Accelerated Muscular Development Programs
High-intensity exercise requires energy utilization rates that exceed the oxidative capabilities of the muscle. Activities such as sprinting require the anaerobic resynthesis of ATP to produce and maintain high levels of muscular force and are therefore limited in duration. Strength training also relies heavily on anaerobic energy sources and requires high force production by specific muscle groups. Adaptations to High-Intensity Exercise and Strength Training The main alterations that occur in response to regular high-intensity exercise or strength training are improvements in the structure and function of the neuromuscular system that allow more efficient production of the forces required for these activities and an enhanced ability to produce the energy required through anaerobic processes. The maximum force a muscle can exert is largely determined by its cross-sectional area. In addition to the neural adaptations, strength training stimulates an increase in muscle size. This...
Seven studies - four RCTs and three non-randomized studies - have shown that strength training improves skeletal muscle strength and endurance in clinically stable coronary patients.6 In the majority of these studies, weight training was added as a strength training component to the exercise regimens of coronary patients, who had already participated in aerobic exercise training for 3 months or more. Documented benefits occurred with both low and high resistance training. Weight carrying tolerance (time) or
Resistance exercise (RE) incorporates all types of strength and weight training and will lead to improvements in both muscle strength and endurance. RE has many proven health benefits, including increases in lean muscular mass, and it has been shown to complement aerobic exercise in the maintenance of basal metabolic rate, important for weight management (Pollock, et al., 2000). In addition, RE can reduce the risk of falling by improving muscular strength and balance (ACSM, 2001). Favourable effects on bone density are associated with resistance exercise (Bjarnason-Wehrens, et al., 2004). Many women in CR, if they are older, will be post-menopausal, and for this group prevention and treatment of osteoporosis are added benefits. The incidence of coronary heart disease increases with age and after the menopause (BHFS, 2004). This coincides with an age-related decline in muscular strength and fat-free mass after the age of 50 (ACSM, 2001). RE has been shown to prevent decline in muscle...
Cell fusion occurs spontaneously under appropriate conditions in vivo, as well as in vitro, and in vivo can be a normal physiological process during the development of several organs and tissues. For example, myoblast-myoblast and myoblast-myotube fusions occur as part of normal skeletal muscle development, and fusion of trophoblast cells to form the giant cells occurs in the development of the placenta. Recent genetic studies in Drosophila and Caenorhabditis elegans have determined some of the genes required for these developmental fusion events.
Ideals of physical attractiveness include defined musculature and smooth (closely cut) hair for men, and smooth skin, beautifully arranged hair, and a full figure for women. Extreme slimness is taken as a sign of illness (translated into English as looking dry ) for both sexes. Both men and women are also admired for their ability to work hard, govern their emotions, and use discretion.
Anatomy classifies muscles into functional groups (flexors extensors, abductors adductors, etc.) based on hypothesized actions. These muscle groups are useful general classifications and are commonly used in fitness education, weight training, and rehabilitation. These hypothesized muscle actions in movements and exercises are used to judge the relevance of various exercise training or rehabilitation programs. This section will show that such qualitative estimations of muscle actions are often incorrect. Similarly, many of the muscle actions hypothesized by coaches and thera Given these many examples of the complexity of muscle actions at the macro and microscopic levels, the hypothesized muscle actions from functional anatomy in many human movements should be interpreted with caution. Seemingly simple questions of what muscles contribute most to walking, jumping, or any movement represent surprisingly complex biomechanical issues. For example, should the word eccentric be used as an...
Unfortunately, athletes are often stereotyped as dumb jocks with gifted physical abilities. How much of movement ability do physical characteristics like muscular strength, speed, and coordination contribute to performance compared to neu-romuscular abilities (a good motor brain) Think about the ability your favorite athlete would have if he she had a stroke that affected part of their motor cortex. In training and conditioning there are several areas of research where there is evidence that the effects of training on muscle activation by the central nervous system is underrated. First, it is well known that the majority of the initial gains in strength training (first month) are related to the neural drive rather than hypertrophy (see Sale 1992). Second, it is known that both normal and injured subjects are not usually able to achieve true maximum muscle force in a maximal voluntary contraction. This is called muscle inhibition and is studied using an electrical stimulation method...
