During intense exercise, there is a net breakdown of body protein as well as an increase in the catabolic hormones adrenocorticotropic hormone (ACTH) and cortisol. ACTH is released by the pituitary gland in response to the fiber damage caused by intense exercise. This increase in ACTH ignites a release of cortisol to help suppress inflammation and trigger the release or breakdown of muscle to amino acids for post-exercise protein synthesis. Though cortisol might assist in the provision of fuel, it also has catabolic properties that may delay recuperation after intense exercise.

Overall, protein synthesis increases in response to insulin, growth hormone, testosterone, and adequate amounts of amino acids, but decreases in response to cortisol, glucocorticoids, glucagon, exercise, and inadequate amount of amino acids Because insulin and growth hormone playa dominant role in everyday protein metabolism, it seems essential to provide an environment for recuperation that promotes either or both of these hormones following exercise. Despite the carbohydrate paranoia that sometimes exists in the world of strength development, a combination of carbohydrate and protein supplementation immediately after intense exercise significantly increases plasma insulin and growth hormone levels and helps to draw the body back into an anabolic state necessary for protein synthesis. Although the direct actions of growth hormone are not fully understood, it is believed that growth hormone facilitates protein synthesis by increasing amino acid transport through plasma membranes, stimulating RNA formation, or activating cellular ribosomes, both of which increase protein synthesis. Insulin acts by inhibiting protein breakdown. Both hormones are essential for skeletal muscle protein accretion.

Following high-intensity exercise, the body begins to replenish blood glucose and muscle and liver glycogen stores. In addition, the body commences the healing of muscle tissue that is damaged or injured during training. To accomplish this, the timing of carbohydrate and protein intake is extremely important. Some have posited that it is the consumption of these macro nutrients immediately following exercise that leads to increased rates of muscle glycogen resynthesis and an augmentation of net muscle protein accretion. Ultimately, this would result in a more rapid recovery, thus allowing an athlete to return to his or her training.

ShareThis

In recent years, both athletes and fitness enthusiasts have benefited from the significant advancements made in sports nutrition. In fact, sports nutrition has become one of the most heavily researched areas of nutrition, and as a result, many concepts are currently being re-examined. Now, it is common for nutritionists to endorse increasing protein intake beyond the recommended daily allowance (RDA) for those involved in many fitness endeavors, and it is also readily accepted that poor nutrition is a primary contributor to overtraining. At the same time, preliminary research, and frequently misinterpreted research, has provided the impetus for recommendations that are often incorrect, unsubstantiated, and even detrimental to health or sports performance.

To make educated recommendations regarding nutritional choices, the basics of energy intake and expenditure must be examined. Instrumental to these calculations is the importance of the proper consumption of carbohydrates, proteins, and fats as they relate to athletic enhancement. Finally, energy intake as it pertains to body composition goals, such as fat loss or increasing lean body mass, will also be outlined.

Some More Facts

Regardless of the method used to determine caloric intake, factors such as weight and body composition management/improvement,optical amplifierдивани achievement of desired performance, and realization of subjective goals ultimately establish an appropriate diet. However, if one is unable to fulfill the preceding factors, he/she will need to modify his/her diet or use appropriate supplementation. Knowledge of sports supplements is imperative, as is a detailed understanding of nutritional concepts in the pursuit of achieving dietary success.

