Endurance Exercise Ebook

Bags, Bells, and Bodyweight Training System

This eBook is designs a program to make you strong and fit in an athletic way, rather than a big and bulky kind of way. This program makes you lean, ripped, and athletic. This gives you a program that makes you actually strong, powerful, and athletic, rather than just looking like you lift. It gives you explosive gains in full body strength and muscle, huge increases in stamina, and a shredded body and mental toughness. This program takes advantage of the three best kinds of bodybuilding equipment: sandbags, kettlebells, and bodyweight workouts. These methods of working out provide much bigger results than a simple pump to your muscles; they actually provide real strength training. In addition, you get 4 free eBooks when you get Bags, Bells, and Bodyweight. You will also get The Sandbag Manual, The Kettlebell Manuel, The Bodyweight Manuel, which all go into more detail about how to use each one to the max. You will also get The Dumbbell Manuel, which shows you what to do if you have no kettlebells. This complete workout system builds whole bodies, not just a few muscles. Read more here...

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The Role Of PGC1a in Exercise Induced Mitochondrial Biogenesis

PPARy coactivator-1a (PGC-1 a) has been termed the master regulator of mitochondrial biogenesis because of its ability to induce mitochondrial biogenesis in a variety of experimental models. In mouse C2C12 skeletal muscle cells, ectopic PGC-1 a expression increases mitochondrial content and oxygen consumption 4 . In addition, overexpression of PGC-1a in skeletal muscle of transgenic mice is sufficient to coordinate a host of muscle adaptations reminiscent of endurance exercise training, including increased mitochondrial content, increased proportion of Type I muscle fibers, and a corresponding increase in muscle fatigue resistance 5 .

Can Exercise Induce Mitochondrial Biogenesis in the Absence of PGC1a

It is clear that PGC-1 a is sufficient to induce mitochondrial biogenesis. However, whether it is necessary for exercise-induced mitochondrial biogenesis is not fully resolved. Leone et al. 29 reported that mitochondrial volume is lower in skeletal muscle of PGC-1a knockout (PGC-1a- -) mice than in WT mice, with a concomitantly reduced expression of Tfam, cytochrome c, and COXIV. In contrast,Arany et al. 30 found no difference in mitochondrial volume in skeletal or cardiac muscle of PGC-1 a- - mice versus WT mice. Nevertheless, both groups showed that PGC-1a- - mice suffer a reduced capacity to increase work output to match an increase in metabolic demand in slow-twitch muscle 29 and in heart 30 . Specifically, PGC-1a- - mice display a diminished capacity for endurance exercise and fatigue resistance 29 and exhibit signs of cardiac dysfunction at an early age 30 . Thus, it is clear that PGC-1 a plays a vital role in the ability of muscle to adapt to heightened energy demands, but the...

Reactive Oxygen Species and Exercise

Aerobic exercise is intrinsically linked to increased oxygen consumption. During exercise the body as a whole uses 10-fold more oxygen than at rest, while in muscle tissue oxygen consumption may increase by 50 to 100-fold 40 .Various studies have demonstrated a connection between this increase in oxygen consumption during exercise and the formation of reactive oxygen species (ROS). In addition it has been shown that macromolecular structures within the cell can be damaged by elevated ROS. In fact, oxidative stress contributes to the accumulation of somatic mutations and oxidative damage to mtDNA. This has been apparent in mitochondrial diseases 41 , tumorgenesis 42 , aging 43 , degenerative diseases 44,45 , and diabetes 46 . However, skeletal muscle not only has the ability to produce ROS, but also has an elaborate system to regulate these reactive molecules and prevent their damaging effects. The cellular antioxidant defense system includes the mitochondrial and cytosolic forms of...

Mitochondrial DNA mtDNA Transcription Factors

Cle led to an increase in Tfam mRNA level after 4 days, leading to an accumulation intramitochondrial Tfam protein, an increase in Tfam-mtDNA binding and mtDNA transcript levels encoding COX subunit III, and a higher COX enzyme activity by day 7. A similar increase in Tfam expression has been found following endurance training in humans 69 . Thus, the increase in Tfam expression during the progression of exercise training contributes substantially to mitochondrial biogenesis in skeletal muscle.