People are attracted to others for a variety of reasons, and there are many different kinds of attraction. One generalization concerning interpersonal attraction is the reward theory, which states that we like people whose behavior provides us with maximum reward at minimum cost. The gain-loss theory suggests that increases in positive, rewarding behavior from another person will have more impact on an individual than constant, invariant reward from that person. Thus, if one considers being liked as a reward, a person whose liking for us increases over time will be liked more than one who has always liked us. Four other theories principles that describe interpersonal attraction are similarity, beauty physical appearance, proximity, and social exchange. The similarity-attraction theory suggests that we like other people whose attitudes, values, and beliefs appear to be similar to our own (cf., matching hypothesis -holds that one tends to interact with, and be...
Strength and conditioning professionals closely monitor training technique, because body position and motion in exercises dramatically affect muscular actions and risk of injury. In strength training, resistances are near maximal, so coordination in most exercises tends to be simultaneous. Imagine someone performing a squat exercise with a heavy weight. Is the safest technique to simultaneously flex the hips and knees in the eccentric phase and then simultaneously extend in the concentric phase If the resistance is lighter (body-
For nearly two hundred years, the phenomenon of the double-muscled animal, a spectacular model of muscular hypertrophy, has intrigued both livestock producers and scientists. Though livestock other than cattle produce double-muscled individuals, recent characterization of the protein myostatin, a specific inhibitor of muscle cell growth, has rekindled interest in the condition.1-1-1 Myo-statin gene mutations are the genetic and biochemical basis for one form of muscular hypertrophy in the bovine and advances in biotechnology have shown new means to exploit the gene involved. One property that sustained interest in the mutation-causing double muscling is the easily recognizable extreme phenotype of the myostatin-null individual. Myostatin knockout mice are characterized by bulging muscular development, with the most extreme hypertrophy apparent in the shoulders and hindquarters. Double-muscled cattle are even more easily discernable than their murine counterparts. The double-muscled...
Acquired neuromyotonia is a rare disorder characterized by widespread muscle twitching (myokymia) and cramps, sometimes associated with muscle hypertrophy, stiffness, weakness, increased sweating and central effects. Onset can be from adolescence to old age. There is an association with thymoma, with myasthenia gravis, and probably also with lung cancer.
Partially frozen meat chunks or blocks are flaked by using a rotating cutting head. The machine has a circular cutting head and the meat is pushed close to the knives by centrifugal force. The size of the flakes is determined by the spacing in the cutting head. This eliminates the mechanical squeezing of the muscle fibers exerted in a conventional grinder, which results in higher moisture loss from the muscle (lean muscle contain about 70 moisture). The meat obtained from the flaker can be easily used in restructured meat products where a musclelike texture is reconstructed from small pieces of meat.
More recently, an insulin-like growth factor-I (IGF-I) transgene has been used to produce transgenic pigs with enhanced muscle development and reduced fat in the carcass, but the transgene did not improve growth rate or feed efficiency. In contrast to the GH transgenic pigs, definitive phenotypes for the IGF-I transgenic pigs were not detected, and no gross abnormalities, pathologies, or health-related problems were encountered. 3
The clinical sign common to all neuromuscular diseases in the cat is weakness. The affected cat is frequently 'floppy', often with ventroflexion of the neck and reduced muscle tone (Figure 7.20). Muscle atrophy is expected, but in some dystrophies (e.g. myotonia and X-linked dystrophy), muscle hypertrophy is present. The severity of the weakness may be variable and muscle involvement can be focal. Skeletal muscle hypertrophy with possible complications sensitivity to stress stiff gait
Plyometrics are common exercises for improving speed and muscular power movements in athletes. Plyometric exercises use weights, medicine balls, and falls to exaggerate stretch-shortening-cycle muscle actions. Considerable research has focused on drop jumps as a lower-body plyometric exercise for improving jumping ability (Bobbert, 1990). Recent research has shown that drop jump exercise programs can increase bone density in children (Fuchs, Bauer, & Snow, 2001). Qualitative analysis of drop jumps is important in reducing the risk of injury in these exercises and monitoring technique that has been observed to vary between subjects (Bobbert et al., 1986). Qualitative analysis is also important because drop jumping and resistance training can affect the technique used in various jumping movements (Hunter & Marshall, 2002). Table 11.2 presents important technique points and cues for drop jumps.
Muscles can create high tensions to initiate motion, but as the speed of shortening increases their ability to create force (maintain acceleration) decreases. Second, the force potential of muscles at small speeds of motion (in the middle of the graph) depends strongly on isometric muscular strength (Zatsiorsky & Kraemer, 2006). This means that muscular strength will be a factor in most movements, but this influence will vary depending on the speed and direction (moving or braking) the muscles are used. Third, the inverse relationship between muscle force and velocity of shortening means you cannot exert high forces at high speeds of shortening, and this has a direct bearing on muscular power. In chapter 6 we will study mechanical power and look more closely at the right mix of force and velocity that creates peak muscular power output. This also means that isometric strength and muscle speed are really two different muscular abilities. Athletes training to...
