Why is dwain chambers a bad role model

Glucose and free fatty acids suppress GH secretion. The GH-releasing properties of some amino acids also form the basis of their marketing as supplements that boost muscle growth and performance. Amino acids, such as arginine, lysine, and ornithine, can stimulate GH release when infused IV or administered orally.

The GH response to amino acid administration has a high degree of interindividual variability and is influenced by training status, sex, age, and diet High oral doses are required to stimulate GH release, frequently causing stomach discomfort and diarrhea.

Oral arginine administered before exercise does not augment GH release induced by exercise There is no evidence that oral supplementation of amino acids, before strength training, increases muscle mass and strength to a greater extent than strength training alone 61 , although protein supplements immediately following exercise may aid recovery. GH secretion is also affected by the fasted and fed states as well as the general nutritional state. Nutrient deprivation enhances GH secretion within 12 hours, doubling by 48 hours.

Under these nutritional conditions, insulin concentrations fall, leading to diminished hepatic IGF-I production and a reduction in feedback inhibition of GH release The enhancement in GH output during nutrient deprivation is a biological response that results in stimulation of lipolysis and subsequently increased lipid utilization, resulting in the sparing of protein 9.

In the fed state, GH secretion is suppressed by the central feedback effects of glucose, fatty acid, insulin, and IGF-I. Obesity is associated with a similar profile of reduced GH output, reversible with weight loss The close relationship between GH secretion and insulin is a reflection of its important role as a metabolic hormone, regulating energy metabolism, substrate partitioning, usage and storage, and the sparing of protein during nutrient deprivation.

Exercise is a potent physiologic stimulus for GH release. There has been intensive study on the mechanisms and significance of exercise on GH secretion. Both resistance and endurance exercise enhance GH secretion, with intensity and frequency being important factors An exercise intensity above lactate threshold and for a minimum of 10 minutes appears to elicit the greatest stimulus to the secretion of GH.

A program of endurance training at or above the lactate threshold enhanced pulsatile GH secretion The mechanisms are not fully understood but include neural input, neuromuscular activity, and a rise in lactate and in core body temperature 64 , A less well-known effect of GH is the stimulation of sweat gland secretion important for thermoregulation.

Skin exocrine function is reversibly impaired in adults with GH deficiency, who demonstrate a greater increase in core body temperature during physical exertion, limiting exercise tolerance GH supplementation in healthy adults enhances lipolysis 68 and reduces oxidative loss of protein 69 during exercise, providing evidence that exercise-evoked GH secretion brings metabolic and homeostatic benefits. Daughaday made the seminal discovery that the growth-promoting action of GH is mediated by the generation from the liver of IGF-I, then called somatomedin later shown to be the same as non-suppressible insulin-like activity , giving rise to the somatomedin hypothesis The hypothesis that IGF-I is produced solely from the liver was challenged by in vitro evidence that several tissues produced this growth factor Not long afterward, Issakson et al.

Elegant tissue-specific knockout studies have since established that GH exerts regulatory control of body and tissue growth through a combination of endocrine and paracrine actions mediated by IGF-I The lipolytic, gluconeogenic, and antinatriuretic actions do not involve IGF-I mediation. Forearm studies in humans employing arteriovenous measurements have revealed that GH stimulates amino acid uptake directly into muscle Thus, GH elaborates a range of effects on metabolism, body systems, and body growth integrated through a mix of direct and indirect IGF-I—mediated action.

GH stimulates the secretion of a number of proteins from the liver and from peripheral tissues. Many GH-responsive proteins have been investigated for their potential as sensitive and specific discriminants of GH use.

Figure 4 shows a schematic representation of the stimulation of components of the IGF system and of bone proteins by endogenous or exogenous GH. In elite athletes, demographic factors account for significant variability in the blood levels of these markers, all falling significantly with age 76 , Therefore, a test based on IGF-I and the collagen markers must take age into account for men and women, whereas ethnicity and sport type are unlikely to be confounders for these markers.

Protein mass is not static but is constantly turning over in a dynamic process of loss and synthesis. Approximately 0. Tracer studies employing steady-state methodology have given insights into how GH regulates whole-body protein anabolism.

