Endurance Exercise Ebook

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Protein Requirements for Endurance Athletes

Given that amino acids can be oxidized as energy during exercise, it is theoretically possible that this may impact on the need for extra dietary protein. The determination of dietary protein requirements for endurance athletes is a function of the duration and intensity of exercise, gender, age, training status, and habitual energy and CHO intake. In a simplistic approach to determining protein requirements, it is possible to calculate the estimated need for dietary protein by an athlete from first principles. For example, if a 70-kg male was running for 1.5 h at 70 VO2peak and protein accounted for 5 of the total energy expenditure, he would oxidize about 15 g of protein. If his basal protein requirement was 0.86 g kg day (60 g), this would represent an additional 25 increase in his daily protein requirement (1.07 g kg day). Most male and female endurance athletes habitually consume more protein than this (Table 7.3). These calculations are only rough estimates and most studies have...

Endurance Exercise and Muscle Breakdown

It shouldn't come as a big surprise when you take a good look at the sinewy physique of elite endurance athletes endurance exercise may increase muscle breakdown. We have to say may, as it is very difficult to assess true protein turnover during aerobic activity. It's just tough to find the right tools to measure this in the lab. This means that it is essential for endurance athletes to be mindful of their protein intake and time it right to help combat this breakdown by promoting synthesis. The jury is still out on whether protein should be consumed during exercise. There are a few studies that have found positive results when their subjects were given both carbohydrates and proteins during a long-duration activity. They found that there may be improvements in protein synthesis and muscle repair following the activity. What it comes down to is that recovery from endurance sport is the key (visit chapter 8 on optimal recovery if this has sparked your interest in what to do after your...

Protein for Endurance Sports

As endurance athletes, you depend on your muscle mass to train for longdistance events. Since muscle is primarily made up of protein, it's understandable that athletes often question whether they're consuming enough protein, the right kinds of protein, and at the right time. And in fact, athletes do have greater needs for protein to meet the demands of endurance exercise, and timing of intake is important.

Do Endurance Athletes Need a Protein Supplement

Before traveling to the local nutritional supplement supplier for a protein supplement, first estimate current protein intake. Since many people, especially males, already eat 100 to 130 grams of protein daily (about two times the RDA) only small if any dietary adjustments may be needed. Furthermore, endurance athletes tend to eat more energy than more sedentary people, so more protein is probably, but not definitely, included. This is because many endurance athletes, especially runners, may eat more plant-based foods including pastas, breads, rice, etc. Thus, even though they may be eating more energy, more of it is coming from carbohydrate-rich sources. Endurance athletes should assess their diet prior to spending their money.

What Are Protein Recommendations for Endurance Athletes

Bodybuilders, power lifters, and football players recognize high protein intakes as an avenue to achieve and maintain enhanced muscle mass. Contrarily, endurance athletes recognize a relatively higher protein (total grams) intake as a means of replacing the body protein used for fuel during training, competition, and recovery and adaptation. Although individual protein requirements will vary with the level of intensity and duration of the activity, some sport nutritionists recognize that 1.4 to 1.75 grams of protein per kilogram body weight will provide adequate protein along with a little extra padding. This is pretty much the same recommendation discussed previously for weight trainers however, because of differences in body weight the resulting protein quantity is lower for endurance athletes.

Do We Use Body Protein for Energy During Endurance Exercise

Depending on the duration of exercise, amino acids may be counted on to generate as much as 6 to 10 percent of the fuel with the remainder split between fat and carbohydrate. The use of amino acids for energy is mostly a consideration for higher-level endurance athletes. This would include people who train seriously several times a week for extended periods such as a couple of hours. This is one reason why marathoners often look very lean but not as muscular as sprinters or milers, for example. One of the most significant reasons that more and more amino acids are used for energy is because cortisol levels in the blood are increased as the higher intensity activity is endured. Cortisol can cause the breakdown of muscle protein and the freed amino acids can be used for energy. Some amino acids will be used directly by muscle to make ATP, while others will circulate to the liver and be converted to glucose.

Minimizing GI Distress Gut Friendly Tips for Endurance Athletes

Almost every endurance and ultraendurance athlete we know has complained about GI distress. Whether you are running a marathon or ultra, a triathlon or adventure race, GI problems are among the most common reasons why endurance athletes drop out of races or have subpar performances. Having to make repeat Porta Potty stops can turn any type of challenging endurance event into a death march.

Endurance Training

Since proteins serve either a structural or functional role within the cell, chronic endurance exercise training would be expected to achieve adaptations that would attenuate the oxidation of protein for energy. This would also be predicted based on the sparing of muscle glycogen that accompanies chronic endurance training, which would tend to attenuate BCOAD activation. Early work by Gontzea et al.73 showed that untrained persons who started endurance training were in a negative nitrogen balance, but as they continued to train, the nitrogen balance became less negative. To date, human data have not yielded consistent findings on the effects of chronic exercise training on protein metabolism. Following endurance exercise training, whole-body protein synthesis at rest is increased.69 143 There is also a greater proportion of leucine flux at rest diverted toward oxidation in the untrained vs. trained athlete.69 However, differences in leucine turnover between trained and untrained...

Endurance Exercise

By far, the amino acid leucine has been most often used to trace the effects of exercise on amino acid oxidation, and many studies have shown that endurance exercise increases leucine oxidation.40-42,66-69 An increase in lysine oxidation has also been observed during endurance exercise.67 During endurance exercise, leucine oxidation demonstrates a positive correlation with exercise intensity.70 Leucine oxidation40,41 and plasma urea content71 also increase with exercise duration. Finally, leucine oxidation increases with glycogen depletion, which may partially explain the increase in leucine oxidation with exercise duration.48 Following endurance exercise, there is a prompt return toward baseline leucine oxidation levels,41 although there appears to be a slight increase in leucine oxidation following eccentric exercise that may persist for up to 10 days.72 This may partially explain why nitrogen balance is negative at the onset of unaccustomed endurance exercise, yet becomes more...

Casual Athlete and Fitness Enthusiast

A second group that would benefit from HMB supplementation is the fitness enthusiast or casual athlete who frequently changes his training routine through periods of low to moderate to high activity and often participates in strenuous single bouts of competitive activity, such as road races, softball games, golf tournaments, etc. Supplementation of 3 g of HMB day should improve the gains experienced from either resistance or endurance training as well as help minimize the muscle damage that occurs during those single bouts of strenuous activity. Furthermore, HMB supplementation also provides an additive health benefit to exercise.

Can Training Allow Muscle Fibers to Change Type

We do know that training results in changes in muscle metabolism, which may make us think that it is possible for Type I fibers to change into Type II fibers and vice versa. However, this probably is not the case. For instance, endurance training can lead to changes associated with Type II muscle fibers that will make them more aerobic. The fibers will adapt to have an increased ability to generate ATP by using oxygen. However, they don't adapt to the point where we would classify them as Type I. Oppositely, we all know that resistance training (for example, weight lifting) improves the strength and power of a muscle group. Although it would be logical to think that half of this effect might be related to adaptations in Type I muscle fibers as though they are being transformed into Type II muscle fibers surprisingly this is not the case either. In fact, as the muscle group grows in size, most of the growth is related to enlargement (hypertrophy) of Type II fibers.

Have You Ever Wondered

. . . if heavy training causes sports anemia Perhaps, in the early stages of training. However, sports anemia isn't really anemia. Because blood volume increases in the early weeks of endurance training, iron concentration in blood dilutes slightly as your body adapts to more physical activity. If you develop sports anemia, that's normal. It will disappear once your training program is off and running. With endurance training your blood's capacity to carry oxygen and your athletic performance will improve. Taking iron supplements isn't helpful or advised.