ShareThis

*

Plantar Fasciitis Plantar fasciitis is an inflammation of the plantar fascia, a broad band of dense, inelastic tissue (fascia) that runs from the heel to the toe on the bottom of your foot. The main function of the plantar fascia is to protect the nerves, blood vessels, and muscles of the foot from injury. The repetitive, weight-bearing fitness activities such as walking and running, the plantar fascia may become inflamed Common symptoms of this condition are pain and tenderness under the ball of the foot, at the heel, or at both locations. The pain of plantar fasciitis is particularly noticeable during your first steps out of bed in the morning. If not treated properly, this injury may progress in severity to the point that weight-bearing exercise is too painful to endure. Uphill running is not advised for anyone suffering from this condition, since each uphill stride stretches(and thus irritates) the already inflamed plantar fascia. This injury can often be prevented by regularly stretching the plantar fascia prior to exercise and by athletic shoes with good arch support and shock absorbency.
*
Shin Splints A general term for any pain that occurs below the knee and above the ankle is shin splints. More than 20 different medical conditions have been identified within the broad description of shin splints. Problems range from stress fractures of the tibia(shinbone) to severe int1ammation in the muscular compartments of the lower leg, which can imerrupt the t10w of blood and nerve supply to the foot. The most common type of shin splints occurs along the inner side of the tibia and is usu ­ ally a combination of a muscle irritation and irritation of the tissues that attach tIle muscles to the bone in this region. Typically, there is pain and swelling along the middle one-third of the posteromedial tibia in the soft tissues, not the bone.

Sedentary people who start a new weight-bearing exercise program are at the greatest risk for shin splints, though well­ conditioned aerobic exercisers who rapidly increase their distance or pace may also develop shin splints. Running is the most frequent cause of shin splints, but those who do a great deal of walking(e.g., mail carriers, waitresses) may also develop this injury.

To help prevent shin splints, wear athletic shoes that have good arch support and shock absorbency. If the severity of this lower-leg condition increases to the point that you cannot comfortably complete your desired fitness activity, see your physician.

Runner’s Knee An overuse condition known as runner’s knee describes a series of problems involving the muscles, tendons, and ligaments about the knee. The most common problem identified as runner’s knee is abnormal movement of the patella(kneecap). Women are more commonly affected by this condition than are men because their wider pelvis makes abnormal lateral pull on the patella by the muscles that act at the knee more likely. In women(and some men). this causes irritation to the cartilage on the back side of the patella as well as to the nearby tendons and ligaments.

The main symptom of this kind of runner’s knee is the pain experienced when downward pressure is applied to the patella after the knee is straightened fully. Additional symptoms may include swelling, redness, and tenderness around the patella, and a dull, aching pain felt in the center of the knee. If you have these symptoms in your knee, your physician will probably recommend that you stop running for a few weeks and reduce daily activities that put compressive forces on the patella until you no longer have any pain around your kneecap.

ShareThis

Animal Studies

Oral or intravenous administration of yohimbine in dogs has resulted in a significant elevation in plasma free fatty acids and an increase in sympathetic nervous system activity. Norepinephrine was significantly elevated following yohimbine administration. Furthermore, chronic oral administration resulted in a reduction in body weight and in food intake, suggesting that alpha2­antagonists may influence satiety. The lipolytic effect of yohimbine may result either from a direct action of yohimbine or from an activation of the sympathetic nervous system.

Human Studies

The interplay of beta-receptors and alphaTreceptors regulates the lipolytic response of adipose tissue to the catecholamines. A supplement which would inhibit the alpha2-receptors would theoretically increase the action of catecholamines on lipolysis. Yohimbine has been shown to effectively increase lipolysis.

An abundance of studies have been done investigating the lipolytic action of yohimbine in humans. In vitro studies using human adipocytes have indicated stimulatory effects of yohimbine on lipolysis when catecholamines are present.

Oral administration of yohimbine to humans has been shown to significantly elevate plasma glycerol and free­fatty acids. Furthermore, the effect of yohimbine was further enhanced during physical exercise when the levels of catecholamines are further elevated. Yohimbine also appears to stimulate norepinephrine levels by increasing sympathetic nerve activity.

When yohimbine was administered during a low­energy diet, patients lost significantly more weight than patients receiving a placebo Energy expenditure did not decline in the patients consuming yohimbine, while the placebo group experienced a 15% reduction in energy expenditure.