Whole-body metabolism can be broken into three components, that is, proteolysis, oxidation, and synthesis, in which the amino acid pools derived from proteolysis are oxidized or resynthesized into protein. Oxidation of amino acids provides a source of energy but represents irreversible loss of protein; it is therefore the hallmark of catabolism. GH directs amino acids from oxidative toward synthetic pathways In contrast, insulin exerts an anticatabolic action by reducing the rate of proteolysis 79 , IGF-I elicits effects that are similar to GH, stimulating protein synthesis and reducing oxidation This observation provides strong evidence that IGF-I plays an important role in mediating the effect of GH on whole-body protein anabolism.

Skeletal muscles are specialized contractile tissues that control posture and physical activity while having an important role in energy metabolism. Their function is dependent on the composition and strength of fiber types that require energy to drive and sustain contractile work.

The stimulation of muscle protein anabolism and growth by GH has led to widespread expectation that it increases muscle strength and power. Muscle function is most commonly defined by strength and power 82 , endpoints reflecting overlapping but different aspects of muscle function. Strength is dependent on muscle size, type, and properties of contractile proteins. Muscle power, a measure of work performed per unit time, is assessed in different ways that vary in duration.

The energy required to support muscle work can be drawn from anaerobic or aerobic processes such as preformed stores or that generated from the oxidative metabolism of substrates Muscle power is influenced by the availability of energy at the time of assessment. The recognition of mitochondrial myopathies as a class of functional muscle disorders arising from defects in mitochondrial respiratory chain enzymes highlights bioenergetics as an important mechanism influencing skeletal muscle function dependent on oxidative phosphorylation The bioenergetics of muscle is an important player determining aspects of muscle function Skeletal muscle is composed of fibers that are made up of different proteins with distinct properties.

Actin and myosin are functional proteins that subserve contractile function, whereas tropomyosin and troponin are structural proteins that keep the contractile proteins in proper alignment and give muscle fibers elasticity and extensibility.

Muscle fibers are classified by myosin heavy chain isoforms mainly into two types. Type I fibers, also known as slow-twitch fibers, contain an abundance of mitochondria and rely on aerobic or oxidative pathways for energy. These fibers determine the endurance capacity of muscle. Type II fibers, also known as fast-twitch fibers, use energy from anaerobic or glycolytic pathways due to their low mitochondrial content.

These fibers have high contractile force, but fatigue easily, and thus support high-intensity activities, such as the high jump, weight lifting, and sprinting.

There are few human studies investigating GH regulation of muscle fiber composition, and most of these entail small numbers. Most studies in adults with GH deficiency have reported no significant difference in fiber type distribution from matched healthy people 86 , Fiber composition does not change significantly after 6 months of GH replacement therapy There is insufficient evidence to support a role of GH in regulating type I or II fibers in human skeletal muscle.

The contractile function of skeletal muscle relies on an adequate supply of chemical energy. During muscle contraction, chemical energy is converted to mechanical energy that leads to movement. Figure 5 illustrates the metabolic processes involved in energy production in muscle and the concept of energy continuum during physical activity.

In humans, chemical energy is available in the form of ATP, which is generated by two energy systems: anaerobic and aerobic 85 , The anaerobic energy system relies on preformed ATP as phosphocreatinestores or ATP production from anaerobic glycolysis, that is, breakdown of glucose in the absence of oxygen. The aerobic energy system generates ATP from oxidation of metabolic fuels such as carbohydrates, lipids, and proteins.

In the cytoplasm, glycolysis leads to the production of pyruvate. In the absence of sufficient oxygen, pyruvate is reduced to lactate, which is released into the circulation and recycled to glucose in the liver. In tissues with adequate oxygen supply, pyruvate and fatty acid are converted to acetyl coenzyme A in the mitochondria. The amount of preformed ATP present in the muscle cells is only sufficient to sustain physical activity for the first 5 to 10 seconds; thereafter, anaerobic glycolysis provides energy for a further 30 to 40 seconds, when aerobic metabolism begins to take over and provides energy for prolonged sustained activity 85 , Time course of the contributions by anaerobic and aerobic energy systems in the provision of energy as ATP during exercise.

Muscle function is dependent on the availability of metabolic fuels and its capacity to synthesize ATP. The energy synthesis from substrate utilization in exercising muscle is regulated by nutritional, genetic, and hormonal factors as well as physical training.

GH stimulates lipolysis during resting condition 89 as well as exercise 90 , leading to an increase in plasma fatty acid levels and consequently fat oxidation.

GH also increases plasma glucose concentration by augmenting glycogenolysis 91 and gluconeogenesis Thus, GH may enhance muscle function by increasing availability of fatty acids and pyruvate as metabolic fuels for energy production.