Cardiomyocyte Dimensions and Contractile Function

Since myocardial tissue from trained humans is not easily available, data at the cellular level have to be derived from experimental models. Several animal models of endurance exercise have been shown to mimic important aspects of human physiology and could help determine the cellular and molecular mechanisms of training-induced improvements of cardiac function 40-44 . In a rat model of endurance training, increased dimensions and improved left ventricle contraction and relaxation can be observed in isolated cardiomyocytes. This demonstrates that improved intrinsic (i.e., without influence of the neuro-hormonal system) cardiomyocyte function can contribute to both the systolic and diastolic improvements that occur in the athlete's heart. Training-induced elongation of left ventricular cardiomyocytes occurs in the absence of changes in sarcomere length 45 and the changes in cardiac contractile function induced by endurance training are due in part to cardiomyocyte length-independent...

Intracellular Calcium Transients

Cardiomyocyte shortening in healthy endurance-trained rats is associated with lower peak systolic and diastolic intracellular Ca2+ and reduced time for the Ca2+ decay from systole 43-45 . Gene analysis approaches demonstrate a marked upregulation of SERCA2 and NCX in trained hearts 43,44,58-61 . Chronically elevated NCX levels are known to reduce systolic Ca2+ 62 and may contribute to the reduced peak systolic Ca2+ observed in cardiomy-ocytes from endurance-trained rats. Furthermore, increased Ca2+ uptake capacity of the SR due to increased SERCA2 expression could account for the increased rate of decay of the Ca2+ transient observed after regular exercise training 43 .

Metabolic Functions

The role of folate in anemia is well established. Anemia was the first deficiency symptom associated with the vitamin.1-3 Folate deficiency is characterized by the inability of erythrocytes to replicate normally,16 resulting in a megaloblastic anemia.17 This is important to athletes, particularly endurance athletes, because of the need to transport oxygen. The large oval cells of this anemia have less hemoglobin and a reduced capacity to carry oxygen through the blood. The relationship between elevated homocysteine and athletes is important, because research suggests that endurance exercises may cause a significant increase in plasma homocysteine. Twenty-five percent of the recreational endurance athletes studied in one trial exhibited hyperhomocys-teinemia in association with low intakes of folate and B12.61 Another study completed with rats indicated that exercise increased endothelial nitric oxide. If this is true in humans, it may have a protective effect against elevated...

Cardiomyocyte Contractility

Previously it has been shown that training-induced elongation of left ventricular cardiomyocytes occurs in the absence of changes in sarcomere length 45 . Also, it appears that the changes in contractile function produced by endurance training are due in part to cardiomyocyte length-independent changes in contractile function. Several lines of evidence support this assumption. Schaible and Scheuer 47 demonstrated that endurance training elicited an increase in end-diastolic volume, stroke work, ejection fraction, and mid-wall fractional shortening in the absence of changes in end-diastolic wall stress in perfused working rat hearts. Additionally, isometric force development by rat left ventricular papillary muscle is increased by endurance training 60 . Despite this, cell length remained significantly above what was observed in controls after 4 weeks of inactivity, whereas the exercise-induced improvement in cardiomyocyte shortening regressed completely within 2 to 4 weeks of...

Cardiomyocyte Calcium Handling

In line with increased rate of cardiomyocyte shortening and relengthen-ing, we find a concurrent increase in the rates of systolic Ca2+ release and diastolic Ca2+ removal in trained normal Sprague-Dawley rats 72 . However, despite increased fractional shortening in normal, healthy Sprague-Daw-ley rats, the Ca2+ amplitude remains unchanged. These data suggest that endurance training induces an increase in the Ca2+ sensitivity of the contractile myofilaments. Previously, it has been shown that the increased Ca2+ sensitivity can be attributed to a higher intracellular pH observed at physiological stimulation frequencies 43,44 . Furthermore, permeabilized cells from trained rats shorten to a greater extent than sedentary cardiomyocytes in the presence of a constant buffered pH. These results indicate that the contractile proteins of the cardiomyocytes from trained rats have an increased intrinsic Ca2+ sensitivity compared to cardiomyocytes from sedentary rats. The cellular basis for these...

