105-909: β-Hydroxy β-methylbutyric acid ( HMB ), otherwise known as its conjugate base , β-hydroxy β-methylbutyrate , is a naturally produced substance in humans that is used as a dietary supplement and as an ingredient in certain medical foods that are intended to promote wound healing and provide nutritional support for people with muscle wasting due to cancer or HIV/AIDS . In healthy adults, supplementation with HMB has been shown to increase exercise-induced gains in muscle size, muscle strength, and lean body mass , reduce skeletal muscle damage from exercise, improve aerobic exercise performance, and expedite recovery from exercise. Medical reviews and meta-analyses indicate that HMB supplementation also helps to preserve or increase lean body mass and muscle strength in individuals experiencing age-related muscle loss . HMB produces these effects in part by stimulating
210-414: A buffer solution . In a buffer, a weak acid and its conjugate base (in the form of a salt), or a weak base and its conjugate acid, are used in order to limit the pH change during a titration process. Buffers have both organic and non-organic chemical applications. For example, besides buffers being used in lab processes, human blood acts as a buffer to maintain pH. The most important buffer in our bloodstream
315-537: A diagnostic biomarker , particularly in the case of metabolic disorders . The following table lists some of these disorders along with the associated HMB concentrations detected in urine or blood plasma. The first reported chemical synthesis of HMB was published in 1877 by the Russian chemists Michael and Alexander Zaytsev . HMB was isolated from the bark of Erythrophleum couminga (a Madagascan tree) in 1941 by Leopold Ružička . The earliest reported isolation of HMB as
420-469: A meta-analysis of seven randomized controlled trials , HMB supplementation can preserve or increase lean muscle mass and muscle strength in sarcopenic older adults. HMB does not appear to significantly affect fat mass in older adults. Preliminary clinical evidence suggests that HMB supplementation may also prevent muscle atrophy during bed rest . A growing body of evidence supports the efficacy of HMB in nutritional support for reducing, or even reversing,
525-411: A before and after sense. The before is the reactant side of the equation, the after is the product side of the equation. The conjugate acid in the after side of an equation gains a hydrogen ion, so in the before side of the equation the compound that has one less hydrogen ion of the conjugate acid is the base. The conjugate base in the after side of the equation lost a hydrogen ion, so in the before side of
630-462: A certain load for some number of repetitions, rests, and repeats this for some number of sets, and the volume is the product of these numbers. For non-weightlifting exercises, the load may be replaced with intensity , the amount of work required to achieve the activity. Training volume is one of the most critical variables in the effectiveness of strength training. There is a positive relationship between volume and hypertrophy. The load or intensity
735-450: A chemical is a strong acid, its conjugate base will be weak. An example of this case would be the splitting of hydrochloric acid HCl in water. Since HCl is a strong acid (it splits up to a large extent), its conjugate base ( Cl ) will be weak. Therefore, in this system, most H will be hydronium ions H 3 O instead of attached to Cl anions and the conjugate bases will be weaker than water molecules. On
840-490: A cholesterol-mediated improvement in muscle cell membrane function. HMB has been shown to stimulate the proliferation , differentiation , and fusion of human myosatellite cells in vitro , which potentially increases the regenerative capacity of skeletal muscle, by increasing the protein expression of certain myogenic regulatory factors (e.g., myoD and myogenin ) and gene transcription factors (e.g., MEF2 ). HMB-induced human myosatellite cell proliferation in vitro
945-430: A conjugate base, depending on which substance is involved and which acid–base theory is used. The simplest anion which can be a conjugate base is the free electron in a solution whose conjugate acid is the atomic hydrogen. In an acid–base reaction , an acid and a base react to form a conjugate base and a conjugate acid respectively. The acid loses a proton and the base gains a proton. In diagrams which indicate this,
1050-489: A day did not additionally increase fat–free mass (FFM), muscle size, or strength, with the caveat that "Increasing age reduces… the efficacy of protein supplementation during RET." It is not known how much carbohydrate is necessary to maximize muscle hypertrophy. Strength adaptations may not be hindered by a low-carbohydrate diet . A light, balanced meal prior to the workout (usually one to two hours beforehand) ensures that adequate energy and amino acids are available for
1155-405: A function similar to an aerobic exercise, but this is not the same as saying that a weight training set is itself an aerobic process. Strength training is typically associated with the production of lactate, which is a limiting factor of exercise performance. Regular endurance exercise leads to adaptations in skeletal muscle which can prevent lactate levels from rising during strength training. This
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#17328546277531260-525: A healthy weight. Improper form can lead to strains and fractures. Weight trainers often spend time warming up before starting a workout, a practice strongly recommended by the National Strength and Conditioning Association (NSCA). A warm-up may include cardiovascular activity such as light stationary biking (a "pulse raiser"), flexibility and joint mobility exercises, static and/or dynamic stretching, "passive warm up" such as applying heat pads or taking
1365-417: A hot shower, and workout-specific warm up, such as rehearsal of the intended exercise with no weights or light weights. The intended purpose of warming up is to enhance exercise effectiveness and reduce the risk of injury. Evidence is limited regarding whether warming up reduces injuries during strength training. As of 2015, no articles existed on the effects of warm up for upper body injury prevention. For