Nutrition Before Exercise Glycogen Loading

Muscle glycogen depletion and low blood glucose levels have been shown to be major factors in the development of fatigue during endurance exercise. Therefore, it is important to ensure optimal glycogen storage prior to exercise and optimal delivery of carbohydrate (CHO) during exercise. Of crucial importance in the pre-competition preparation of an endurance athlete is defining the best method to optimize the body's glycogen levels. In the past, Scandinavian researchers introduced a supercompensation diet. Their recommended strategy and diet is as follows. One week prior to an important race, a bout of exhausting endurance exercise is performed in order to deplete the glycogen stores. Over the next 3 days a high fat diet is ingested, ideally with less than 20 of the energy intake as CHO. During the remaining period leading up to the race, the athlete should ingest a high CHO diet with less than 20 of the energy intake being derived from fat. No endurance training should be undertaken...

Training And Body Composition

Body composition is responsive to the demands of systematic training, as is evident in the observations on wrestlers. It is essential to consider separately observations in growing and maturing youth and in mature adults. Of relevance, are changes in body composition associated with training greater than those associated with normal growth and maturation The increase in FFM (hydrostatic weighing) observed in youth regularly active in sport from 11 to 17 years old would seem to suggest an increase greater than that expected with normal growth and maturation 57,58 . This group of boys was larger in size and advanced in biologic maturation, however, compared with their age peers not engaged in sport. Similarly, among boys 11 to 13 years old undergoing a 5-month endurance training program, larger FFM (40K) were observed in boys advanced in sexual maturation 59 , suggesting perhaps that the boys were in their growth spurts 35 . The two studies highlight the difficulties in attempting to...

Bad Cardio vs Good Cardio

Another factor to keep in mind regarding the benefits of physical variability is the internal effect of various forms of exercise on our body. Scientists have known that excessive steady state endurance exercise (different for everyone, but sometimes defined as greater than 60 minutes per session most days of the week) increases free radical production in the body, can degenerate joints, reduces immune function, causes muscle wasting, and can cause a pro-inflammatory response in the body that can potentially lead to chronic diseases. On the other hand, highly variable cyclic training has been linked to increased anti-oxidant production in the body and an anti-inflammatory response, a more efficient nitric oxide response (which can encourage a healthy cardiovascular system), and an increased metabolic rate response (which can assist with weight loss). Furthermore, steady state endurance training only trains the heart at one specific heart rate range and doesn't train it to respond to...

Protein And Performance

Determination of appropriate protein intake to optimize performance, by any method, is limited by the definition of the population to be targeted. Generally, studies broadly divide athletes into strength or power athletes and endurance athletes. These broad distinctions may not be specific enough to provide appropriate protein intake information for many athletes. There have been attempts to categorize various athletic groups further. Tarnopolsky 16 considered that endurance athletes may be divided into three broad categories and estimated protein needs for these groups. Delineations such as these provide more information for practitioners, but as is pointed out in Tarnopol-sky's article, there are individuals who do not fit the broad categorizations. It seems clear that, at this juncture, there are ample gaps in knowledge that do not allow general recommendations that may be meaningful to all athletes. Football and rugby players incorporate a great deal of power and endurance...

Methodologic Considerations

Application of nitrogen balance measurements to athletes may be especially unsuitable. For a strength athlete, whose goal is to increase lean body mass and ultimately muscle strength and size, protein requirements set to attain nitrogen balance are inappropriate rather, the athlete aims to consume enough dietary protein to induce a positive nitrogen balance 11 . It may be more appropriate to discuss protein requirements with respect to the strength athlete as the effect of dietary protein on protein synthesis and breakdown 51 . Similarly, consideration of nitrogen balance only may not be appropriate for an endurance athlete balance may be attained, but with a compromise in some physiologically relevant processes, such as upregulation of enzyme activity, capillarization, or mitochondrial biogenesis after endurance training 16 . The nitrogen balance approach underlies the establishment of dietary reference intake for protein in sedentary individuals, so comparison of like with like...

Ergogenic effects Endurance Activities

The speculation that glutamine supplementation can enhance performance during endurance activities is largely based on the acute immune system suppression observed during strenuous exercise. Since glutamine is utilized as a fuel source for immune system cells, the assumption is that supplementary glutamine will attenuate the mobilization of glutamine from the skeletal muscle. Prolonged endurance exercise, such as marathon running, may reduce plasma glutamine concentration. Plasma glutamine concentrations seem to significantly decrease in overtrained athletes compared to control, nonovertrained athletes.36 Physical stress such as illness or increased physical activity can induce hypercatabolic states, thereby decreasing the body's endogenous rate of glutamine synthesis, making it a conditionally essential amino acid. Early studies suggested that glutamine may be beneficial to endurance athletes because of its impact on muscle glycogen synthesis, by serving as a substrate for...

Effects on physical performance

Physical activity is recognized as one factor that affects polyunsaturated fatty acid status.5 Physical activity per se induces changes in the phospholipid fatty acid composition of muscle membranes.5,95 The effects of an aerobic exercise program (55 VO2 peak) on phospholipid fatty acid composition of ro-3 and ro-6 fatty acids in the skeletal muscle have been examined in sedentary subjects.95 Six weeks of physical training showed changes in the levels of ro-3 (EPA, DHA, and docosapen-taenoic acid) fatty acids, decreased the proportion of ro-6 (linoleic acid, dihomo-y-linolenic acid, and arachidonic acid) fatty acids in muscle phospholipids, and reduced the ro-6 to ro-3 ratio.96 Similar results were reported by Helge et al.95 when investigating the effect of endurance training of the knee extensor of one leg for 4 weeks on the muscle membrane phospholipid fatty acid composition. After 4 weeks of

Influence of Chronic Exercise Training on Carnitine Status

It is widely accepted that chronic-endurance aerobic training can induce changes within the skeletal muscle to enhance performance and increase endurance. Some of these changes include increased capillary density, increased enzymatic concentration, and an increase in the size and number of mitochondria. This is associated with an increased ability of the athlete to oxidize FAs, in the form of intramuscular trigylcerides, for fuel. This phenomenon has led researchers to analyze the potential changes that might occur with carnitine concentrations in all pools, including urinary excretion, plasma, and muscle. It is important to point out that there are studies that found differences in carnitine concentrations after training. One such study by Arenas et al.66 found that endurance athletes showed a significant decrease in free and total muscle carnitine content after 4 months of training, and that these changes were not as severe as those seen in sprinters. The authors suggest66 these...

Components of Physical Fitness

Muscular Endurance The ability of a muscle or group of muscles to perform repetitive contractions over a period of time. Endurance is a key for everyday life activities and operates with muscular endurance to help maintain good posture and prevent back and leg pain. In addition, endurance can en

Overtraining Syndrome

The overtraining syndrome can present with a wide range of symptoms (See Table 13-2). Overtraining is generally associated with endurance sports, such as swimming or running. Cross-training, rest, and taking time off from certain physical activities will all reduce or prevent overtraining symptoms. The person who continues training despite the symptoms listed in Table 13-2 will only become more overtrained, continue to have decreases in performance, and will be at an increased risk for injury.

Effects of Disordered Eating on Health and Performance

The effects of disordered eating on an athlete's performance vary, but largely depend on the severity and chronicity of the disordered eating behaviors and the physiologic demands of the sport 18 . An athlete who engages in severe energy restriction or who has been bingeing and purging for a long time is likely to experience a greater decrease in performance than one who has engaged in milder weight control behaviors for a shorter time. Likewise, athletes involved in endurance sports and other physical activities with high energy demands (eg, distance running, swimming, cycling, basketball, field hockey, and ice hockey) are likely to be more negatively affected than athletes involved in sports with lower energy demands (eg, diving, gymnastics, weightlifting). The potential consequences of disordered eating on health and performance are presented in Table 3.

Smart About Fat Still Best

Unlike glycogen, fat needs oxygen for energy metabolism. That's why endurance sports, fueled in part by fat, are called aerobic activities. Aerobic means with oxygen, and aerobic activities require a continuous intake of oxygen. The more you train, the more easily you breathe during longer activity the oxygen you take in helps convert fat to energy. percent of your total calories from fat is a good guideline. Most of your food energy should come from carbohydrates. With a high-fat diet your carbohydrate or protein intake may come up short. Less than 15 percent of calories from fat doesn't provide enough calories or enough fat for other health roles, especially for those involved in endurance sports. Getting enough essential fatty acids is also important for health and peak performance.