Analysis of the changes in gene expression pattern associated with biological processes is critical to understand gene function. The recent development of powerful high-throughput differential gene expression techniques allows simultaneous detection of differential expressions of tens of thousands of genes in a single experiment1-5-1 (Table 1). Among commonly used techniques, DNA microarray has attracted tremendous interest among biologists since its introduction in 1995. 2-5 Utilizing a simultaneous two-color hybridization scheme, DNA microarray promises sensitive, quantitative monitoring of gene expression profiles on the whole genome scale. Such a tool has been applied to farm animal research for studying reproduction, muscle development, fat deposition, nutrient utilization, and disease resistance for all major livestock species. 2-4 Hundreds of putatively important genes have been identified and their biological functions are being confirmed.
Unlike the dietary approaches mentioned above, increased attention to exercise has been related not only to enhanced short-term weight loss, but also long-term weight loss. In fact, the benefit of exercise has been particularly effective in the long term. Recent research has focused on type of exercise that may produce the best weight losses. In 1995, R.E. Anderson and colleagues found no differences in treatment programs using aerobic exercise, resistance training (weight lifting), or the combination of aerobic exercise and resistance training (although all yielded significant weight losses). In 1985, Leonard Epstein and colleagues reported that lifestyle exercise (e.g., using stairs instead of an elevator), produced somewhat more weight loss in children than did aerobic exercise, although both of these types of exercise promoted far better weight maintenance than did calisthenics. Similarly, in 1995, these researchers found that children who were taught to decrease sedentary...
Dystrophin-deficient kittens cannot be differentiated from healthy kittens at birth, although they have a slower growth rate than their normal littermates. Appendicular muscular hypertrophy is evident at around 10 weeks of age, and is followed by hypertrophy in the axial musculature, especially the cervical muscles. White nodules consisting of dystrophic calcifications may appear on the edges of the enlarged tongue and disappear spontaneously a few weeks later (Figure 7.21). Cats with HFMD have a slightly stilted gait, and they 'bunny hop' when they run. Occasionally, the gait is more abnormal, with marked stiffness and reluctance to move, probably associated with episodes of increased muscle fibre necrosis. Figure 7.21 An adult dystrophin deficient cat with muscular hypertrophy and hypertrophy of the tongue. (Courtesy of F. Gaschen.) Figure 7.21 An adult dystrophin deficient cat with muscular hypertrophy and hypertrophy of the tongue. (Courtesy of F. Gaschen.)
CARDIAC LESIONS CONGENITAL AND ACQUIRED Infants with history of BPD may present with mild illness with rapid deterioration. Prolonged mechanical ventilation in the neonatal period causes smooth muscle hypertrophy and pulmonary hypertension, leading to cardiac disease. It may be necessary to distinguish pulmonary edema as a cause of wheezing usually a history of diuretic use will aid in diagnosis. Congenital heart lesions causing congestive heart failure will also present with wheezing that may have been mistaken for asthma, exacerbated by concurrent viral infection. Other clues such as feeding difficulties, failure to thrive, hepatosplenomegaly, genetic syndromes, and radiographs revealing abnormal cardiac silhouettes point to a cardiac etiology. Workup to exclude viral myocarditis should be considered in the previously well child.
A member of the transforming growth factor-beta superfamily. Myostatin is an inhibitor of skeletal muscle development, and defects in this growth factor lead to increases in myoblast proliferation and subsequent increases in muscle fiber number that characterize the double-muscled condition of cattle. This again illustrates the important effects of fetal development on postnatal growth.
You have just met a member of the opposite sex, whom you find extremely attractive. This person appears to enjoy your company, compliments your physical attractiveness, and after a few minutes of conversation, suggests that you should meet again, so that you can spend more time together . It becomes obvious that you have both been flirting with each other, and that an intimate acquaintance is a very real possibility.
The fact that poultry meat is considered to be a source of lean meat and has a higher level of unsaturated fat as compared with red meat has resulted in a significant increase in poultry meat consumption in North America (Table 1) and around the world. Overall, the composition of poultry meat is dependent on species, strain, sex, age, and diet. Table 4 illustrates that species vary in their fat content. Turkey meat is usually lower in fat than chicken, while goose and duck meat are higher in fat. In poultry fat is deposited either under the skin or in the abdominal cavity. Therefore it is easy to obtain very lean poultry meat by separating the skin from the flesh. This is different from red meat where marbling or intramuscular fat deposits are visible within a meat cut and are difficult to separate from the lean muscle. The diet of the monogastric birds can also significantly affect the composition of the meat. Carcass fat content and composition is particularly sensitive to the type...