1470-421: A human metabolite was by Tanaka and coworkers in 1968 from a patient with isovaleric acidemia . The effects of HMB on human skeletal muscle were first discovered by Steven L. Nissen at Iowa State University in the mid-1990s . Nissen founded a company called Metabolic Technologies, Inc. (MTI) around the time of his discovery, which later acquired six HMB-related patents that the company has used to license
1575-443: A hydrogen ion in the reverse reaction. On the other hand, a conjugate base is what remains after an acid has donated a proton during a chemical reaction. Hence, a conjugate base is a substance formed by the removal of a proton from an acid, as it can gain a hydrogen ion in the reverse reaction. Because some acids can give multiple protons, the conjugate base of an acid may itself be acidic. In summary, this can be represented as
1680-411: A hydrogen ion to produce the water molecule. Also, OH can be considered as the conjugate base of H 2 O , since the water molecule donates a proton to give NH 4 in the reverse reaction. The terms "acid", "base", "conjugate acid", and "conjugate base" are not fixed for a certain chemical substance but can be swapped if the reaction taking place is reversed. The strength of a conjugate acid
1785-443: A lack of oxygen, passing out, and increased blood pressure . The general procedure of this method is to inhale when lowering the weight (the eccentric portion) and exhale when lifting the weight (the concentric portion). However, the reverse, inhaling when lifting and exhaling when lowering, may also be recommended. There is little difference between the two techniques in terms of their influence on heart rate and blood pressure. On
1890-546: A medical food and the Revigor brand of HMB as an active ingredient in food products (e.g., certain formulations of Ensure) and other medical foods (e.g., certain formulations of Juven). Conjugate base A conjugate acid , within the Brønsted–Lowry acid–base theory , is a chemical compound formed when an acid gives a proton ( H ) to a base —in other words, it is a base with a hydrogen ion added to it, as it loses
1995-540: A member of the carboxylic acid family of organic compounds . It is a structural analog of butyric acid with a hydroxyl functional group and a methyl substituent located on its beta carbon . By extension, other structural analogs include β-hydroxybutyric acid and β-methylbutyric acid . A variety of synthetic routes to β-hydroxy β-methylbutyric acid have been developed. The first reported chemical syntheses approached HMB by oxidation of alkene , vicinal diol , and alcohol precursors: Depending on
2100-539: A meta-analysis study that investigated the effects of creatine supplementation on repeated sprint ability, it was discovered that creatine increased body mass and mean power output. The creatine-induced increase in body mass was a result of fluid retention. The increase in mean power output was attributed to creatine's ability to counteract the lack of intramuscular phosphocreatine . Creatine does not have an effect on fatigue or maximum power output. As with other sports, weight trainers should avoid dehydration throughout
2205-418: A moderate or slower tempo of movement for novice- and intermediate-trained individuals, but a combination of slow, moderate, and fast tempos for advanced training. Intentionally slowing down the movement tempo of each repetition can increase muscle activation for a given number of repetitions. However, the maximum number of repetitions and the maximum possible load for a given number of repetitions decreases as
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#17328546277532310-411: A muscle group three times per week is superior to a twice-per-week protocol remains to be determined. The rest period is defined as the time dedicated to recovery between sets and exercises. Exercise causes metabolic stress, such as the buildup of lactic acid and the depletion of adenosine triphosphate and phosphocreatine. Resting 3–5 minutes between sets allows for significantly greater repetitions in
2415-553: A significantly lower training volume than a traditional exercise format with rests. However, agonist–antagonist supersets result in a significantly higher training volume when compared to a traditional exercise format. Similarly, holding training volume constant but performing upper–lower body supersets and tri-sets reduce elapsed time but increased perceived exertion rate. These results suggest that specific exercise orders may allow more intense, more time-efficient workouts with results similar to longer workouts. Periodization refers to
2520-459: A slower 3/0/3/0 tempo and 80-90% 1RM loads with a faster 1/1/1/0 tempo. It may be beneficial for both hypertrophy and strength to use fast, short concentric phases and slower, longer eccentric phases. Research has not yet isolated the effects of concentric and eccentric durations, or tested a wide variety of exercises and populations. In general, more weekly training sessions lead to higher increases in physical strength. However, when training volume
2625-461: A small contribution. Weight training is commonly perceived as anaerobic exercise, because one of the more common goals is to increase strength by lifting heavy weights. Other goals such as rehabilitation, weight loss, body shaping, and bodybuilding often use lower weights, adding aerobic character to the exercise. Except in the extremes, a muscle will fire fibres of both the aerobic or anaerobic types on any given exercise, in varying ratio depending on
2730-467: A small fraction of HMB's metabolic precursor, L -leucine , is metabolized into HMB, pharmacologically active concentrations of the compound in blood plasma and muscle can only be achieved by supplementing HMB directly. A healthy adult produces approximately 0.3 grams per day, while supplemental HMB is usually taken in doses of 3–6 grams per day. HMB is sold at a cost of about US$ 30–50 per month when taken in doses of 3 grams per day. HMB
2835-473: A static stretching protocol. Static stretching, performed either before or after exercise, also does not reduce muscle soreness in healthy adults. In weight training, as with most forms of exercise, there is a tendency for the breathing pattern to deepen. This helps to meet increased oxygen requirements. One approach to breathing during weight training consists of avoiding holding one's breath and breathing shallowly. The benefits of this include protecting against