New Prospects in the Study of Skeletal Muscle Adaptation in Response to Physical Exercise

Among physiological stimuli, exercise is extremely effective in modulating muscle gene expression. Adult skeletal muscle tissue displays high plasticity in response to repeated bouts of contractile activity and endurance exercise training is strongly correlated with increased steady-state levels of many mRNAs encoding mitochondrial proteins and with increased mitochondr-ial density 70-72 . Activation of gene expression and increase in mito-

Biochemical Status In Athletes

Studies that have simply screened B12 status show little difference between athletes and non-athletes. Brotherhood et al.25 compared the status of numerous hematologic parameters in 40 male long-distance runners with 12 matched controls. They reported no differences between these groups in serum B12 levels. Matter et al.,26 in a study of 85 female marathoners, reported normal vitamin B12 levels. The biochemical status of 17 of the I-class athletes, characterized by Barry et al.,19 included serum B12 and folate levels in the normal range for all athletes. None of these athletes was an active consumer of vitamin supplements. Hermann et al.,27 in a study of the effects of intense endurance exercise (running or bicycling) on homocysteine levels, measured the pre-race serum levels of vitamin B12 in those subjects who also had an elevated plasma homocysteine level. All 23 athletes with high homocysteine levels, out of the total of 100 athletes, had a low serum B12 level, suggesting that a...

Exercisemediated Changes In Vitamin E Status

Most,26-30 but not all,1331-33 of the studies investigating the response of plasma vitamin E to exercise reported increases in plasma a-tocopherol concentration post-exercise, regardless of treatment (supplemented vs. non-supplemented). However, some studies have reported decreased plasma a-tocopherol concentrations post-exercise.3435 Whether increased a-tocopherol concentrations can be attributed to increased rates of lipoprotein secretion during exercise remains under investigation. An increase in total plasma a-tocopherol in response to endurance exercise may be due to increased output of a-tocopherol from the liver, perhaps as a result of increased VLDL production, but might also be an oxidative stress-dependent response. With some exception,13 plasma a-tocopherol consistently increases post-exercise in response to ultra-endurance exercise,27-30 whereas plasma Studies using deuterium-labeled tocopherols have demonstrated that the various forms of vitamin E are absorbed and...

Ergogenic Effects Of Vitamin E

Although many researchers have examined the effects of vitamin E supplementation on athletic performance, there is little evidence of an ergogenic effect. Aerobic capacity as measured by maximal oxygen consumption (VO2max) increases in response to training, but not in response to vitamin E supplementation.34,48-50 Similarly, vitamin E supplementation does not appear to improve cycling work capacity35 64 or marathon run time.28 29 Finally, there is no evidence that vitamin E supplementation improves strength training parameters including maximal strength, explosive power and muscular endurance.53 However, the decrease in torque production following endurance exercise may be more a result of central fatigue than damage at the level of the skeletal muscle. Millet et al.73 reported that the 30 decrease in isometric maximal voluntary contractior (MVC) of the knee extensors following a 65 km ultramarathon was due primarily to a decrease in maximal voluntary activation. It is unknown whether...

Summary And Conclusions

Despite the apparent increased requirement for vitamin E during endurance exercise,30 there is little evidence for an ergogenic effect of vitamin E. Supplementation has no apparent effect on VO2 max,3448-50 cycling work capacity35 64 or marathon run time.28 29 There is also little support for vitamin E supplementation on strength training parameters including maximal strength, explosive power and muscular endurance.53 Chronic vitamin E supplementation appears to attenuate the inflammatory response in untrained subjects participating in moderate intensity exercise.828688 Supplementation appears to be less effective in trained subjects participating in endurance exercise,2431 87 possibly due to an enhanced ability to modulate the inflammatory response following training that is independent of supplementation.