Nutrition During Exercise

The amount of CHO ingested is important for its contribution to energy expenditure and sparing of liver glycogen. However, the oxidation of exogenous CHO does not exceed 1.0-1.1 g min, even when much greater quantities are ingested. This observation suggests that the maximum CHO intake during exercise should not exceed 60 g h. Nowadays, CHO electrolyte drinks and energy bars, which are promoted to give rapid provision of CHO and fluid, are the most common food supplements in endurance sports. Untrained individuals may benefit as much from the CHO fluid supply as trained athletes.

Linking the energy contributions of fats and proteins

As for protein, a diet providing about 15 to 18 energy from protein should be more than adequate. Such a diet supplies 100 to 150 g of protein, depending on the total caloric intake. With 35 of the total energy being derived from fat and 15 or so from protein, the remainder of energy, or 50 of calories, would be provided by carbohydrates, both starches and sugars. No recommendation is made for alcohol, which may provide from 1 to 3 of total calories in the general population. The actual energy distributions may vary quite a bit for competitive athletes in endurance sports, who typically have higher intakes of carbohydrates (60 or more) and protein (20 or higher). In this scenario, fat intake would be approximately 20 or so.

All About Muscle Glycogen

Muscle glycogen is stored carbohydrate in your muscle. Imagine this After you eat and digest a meal, the amount of carbohydrate that you immediately need will get used as fuel, but the rest (up to a point) will be stored in your muscles for future fuel. Athletes in ultra-endurance sports such as soccer, basketball, hockey, and distance running rely on high-octane muscle fuel for energy. In fact, between the grueling practice sessions and vigorous competitions, serious endurance athletes are constantly depleting and restoring their muscle glycogen stores, so they require much more carbohydrate-rich foods than athletes involved in less aerobic activity (golf, archery, and martial arts). What happens if you don't replenish your muscle-glycogen stores Simple If you run out of glycogen, you run out of energy. The amount of muscle fuel you have determines how long you can exercise. As a car needs a full tank of gas before heading out on a long trip, an endurance athlete requires sufficient...

Dietary Protein Intake

The level of dietary protein intake influences protein metabolism in response to exercise. During and after endurance exercise, the provision of extra protein (beyond requirement) resulted in an increase in leucine oxidation68,96,97 and in one study appeared to attenuate muscle FSR.10 The latter study measured mixed-muscle FSR in response to three different protein intakes (0.8, 1.8, 3.6 g kg day) in endurance-trained athletes and found that FSR was lowest at the highest protein intake level,10 yet whole-body leucine oxidation was greatest (a nutrient excess).97 Our group has shown that the provision of dietary protein at levels above requirement (e.g., 2.8 vs. 1.8 g kg day) resulted in an exponential increase in amino acid oxidation with no further increase in protein synthesis in male strength athletes.53 In addition, the provision of dietary protein at 2.6 g kg day during resistance exercise training in young males doing weight training did not confer any strength or mass benefits...

Resting Metabolic Rate And Changes In Body Composition

Aging brings on alterations in resting metabolic rate (RMR) and changes in body composition. Aging is associated with declines in all components of energy expenditure RMR, thermic effect of food, and energy expenditure 13 . Early research suggested an inverse relationship between RMR and aging (the older one got, the more decline in RMR was seen), but more recent studies suggest that the age-related decline in RMR can be attenuated by regular exercise 14 . Van Pelt and colleagues 15,16 studied RMR in men and women. Sixty-five healthy women (21-35 years old and 50-72 years old) were recruited to study age-related decline in RMR. Subjects were divided into groups of controls, endurance-trained runners, or swimmers. The primary finding from the study is that the decline expected in RMR with aging is attenuated in older women who remain physically active 15 . The research group conducted a similar study with men (n 137 19-36 years old and 52-75 years old). They reported that adjusted RMR...

Nutritional status assessment

In addition to exercise, an individual's dietary intake can also have an influence on his plasma glutamine concentrations. Blanchard et al.28 observed high-carbohydrate (70 ) diets to increase plasma glutamine concentrations compared to low-carbohydrate (45 ) (i.e., high-protein) diets in endurance-trained men completing exercise trials. However, muscle glutamine concentrations did not differ between the two groups, and no association was observed between plasma glutamine concentrations and changes in muscle glycogen concentrations. This suggests that the effect of carbohydrate intake on plasma glutamine is not influenced by the muscle glycogen stores. Likewise, Gleeson et al.29 observed low-carbohydrate diet (7 ) to be associated with a reduction in plasma glutamine concentrations during recovery compared to a high-carbohydrate diet (75 ). Low-carbohydrate and high-protein intakes have been suggested to result in lowering plasma glutamine levels due to a disruption in the acid-base...

Ergogenic benefits Performance

Another study was conducted with cyclists to examine the effectiveness of CHO vs. CHO + MCTGs on metabolism and performance. Eight endurance-trained men completed a 35 kJ kg time trial as quickly as possible while consuming 250 ml 15 The effects of ingesting different amounts of MCTGs and CHO on gastric symptoms, fuel metabolism, and exercise performance were measured in nine endurance-trained cyclists by Goedecke et al. During exercise, the cyclists ingested 400 ml of 10 glucose, 10 glucose + 1.72 MCTGs, or 10 glucose + 3.44 MCTGs solutions at the start of exercise and 100 ml every 10 min thereafter. Gastrointestinal symptoms were not a problem. MCTGs raised serum FFAs and P-hydroxybutyrate concentrations but did not affect fuel oxidation or the time trial performance.71 Hawley also reported that an increase in serum FFAs did not effect exercise capacity.7273 In yet another review, Hawley included long-term adaptation to high-fat diets (> 7 days) and concluded that high-fat,...

Protein Supplementation

In terms of nutritional requirement, it appears that protein supplementation by increasing daily protein intake to a level higher than 12-15 en will be too high for most athletes. Since a higher daily energy intake in endurance athletes will result in higher protein intake, as well, the value of protein supplementation for endurance sport can be questioned. Based on the observed relationship between energy consumption and protein consumption, athletes expending and eating 5000 kcal day will ingest twice as much protein as people not involved in exercise and expending ingesting only 2500 kcal day. Protein intake for any endurance athlete will thus be sufficient as long as the diet is well composed and contains a variety of protein sources such as lean meat, fish, dairy products, eggs and vegetable protein. Supplementation may be warranted for athletes who compete in weight classes and combine intensive training with weight reduction programmes. Also vegetarian athletes, who consume low...

Carbohydrate CHO Intake

It has been known for many years that CHO intake has a significant sparing effect upon amino acid oxidation and protein balance.8190 The dietary interaction between protein and CHO may have implications for those athletes who habitually consume fad diets that stress a very low CHO intake. Given that CHO is the predominant fuel utilized during endurance exercise,40,41 and that this substrate can become depleted during prolonged endurance exercise,40 it is important for amino acid metabolism to be considered in light of CHO intake and storage (i.e., glycogen) status of the athlete. CHO loading has been shown to attenuate plasma and sweat urea excretion following endurance exercise.91 Furthermore, CHO supplementation increases whole-body protein synthesis92 and attenuates proteolysis.93 We have reported that both men and women show attenuated total amino acid oxidation (serial urinary urea excretion) during endurance exercise when CHO supplements are consumed during exercise.55 These...

What Causes Muscle Exhaustion in Endurance Activities

A principal factor associated with exhaustion during endurance exercise is the availability of carbohydrates to working muscle. Quite simply, when muscle glycogen stores are depleted, muscle exhaustion ensues shortly thereafter. The depletion of muscle glycogen along with dehydration are the most significant contributors to exhaustion or what endurance athletes call hitting the wall or bonking. From this it is easy to see why sport drinks such as PowerAde , Gatorade , and Accelerade are so popular. Electrolyte imbalances may also lead to fatigue, but this might occur only during very long efforts in which only water is provided. Today, with the popularity of sport drinks and endurance foods the risk of an electrolyte imbalance is often reduced.