2940-437: A study where participants consumed 2.42 grams of pure HMB-FA while fasting, the average plasma HMB concentration increased from a basal level of 5.1 μM to 408 μM after 30 minutes. At 150 minutes post-ingestion, the average plasma HMB concentration among participants was 275 μM. Abnormal HMB concentrations in urine and blood plasma have been noted in several disease states where it may serve as
3045-498: A training set. If the desired muscle group is not challenged sufficiently, the threshold of overload is never reached and the muscle does not gain in strength. At a particularly advanced level, however, "cheating" can be used to break through strength plateaus and encourage neurological and muscular adaptation. Maintaining proper form is one of the many steps in order to perfectly perform a certain technique. Correct form in weight training improves strength, muscle tone, and maintaining
3150-399: A transparent, colorless to light yellow liquid which is soluble in water. β-Hydroxy β-methylbutyric acid is a weak acid with a p K a of 4.4. Its refractive index ( n 25°C λ = 589 n m {\displaystyle {\mathit {n}}_{\text{25°C}}^{\mathrm {\lambda =589nm} }} ) is 1.42. β-Hydroxy β-methylbutyric acid is
3255-564: A typical exercise session, to determine how much fluid is lost during the workout. The greatest source of fluid loss during exercise is through perspiration, but as long as fluid intake is roughly equivalent to the rate of perspiration, hydration levels will be maintained. Under most circumstances, sports drinks do not offer a physiological benefit over water during weight training. Insufficient hydration may cause lethargy, soreness or muscle cramps . The urine of well-hydrated persons should be nearly colorless, while an intense yellow color
β-Hydroxy β-methylbutyric acid - Misplaced Pages Continue
3360-416: A year. Studies on young adults taking 6 grams of HMB per day for up to 2 months have also reported no adverse effects. Studies with supplemental HMB on young, growing rats and livestock have reported no adverse effects based upon clinical chemistry or observable characteristics; for humans younger than 18, there is limited data on the safety of supplemental HMB. The human equivalent dose of HMB for
3465-639: Is a table of common buffers. A second common application with an organic compound would be the production of a buffer with acetic acid. If acetic acid, a weak acid with the formula CH 3 COOH , was made into a buffer solution, it would need to be combined with its conjugate base CH 3 COO in the form of a salt. The resulting mixture is called an acetate buffer, consisting of aqueous CH 3 COOH and aqueous CH 3 COONa . Acetic acid, along with many other weak acids, serve as useful components of buffers in different lab settings, each useful within their own pH range. Ringer's lactate solution
3570-585: Is affected by the time that it is used relative to exercise. The greatest reduction in skeletal muscle damage from a single bout of exercise has been shown to occur when HMB-Ca is ingested 1–2 hours prior to exercise or HMB-FA is ingested 30–60 minutes prior to exercise. In 2006, only about 2% of college student athletes in the United States used HMB as a dietary supplement. As of 2017, HMB has found widespread use as an ergogenic supplement among athletes. As of 2018, HMB has not been banned by
3675-602: Is also contained in several nutritional products and medical foods marketed by Abbott Laboratories (e.g., certain formulations of Ensure and Juven ), and is present in insignificant quantities in certain foods, such as alfalfa , asparagus , avocados , cauliflower , grapefruit , and catfish . Supplemental HMB has been used in clinical trials as a treatment for preserving lean body mass in muscle wasting conditions, particularly sarcopenia , and has been studied in clinical trials as an adjunct therapy in conjunction with resistance exercise . Based upon two medical reviews and
3780-609: Is also present in insignificant quantities in certain foods, such as alfalfa , asparagus , avocados , cauliflower , grapefruit , and catfish . The effects of HMB on human skeletal muscle were first discovered by Steven L. Nissen at Iowa State University in the mid-1990s . As of 2018, HMB has not been banned by the National Collegiate Athletic Association , World Anti-Doping Agency , or any other prominent national or international athletic organization. In 2006, only about 2% of college student athletes in
3885-525: Is also sometimes called linear periodization, but this designation is considered a misnomer. Sequential or block periodization concentrates training into periods ("blocks"). For example, for athletes, performance can be optimized for specific events based on the competition schedule. An annual training plan may be divided hierarchically into several levels, from training phases down to individual sessions. Traditional periodization can be viewed as repeating one weekly block over and over. Block periodization has
3990-576: Is an example where the conjugate base of an organic acid, lactic acid , CH 3 CH(OH)CO 2 is combined with sodium, calcium and potassium cations and chloride anions in distilled water which together form a fluid which is isotonic in relation to human blood and is used for fluid resuscitation after blood loss due to trauma , surgery , or a burn injury . Below are several examples of acids and their corresponding conjugate bases; note how they differ by just one proton (H ion). Acid strength decreases and conjugate base strength increases down
4095-420: Is catalyzed by an uncharacterized enzyme which converts it to β-hydroxy β-methylbutyryl-CoA ( HMB-CoA ). HMB-CoA is metabolized by either enoyl-CoA hydratase or another uncharacterized enzyme, producing β-methylcrotonyl-CoA ( MC-CoA ) or hydroxymethylglutaryl-CoA ( HMG-CoA ) respectively. MC-CoA is then converted by the enzyme methylcrotonyl-CoA carboxylase to methylglutaconyl-CoA ( MG-CoA ), which