With exercise there is an increase in cardiac output and blood flow to exercising muscles. This local increase in perfusion can be substantial and it directs the supply of substrates to where they are most needed as well as helping clear lactate from the exercising muscle and transporting it to the liver for recycling into glucose the Cori cycle.

It is widely assumed that an increase in whole-body lipid oxidation reflects the action of GH on skeletal muscle. This traditional thinking was challenged by studies in rodents as well as humans, suggesting that GH action is tissue specific.

Tollet-Egnell et al. Assuming that these transcriptional changes reflect effects on protein expression, the findings suggest that GH inhibits oxidative metabolism of substrates favoring nonoxidative anaerobic pathways for ATP synthesis in skeletal muscle.

This possibility is supported by a study in trained cyclists, in which GH use was associated with increased plasma lactate levels during moderate to intense exercise compared with placebo, implying an increased rate of anaerobic disposal of pyruvate In summary, GH effects on substrate metabolism are tissue specific.

Recent evidence suggests that GH may promote nonoxidative or anaerobic substrate metabolism in skeletal muscle for ATP synthesis, findings contrary to its effects on whole-body metabolism In adults with GH deficiency given replacement doses of GH, the stimulation of whole-body protein anabolism and of lipid utilization translate into an increase of lean body mass LBM and a diminution of fat mass 6 , 7. The effects on body composition are highly reproducible and are a consistent finding in children, adults, and older people who are either GH deficient or sufficient Another meta-analysis of 44 articles describing 27 study samples in young fit adults who had received hGH reported that average LBM increased by 2.

LBM is a heterogeneous compartment comprising muscle, bone, viscera, connective tissue, and fluid distributed in the extracellular and intracellular compartments.

Most studies employ methods that do not allow the quantification of the subcomponents of the lean compartment. A review of techniques for measurement of body composition is beyond the scope of this review. Conceptually, the fat-free compartment can be divided into bone and body cell mass and extracellular fluid.

Thus, an apparent increase in lean mass can arise from an expanded extracellular fluid volume and can be erroneously interpreted as a gain in muscle mass when the fluid component is not measured or known. This is a pertinent consideration in interpreting the effects of GH because of its potent sodium and thus fluid-retaining properties In a study of recreational athletes, GH treatment of 8 weeks increased the lean mass by an average of 2.

Changes in soft tissue composition and in particular the lean component require cautious appraisal and interpretation, as the changes are unlikely always to reflect similar gains in muscle mass. Lean mass is not always muscle mass, and interpretation of data based on imaging must bear the component of tissue fluid in mind. This section reviews the outcomes of GH supplementation in athletes on four of the most common measures of physical performance: strength, power, endurance, and sprint capacity.

We provide information on the assessment methodologies and select double-blind placebo control trials for analysis, unless otherwise stated. Muscle strength is defined as maximal force in newtons or torque in newton-meters that is generated by a muscle or a group of muscles during maximal voluntary contraction Muscle strength is commonly assessed by measuring the force or torque produced during an isometric or isokinetic contraction.

There is clear evidence that long-term replacement of GH normalizes muscle strength in adults with GH deficiency who have reduced isometric and isokinetic muscle strength These studies assessed biceps strength , quadriceps strength , the strength of seven muscle groups , and isometric dead lift These studies reported no significant effect of GH on muscle strength 98 Fig.

Meta-analysis of the effect of GH treatment on muscle strength top panel and on maximum oxygen uptake Vo 2 max in placebo-controlled trials of recreational athletes. Muscle power is defined as work performed per unit of time and is expressed in joules per second or watts.

It is described in terms of aerobic and anaerobic power, depending on which energy source is predominantly used to do the work. Thus, muscle power can be assessed by measuring aerobic exercise capacity and anaerobic exercise capacity In the athletic world, it supports activities such as a marathon, football, and tennis, whereas in day-to-day life, it relates to activities such as walking.

Numerous double-blind, placebo-controlled and long-term open label trials have reported the positive effects on aerobic exercise capacity in adults with GH deficiency However, there is no convincing evidence that Vo 2 max is affected by GH treatment in healthy young adults The data indicate that GH supplementation in the doses used do not improve cardiorespiratory and muscle function in young healthy adults.

Anaerobic exercise capacity is defined as the total amount of work performed during a maximal exhausting exercise of a short duration that is powered by ATP supplied under anaerobic conditions The Wingate test, which measures maximal power output during 30 seconds by cycle ergometry, is a widely used test of anaerobic capacity.