How Are Amino Acids Broken Down

Amino acids can be used for ATP production in several ways. By consuming a lot of protein, excessive amino acids will be broken down in the liver mainly. Once the nitrogen is removed from the amino acids, the remaining molecule can be converted to molecules in the energy pathways such as pyruvate, acetyl CoA, or those that are part of the Krebs' cycle. This makes the generation of energy from amino acids aerobic. Meanwhile, during fasting and endurance exercise some amino acids can be converted to glucose in the liver. And, some amino acids can be used during fasting to produce ketone bodies. Both the glucose and ketone bodies produced via amino acids will be used by other tissue such as the brain and muscle.

How Does the Carbohydrate in Sport Drink Help Sustain Performance

One of the principal factors involved in the onset of exhaustion or fatigue is a depletion of muscle glycogen stores. The carbohydrate in sport drinks becomes an available source of glucose to working muscle. It was once thought that the carbohydrate in a sport drink might slow the rate of glycogen breakdown and thus prolong endurance exercise. However, research has shown that the carbohydrate in a sport drink actually becomes an increasingly more important carbohydrate source for working muscle as glycogen stores wane. This contribution seems to be significant enough to push back the onset of fatigue. This could be the difference in finishing strongly during a marathon or fatiguing in the last couple of miles.

Protein Requirements for Resistance Athletes

In contrast to endurance exercise, resistance exercise results in muscle hypertrophy98,166 rather than an increase in amino acid oxidation and mitochondrial biogenesis.40,56 If, for example, there are no changes in efficiency of amino acid retention, there must, at some point, be a protein intake in excess of basal requirements to provide the amino acids required for anabolism. The extent of this increased need is again a function of the basal state of training, the duration, and the intensity of the training program.

Summary of Carnitine and Training Effects

Carnitine supplementation has been postulated to influence performance by increasing the delivery of FAs into the mitochondria to prolong endurance exercise as well as delay fatigue by sparing muscle glycogen. Improving performance is a central theme in nutrition and sport and provides a basis for the implementation of a supplement to an individual's diet. It is therefore pertinent to examine the effects of supplementation on performance to validate the efficacy of an ergogenic aid.

Eating During Extensive Exercise

Ideally, during extensive exercise that lasts for more than 60 minutes, you should try to balance your water and energy output with enough fluid to match your sweat losses and enough carbohydrate to provide energy and maintain normal blood sugar level. You can significantly increase your stamina by consuming about 100 to 250 calories (25 to 60 g) of carbohydrate per hour while performing endurance exercise, after the first Better yet, mix up your foods and fluids so that you get a variety of types of carbohydrate. Instead of just sports drinks, choose a sports drink and a banana or (part of) an energy bar plus extra water. Because different sugars use different transporters, you can absorb more carbohydrate and have more fuel to support your endurance exercise (Jentjens et al. 2006). Engineered sports foods commonly contain only one or two types of sugar, so don't hesitate to experiment with natural foods that offer more of a variety of carbohydrate. Whatever the situation, endurance...

Vitamin and Mineral Needs

Currently, the micronutrient requirements of people engaged in endurance activities are not well-defined. Because of the nature of your training, your daily overall needs may be 1.5 to 3 times greater than those of the average man. If you eat a healthy diet, your daily vitamin and mineral needs should be met from a variety of different foods (See Appendixes 5 and 6 for information on food sources of various vitamins and minerals). Because endurance exercise may increase your need for antioxidants, it is recommended that each day you should eat several foods rich in antioxidants (vitamin C, vitamin E and beta carotene), as shown in the table on the next page.

Interaction of Nutrients

There has been an interest in the timing of nutrient delivery and the effects on glycogen synthesis in the recovery from endurance exercise.113,114 Studies have demonstrated that glycogen resynthesis is more rapid if the glucose is provided in the immediate post-exercise period vs. a 2-h delay,114 and that there may be a synergistic effect from the addition of protein to glucose drinks.113 However, in a recent study our group did not find evidence for a synergistic increase in postendurance exercise glycogen recovery with isoenergetic protein-glucose supplements vs. glucose alone.75 At higher levels of energy intake some have found that the addition of protein to carbohydrate may enhance the rate of post-exercise gly-cogen resynthesis compared with an isoenergetic carbohydrate only drink,115 while others have not,116 even with nonisoenergetic diets.117 Following resistance exercise, we found that isoenergetic glucose-protein supplements were similar in terms of glycogen resynthesis...

Branched Chain Amino Acids

Of the amino acids discussed, three of them are termed branched-chain based on their structure. They are leucine, isoleucine, and valine. They are special because they can be used as an energy source for the muscles when needed. The use of these amino acids may come into play late in endurance exercise when glycogen stores are running low. About 25 percent of the protein in whole food sources is made up of these branched-chain amino acids. Despite their presence in food, supplement enthusiasts have investigated their role as an ergogenic aid.

Models and Measurement of Protein Metabolism

The majority of the energy for endurance exercise is derived from the oxidation of lipid and CHO. As mentioned above, skeletal muscle has the metabolic capacity to oxidize certain amino acids for energy. While it may seem counterproductive to oxidize proteins during exercise since they serve either a structural or functional role, amino acid oxidation may also be required for exchange reactions in the tricarboxylic acid cycle, and this may increase their net utilization.63 Early studies evaluated urea excretion as an indicator of protein oxidation (urea is a breakdown product formed in the liver following amino acid oxidation) and found that urinary urea excretion was higher following endurance exercise than at rest.464 This increase is missed if sweat is not collected because urea and other nitrogen compounds are contained in sweat.6566 For example, a person exercising

Plasma and Muscle Glutamine Levels in Catabolic Stress

There are also reports of decreased plasma glutamine concentrations after endurance exercise (Parry-Billings et al., 1992b Rohde et al., 1996b Castell et al., 1997) and athletic training (Keast et al., 1995 Hack et al., 1997) and in the overtrained athlete (Parry-Billings et al., 1992b).

Top Non Traditional Muscle Building Fat Blasting Workouts

Now compare that to the emaciated weakling physiques of many marathoners, and you'll see that sprinting is where the action is at for a healthy, ripped, powerful body Now I don't want to upset all of you distance runners out there. Hey, if distance running is something you enjoy, then go right ahead. But don't say you're doing it for the health benefits, because I might just have to disagree. Section 2.1 in this book provided my full opinion on why I believe highly variable intensity exercise (such as sprinting and interval training) is far superior to steady state endurance exercise (such as jogging, endurance cycling, or any same-pace cardio). 8. Mountain Biking - As you may have figured out by now, I'm not a proponent of steady pace endurance exercise, but rather, highly variable intensity exercise that works with bursts of exertion followed by recovery intervals. Well, mountain biking fits this bill perfectly. You get the leg pumping exertion during the uphill climbs, while...

Theoretical Ergogenic Benefits of Creatine Supplementation

Table 9.2 lists the types of exercise and sports that creatine supplementation has been suggested to influence, while Sidebar 9.2 lists the reported ergogenic benefits of creatine supplementation. Increasing muscle availability of creatine and PCr can affect exercise and training adaptations in several ways. First, increasing the availability of PCr in the muscle may help maintain availability of energy during high-intensity exercise like sprinting and intense weight lifting. Second, increasing the availability of PCr may help speed recovery between sprints or bouts of intense exercise. These adaptations would allow an athlete to do more work over a series of sprints or sets of exercise, theoretically leading to greater gains in strength, muscle mass, or performance over time. For this reason, creatine supplementation has primarily been recommended as an ergogenic aid for power strength athletes or patients who need to increase strength, power, or maintain muscle mass. However, recent...