4200-447: Is mediated through the phosphorylation of the mitogen-activated protein kinases ERK1 and ERK2 . HMB-induced human myosatellite differentiation and accelerated fusion of myosatellite cells into muscle tissue in vitro is mediated through the phosphorylation of Akt , a serine/threonine-specific protein kinase . The free acid ( HMB-FA ) and monohydrated calcium salt ( HMB-Ca ) forms of HMB have different pharmacokinetics . HMB-FA
4305-526: Is mediated via activation of PGC-1alpha which alter the LDH (lactate dehydrogenase) isoenzyme complex composition and decreases the activity of the lactate generating enzyme LDHA, while increasing the activity of the lactate metabolizing enzyme LDHB. Supplementation of protein in the diet of healthy adults increases the size and strength of muscles during prolonged resistance exercise training (RET); protein intakes of greater than 1.62 grams per kilogram of body weight
β-Hydroxy β-methylbutyric acid - Misplaced Pages Continue
4410-451: Is metabolized after several hours, with roughly 5% ( 2–10% range) of dietary L -leucine being converted to HMB. The vast majority of L -leucine metabolism is initially catalyzed by the branched-chain amino acid aminotransferase enzyme, producing α-ketoisocaproate (α-KIC). α-KIC is mostly metabolized by the mitochondrial enzyme branched-chain α-ketoacid dehydrogenase , which converts it to isovaleryl-CoA . Isovaleryl-CoA
4515-415: Is more readily absorbed into the bloodstream and has a longer elimination half-life (3 hours) relative to HMB-Ca (2.5 hours). Tissue uptake and utilization of HMB-FA is 25–40% higher than for HMB-Ca. The fraction of an ingested dose that is excreted in urine does not differ between the two forms. After ingestion, HMB-Ca is converted to β-hydroxy β-methylbutyrate following dissociation of
4620-836: Is normally a sign of insufficient hydration. The effects of strength training include greater muscular strength, improved muscle tone and appearance, increased endurance, cardiovascular health, and enhanced bone density. Strength training also provides functional benefits. Stronger muscles improve posture , provide better support for joints , and reduce the risk of injury from everyday activities. Progressive resistance training may improve function, quality of life and reduce pain in people at risk of fracture, with rare adverse effects. Weight-bearing exercise also helps to prevent osteoporosis and to improve bone strength in those with osteoporosis. For many people in rehabilitation or with an acquired disability , such as following stroke or orthopaedic surgery, strength training for weak muscles
4725-425: Is not harmful. The speed or pace at which each repetition is performed is also an important factor in strength and muscle gain. The emerging format for expressing this is as a 4-number tempo code such as 3/1/4/2, meaning an eccentric phase lasting 3 seconds, a pause of 1 second, a concentric phase of 4 seconds, and another pause of 2 seconds. The letter X in a tempo code represents a voluntary explosive action whereby
4830-444: Is often normalized as the percentage of an individual's one-repetition maximum (1RM). Due to muscle failure, the intensity limits the maximum number of repetitions that can be carried out in one set, and is correlated with the repetition ranges chosen. Depending on the goal, different loads and repetition amounts may be appropriate: Training to muscle failure is not necessary for increasing muscle strength and muscle mass, but it also
4935-422: Is proportional to its splitting constant . A stronger conjugate acid will split more easily into its products, "push" hydrogen protons away and have a higher equilibrium constant . The strength of a conjugate base can be seen as its tendency to "pull" hydrogen protons towards itself. If a conjugate base is classified as strong, it will "hold on" to the hydrogen proton when dissolved and its acid will not split. If
5040-614: Is readily available from the aldol condensation of acetone. An organometallic approach to HMB involves the carboxylation of tert -butyl alcohol with carbon monoxide and Fenton's reagent ( hydrogen peroxide and ferrous iron ). Alternatively, HMB can be prepared through microbial oxidation of β-methylbutyric acid by the fungus Galactomyces reessii . The concentration of naturally produced HMB has been measured in several human body fluids using nuclear magnetic resonance spectroscopy , liquid chromatography–mass spectrometry , and gas chromatography–mass spectrometry methods. In
5145-418: Is subsequently converted to HMG-CoA by methylglutaconyl-CoA hydratase . HMG-CoA is then cleaved into acetyl-CoA and acetoacetate by HMG-CoA lyase or used in the production of cholesterol via the mevalonate pathway . HMB is synthesized in the human body through the metabolism of L -leucine , a branched-chain amino acid . In healthy individuals, approximately 60% of dietary L -leucine
5250-411: Is subsequently metabolized by isovaleryl-CoA dehydrogenase and converted to MC-CoA , which is used in the synthesis of acetyl-CoA and other compounds. During biotin deficiency , HMB can be synthesized from MC-CoA via enoyl-CoA hydratase and an unknown thioesterase enzyme, which convert MC-CoA into HMB-CoA and HMB-CoA into HMB respectively. A relatively small amount of α-KIC is metabolized in
5355-463: Is sufficient to maximize strength gain, compared to shorter intervals 20s-60s and longer intervals of 5 minutes. Intervals of greater than 5 minutes have not been studied. Starting at 2 minutes and progressively decreasing the rest interval over the course of a few weeks to 30s can produce similar strength gains to a constant 2 minutes. Regarding older individuals, a 1 minute rest is sufficient in females. The largest increases in strength happen for
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#17328546277535460-465: Is targeted, the focus will be on specific muscle groups used in that sport. Various exercises may target improvements in strength, speed, agility, or endurance. For other populations such as older individuals, there is little information to guide exercise selection, but exercises can be selected on the basis of specific functional capabilities as well as the safety and efficiency of the exercises. For strength and power training in able-bodied individuals,