Safety and Toxicity

Alpharreceptors are present in a number of tissues including heart, arteries, lung, and adipose tissue. Therefore, yohimbine could react with any of these receptors and influence those tissues. However, both animal and human studies indicate that cardiovascular changes are either nonexistent or minimal following yohimbine administration.

Some side effects associated with yohimbine include feelings of panic, clumsiness, and confusion. There have also been reports of chills, nausea, and tremors. The prescription form of yohimbine is normally prescribed for impotence problems; therefore, individuals may experience heightened sexual arousal. Furthermore, there have been reports of mood disturbances and anxiety.

Another concern regarding yohimbe is the purity of the dietary supplement. Yohimbine is the major alkaloid of the plant and the active ingredient. The bark of the tree has been reported to contain 6% total alkaloids, 10-15% of which are yohimbine. Most dietary supplements have been standardized to 3% yohimbine. Therefore, a 100-mg dose of yohimbe will contain only 3 mg of yohimbine. In research studies, yohimbine is usually administered at a dose of about 0.2 mg/kg of body weight.

ShareThis

Supplements are designed to promote fat loss. The term fat loss will be used rather than weight loss because the latter term does not differentiate between muscle mass and fat mass. Supplements designed to promote fat loss can function on one of a number of different principles. These principles as well as the most commonly used fat loss supplements.

Over the last 20 years, there has been about a 10% increase in the prevalence of overweight individuals. Furthermore, one in five adolescents are considered obese, which is a 45% increase Because of societal pressures, it seems that everyone has used or at least has thought of using a fat loss product at one time or another. This includes adolescents as well as older adults. Just because these supplements are sold in health food and vitamin stores does not guarantee their safety. Some of these supplements may have cross-reactivity with some prescription medications and alcoholic beverages.
Increase in Fat Oxidation

Several factors are involved in the use of lipids as fuel. For muscles to oxidize fatty acids, fat (triacylglycerol) must first be mobilized from the adipose tissue. This is referred to as lipolysis. Once the free fatty acids are lysed and released from adipose tissue, they must be transported by albumin in the blood to the muscle, where uptake occurs via a specific transporter protein called the fatty acid binding protein (FABP) When the free fatty acid (FFA) enters the muscle it is activated, after which the activated fatty acid is transported into the mitochondria where Beeta-oxidation occurs.

Theoretically, an increase in fatty acid oxidation could be achieved at anyone of seven sites. However, the mobilization of free fatty acids from the adipose tissue appears to be the best site because the uptake of FFA by the muscle is dependent on the arterial blood concentration of FFA. The more FFA released by the adipose tissue, the higher the concentration of FFA in the circulation. Therefore, any product that increases lipolysis should increase fatty acid oxidation at the muscle.
Mechanism of Action for Fat Loss Supplements

Supplements marketed to promote fat loss can theoretically function on one of a number of principles, from increasing adipose tissue lipolysis or fat breakdown, to suppressing the appetite or the desire for food to reducing the amount of fat absorbed from food during the digestive process. To better understand how fat loss supplements function, their potential mechanisms of action should first be understood.

ShareThis

Remember that resistance training exercises cause microscopic damage(tears) to muscle fibers, and the rebuilding process that increases the size and capacity of the muscle takes about 2.4 to 48 hours. Thus resistance training exercise programs should include at least one day of rest and recovery between workouts before overloading the same muscles again.

Resistance Training Program Guidelines

• Resistance training should be an integral part of an adult fitness program and of sufficient intensity to enhance strength, muscular endurance, and maintain fat-free mass(FFM).

• Resistance training should be progressive in nature, individualized, and provide a stimulus(overload) to all major muscle groups in the body

• One set of 8 to 10 different resistance exercises that condition the major muscle groups 2. to 3 days per week is recommended.

• Most healthy individuals should complete one set of 8 to 12 repetitions for each selected exercise; for older(50 to 60 years of age and above) and more frail persons, one set of 10 to 15 repetitions may be more appropriate.

• The goal of this type of resistance training program is to develop and maintain a significant amount of muscle mass, endurance, and strength to contribute to overall fitness and health throughout the life span.