Mitochondrial Biogenesis

PGC1a regulation seems finely tuned to reflect cellular energy demands, with conditions of increased energy needs, such as cold, physical exercise, or fasting inducing its expression. Fasting induces hepatic PGC1a expression, which increases gluconeogenesis, while physical activity induces its expression in heart and skeletal muscle, thus increasing mitochondrial biogenesis and oxidative phosphorylation. As mentioned before, PGC1a was originally discovered as a cold inducible transcription factor in adaptative thermogenesis, the physiological process through which energy is dissipated as heat in response to environmental conditions such as cold or overfeeding. BAT in rodents and skeletal muscle in humans are the main sites involved in this process. Biochemically, the adaptive thermogenic process needs the stimulation of mitochondria (increasing nutrients catab-olism) and the uncoupling of oxidative phosphorylation through the expression of the uncoupling protein UCP1. This protein...

Conclusions And Opportunities For Future Research

Although there is little research on the involvement of iodine in exercise performance or recovery from exercise, iodine is essential for the maintenance of normal metabolism and for normal growth and development and, therefore, is likely to take part in various processes of importance to exercising individuals. Given iodine's key functions, it is surprising that more research has not been done in this area. Clearly, there are many questions to be answered. Strenuous activity and endurance training cause some changes in thyroid metabolism, but it is not clear whether these changes are temporary or permanent or whether they have any biological significance. In spite of the increased turnover of T4, it appears that serum levels of T4 and T3 do not change substantially, which leaves a major discrepancy in the reported observations. It is not clear how exercise can cause both decreased iodine uptake and increased thyroid turnover while serum hormone levels remain unaltered.34 Preliminary...

Effects Of Increased Intake Of Vitamins And Trace Minerals On Exercise Performance And Metabolism

Effects of micronutrient deficiencies on exercise performance have been studied for many years, and will be discussed in detail in subsequent chapters in this volume. Usually, decreases in physical performance are found when one or more vitamins or trace minerals are known to be deficient, based on extended lack of dietary intakes or reduced indicators of status (usually serum levels).18-34 These findings were first demonstrated in the 1940s before fortification of refined foods with iron and a few B vitamins was widespread. Decrements in physical performance due to deficient status in one or more vitamins or trace minerals continue to be documented in recent times by experimental depletion or examination of subjects in countries without food fortification.23-31 Iron-deficiency anemia in endurance athletes is still encountered, and is well-known to eventually reduce perfor-mance.22,28,29,32-34 At this time, it is generally agreed that measurable deficiencies of thiamin, ribo-flavin,...

Exercise Induced Improvements in Maximal Oxygen Uptake

In contrast to many studies 46, 47, 70, 71 we find that regular exercise training induces a substantial increase in VO2max in the rat-treadmill-model VO2max increases on average 10 per week until it levels off after 6-8 weeks of exercise training 42, 43, 72 . This is likely a result of the high aerobic intensity of the training regimen. Differences in training response reported in the literature are probably due to different training regimens used and or insufficient control of relative exercise intensity. The load required to produce a training effect has to increase as the performance improves during the course of training 8 . The training load should, therefore, be set relative to the level of fitness of the individual. Christensen 73 demonstrated, in humans, the need for a gradual increase in training load with improved performance, in the case of the effect on heart rate, as early as 1931. He observed that regular endurance training at a given exercise rate gradually lowered the...