Energize for Exercise

If you're an athlete and not aware that you need carbohydrates to fuel your workouts, then this is an exciting read for you Carbohydrates, as will be discussed in the chapters devoted solely to pre-, during, and postexercise, are imperative to performance and recovery. The recommended daily carbohydrate allowance for athletes is about 2.3 to 3.2 grams per pound of body weight during periods of training, and even higher for those endurance athletes in season it's closer to 3.2 to 4.5 grams per pound of body weight. Here are the carbohydrate needs for athletes

Fueling Your Body During Prolonged Endurance Activity

Some sports are so lengthy they require feedings throughout the event, to help supply your body with glucose when glycogen stores are running low. For example, marathon runners (and other endurance athletes such as soccer players) need to take about 30-60 grams of carbohydrate per hour, which translates into a mere (but important) 120-240 calories. Although it's a minuscule amount, these calories should be spread out over each hour. The simplest method is to drink one of the popular sports drinks during the event. You can hydrate and carbo-hydrate your body at the same time.

Doesnt Exercise Aerobic or Strength Training Raise the Metabolic Rate Post Exercise

While this was once thought to be true, more recent research suggests that endurance athletes, such as marathoners and triathletes, have a few hours or even days after their events where their RMR is elevated but for most athletes, the increase in RMR post-exercise is not enough to get excited about.

Exercise Training Effects on Triglycerides

One of the more extensive reviews of the effects of exercise on lipids and lipoproteins was conducted by Durstine and Haskell.36 First, in analyzing several cross-sectional studies comparing inactive controls to either endurance athletes, runners, crosscountry skiers, tennis players, or individuals with longer treadmill test times, they concluded that generally active individuals have lower triglyceride concentrations. With regard to exercise-training studies, they reported that training also generally reduced the triglyceride levels if the baselines were elevated. They also found that the degree of reduction in triglycerides was related to both the baseline amount of triglyceride elevation and to the volume of exercise training, but that in women, these findings were not as consistent.

What Happens to Body Protein When We Exercise

Driven by primarily by cortisol as well as epinephrine, both of which are elevated in circulation during exercise. Cortisol promotes muscle protein breakdown during the exercise while epinephrine promotes the conversion of amino acids to glucose in the liver. Since cortisol is a stress-related hormone, the degree to which this happen depends on how hard you exercising and for how long. Thus for shorter, less intense exercise sessions (for example, walking and casual bicycling) this isn't a consideration however for recreational and competitive endurance athletes and heavyweight trainers it is. We will explore this further in Chapter 11.

Is It Possible to Increase the Amount We Sweat

Because sweating is such an important means of removing heat, distance runners and other endurance athletes become better sweaters. This means that their sweat glands and tubes have adapted during the athlete's training to produce larger volumes of sweat but containing less sodium and chloride. This helps keep them from overheating but at the same time it keeps them from losing excessive amounts of the key electrolytes in sweat. A well trained endurance athlete may sweat 2 to 3 liters per hour of exercise. That's more than 8 to 12 cups.

Can Glycerol Support Better Hydration for Athletes

Alternatively, glycerol supplementation in conjunction with water consumption may be of benefit to endurance athletes preparing to perform in warmer environments. It is proposed that glycerol can enhance water retention prior to an event and thus may allow more sweat to be lost prior to any reductions in performance due to dehydration. Scientists have also reported that glycerol supplementation prior to an event increases heat tolerance during competition in warmer environments. This could potentially aid athletes training or competing in warmer environments without ample opportunity to drink fluids. One example of this type of competition is soccer. However, glycerol may lead to digestive tract discomfort so athletes will have to experiment here as well.

What Are the Training Adaptations That Occur From Aerobic Exercise

Exercise, muscle enlargement (hypertrophy) is much less pronounced, if at all. However, muscle will adapt in another amazing way. Here the adaptation allows the trained muscle to have greater endurance by increasing its aerobic ATP generative capacity. In doing so there is an increase in the number of mitochondria in the trained muscle cells. Furthermore, the trained muscle develops more capillaries to deliver blood. The increase in the number of capillaries provides more oxygen and energy nutrients during exercise. The heart grows a little as well to provide a more powerful stroke and greater cardiac output (blood delivery) to working muscles. A greater heart stroke is often reflected by a slower heart rate when not exercising. Some top endurance athletes have resting heart rates as low as 40 to 45 beats per minute whereas inactive people tend to have heart rates between 60 and 75 beats per minute.

Who Would Benefit from a Sport Drink

For a well nourished and hydrated weight-training athlete, there is probably no need for a sport drink unless he or she is training for longer periods and sweating profusely. The need for sport drinks for endurance athletes largely depends on the duration of exercise and the environmental conditions. Generally, for single shorter events such as 5-kilometer runs and half-hour aerobic sessions there isn't a need. However, as an event or training session becomes longer, the need increases. For bouts lasting an hour or more, water replacement is certainly necessary and performance can be enhanced by a sport drink.

Habitual Protein Intakes of Resistance Athletes

Habitual Protein Intakes of Male and Female Endurance Athletes Habitual Protein Intakes of Male and Female Endurance Athletes In summary, the majority of strength and endurance athletes consume adequate protein and energy to meet their needs. Even when one takes into account the modest increases required by certain athletes (see below), most athletes are still above these levels. It appears that the human body homeostatically adapts to exercise by matching protein and energy intakes to cover any increase in demand from the activity in question. In some groups, there are extrinsic pressures to restrict intake for weight class or aesthetic reasons. In fact, certain groups may not even be attaining the recommended intake levels for sedentary individuals. Each athlete must be considered as an individual when determining the adequacy of dietary protein and energy intakes. The identification of the at risk groups above may help the nutritionist or coach to be aware of those who may need...

Modern Sports Nutrition

Much of the sports nutrition research that was originally conducted was on endurance athletes such as marathon runners and cyclists. This is largely because endurance athletes are more likely to become carbohydrate-depleted than athletes in stop-and-go, power-oriented sports, and because endurance athletes need strategies in place to combat the environmental conditions they must compete in for hours on end.

Carbohydrates and Athletic Performance

Carbohydrate present in muscle (300 g), liver (90 g), and body fluids (30 g) is the major fuel for physical performance. The ATP stored in muscle cells can only give high-power output for a few seconds. It can be resynthesized anaerobically for a further few seconds (5-8) by using the phosphate from creatinine phosphate. These short, intense bursts of muscular activity are found in sprints (100 meters), track and field events, and sports such as tennis, hockey, football, gymnastics, and weightlifting. If the maximum effort lasts for 30 seconds, then breakdown of muscle glycogen can supply the energy, with buildup of muscle lactic acid. Most physical activity, however, requires an energy source that can power muscles for longer periods. The duration and intensity of exercise determines the mix of fuel used. In resting or light activity, about 60 is from free fatty acids (FFAs) and tri-glycerides in muscles. At moderate levels of activity (approximately 50 of the maximum O 2 uptake),...

Carbs for the Female Athlete

Research reported in Sports Medicine and other scientific journals shows that female athletes are at greater risk of running a carbohydrate deficit than their male counterparts. A recent review of the literature shows that women are more likely to chronically or at least periodically restrict carbohydrates to achieve low body fat levels. This is particularly true for female endurance athletes and women competing in sports that place particular emphasis on a lean frame, such as figure skating or gymnastics.

Fluids During Exercise

What should you drink during exercise The recommended fluid replacer contains a little sodium to stimulate thirst, a little potassium to help replace sweat losses, and a little carbohydrate (sugar) to provide energy. More precisely, the drink should contain 110 to 170 milligrams of sodium per 8 ounces (20 to 30 milliequivalents (mEq) sodium L) 20 to 50 milligrams of potassium per 8 ounces (2 to 5 mEq potassium L) and about 12 to 24 grams of carbohydrate per 8 ounces (in a 5 to 10 percent sugar solution, for 50 to 95 calories) (ACSM 2007). You can consume these nutrients via standard foods such as pretzels and bananas as well as engineered foods (see chapter 11), which can be more convenient for runners, triathletes, and other endurance athletes.