• If sufficient time is available, multiple-set resistance exercise regimens using heavier weights and fewer repetitions will result in greater strength gains and fitness benefits.

Ballistic stretching Techniques that employ the repetitive, rapid stretching of muscles with no holding or the stretch at a terminal position; not recommended because of the risk of injury to muscle and/or tendon

Muscular strength The amount of force that a muscle is capable of exerting.

One repetition maximum(1 RM) The amount of weight/resistance that can be lifted/moved one time, but not twice; a common measure of strength.

Muscular endurance A muscle’s ability to exert force repeatedly without fatiguing

Resistance exercise program A regular program of exercises designed to improve muscular strength and endurance in the major muscle groups.

Hypertrophy Increased size(girth) of a muscle.

What Do You Think?

What types of resistance equipment can you currently access? Based on what you’ve read, what specific actions can you take to increase your muscular strength? Muscular endurance? How would you measure your improvement?

ShareThis

Principles of Strength Development

There are three key principles to understand if you intend to maximize muscular strength and endurance benefits from your resistance exercise program. Unless you follow these principles, you are likely to be disappointed in the results of your program.

• The Tension Principle The key to developing strength is to create tension within a muscle. The more tension you can create in a muscle, the greater your strength gain will be. The most common recreational way to create tension in a muscle is by lifting weights. While weight lifting is one method of producing tension in a muscle, any activity that creates muscle tension-for example, riding a bike up a hill-will result in greater strength.

• The Overload Principle The overload principle is the most important of the three key principles for improving muscular strength. Everyone begins a resistance training program with an initial level of strength. To increase that level of strength, you must regularly create a degree of tension in your muscles that is greater than they are accustomed to. This overloading of your muscles will cause your muscles to adapt to the new level of overload. As your muscles respond to a regular program of overloading by getting larger(hyper trophy), they become capable of generating more tension.

Some women avoid resistance exercise because they fear that they’ll develop large “bulky” muscles, while others are frustrated because their weight-lifting efforts in the gym don’t produce the same results as in their male friends. The main reason for this difference is the hormone testosterone. Before puberty, testosterone levels in blood are similar for both boys and girls. During adolescence, testosterone in men increase about tenfold to its adult level; testosterone in women remains at prepubertal levels throughout adulthood. Women’s muscles will hypertrophy from regular exercise but typically not to the same degree as in adult males. The difference in maximum attainable hypertrophy between men and women is not currently known.

ShareThis

The body may also produce its own satiety chemical or hormone that suppresses the appetite. The Set-Point Theory suggests that fat cells prefer to maintain a certain size. When there is a reduction in the size of the adipocyte due to dieting, a signal is sent to the hypothalamus resulting in an increase in appetite. As the fat cell regains its size, another signal is sent to the hypothalamus, which instructs the hypothalamus to reduce or stop the desire to eat.

The maintenance of a perfect body weight is a survival mechanism for higher organisms including mammals. Furthermore, the maintenance of body weight requires both the maintenance of energy and nutrient balance. This means that the diet must contain both adequate amounts of calories, macronutrients (carbohydrate, protein, and fat), and micro nutrients (vitamins and minerals).

Research using rodents may have discovered the signal for the Set-Point Theory. The signal is called leptin, and it appears to have a dual role, it decreases food intake and increases energy expenditure resulting in an increase in fat oxidation. When rats are bred to be deficient in this hormone, it causes them to overeat and become obese. When this hormone is administered to rats, it causes them to stop eating and increases fat oxidation, resulting in fat loss but not a loss in lean tissue (i.e., muscle). However, human research indicates that the hormone is not the problem, but rather the transporter. Obese individuals appear to develop a resistance to leptin that is similar to insulin resistance. Therefore, it may be impractical to expect leptin administration to humans to be a viable means of controlling obesity. If the transporters are already saturated or downregulated from excessive endogenous leptin, it does not make sense to provide more. Therefore, research has begun to focus on the leptin transporter and binding site in hopes of discovering the post-binding signaling cascade and any potential defects in this system. Leptin research is interesting and may one day provide a drug to control obesity, but this probably won’t happen for many years. For more information on leptin, read the excellent reviews by Hwang et al. and by requier and Tappy. Although several mechanisms could be used as a target for fat loss, most of the dietary supplements targeted as a fat loss agent do not have scientific research to support their claims.