Role of Copper in Blood Cell Formation and Function

The primary function of erythrocytes is to transport oxygen from the lungs to other tissues. Physiological oxygen deficit associated with physical endurance exercise leads to increased expression of the hematopoietic hormone, erythropoietin that results in elevated erythropoiesis and oxygen capacity of the blood. However, the formation of erythrocytes depends on the maturation of colony-forming units in the bone marrow. Copper clearly has a role in the maturation of blood cells in bone marrow and low dietary copper intakes may impair the formation of erythrocytes in response to the oxygen deficit created by endurance exercise. Although dietary copper requirements for optimal physical performance have not been thoroughly investigated, intakes at the RDA for copper are recommended to assure proper erythrocyte maturation in the bone marrow in response to exercise training.

Effects Of Selenium On Athletic Performance

In trained athletes participating in a half marathon, Duthie et al.71 found no significant differences in erythrocyte GSHPx activity pre-race and up to 120 hr post-race. They also noted no significant change in erythrocyte catalase or SOD, but total GSH and GSH values were significantly lower than pre-race values at 5 min post-race. While plasma creatinine kinase, an index of damage to muscles, was elevated in plasma post-race, conjugated dienes and TBARS, indexes of oxidative damage, were not elevated by the exercise. Erythrocytes were more susceptible to hydrogen peroxide-induced peroxidation after the half marathon, however. Using a cross-over design, Dragan and co-workers72 evaluated the effect of a 150 g Se supplement or placebo given before a 2-hour endurance training session on 33 swimmers. No significant differences were noted in alondialdehyde in serum. Also, in another cross-over design experiment, they administered 100 g Se or placebo Acute exercise also results in an...

Respiratory muscle strength

Rest between training exercises.28 In addition, strength training differs conceptually and in practice from endurance training.29 For the respiratory muscles, training is ill defined and although it is felt that the respiratory muscles should behave in a similar manner to other muscle groups, definitive studies have yet to show how they may be trained. It is likely that the response to training will in part be genetically determined. The general observation that some individuals are responsive to and have ability at certain types of exercise has led to studies showing genetic differences in the response to training according to genotype.30 A genetic polymorphism of the angiotensin converting enzyme (ACE) gene has been described with a 256 base pair deletion or insertion, termed DD or II.31 In de-trained subjects there is an 11-fold difference between homozygous subgroups in response to performing a repetitive biceps exercise.30 Recently, respiratory muscle strength and endurance was...

Watersoluble Vitamins And Choline

Folate functions in nucleic acid synthesis and is a component of several enzymes involved in amino acid metabolism. Folate deficiency is primarily manifested as megaloblastic anemia. Any type of anemia can influence physical performance, particularly in endurance athletes. No measurable increase in athletic performance has been observed in athletes who consumed amounts of folate higher than that recommended for the general population. Folate can lower plasma homocysteine concentrations. Research is needed on the relationships between exercise and hyperhomocysteine-mia, if any. The UL for folate for adults is 1000 g day from fortified foods or supplements, but not other foods.7

Sarah Blanton and Steven L Wolf

Other functional constituents of the neuromus-cular system relevant to strength include local muscular endurance (the ability to resist muscular fatigue) and muscular power (force applied multiplied by the velocity of movement) (Deschenes and Kraemer, 2002). Limitations in endurance often

Effect of Exercise on Thyroid Function

Increased T4 turnover is consistent with studies showing approximately half as much iodine in the thyroid glands of exercising rats as in those of non-exercising rats.33 There was no significant difference in the rate of renewal of thyroidal iodine between these groups, resulting in less storage of iodine in the exercising rats. Endurance training is associated with lower uptake of radio-iodine by the thyroid of humans. Hooper and colleagues34 observed that human volunteers who ran at least 10 miles per week had lower mean 24-hour thyroid radio-iodine uptake (8 3 ) than nonexercising subjects (14 5 ). In spite of the reduced uptake in these subjects, other thyroid function tests, such as T3, T4 and TSH, did not differ significantly, nor did urinary iodine excretion.34 Khoral35 also found that the percent uptake of a dose of 131I into thyroids of 16 athletes immediately after exercise was lower than resting values 2 hours later, while Wilson36 observed 24-hour uptake in 17 men to fall...