Have You Ever Wondered J

For caffeine-sensitive athletes, caffeine may exacerbate pre-event anxiety and its symptoms. Although caffeine may have a mild diuretic effect that may not last long, noncaffeinated beverages are advised when rapid rehydration is needed, perhaps between tournament events. That's also an issue in hot weather and for endurance athletes. Besides fluid and energy, sports drinks supply electrolytes. As you perspire, your body loses very small amounts of sodium and other electrolytes. For most athletes, a normal diet replaces what's lost. But endurance athletes perspire much more, so they're at greater risk for sodium depletion. Sodium and other electrolytes in sports drinks may be beneficial. During exercise that's longer than 60 minutes, or for exercise performed in high heat or humidity, drinks with electrolytes help to enhance fluid absorption. See Electrolytes Sweat 'Em later in this chapter. If you're an endurance athlete, experiment with sports drinks and other fluids during...

Condiments and sauces such as Worcestershire sauce horseradish ketchup and mustard

The Dietary Guidelines for Americans (2005) recommend that you consume foods with less than 2300 milligrams sodium or about 1 teaspoon salt each day. The AI for sodium is 1500 mg per day for adults. This amount does not apply to highly active individuals, such as endurance athletes and certain workers (such as foundry workers) who lose large amounts of sweat on a daily basis and therefore need more sodium. All adults exceed the AI each day. About 95 percent of adult men and 75 percent of adult women exceed the Tolerable Upper Intake Level of 2300 mg of sodium per day. Figure 7-5 gives strategies for reducing sodium intake.

Special Concerns For Athletes On Vegetarian Diets

Scandinavian researchers in the 1960s were the first to demonstrate that the ability to exercise at a high intensity was related to the pre-exercise level of muscle glycogen.1 Body glycogen stores play an important role in intense exercise (70-85 of peak aerobic power) that is either prolonged and continuous (e.g., running, swimming, and cycling), or of an extended intermittent, mixed anaerobic-aerobic nature (e.g., soccer, basketball, ice hockey, or repeated exercise intervals). Endurance athletes have been urged to ingest plant sources of carbohydrates to optimize muscle and liver glycogen stores.1,34,35 At the high intensities necessary for athletic training and competition, the metabolism of body carbohydrate stores provides the major fuel for muscle contraction, and, when these reach low levels, fatigue occurs.34,35 About 500-800 grams of carbohydrate per day (or 8-10 g kg body weight or 60-70 of energy intake) have been recommended for athletes training intensively for more than...

Carbohydrates during Exercise

Hundreds of studies have shown that carbohydrates consumed during exercise delay fatigue in endurance athletes, but carbohydrates during exercise also are important for athletes in high-intensity stop-and-go sports such as soccer, ice hockey, tennis, basketball, baseball, and football, as well as in precision sports. Carbohydrate consumption during all sports can help ward off fatigue within muscles but also the mental fatigue that can be associated with sports requiring lots of concentration. Remember, the brain is the hungriest of all organs for glucose. In fact, the brain is twenty to thirty times more metabolically active than muscles, and unlike other tissues, the brain can utilize only glucose for fuel.

How Does the Brain Know Which Type of Muscle Cells to Use for Different Sports

Versely, successful endurance athletes tend to have a greater percentage of Type I muscle fibers. This allows them to generate more force through aerobic energy systems in muscle cells. They can perform at a higher intensity before they generate critical amounts of lactic acid.

The thirty gram rule exposed By Will Brink

Some times by as mush as 225 As mentioned in the chapter, some researchers came to the conclusion that protein intakes for athletes should range from approximately 1.2 grams of protein per kilogram of bodyweight, for endurance athletes and up to 1.8g of protein per kg for strength training athletes.

Can Diet Affect the Onset of Exhaustion

A high carbohydrate diet allows the body to replenish glycogen stores in-between training sessions. Contrary to what many people think, it actually takes a while to rebuild muscle glycogen stores that have been used during exercise. In fact, if an endurance athlete reduces his or her muscle glycogen to nadir levels during training or competition it can take an entire day to rebuild them. This means that the athlete should eat carbohydrates immediately after completing a training session and throughout that day to provide the needed glucose to rebuild those stores.

From Dietary Protein Intake

Cyclist consumes about 3000 kJ as protein, which is equivalent to 126 g of protein, which in turn represents about 19 g of BCAAs, or twice the amount of the sedentary individual. The requirement for protein may actually be higher in the endurance athlete because some amino acids, including the BCAAs, are oxidized in increased amounts during exercise compared with rest.36-9 On the other hand, the efficiency of protein utilization appears to be increased with exercise training, and thus the dietary protein requirement may not be very different in athletes compared with less active or even sedentary individuals.46,47

Vitamin Restoration And Supplementation

As discussed in the chapters on minerals and trace elements (Chapters 6 and 7), individuals at potential risk of marginal micronutrient supply are those who consume low caloric diets for prolonged periods of time. A relatively low supply of vitamins may also occur when large amounts of processed foods constitute the major part of the daily diet. This has been observed to be the case in endurance athletes who ingest relatively large amounts of refined CHO as energy drinks during their sports events (23, 58, 165). The reason for this has been discussed in Chapter 2. In both situations the required micronutrient density (i.e. the amount of vitamins present per 1000 kcal energy intake) is higher than can be achieved in the diet. In these situations athletes may be advised to take a daily vitamin-mineral-trace element supplement (not more than 1-2 times RDA daily) to enhance micronutrient density and secure an appropriate intake.

Amino Acid Classification

What if we eat too little protein Few Americans are at risk of eating too little protein. However, individuals on severely restricted diets, those who are unable to eat, and those whose needs are increased because of illness or trauma may experience protein deficiency. To replenish the pools of essential amino acids that have been depleted, in order to make critical proteins such as enzymes and hormones, the body of a protein-deficient person begins to rob protein from muscle by digesting that protein to its constituent amino acids. Because muscle is needed for various vital functions (for example, diaphragm muscles for breathing and heart muscles for pumping our blood), the loss of large amounts of muscle protein can be fatal. Fortunately, the vast majority of people, even those who engage in regular, rigorous endurance exercise, can easily meet their need for protein by eating a balanced diet based on the Food Guide Pyramid.

Preexercise Caffeine A Stimulating Topic

Caffeine is a popular preexercise energizer and is known to help athletes train harder and longer. Caffeine stimulates the brain and contributes to clearer thinking and greater concentration. There are many good studies on the use of caffeine for both endurance exercise, such as long runs and bike rides, and short-term, higher-intensity exercise, such as soccer. The vast majority of the studies conclude that caffeine does indeed enhance performance (by about 11 percent) and makes the effort seem easier (by about 6 percent). Endurance athletes notice more benefits than those who do shorter bouts of exercise (Doherty and Smith 2005).

Rehydration Solutions

Rehydration solutions for athletes are generally designed to replace fluid and minerals lost by sweating and also limited amounts of energy in the form of CHO. All three substances are either lost or used during endurance exercise. Higher exercise intensities require a higher degree of energy production for which CHO as energy source is most suitable. Accordingly, with higher exercise intensities, more metabolic heat will be produced. Consequently sweat rate will be increased, as will the excretion of electrolytes. The longer the exercise lasts, the larger the amount of fluid, electrolytes and CHO needed to replace the losses.

Tools to Test if You Are Overly Fat or Underweight

Following are some examples of BMI scores for athletes from various sports. As you can see, athletes come in all sizes and shapes. However, despite wide differences in height and weight, virtually all the athletes fall between 18 and 25, which is considered normal or healthy. You will find endurance athletes at the lower end of normal and ball sport athletes at the higher end. Use this as a guide when evaluating your BMI and your body.

Vitamin And Mineral Use By Athletes

The myth that l-carnitine enhances fat oxidation is plausible enough to persuade many endurance athletes as well as people willing to slim and reduce their body fat to use this supplement (368). A number of studies have analysed the nutritional knowledge of athletes and their trainers (350, 351, 353, 354, 356, 357, 359-361). These studies tend to show that a better level of information about aspects of daily nutrition and about efficiency of food supplements leads to a more reasonable ingestion of supplements. Basic knowledge about the type of sport in which the athlete is involved and the consequences that this has for food consumption is considered to be important. Many endurance athletes, for example, do not realize that they ingest substantially more food, on a daily basis, than non-endurance athletes. The consequences of this larger food consumption are also an increased consumption of most micronutrients and of proteins. In this respect we had observed the opinion among coaches...