5565-636: Is the carbonic acid-bicarbonate buffer , which prevents drastic pH changes when CO 2 is introduced. This functions as such: CO 2 + H 2 O ↽ − − ⇀ H 2 CO 3 ↽ − − ⇀ HCO 3 − + H + {\displaystyle {\ce {CO2 + H2O <=> H2CO3 <=> HCO3^- + H+}}} Furthermore, here
5670-415: The National Collegiate Athletic Association , World Anti-Doping Agency , or any other prominent national or international athletic organization. The safety profile of HMB in adult humans is based upon evidence from clinical trials in humans and animal studies . In humans, no adverse effects in young adults or older adults have been reported when HMB is taken in doses of 3 grams per day for up to
5775-441: The lactate threshold ; improve joint and cardiac function; and reduce the risk of injury in athletes and the elderly. For many sports and physical activities, strength training is central or is used as part of their training regimen. Strength training follows the fundamental principle that involves repeatedly overloading a muscle group. This is typically done by contracting the muscles against heavy resistance and then returning to
5880-519: The liver by the cytosolic enzyme 4-hydroxyphenylpyruvate dioxygenase (KIC dioxygenase), which converts α-KIC to HMB. In healthy individuals, this minor pathway – which involves the conversion of L -leucine to α-KIC and then HMB – is the predominant route of HMB synthesis. β-Hydroxy β-methylbutyric acid is a monocarboxylic β-hydroxy acid and natural product with the molecular formula C 5 H 10 O 3 . At room temperature, pure β-hydroxy β-methylbutyric acid occurs as
5985-414: The mechanistic target of rapamycin (mTOR) and subsequent activation of mTORC1 Tooltip mechanistic target of rapamycin complex 1 , which leads to protein biosynthesis in cellular ribosomes via phosphorylation of mTORC1's immediate targets (i.e., the p70S6 kinase and the translation repressor protein 4EBP1 ). Supplementation with HMB in several non-human animal species has been shown to increase
6090-417: The muscle cell membrane , thereby enhancing membrane integrity and function. The effects of HMB on muscle protein metabolism may help stabilize muscle cell structure. One review suggested that the observed HMB-induced reduction in the plasma concentration of muscle damage biomarkers (i.e., muscle enzymes such as creatine kinase and lactate dehydrogenase ) in humans following intense exercise may be due to
6195-464: The no-observed-adverse-effect level (NOAEL) that was identified in a rat model is approximately 0.4 g/kg of body weight per day. Two animal studies have examined the effects of HMB supplementation in pregnant pigs on the offspring and reported no adverse effects on the fetus. No clinical testing with supplemental HMB has been conducted on pregnant women, and pregnant and lactating women are advised not to take HMB by Metabolic Technologies, Inc. ,
6300-409: The production of proteins and inhibiting the breakdown of proteins in muscle tissue. No adverse effects from long-term use as a dietary supplement in adults have been found. HMB is sold as a dietary supplement at a cost of about US$ 30–50 per month when taking 3 grams per day. HMB is also contained in several nutritional products, including certain formulations of Ensure and Juven . HMB
6405-422: The range of motion and eccentric overload . Some bodyweight exercises do not require any equipment, and others may be performed with equipment such as suspension trainers or pull-up bars . Strength training exercise is primarily anaerobic . Even while training at a lower intensity (training loads of ~20-RM), anaerobic glycolysis is still the major source of power, although aerobic metabolism makes
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#17328546277536510-408: The serum concentration of growth hormone and insulin-like growth factor 1 (IGF-1) via an unknown mechanism, in turn promoting protein synthesis through increased mTOR phosphorylation. Based upon limited clinical evidence in humans, supplemental HMB appears to increase the secretion of growth hormone and IGF-1 in response to resistance exercise. As of 2016, the signaling cascade that mediates
6615-489: The Brønsted–Lowry theory, which said that any compound that can give a proton to another compound is an acid, and the compound that receives the proton is a base. A proton is a subatomic particle in the nucleus with a unit positive electrical charge. It is represented by the symbol H because it has the nucleus of a hydrogen atom , that is, a hydrogen cation . A cation can be a conjugate acid, and an anion can be
6720-728: The HMB-induced reduction in muscle protein breakdown has not been identified in living humans, although it is well-established that it attenuates proteolysis in humans in vivo . Unlike L -leucine , HMB attenuates muscle protein breakdown in an insulin -independent manner in humans. HMB is believed to reduce muscle protein breakdown in humans by inhibiting the 19S and 20S subunits of the ubiquitin–proteasome system in skeletal muscle and by inhibiting apoptosis of skeletal muscle nuclei via unidentified mechanisms. Based upon animal studies, HMB appears to be metabolized within skeletal muscle into cholesterol , which may then be incorporated into
6825-452: The NCSA recommends emphasizing integrated or compound movements (multi-joint exercises), such as with free weights, over exercises isolating a muscle (single-joint exercises), such as with machines. This is due to the fact that only the compound movements improve gross motor coordination and proprioceptive stabilizing mechanisms. However, single-joint exercises can result in greater muscle growth in
6930-414: The United States used HMB as a dietary supplement. As of 2017, HMB has found widespread use as an ergogenic supplement among young athletes. HMB is sold as an over-the-counter dietary supplement in the free acid form, β-hydroxy β-methylbutyric acid (HMB-FA), and as a monohydrated calcium salt of the conjugate base , calcium β-hydroxy β-methylbutyrate monohydrate (HMB-Ca, CaHMB). Since only
7035-430: The actual velocity and duration is not controlled and may be involuntarily extended as fatigue manifests, while the letter V implies volitional freedom "at your own pace". A phase's tempo may also be measured as the average movement velocity. Less precise but commonly used characterizations of tempo include the total time for the repetition or a qualitative characterization such as fast, moderate, or slow. The ACSM recommends