Rib Stress Fracture Volleyball

The posterolateral aspects of the fourth through sixth ribs are most commonly injured in golfers 17 . This is because compression and tension stresses of the serratus anterior are maximal on the posterolateral segment of the ribs, as demonstrated by a two-dimensional finite analysis of the muscle 26 . The ribs on the leading arm side are most commonly involved, most likely because of constant moderate activity of the serratus muscle through all phases of the golf swing on the leading side compared with the trailing side where the muscle is primarily activated only during the acceleration and early follow-through phase of the swing, as shown in an electromyographic study 27 . The constant activity of the serratus anterior muscle on the leading side may make it more susceptible to fatigue and decrease its ability to protect the ribs from stress fractures 27 . Therefore, these authors recommend a strengthening and endurance training program to prevent fatigue of this muscle 27 .

Vitamin E Supplementation In Exercise

Studies carried out at sea level have also shown conflicting results. Kaikkonen et al.13 demonstrated that LDL from subjects supplemented with only 13.5 mg day d-a-tocopherol and 90 mg coenzyme Q10 for 3 weeks had a 17 lower susceptibility to oxidation following a marathon run than LDL from the placebo group. In contrast, supplementation with 294 mg vitamin E, 1000 mg vitamin C and 60 mg coenzyme Q10 daily for 4 weeks had no effect on the exercise-induced increases in conjugated dienes following a 31 km run in trained endurance athletes.27 Mastaloudis et al.24 supplemented runners with placebos or 300 mg vitamin E and 500 mg vitamin C twice a day (total of 1000 mg) (Figure 13.2). Lipid peroxidation as assessed by F2-IsoPs increased dramatically in the placebo group following the 50 km ultramarathon, but the increase was

Oxidative Stress And Damage

In response to endurance exercise, oxygen (O2) consumption increases 10- to 20-fold systemically and as much as 100- to 200-fold at the level of the skeletal muscle, resulting in substantially increased mitochondrial electron flux.36 Vigorous exercise results in increased lipid peroxidation,30 DNA damage37 and protein oxidation.38

Evidence of the Athletes Heart

The athlete's heart is a hypertrophied heart with an increase in left ventricle volume and enhanced pumping capacity. A high level of VO2max, regardless of whether it is intrinsic or acquired, associates with the athlete's heart. Left ventricular weights scaled appropriately to body mass were 19 higher in HCR vs. LCR 66 . In both HCR and LCR, regular endurance exercise increased left ventricular weights and cardiomyocyte length significantly, but the increase is significantly higher in HCR than in LCR. This suggests that the HCR not only has evolved into having a higher intrinsic aerobic fitness, but also possess a higher responsiveness to exercise training than LCR, which may be traced back to its genome. We have also demonstrated a development of the heart into the athlete's heart in normal Sprague Dawley rats, as endurance training also in this model increases left ventricular mass and cardiomyocyte length and width 72 . It is apparent from our studies and This fits with Peter...

Degenerative Muscular Disorders

Inspiratory resistive exercises have been shown to increase endurance of respiratory muscles but not vital capacity. y When indicated, intermittent ventilatory assistance ameliorates symptoms of hypoventilation but does not slow the deterioration of respiratory function. If assisted ventilation is employed when vital capacity falls below 10 percent of normal, it can prolong survival by 3 to 4 years. y

Contraception

Some studies have shown that oral contraceptive pills (OCP) seem to have a protective effect in preventing stress fractures in female athletes 17,75 . It appears that exogenous estrogen may help curb further bone loss in the hypo-estrogenic amenorrheic athlete however, it may not be sufficient to stimulate bone growth 71,76-79 . Several small studies of amenorrheic women or those with anorexia have found BMD at the lumbar spine or hip to be higher for women taking OCP compared with those who were not 76,77,80 , whereas other studies show no significant change 71,78 . It has also been theorized that OCP may act through another mechanism, such as improving bone microarchitecture and quality without significantly affecting BMD 4 . However, to add to the controversy, a recent study by Hartard and colleagues 81 has shown that OCP use is associated with decreased BMD of the spine (7.9 ) and the femoral neck (8.8 ) in female endurance athletes compared with non-OCP users. The authors 81 also...