Energy Sources Carbohydrate and

Along with proper training, dietary choices have a strong influence on the amount of glucose stored in muscle. Diets high in carbohydrate stimulate muscles to store more glucose and can increase endurance.2,3 Athletes consuming 60-70 of calories as carbohydrates are better able to build large reserves of muscle glycogen than those consuming 40 of calories as carbohydrate (the normal amount of carbohydrate in the typical diet is about 45 ).2 For endurance athletes, at least two-thirds of total calories should come from carbohydrate. This means eating 500-600 g of carbohydrate each day. Emphasis should be on eating complex carbohydrates because, compared with

Nonendurance Activities

This lack of an effect of glutamine supplementation during resistance training may be due to the utilization of glutamine by other tissues before it reaches the peripheral circulation and skeletal muscle. Glutamine serves as a gluconeogenic precursor when muscle glycogen is depleted by approximately 90 however, resistance training typically produces approximately 40 depletion in muscle glycogen, which may not be severe enough to benefit from glutamine supplementation.46 Serving as an energy source of the immune cells is another proposed ergogenic effect of glutamine.19,40 Exhaustive endurance exercise has been shown to suppress

The Effect Of A Vegetarian Diet On Performance

The question of whether the multiple benefits of vegetarian dietary practices extend to enhanced physical fitness and performance has been explored since early in the 20th century.2-4 A few simple studies conducted prior to 1910 reported augmented muscular endurance (e.g., holding arms out horizontally, deep knee bends, and leg raises) in vegetarian vs. non-vegetarian subjects, but these results have not been confirmed in subsequent research.2-4 Meyer et al.23 studied the effect of a vegetarian diet on running performance (5- to 8-kilometer test runs). The subjects completed the runs before and after being on the diet for 2 weeks, and then again 2 weeks after returning to a non-vegetarian diet. No significant differences were found between the trials, suggesting that the vegetarian diet had neither a beneficial nor detrimental effect on aerobic endurance. Two papers have been published on a study of eight well-trained male athletes in Denmark who consumed either a lacto-ovo-vegetarian...

Vitamin and Minerals at a Glance

Also referred to as pyridoxal, this B vitamin is essential for about a hundred reactions in the body, including the production and metabolism of carbohydrates, fats, and proteins. It also is involved in the manufacture of compounds necessary for hemoglobin, the compound that carries oxygen through the bloodstream. While some initial studies suggested that endurance athletes may have increased needs for B6, more recent data suggest that the RDA is adequate. Exercise-induced low-plasma sodium, also called hyponatremia (sodium concentration of < 130 mmol l, normal range 135 to 146 mmol l), has been observed with increasing frequency during the past decade, with reports of up to nearly 30 percent of endurance athletes being affected. Hyponatremia has been reported in many endurance athletes, from marathoners to Ironman competitors, and is thought to occur when athletes become dehydrated and drink water only without additional sources of sodium (i.e., sports drinks, bars, or gels). Most...

Individual Vitamins And Influence Of Exercise

Vitamin E is an antioxidant and scavenges free radicals to protect cell membranes from lipid peroxidation. It functions in concert with vitamin C, beta-carotene and selenium, and also protects red blood cells from haemolysis (14, 131, 171). In the period 1970-1980, special attention was given to this vitamin after reported beneficial effects of its supplementation on oxygen consumption and physical performance. As is the case with vitamin C, many of these studies were also not well controlled or suffered from poor statistical design. Critical analysis of the literature and more recent results from well designed double blind studies did not bring any solid evidence for performance improvement (13, 14, 84, 171, 206). It has been observed that endurance athletes in general have low vitamin E serum levels. This may be an indication of either marginal vitamin E supply with food or increased usage in antioxidant defence mechanisms. Vitamin K serves a function in bone mineralization. This...

Exercise Training Effects on Fasting Plasma Glucose

Results from cross-sectional studies of young and old endurance athletes compared to young and old (lean and not lean) untrained individuals show that untrained individuals have decreased insulin action and decreased glucose tolerance compared to young and old athletes.61 The master athletes, compared to young athletes, had essentially identical insulin and glucose responses to an oral glucose-tolerance test, indicating that age need not result in impaired glucose tolerance. The authors suggested that earlier studies that had shown no improvement in insulin action or glucose

Quick and Slow Forms of Carbohydrate

In theory, low-glycemic index foods (apples, yogurt, lentils, beans) provide a slow release of glucose into the bloodstream, and high-glyce-mic index foods (sports drinks, jelly beans, bagels) quickly elevate blood sugar. Could low-GI foods help endurance athletes perform better by providing sustained energy during long bouts of exercise Are high-GI foods best to consume immediately after exercise to rapidly refuel the muscles and, thereby, enhance subsequent performance only create digestive distress. To enjoy sustained energy, simply eat a tried-and-true preexercise meal or snack and then, after the first hour, consume about 200 to 250 calories of carbohydrate per hour of endurance exercise. (See chapters 9 and 10 for more information about fueling before and during exercise.)

Nutritional Considerations For Strength Training

Strength training should complement endurance training workouts. The specific benefits of strength training include Because strength training makes you stronger, it will also reduce your risk for injuries that typically accompany endurance training. Finally, strength training can make you faster at tasks that require quick, short bursts of activity (such as a running from a boat to land).

Weight Loss Workbook Steps to Lose More Fat and Keep More Muscle

To maximize fat loss, it's important to take the right steps to lose weight, which is to only moderately cut calories and watch nutrient timing and protein quality in the diet to help spare as much lean tissue as possible. Most research suggests that a combination of diet and exercise is best for achieving weight loss and keeping it off. However, when it comes to just losing weight, diet is the most effective. Consider this study Six endurance-trained men followed a diet with a 1,000-calorie-per-day deficit for seven days by either (a) exercising more while maintaining their caloric intake, or (b) eating less while keeping exercise the same. The exercise group lost only 1.67 pounds, and the diet group lost 4.75 pounds. However, other studies in well-controlled environments have found that whether the caloric deficit is attained by diet or exercise, the net weight loss should be the same. RMR x 2.4 weight maintenance for endurance athletes -Total Daily Energy Expenditure

Side Bar The Glycerol Story is it a carb

Some studies have found mild improvements in endurance athletes given glycerol (Wagner, D.R., 1999 Montner, P., et al., 1996.) but studies have been mixed with some finding no effect. As with all science, there isn't a unanimous consensus on glycerol's effects. Some sports nutrition companies sell glycerol to bodybuilders as a plasma expander as glycerol can pull fluids into the vascular system temporarily and may enhance the pump you feel in the gym or when stepping on stage.

Relationship of Skeletal Muscle Insulin Resistance and Intramyocellular Lipid Accumulation

One of the difficulties with the lipotoxicity hypothesis of insulin resistance is the apparent paradox of increased IMTG in muscle of highly trained athletes, who are very insulin sensitive.37 However, the recent report by He, et al.43 may help to understand the role of muscle lipids in insulin resistance. They measured the size and quantity of mitochondria and lipid droplets in muscle from obese patients before and after weight loss and an endurance-exercise trial. After weight loss and exercise, the subjects improved insulin sensitivity by approximately 40 percent, but there was no change in the amount of intramuscular lipid. However, the mitochondria were larger, the lipid droplets were smaller, and the change in size of both mitochondria and lipid droplets correlated with the improvement in insulin sensitivity. They speculate that the smaller lipid droplets have a larger surface area that provides access for hydrolysis and utilization. In addition, the ratio of mitochondria to...