Sporting activities that require short-term, high-intensity physical activity, such as sprinting, require considerable energy support from anaerobic ATP. All physical activities including activities of daily living also depend on anaerobic energy for initiation, for the first few seconds, before aerobic metabolism becomes the predominant energy source , Only one study has investigated the effects of GH on anaerobic exercise capacity This double-blind, placebo-controlled study in recreational athletes reported a significant improvement of 3.

When translated to proportionate time reductions, the 3. This improvement occurred without a significant change in body cell mass or in muscle strength and power jump height , suggesting that muscle anabolism is unlikely to explain the improvement in sprint capacity Fig. Jump height represents instantaneous work whereas the Wingate test involves all-out intensive exercise on a cycle ergometer for 30 seconds.

Although both tests measure anaerobic power, the energy required for jumping is drawn from phosphocreatine stores whereas that for the longer Wingate test is drawn from phosphocreatine stores and ATP derived from glycolysis. Stimulation of ATP generation from anaerobic glycolysis enhances the production of lactate. The finding of higher lactate concentrations in people undergoing evaluation of physical capacity after GH treatment provides evidence that the anaerobic energy system is stimulated by GH.

In a study by Meinhardt et al. Along with previous studies in athletes reporting that GH treatment did not improve muscle strength , or endurance , , the collective evidence indicates that GH exerts a selective ergogenic effect on sprint capacity. GH effects on physical performance in recreational athletes.

This figure illustrates the percentage change after GH or placebo treatments in 96 subjects for four measures of physical performance: Vo 2 max, strength dynamometry , jump height, and sprint capacity Wingate test. These results in athletes stand in contrast to a report by Graham et al. They observed a beneficial effect on strength, endurance, and sprint capacity compared with a similar group who did not receive GH. Conducted as an open-label study, a placebo effect see below cannot be ruled out.

The observation that GH may improve aspects of physical performance in a setting of abstinent anabolic steroid dependency requires confirmation in a blinded, placebo-controlled study. The collective published information on the performance outcomes of GH treatment are limited by the dose and duration of treatment and evaluation The dose corresponds to about twofold to threefold daily production rates in young adults.

It is possible that higher doses for longer periods may have induced a greater effect on sprint capacity or a measurable improvement in strength and endurance. Conversely, the ability to detect a small effect requires a much larger sample size. It is not known what doses are used covertly for doping and the cocktails with other substances, including anabolic steroids, nor their combined effects.

It is widely known that athletes commonly dope with a cocktail of prohibited substances and rarely with a single agent. Again, used during the off-season. Rubbed into the skin, the substance was used to offset suppression of the naturally produced testosterone caused by the use of THG.

A drug used predominantly by endurance athletes, it was injected once a week in the off-season to increase red blood cell count and oxygen-carrying ability. Injected three times a week by Chambers to aid muscle growth in the off-season.

Although primarily associated with the treatment of diabetes, Chambers used the substance after heavy weight sessions to speed up the transportation of sugar.

Chambers would take a mg tablet to boost alertness and overcome fatigue. From a medical perspective, although there may well be short-term gains in physical performance, there must also be considerable short- and long-term risks to health There may be endocrine reasons behind some stacking protocols; thus, the combined administration of GH, testosterone, and insulin is likely to have a greater effect than one component alone because physiologically they work synergistically in building and maintaining LBM 9 , Sex steroids modulate the metabolic action of GH, with estrogens inhibiting GH and androgens enhancing the effect of GH.

There is sexual dimorphism on body composition in that the gains in lean mass and loss of fat mass with GH replacement are attenuated in women In GH deficiency, the magnitude in gain of lean mass and loss of fat mass is less in women than in men for the same, if not higher, replacement dose of GH In recreational athletes, the stimulation of IGF-I and collagen proteins by the same GH dose is greater in men than in women and is amplified by coadministration of testosterone In normal men, the anabolic effects of testosterone and GH on anabolism and lipolysis are additive 56 , respectively, increasing lean mass and reducing fat mass Studies in older men have reported significant improvement in strength and endurance from combined treatment with GH and testosterone where GH alone was without significant effect , In athletes, 6 weeks of GH treatment improved sprint capacity in men, an effect that more than doubled by coadministration of testosterone Thus, there is strong evidence that testosterone enhances the action of GH.