7140-491: The advantage of focusing on specific motor abilities and muscle groups. Because only a few abilities are worked on at a time, the effects of fatigue are minimized. With careful goal selection and ordering, there may be synergistic effects. A traditional block consists of high-volume, low-intensity exercises, transitioning to low-volume, high-intensity exercises. However, to maximize progress to specific goals, individual programs may require different manipulations, such as decreasing
7245-645: The anabolic window is not particularly narrow and protein can also be consumed before or hours after the exercise with similar effects. Glucose (or another simple sugar) is often consumed as well since this quickly replenishes any glycogen lost during the exercise period. If consuming recovery drink after a workout, to maximize muscle protein anabolism, it is suggested that the recovery drink contain glucose (dextrose), protein (usually whey ) hydrolysate containing mainly dipeptides and tripeptides, and leucine . Some weight trainers also take ergogenic aids such as creatine or anabolic steroids to aid muscle growth. In
7350-528: The anaerobic muscle fibre uses its fuel faster than the blood and intracellular restorative cycles can resupply it, the maximum number of repetitions is limited. In the aerobic regime, the blood and intracellular processes can maintain a supply of fuel and oxygen, and continual repetition of the motion will not cause the muscle to fail. Circuit weight training is a form of exercise that uses a number of weight training exercise sets separated by short intervals. The cardiovascular effort to recover from each set serves
7455-477: The blood plasma and cerebrospinal fluid (CSF) of healthy adults, the average molar concentration of HMB has been measured at 4.0 micromolar (μM). The average concentration of HMB in the intramuscular fluid of healthy men of ages 21–23 has been measured at 7.0 μM. In the urine of healthy individuals of any age, the excreted urinary concentration of HMB has been measured in a range of 0–68 micromoles per millimole (μmol/mmol) of creatinine . In
7560-431: The breast milk of healthy lactating women, HMB and L -leucine have been measured in ranges of 42–164 μg/L and 2.1–88.5 mg/L. In comparison, HMB has been detected and measured in the milk of healthy cows at a concentration of <20–29 μg/L. This concentration is far too low to be an adequate dietary source of HMB for obtaining pharmacologically active concentrations of the compound in blood plasma. In
7665-543: The calcium moiety in the gut. When the HMB-Ca dosage form is ingested, the magnitude and time at which the peak plasma concentration of HMB occurs depends on the dose and concurrent food intake. Higher HMB-Ca doses increase the rate of absorption , resulting in a peak plasma HMB level ( C max ) that is disproportionately greater than expected of a linear dose-response relationship and which occurs sooner relative to lower doses. Consumption of HMB-Ca with sugary substances slows
7770-522: The care of a doctor in individuals with muscle wasting due to HIV/AIDS or cancer , to promote wound healing following surgery or injury, or when otherwise recommended by a medical professional. Juven, a nutrition product which contains 3 grams of HMB-Ca , 14 grams of L -arginine , and 14 grams of L -glutamine per two servings, has been shown to improve lean body mass during clinical trials in individuals with AIDS and cancer, but not rheumatoid cachexia . Further research involving
7875-422: The company that grants licenses to include HMB in dietary supplements, due to a lack of safety studies. Several components of the signaling cascade that mediates the HMB-induced increase in human skeletal muscle protein synthesis have been identified in vivo . Similar to HMB's metabolic precursor , L -leucine , HMB has been shown to increase protein synthesis in human skeletal muscle via phosphorylation of
7980-537: The effects of HMB on muscle strength and lean body mass are limited. HMB affects muscle size, strength, mass, power, and recovery in part by stimulating myofibrillar muscle protein synthesis and inhibiting muscle protein breakdown through various mechanisms, including the activation of mechanistic target of rapamycin complex 1 (mTORC1) and inhibition of proteasome -mediated proteolysis in skeletal muscles. The efficacy of HMB supplementation for reducing skeletal muscle damage from prolonged or high-intensity exercise
8085-522: The equation, the compound that has one more hydrogen ion of the conjugate base is the acid. Consider the following acid–base reaction: Nitric acid ( HNO 3 ) is an acid because it donates a proton to the water molecule and its conjugate base is nitrate ( NO 3 ). The water molecule acts as a base because it receives the hydrogen cation (proton) and its conjugate acid is the hydronium ion ( H 3 O ). One use of conjugate acids and bases lies in buffering systems, which include
8190-421: The exercises in the beginning of a session. Supersets are defined as a pair of different exercise sets performed without rest, followed by a normal rest period. Common superset configurations are two exercises for the same muscle group, agonist-antagonist muscles, or alternating upper and lower body muscle groups. Exercises for the same muscle group (flat bench press followed by the incline bench press) result in
8295-436: The experimental conditions, cycloaddition of acetone and ketene produces either β-isovalerolactone or 4,4-dimethyloxetan-2-one, both of which hydrolyze under basic conditions to yield the conjugate base of HMB. The haloform reaction provides another pathway to HMB involving the exhaustive halogenation of the methyl-ketone region of diacetone alcohol with sodium hypobromite or sodium hypochlorite ; Diacetone alcohol
8400-471: The following chemical reaction : acid + base ↽ − − ⇀ conjugate base + conjugate acid {\displaystyle {\text{acid}}+{\text{base}}\;{\ce {<=>}}\;{\text{conjugate base}}+{\text{conjugate acid}}} Johannes Nicolaus Brønsted and Martin Lowry introduced