ShareThis

The primary category of physical activity known to improve cardiorespiratory endurance is aerobic exercise. The term aerobic means “with oxygen” and describes any type of exercise, typically performed at moderate levels of intensity for extended periods of time, that increases your heart rate. Aerobic capacity(commonly written as VO₂ max) is defined as the maximum volume of oxygen consumed by the muscles during exercise.

To measure your maximal aerobic capacity, an exercise physiologist or physician will typically have you exercise on a treadmill. He or she will initially ask you to walk or run at an easy pace, and then, at set time intervals during this graded exercise test, will gradually increase the workload(i.e., a combination of running speed and the angle of incline of the treadmill) to the point of maximal exertion. Generally, the higher your cardiorespiratory endurance level, the more oxygen you can transport to exercising muscles and the longer you can maintain a high intensity of exercise prior to exhaustion.

According to the exercise testing guidelines of the American College of Sports Medicine, maximal aerobic capacity treadmill tests should not be conducted on men over 40 or women over 50 without a prior comprehensive physical examination and permission from their physicians.

Aerobic Fitness Programs

Researchers tell us that a physically active lifestyle is the key to improved cardiovascular health, but what level of activity is required to improve aerobic fitness? There are numerous variables in any particular aerobic activity, but for healthy young adults, aerobic activity that works your heart at a moderate intensity(approximately 70 percent of your maximum heart rate, or about 140 to 160 beats per minute) for prolonged periods of time(20 to 60 minutes of continuous activity) will improve your fitness level.

The most beneficial aerobic exercises are total body activities involving all the large muscle groups of your body, for example, swimming, cross-country skiing, or rowing. If you have been sedentary for quite a while, simply initiating a physical activity program may be the hardest task you’ll face. Don’t be put off by the next-day soreness you are likely to feel in your long-dormant muscles. The key is to begin your exercise program at a very low intensity, progress slowly … and stay with it. For example, if you choose an aerobic fitness program that involves jogging, you’ll need several weeks of workouts combining walking and jogging before you will reach a fitness level that enables you to jog continuously for 15 to 20 minutes.

You will need to adjust the frequency, intensity, and duration of your aerobic activity program to accommodate your initial level of cardiorespiratory fitness. As you progress, add to your exercise load by increasing exercise duration or intensity, but do not increase both at the same time.

• Determining Exercise Frequency If you are a newcomer to regular physical activity, the frequency of your aerobic exercise bouts should be at least three times per week. The surgeon general’s recommendation is for moderate amounts of daily physical activity. As your fitness level improves, your goal should be to exercise 20 to 30 minutes per day, five days a week.

• Determining Exercise Intensity Your aerobic exercise program should employ activities of moderate intensity that use large muscle groups and can be maintained for prolonged periods of time. The measure of such a workout is your target heart rate, which is a percentage of your maximum heart rate. To calculate target heart rate, subtract your age from 220 for females or from 226 for males. The result is your maximum heart rate. You determine your target heart rate by calculating a desired percentage of maximum heart rate, often 60 percent. If you are a 20-year-old woman, your maximum heart rate is 200(220 - 20). Your 60-percent target heart rate would be 120(200 x .60). People in poor physical condition should set a target heart rate between 40 and 50 percent of maximum. As your condition improves, you can gradually increase your target heart rate. Increases should be made in small increments: Increase from 40 to 45 percent; then from 45 to 50 percent. Because of the potential risks and adherence-to-exercise problems associated with high-intensity activity(> 80% of maximum heart rate), moderate-intensity activity of longer duration is suggested for adults who are not training for competitive athletics.