Countering Age Associated Changes in Fitness

Ever heard the saying use it or lose it This is true for physical fitness. Whether it is muscle strength or aerobic endurance, if you do not remain physically active as you age you cannot maintain the muscle mass or heart adaptations you need for peak performance (review the effects of detraining listed in Chapter 4). Though aging can lead to decreases in fitness levels, the amount of decline can be offset by a regular exercise routine. Therefore, age itself does not predispose you to have large decrements in physical performance.

Weight Loss Myths and Truths

I commonly hear marathoners, triathletes, and other highly competitive endurance athletes complain, For all the exercise I do, I should be pencil thin. They fail to lose fat because they put all of their energy into exercising then tend to be sedentary the rest of the day as they recover from their tough workouts. A study of male endurance athletes who reported a seemingly low calorie intake found they did less spontaneous activity than their peers in the nonexercise parts of their day (Thompson et al. 1995). You need to eat according to your whole day's activity level, not according to how hard you trained that day.

Strength Training

Besides calisthenics, strength exercises with light-weight, portable equipment, such as elastic tubing, dumbbells or a ball, can be performed in small spaces. Examples of these exercises are shown in Table 10-1. Regardless of the equipment used, the general principles and techniques outlined in Chapter 7 for muscle strength and endurance training apply. Follow the set and rep recommendations outlined in Chapter 8 for calisthenic exercises, starting with one set of eight reps. Include exercises for each of the major muscle groups mentioned in Chapter 7, Figure 7-2.

Phosphate Intake

There is considerable controversy about the extent to which athletes are any more iron deficient than the normal population, especially with respect to haemoglobin concentrations, which are known to be relatively low in many endurance athletes. An explanation for this observation may be the plasma volume increase as a result of endurance training. The absolute amount of circulating haemoglobin in this case is not necessarily lower but rather an effect of the increased plasma volume resulting in pseudo anaemia. However, over the last 10 years a large body of evidence has indicated that a substantial number of athletes involved in regular training do also have decreased iron stores, indicated by reduced bone marrow iron, enhanced iron binding capacity and low serum ferritin levels. Serum ferritin levels have to be considered with care as stressful exercise has been shown to result in temporarily increased levels. Thus serum ferritin levels obtained shortly after intense endurance...

Vitamin E

Vitamin E supplementation and endurance exercise are there benefits Sports Medicine 29 2 (2000), p. 73-83. Rokitzki, L and E. Logemann, et al. Alpha-Tocopherol supplementation in racing cyclists during extreme endurance training, Int. Jour. Sport Nutr. 4 3 (1994), p. 253-64.

Summary

Decombaz, J., Gmuender, B., Sierro, G., and Ceretelli, P., Muscle carnitine after strenuous endurance exercise. J. Appl. Physiol., 72, 423-427, 1992. 62. Marconi C., Sassi, G., Carpenelli, A., and Ceretelli, P, Effects of L-carnitine loading on the aerobic and anaerobic performance of endurance athletes. J. Sports Sci., 54, 131-135, 1985. 64. Janssen, G.M.E., Scholte, H.R., Vaandrager, M.H.M., and Ross, J.D., Muscle carnitine level in endurance training and running a marathon. Int. J. Sports Med., 10, S153-S155, 1989. 77. Colombani, P., Wenk, C., Kunz, I., Krahenbuhl, S., Kuhnt, M., Arnold, M., Frey-Rindova, P., Frey, W., and Langhans, W., Effects of L-carnitine supplementation on physical performance and energy metabolism of endurance trained athletes a doubleblind crossover study. Eur. J. Appl. Physiol., 73, 434-439, 1996.

Carbohydrate Loading

A good way to maximize glycogen stores in preparation for competition is to loadcarbo-hydrate.3 One week before the event the athlete should train long and hard over the course of a day in an attempt to completely drain muscle glucose stores. This is followed by 3 days of only light to moderate training and a diet that minimizes replacing the depleted muscle glycogen - one very low in carbohydrate and higher in fat and protein. Finally, in the 3 days prior to the event, the athlete stops training and consumes a diet very high in carbohydrate (70 of calories). This cycle - intense depletion, limited glucose supply, then sudden abundance - triggers glucose stores in muscle to rebound to three to four times the normal level.3,4 This can significantly increase endurance, particularly in events lasting longer than 90 minutes. Fig. 5.40 Increased protein requirements of athletes. The daily protein requirementfor endurance athletes is 1.2-1.4 g protein kg body weight and for strength...

Female Athlete Triad

The female athlete triad is a common nutritional disorder among female athletes caused by the drive of girls and women to be unrealistically thin in an attempt to improve performance. The disorder is most common in sports judged by build (e.g., gymnastics, diving, figure skating), sports with a weight classification (e.g., light-weight crew), and endurance sports (e.g., distance running). It is characterized by three interrelated conditions (1) disordered

Protein

Protein is essential to build and repair muscle tissue. Protein allows muscles to contract, gain in size, and increase in strength. Loading up on protein does not guarantee larger muscles. Protein in excess of the body's needs is stored as fat, not protein. Muscle growth comes from hard work, proper training, and balanced nutrition. Food sources of protein include lean meat and poultry (fish and chicken), fish, legumes (dried beans and peas), nuts, seeds, and dairy products. Protein needs for active athletes, especially endurance sports, are higher than for non-athletes. The maximum recommended amounts of protein is 1.2 to 1.4 g kg of body weight. This requirement can be met through diet alone.

Calcium

There are other things that take place both inside and outside the muscle that add to fatigue, but that's for another place and time as the explanation would be bor--- , overly detailed. Interestingly, it has been found that athletes increase their rate of calcium loss in sweat from prolonged endurance sports, and increase their loss in urine after intense weight training.

Did You Know

Fact Although a lean, muscular body may enhance health and athletic performance, you can be too lean. Among its many functions, fat cushions body organs, providing protection from injury. During endurance sports (running, cycling, swimming), both carbohydrate and fat provide energy for working muscles. If you're too lean, you may tire too quickly. And restricting energy intake too much to avoid body fat may create a nutrient deficiency.

Sodium Solutions

By using higher-sodium sports drinks and gels, you should be able to keep your sodium levels adequate during endurance and ultraendurace training and racing. Most athletes strive for 500 mg to 1,000 mg (1 g) sodium per hour. You can easily accomplish this with, for example, two PowerBar Gels (200 mg of sodium per packet) and 16 ounces of PowerBar Endurance sport drink (380 mg of sodium) totaling 780 mg of sodium as well as 96 g of carbohydrates.

As and GH Release

Eto et al. investigated highly trained cyclists ages 18 to 22 ingesting 20 g of glutamate-ARG (AG) salt per day and found that although AG had no effect on resting plasma levels of hGH, the AG subjects had marked reduction in cortisol and hGH compared to the placebo group during and after exercise. Those results suggest that AG may modify energy metabolism during endurance exercise.

Fat for Recovery

While carbs and protein are certainly dietary priorities for athletes, don't forgo healthy fats during recovery. Your muscles contain lipid droplets or small deposits of fat called intramyocellular lipids or IMCL. Scientists theorize that these muscle lipids may be important sources of muscle fuel early in exercise, which may help spare muscle glycogen stores for later. These muscle lipids get depleted during endurance exercise, and many endurance athletes eat very-low-fat diets in their quest to consume enough carbs, causing them to fall short of meeting their daily needs for lipid reloading during recovery.

Water on the Brain

While the vast majority of athletes suffer from dehydration, a growing number of athletes drink too much water during endurance exercise and develop a life-threatening condition when their blood sodium levels drop below normal levels. Low blood sodium levels disrupt the normal osmotic balance across the blood-brain barrier and cause water to seep into the brain, leading to cerebral edema (brain swelling). That's a bad thing. Hyponatremia tends to be more common among slower endurance athletes (e.g., marathon runners, cyclists, and triathletes) who are out on courses for many hours and drinking excessive amounts of water, as opposed to sodium-containing sports drinks. It is also up to three times more likely among female athletes than male (smaller body size appears to be key, not so much gender), and misuse of nonsteroidal antiinflammatory medications may increase risk. Studies have found that 10 percent or more of Ironman and marathon finishers have some degree of hyponatremia (most...