8505-417: The intense bout of exercise. The type of nutrients consumed affects the response of the body, and nutrient timing whereby protein and carbohydrates are consumed prior to and after workout has a beneficial impact on muscle growth. Water is consumed throughout the course of the workout to prevent poor performance due to dehydration . A protein shake is often consumed immediately following the workout. However,
8610-551: The intensity and increasing volume. Undulating periodization is an extension of block periodization to frequent changes in volume and intensity, usually daily or weekly. Because of the rapid changes, it is theorized that there will be more stress on the neuromuscular system and better training effects. Undulating periodization yields better strength improvements on 1RM than non-periodized training. For hypertrophy, it appears that daily undulating periodization has similar effect to more traditional models. A training split refers to how
8715-436: The lifter will have more strength and stamina since the blood has begun to flow to the muscle groups. Pulse raisers do not have any effect on either 1RM or submaximal training. Static stretching induces strength loss, and should therefore probably not be performed before strength training. Resistance training functions as an active form of flexibility training, with similar increases in range of motion when compared to performing
8820-529: The lifting of weights . It can also incorporate a variety of training techniques such as bodyweight exercises , isometrics , and plyometrics . Training works by progressively increasing the force output of the muscles and uses a variety of exercises and types of equipment . Strength training is primarily an anaerobic activity, although circuit training also is a form of aerobic exercise . Strength training can increase muscle , tendon , and ligament strength as well as bone density , metabolism , and
8925-428: The load on the intensity of the contraction. This is known as the energy system continuum. At higher loads, the muscle will recruit all muscle fibres possible, both anaerobic ("fast-twitch") and aerobic ("slow-twitch"), to generate the most force. However, at maximum load, the anaerobic processes contract so forcefully that the aerobic fibers are completely shut out, and all work is done by the anaerobic processes. Because
9030-441: The loss of muscle mass, muscle function , and muscle strength that occurs in hypercatabolic disease states such as cancer cachexia ; consequently, the authors of two 2016 reviews of the clinical evidence recommended that the prevention and treatment of sarcopenia and muscle wasting in general include supplementation with HMB, regular resistance exercise, and consumption of a high-protein diet . Clinical trials that used HMB for
9135-882: The lower limbs, several programs significantly reduce injuries in sports and military training, but no universal injury prevention program has emerged, and it is unclear if warm ups designed for these areas will also be applicable to strength training. Static stretching can increase the risk of injury due to its analgesic effect and cellular damage caused by it. The effects of warming up on exercise effectiveness are clearer. For 1RM trials, an exercise rehearsal has significant benefits. For submaximal strength training (3 sets of 80% of 1RM to failure), exercise rehearsal does not provide any benefits regarding fatigue or total repetitions for exercises such as bench press, squats, and arm curl, compared to no warm-up. Dynamic warm-ups (performed with greater than 20% of maximal effort) enhance strength and power in upper-body exercises. When properly warmed up
9240-557: The neurological aspects of strength, the ability of the brain to generate a rate of neuronal action potentials that will produce a muscular contraction that is close to the maximum of the muscle's potential. </ref> Strength training also requires the use of proper or ' good form ', performing the movements with the appropriate muscle group, and not transferring the weight to different body parts in order to move greater weight (called ' cheating '). An injury or an inability to reach training objectives might arise from poor form during
9345-444: The new bond formed between the base and the proton is shown by an arrow that starts on an electron pair from the base and ends at the hydrogen ion (proton) that will be transferred: [REDACTED] In this case, the water molecule is the conjugate acid of the basic hydroxide ion after the latter received the hydrogen ion from ammonium . On the other hand, ammonia is the conjugate base for the acidic ammonium after ammonium has donated
9450-514: The next set versus resting 1–2 minutes. For untrained individuals (no previous resistance training experience), the effect of resting on muscular strength development is small and other factors such as volitional fatigue and discomfort, cardiac stress, and the time available for training may be more important. Moderate rest intervals (60-160s) are better than short (20-40 s), but long rest intervals (3–4 minutes) have no significant difference from moderate. For trained individuals, rest of 3–5 minutes
9555-455: The organization of training into sequential phases and cyclical periods, and the change in training over time. The simplest strength training periodization involves keeping a fixed schedule of sets and reps (e.g. 2 sets of 12 reps of bicep curls every 2 days), and steadily increasing the intensity on a weekly basis. This is conceptually a parallel model, as several exercises are done each day and thus multiple muscles are developed simultaneously. It
9660-512: The other hand, for people working with extremely heavy loads (such as powerlifters ), breathing à la the Valsalva maneuver is often used. This involves deeply inhaling and then bracing down with the abdominal and lower back muscles as the air is held in during the entire rep. Air is then expelled once the rep is done, or after a number of reps is done. The Valsalva maneuver leads to an increase in intrathoracic and intra-abdominal pressure. This enhances
9765-462: The other hand, if a chemical is a weak acid its conjugate base will not necessarily be strong. Consider that ethanoate, the conjugate base of ethanoic acid, has a base splitting constant (Kb) of about 5.6 × 10 , making it a weak base. In order for a species to have a strong conjugate base it has to be a very weak acid, like water. To identify the conjugate acid, look for the pair of compounds that are related. The acid–base reaction can be viewed in