There are no published studies investigating the impact of estrogen on physical performance during GH therapy. GH may accelerate recovery from soft-tissue injury, based on the known effects of GH on connective tissue formation, as indicated by an increase in collagen synthesis markers , In healthy young men, 14 days of GH treatment increased matrix collagen synthesis by up to sixfold in skeletal muscle and tendon The increased synthesis in muscle and tendon collagen suggests that GH could strengthen the supporting connective tissue of muscle.

There may be a psychological effect of substance administration through a placebo effect. It refers to a favorable outcome arising purely from the belief that one has received a beneficial treatment Placebo treatment can modulate pain pathways, increase endogenous opioids, and influence the neuroendocrine and immune systems Placebo treatment increases physical performance and pain endurance and reduces muscle-fatigue perception — In their double-blind, controlled study, Meinhardt et al.

All participants completed a self-evaluation questionnaire along with physical performance testing before and after 8 weeks of treatment. The questionnaire inquired whether the participants thought they were on placebo or GH treatment and what impact they thought the treatment had on their performance, without knowledge of the performance data. Mean perceived performance scores were higher for incorrect guessers compared with correct guessers; however, there was a trend to significance only for sprint capacity Fig.

For women, there were no significantly greater outcomes for those who guessed incorrectly compared with correctly. In short, athletes who thought they were on active treatment not only had a perceived improvement in performance, but also in measured physical performance. The effect was greater in men.

In conclusion, a placebo effect may contribute to perceived and actual performance-enhancing effects of GH, particularly in men However, GH treatment only imparted a beneficial effect on sprint capacity compared with placebo. Changes in measured performance in placebo-treated recreational athletes participating in a double-blind controlled study who thought they were on GH and those who thought they were on placebo. The performance measures were Vo 2 max, dead lift dynamometry, jump height, and sprint capacity Wingate test The adverse effects from GH arise from its antinatriuretic, metabolic, and growth-promoting properties Most of the acute adverse effects reported in healthy adults arise from fluid retention.

These include edema, carpal tunnel syndrome, myalgia, and arthralgias. The severity of these adverse effects may be worsened by concurrent abuse of anabolic steroids, with the magnitude of fluid retention and the development of cardiac hypertrophy and myopathy , Acromegaly is an appropriate model to gauge the potential harm of long-term GH excess.

Among the long-term complications of acromegaly are cardiac hypertrophy, cardiomyopathy, muscle weakness , , hypertension , arthropathy , , diabetes , and possible increased risk of malignancy The abuse of GH carries an increased health risk, which could be even greater when taken as a cocktail with other substances.

Simeon Williamson, who finished second to Chambers and may yet miss out on selection if UK Athletics backs down, cited Chambers as one of his sporting heroes in his profile shown on television. What noise was generated in the funereal atmosphere was also certainly in favour of Chambers.

His lawyer wants him not only to be forgiven for his deeds and comments but also to be used as some sort of role model for those aspiring to be champions.

They may all be right but, I'm sorry, I just don't buy it. Whatever Dwain, his lawyer and supporters think the sport owes him, they are just plain wrong. Over the past 10 years in particular, every time an athlete went down the route deliberately chosen by Chambers it caused far more damage to the sport and its image than any two-year ban could ever be considered recompense for.

The chance for offenders to rehabilitate should be a fundamental tenet of any civilised society but it is always a long, hard path for those who attempt to travel that way and it should never be done at the expense of others.

He will be denying some young sprinter the chance to represent Great Britain. He relates the story of a church whose carving of Christ carrying the cross was modelled on Chambers' legs. It's quite symbolic that Dwain's legs are carrying Jesus away from the cross.

Running off the cross. Symbolically that's really where we're at right now. The question now is whether, at the age of 34, Chambers can have any competitive impact on an international sprinting scene dominated by men who can post subsec times for fun. The sprinter is currently training in Jamaica, the hotbed of global sprinting these days, and Agha says Chambers is holding his own against some of the best in the world.

Whether he can convert that experience into success at London is anyone's guess. Dwain Chambers goes from pariah to mentor as opinions turn. When the sprinter challenged his Olympic ban in he was openly scorned, now he will be openly welcomed back. Dwain Chambers has gone from being viewed as a pariah to a mentor by athletics officials. Topics Dwain Chambers Drugs in sport Athletics features. Reuse this content. Government prosecutors were seeking a month prison term for Graham setting up his track athletes with banned drugs.

Jones was sentenced to six months jail on January Dwain's back on track.