contractile proteins are incorporated into existing myofibrils. However, if a myofibril becomes sufficiently large, a separate population of cells known as adult myoblasts will divide and fuse with existing fibers, resulting in hyperplasia.

Neuromotor Training

As you learned earlier, muscle contractions are triggered by nerve impulses. Each muscle fiber is fed by one nerve cell axon. These axons are part of a single motoneuron or nerve cell. A single motoneuron may control hundreds of individual fibers. When viewed together, they form a motor unit. As the signal for contraction increases, more motor units are recruited, and these motor units are stimulated to fire more frequently.

Even during maximal effort, you are not likely to activate all the motor units (and hence muscle fibers) for a specific muscle. However, through regular training, you can increase the number of motor units recruited to stimulate muscle contraction. In fact, this effect accounts for any immediate strength gains you experience. In other words, you're training the muscle to be used more and more completely through the available physiologic mechanisms.

In fact, from a neuromotor standpoint, your training is more like practice, and your fitness more like skill level. By improving the proficiency in neural activity and motor coordination, you lower the amount of energy expenditure required to perform the desired exercise or event. Improved coordination also lessens the risk of accidents and injury and reduces the stress placed on the cardiovascular system.

In addition, maintaining neuromotor drive can actually overcome feelings of fatigue. Elite athletes may be neurologically better able to shut out the strong desire (but not necessarily physiologic need) to reduce intensity of effort in response to sensations of fatigue. A fatigue-induced reflex mechanism seems to keep the motoneuron firing rates at the minimal level necessary to maintain the task, which also minimizes the rate at which strength and function is impaired.

Muscle Fiber Type

Although your genes determine your basic muscle structure and physiology, you can, through training, alter their method of energy metabolism, size, and vascularization. Muscle fibers adapt to the stresses placed on them. The type of training you select will affect the muscle fiber types involved in the activity. Further, within the recruited fibers (recruited by the chosen physical activity, whether strength or endurance training), only the organelles, enzymes, and molecules stimulated beyond a threshold for adaptation will undergo significant changes. For example, mitochondria (the organelle responsible for oxidative or fat-burning energy) will be stimulated to increase in number and size only when placed under sufficient aerobic stress.

With consistent and appropriate endurance training, both slow and fast muscle fibers increase their aerobic capacity through more and larger mitochondria, higher levels of oxidative (fat-burning) enzymes, increased fat stores within the muscles (for faster access to energy), lower production of lactate, and higher resting energy levels. With consistent strength training, fibers increase their anaerobic capacity and become more efficient at burning glycogen (a form of stored carbohydrate), ATP, and creatine phosphate; in addition, fast-twitch fibers, rather than slow-twitch fibers, are preferentially increased in size (through increased number of myofibrils). However, research to date does not support the common belief that you can, through training, actually convert one fiber type to another.

If you engage in endurance training, you will become better at burning fat, conserving carbohydrates, and delaying lactic acid build-up in the muscle tissue. In two to three months of training, an increase in the density and use of capillaries increases blood flow to Type I fibers (slow twitch) and decreases blood flow to Type IIb fibers (fast glycolytic fibers).

If you engage in moderate strength training, the cross-sectional size of both Type I and Type II fibers will increase, which in turn translates into increases in force production. If you engage in high-intensity power training, you will selectively enlarge Type II fibers and reduce mitochondrial size and number.

Recovery

Muscle soreness that develops immediately following intense activity is caused by poor blood flow and lack of oxygen. With consistent training, your muscles will grow additional capillaries to increase blood flow and hence oxygen and nutrient delivery (remember, slow twitch muscles are red because they are fed by more capillaries).

Delayed muscle soreness (one or two days after intense activity) is more likely due to damage to the muscles and/or connective tissues and will be discussed in a future article. Younger athletes experienced delayed or residual muscle soreness sooner (as soon as 12 hours after activity) than older athletes (may take as long as 36 hours), possibly due to a decrease in the permeability of muscle cell membranes that occurs with age.


Copied From: roadcycling.com/training/adaptationsofskeletalmuscletoexercisetraining.shtml

[LuckySmile]

Light, you feeling better and back to running yet?

I got 3-1 block jogs in with my walk today, but it seemed to take just as long to do my circut (I ended up walking slower after) Hopefully this will change as I get fitter.

[Light]

I did not run for about one week. I plan to, but I've found a better cardio. I've played one hour volleyball with some friends. It's is a really good workout especially if you get into it and like to win.

I plan to jog/play on regular bases if Ill make time for it.

[LuckySmile]

[Light]

Danceing is also great. Good for body and spirit

[Didi]

Hey, everybody! I’ve been reading your posts, Light, and I think you’re a great example! I’m a jogger myself and it’s the only exercise that really gets me going overall. I’ve been talking to a professional who told me that jogging is one of the best solutions to keep fit, without those ugly muscles (in a girl, that is :oops)! It’s important to know, though, that the best route for jogging is on soft surfaces and not concrete, because it can get you serious joint problems. Good luck, Light, and everybody who follows!

[jlmorgan]

Hi, I'm new here. I run 7 miles 5 days a week. It has been very hard to keep it up with the heat of the summer. I have been using my treadmill with a fan blowing on me. I have developed heat rash and the doctor told me I need to quit running for several weeks. Has anyone else had this occor? Thanks