9870-421: The rate of HMB absorption, resulting in a lower peak plasma HMB level that occurs later. HMB is eliminated via the kidneys , with roughly 10–40% of an ingested dose being excreted unchanged in urine. The remaining 60–90% of the dose is retained in tissues or excreted as HMB metabolites. The fraction of a given dose of HMB that is excreted unchanged in urine increases with the dose. The metabolism of HMB
9975-433: The right to manufacture and incorporate HMB into dietary supplements. When it first became available commercially in the late 1990s, HMB was marketed solely as an exercise supplement to help athletes and bodybuilders build muscle. MTI subsequently developed two HMB-containing products, Juven and Revigor, to which Abbott Nutrition obtained the market rights in 2003 and 2008 respectively. Since then, Abbott has marketed Juven as
10080-411: The starting position. This process is repeated for several repetitions until the muscles reach the point of failure. The basic method of resistance training uses the principle of progressive overload , in which the muscles are overloaded by working against as high resistance as they are capable of. They respond by growing larger and stronger. Beginning strength-trainers are in the process of training
10185-504: The structural integrity of the torso—protecting against excessive spinal flexion or extension and providing a secure base to lift heavy weights effectively and securely. However, as the Valsalva maneuver increases blood pressure, lowers heart rate, and restricts breathing, it can be a dangerous method for those with hypertension or for those who faint easily. Training volume is commonly defined as sets × reps × load. That is, an individual moves
10290-401: The table. In contrast, here is a table of bases and their conjugate acids. Similarly, base strength decreases and conjugate acid strength increases down the table. Resistance exercise Strength training , also known as weight training or resistance training , involves the performance of physical exercises that are designed to improve physical strength . It is often associated with
10395-744: The targeted muscles, and are more suitable for injury prevention and rehabilitation. Low variation in exercise selection or targeted muscle groups, combined with a high volume of training, is likely to lead to overtraining and training maladaptation. Many exercises such as the squat have several variations. Some studies have analyzed the differing muscle activation patterns, which can aid in exercise selection. Commonly used equipment for resistance training include free weights—including dumbbells , barbells , and kettlebells — weight machines , and resistance bands . Resistance can also be generated by inertia in flywheel training instead of by gravity from weights, facilitating variable resistance throughout
10500-474: The tempo is slowed. Some trainers calculate training volume using the time under tension (TUT), namely the time of each rep times the number of reps, rather than simply the number of reps. However, hypertrophy is similar for a fixed number of repetitions and each repetition's duration varying from 0.5 s - 8 s. There is however a marked decrease in hypertrophy for "very slow" durations greater than 10 s. There are similar hypertrophic effects for 50-60% 1RM loads with
10605-410: The trainee divides and schedules their training volume, or in other words which muscles are trained on a given day over a period of time (usually a week). Popular training splits include full body, upper/lower, push/pull/legs, and the "bro" split. Some training programs may alternate splits weekly. Exercise selection depends on the goals of the strength training program. If a specific sport or activity
10710-813: The treatment of cancer cachexia with Juven over a period of several months is required to adequately determine treatment efficacy. With an appropriate exercise program, dietary supplementation with 3 grams of HMB per day has been shown to increase exercise-induced gains in muscle size, muscle strength and power, and lean body mass, reduce exercise-induced skeletal muscle damage, and expedite recovery from high-intensity exercise. Based upon limited clinical research, HMB supplementation may also improve aerobic exercise performance and increase gains in aerobic fitness when combined with high-intensity interval training . These effects of HMB are more pronounced in untrained individuals and athletes who perform high intensity resistance or aerobic exercise. In resistance-trained populations,
10815-645: The treatment of muscle wasting have involved the administration of 3 grams of HMB per day under different dosing regimens. According to one review, an optimal dosing regimen is to administer it in one 1 gram dose, three times a day, since this ensures elevated plasma concentrations of HMB throughout the day; however, as of 2016 the best dosing regimen for muscle wasting conditions is still being investigated. Some branded products that contain HMB (i.e., certain formulations of Ensure and Juven) are medical foods that are intended to be used to provide nutritional support under
10920-472: The workout by drinking sufficient water. This is particularly true in hot environments, or for those older than 65. Some athletic trainers advise athletes to drink about 7 imperial fluid ounces (200 mL) every 15 minutes while exercising, and about 80 imperial fluid ounces (2.3 L) throughout the day. However, a much more accurate determination of how much fluid is necessary can be made by performing appropriate weight measurements before and after
11025-446: Was equalized, training frequency had no influence on muscular strength. In addition, greater frequency had no significant effect on single-joint exercises. There may be a fatigue recovery effect in which spreading the same amount of training over multiple days boosts gains, but this has to be confirmed by future study. For muscle growth, a training frequency of two sessions per week had greater effects than once per week. Whether training
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