Summary

Stress fractures are common injuries, particularly in endurance athletes. Stress fracture management should take into consideration the injury site (low versus high risk), the grade (extent of microdamage accumulation), and the individual's competitive situation. Low-risk stress fractures usually respond well to nonoperative management, and treatment is largely guided by the patient's symptoms. High-risk stress fractures should be treated more aggressively with absolute rest or surgical fixation, with the goal of fracture healing and minimizing risk of complete fracture or refracture. The overall goal of treatment is to allow activity and avoid deconditioning when appropriate, while minimizing the risk of significant complication to the athlete. Overtreatment of low-risk stress fractures can result in unnecessary deconditioning and loss of playing time. Undertreatment of a high-risk stress fracture may place the athlete at risk of a significant complication, putting the athlete's...

Conclusions

Folate is necessary for the synthesis of DNA and RNA. A deficiency of folate will affect many systems but is primarily manifested by a megaloblastic anemia. Any type of anemia could affect the performance of athletes, particularly endurance athletes. Supplementation with folate will correct the anemia and thus possibly improve the athletes' performance, but there is no strong evidence that an increase in folate beyond the amount recommended for the general population will produce a measurable increase in athletic performance. Additional research will determine whether an increase in folate consumption is needed by the athlete to prevent disease due to a possible increase in homocysteine levels secondary to exercise.

Athletes

A special concern should be noted because there are subsets of athletes who follow vegetarian diets for reasons of health or otherwise. As discussed above, the vitamin B12 intake of strict vegetarians can be very low (0.4 g d,17 compared with the current RDA of 2.4 g d) and long-term consumption of vegetarian diets may lead to reduced serum B12 levels.18 However, other studies suggest that vitamin B12 intake by vegetarian athletes may be sufficient to maintain normal B12 status. Eisenger et al.23 combined a study of the effects of exercise on B12 intake with a study of the effects of a vegetarian diet on exercise performance. For an ultra run involving a 1000-km run over a 20-d period, two groups of athletes were studied, 30 who consumed a regular western diet and 25 who consumed an LOV diet. Both diets were strictly controlled by study personnel and contained the same energy content and the same carbohydrate-fat-protein distribution. Participants consumed the diets ad libitum,...

Recommendations

While vitamin E has no apparent effect on exercise performance, it has been demonstrated that its utilization increases during endurance exercise 30 therefore, endurance athletes may have a higher requirement for vitamin E. There is also evidence that those participating in repeated bouts of exercise on the same day or consecutive days may benefit from vitamin E supplementation by

Dietary Iron

Future research should examine the effects of iron supplementation on serum transferrin receptor concentration in endurance athletes. Improvement in performance may be linked to low tissue iron status. Changes in sTfR following iron supplements may explain why some nonanemic athletes increase in endurance. Inclusion of sTfR measurements during training studies with athletes should provide further insight about depletion of iron stores and tissue iron deficiency.

Aerobic Capacity

Most previous works regard VO2max as the single best indicator of an individual's cardiorespiratory endurance capacity 8 . Although traditionally related to endurance performance such as cross-country skiing and running,VO2max has recently been established as a strong predictor of cardiovascular morbidity and mortality 9 . Improved VO2max can be acquired through endurance training and is associated with salutary adaptations in multiple organ systems.An assessment ofVO2max offers a precise measure of the capacity to transport and utilize oxygen that is the functional capacities of the lungs, cardiovascular system, and muscle mitochondria combined. At maximal aerobic exercise, the majority of evidence demonstrates a VO2max that is supply limited 10-14 . This appears to be evident in highly trained athletes 15 and in average fit humans 16 . Consequently, cardiac output and more precisely stroke volume, has a major influence on VO2max 13-18 , whereas maximal heart rate as an inherited and...

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