Once you know your target heart rate, you can determine how close you are to this value during your workout. You’ll need to stop exercising briefly in order to measure your heart rate. To take your pulse, lightly place your index and middle fingers(don’t use your thumb) over one of the carotid arteries in your neck (along either side of your Adam’s apple), or over one of the radial arteries (thumb side) of your wrist.

Be sure to start counting your pulse immediately after you stop exercising, as your heart rate will decrease quickly. Using a watch or clock, take your pulse for six seconds and multiply this number by 10(just add a zero to your count) to get the number of beats per minute(bpm). Your pulse should be within a range of about 5 bpm above or below your target heart rate. If necessary, increase or decrease the pace or intensity of your workout to achieve your target heart rate.

A target heart rate of 70 percent of maximum is sometimes called the “conversational level of exercise” because you are able to talk with a partner while exercising. If you are a novice and you are breathing so hard that talking is difficult. your intensity of exercise is too high. If you can sustain a conversational level of aerobic exercise for 20 to 30 minutes, you will improve your cardiorespiratory fitness.

The lower the intensity of the activity, the longer the duration you’ll need to get the same caloric expenditure. For example, a 180-pound man will expend 288 calories per hour of playing golf if he carries his clubs, but will burn 805 calories per hour if he is cross-country skiing. Your goal should be to expend 300 to 500 calories per exercise session, with an eventual weekly goal of 1,500 to 2,000 calories.

Since many of the health benefits associated with cardiorespiratory fitness activities take about one year of regular exercise to achieve, you shouldn’t expect an immediate reduction in your risk of cardiovascular disease when you start an exercise program. However, any low-to-moderate-intensity physical activity, even if it does not meet all the cardiorespiratory exercise.

Cardiorespiratory fitness The ability of the heart, lungs, and blood vessels to supply oxygen to skeletal muscles during sustained physical activity.

Aerobic exercise Any type of exercise, typically performed at moderate levels of intensity for extended periods of time (typically 20 to 30 minutes or longer), that increases heart rate.

Aerobic capacity The current functional status of a person’s cardiovascular system; measured as VO₂ max.

Graded exercise test A test of aerobic capacity administered by a physician, exercise physiologist, or other trained person; two common forms are the treadmill running test and the stationary bike test.

ShareThis

An exercise intervention program was used in conjunction with the dietary supplement. The supplement, in most cases, did not produce a great effect, if any. The key to fat loss is that caloric expenditure must be greater than caloric intake. If it is not, fat loss will not occur.

Although new fat reduction supplements will appear on the market, the main physiological mechanism of body weight regulation, energy balance, is reflected by energy intake and energy expenditure. Excess energy intake without a concomitant rise in energy expenditure will result mainly in the deposition of fat into adipocytes. This excess energy may be in the form of carbohydrates, fat, and protein. A balanced diet with energy expenditure exceeding energy intake is the best form of fat reduction-guaranteed.

Reducing Lipid Absorption

Dietary lipid (predominately fat) is digested by specific enzymes including lipases, phospholipids, and cholesterol esterase. Most of the lipid digestion occurs in the duodenum of the small intestine in which lipids are emulsified by the detergent action of bile salts. Lipids and bile salts spontaneously form micelles. The micelles contain fatty acids and cholesterol, and serve as transporters. Micelles migrate to the brush border where lipids diffuse out of the micelles into mucosal cells.

Agents that can prevent lipid digestion and/or absorption appear an attractive approach as a fat loss mechanism or, more importantly, reducing blood cholesterol levels. In fact, there are some prescriptions and fat substitutes that function to reduce fat absorption. However, a reduction in lipid absorption has potentially negative side effects, including gastrointestinal discomfort, diarrhea, and a reduction in the absorption of fat soluble vitamins.

ShareThis