Protein plays a satiety, thermogenic and lean muscle preservation role during weight loss. Skov et al. (1999) compared a control group to two treatment groups that consumed either a high carbohydrate and low protein (12 energy) diet or a high protein (25 energy) and low carbohydrate diet. Both groups were on reduced fat diets and obtained 30 of their energy from fat. Foods that had the desirable protein, carbohydrate and fat levels were designated for each group. Each group consumed the various food products 'ad libitum'. After a six-month time period the high protein group lost more (8.7 kg) than the high carbohydrate group (5.0 kg). Part of the difference was attributed to a protein satiety effect. The high protein group consumed less food energy (9.3 MJ day) compared to the high carbohydrate group (11.2 MJ day). It was also pointed out that the thermogenic effect of protein is much higher than carbohydrate (30 versus 4-8 ) resulting in more calories being 'burned' when protein is...
Young children, aged 3 mo to 2 yr, are usually found in an adult bed or their own crib bed (117). One study showed that wedging was seen primarily in 3- to 6-mo-old children (117). At this stage, infants have the capability to move to the corners of beds and cribs, but they do not have the muscle development to be able to extricate themselves out of a wedged position. They become wedged between the mattress and
1.2-1.4 g kg-1 day-1, whereas athletes engaged in strength and power training may need as much as 1.6-1.7gkg-1 day-1. In strength and power sports such as weightlifting, sprinting, and bodybuilding, the use of high-protein diets and protein supplements is especially prevalent, and daily intakes in excess of 4gkg-1 are not unusual. Scientific support for such high intakes is generally lacking, but those involved in these sports are adamant that such high levels of intake are necessary, not only to increase muscle mass, but also to maintain muscle mass. This apparent inconsistency may be explained by Millward's adaptive metabolic demand model, which proposes that the body adapts to either high or low levels of intake, and that this adjustment to changes in intake occurs only very slowly.
Adolescence is a unique time of rapid growth, with half of eventual adult weight and 45 of peak bone mass accumulated during adolescence. Adolescence is a time when peak physical muscular development and exercise performance is reached. However, adolescent diets are often notorious for their reliance on snacks and 'junk foods' that are high in calories, sugar, salt, and saturated fat, which could provide extra energy for high-activity demands of teenagers, but often risk becoming part of bad habits leading to obesity and increased risk of atherosclerotic heart disease in later life. Although most studies have been on older subjects, it is now clear that many Western diseases, especially heart disease, stroke, diabetes, hypertension, and many cancers, are diet related, and that diets high in saturated fat and low in fruits, vegetables, and fiber may increase risks of heart disease.
Transcription factors in the MyoD muscle regulatory factor (MRF) family are responsible for muscle development and, when expressed, can induce myogenesis in nonmyogenic cell types. 4 Avian, bovine, and porcine studies have shown that MyoD and myogenin expression precede myotube formation. Muscle from double-muscled cattle expresses higher levels of MyoD and myostatin reflecting the importance of these factors in inhibiting proliferation. The interaction of various transcription factors is also key in regulating cell differentiation as shown by the myostatin-induced Smad3 phosphorylation and interaction with MyoD, which inhibits differentiation in cultured cells. Myostatin is also a potent inhibitor of Pax-3 and Myf-5, which are associated with proliferation, whereas follistatin promotes Pax3-enhanced proliferation in muscle. Alternatively, some transcription factors are involved in cellular processes other than terminal differentiation.
Many human male-female physical differences are immediately obvious compared with women, men on average have more upper-body strength and muscular development, larger jaws, and heavier brow ridges. Women have breasts and hips. Less obvious in some cultures, men have penises and testes, and women have clitora, labia, and vaginas. Many of these differences have obvious selective relevance and reflect our evolutionary history. Women's wider hips (as well as hormonal shifts in childbirth) facilitate giving birth permanently enlarged breasts appear to have evolved in the context of sexual selection (Low, 2000 Low, Alexander, & Noonan, 1987 Mealey, 2000). Men's heavier facial features, versus women's more neotenic faces, appear to relate to sexual selection and mate choice (review in Buss, 1999).
Important to the study of sex differences. In his book The Evolution of Desire, Buss (1994) outlined the different mate choice preferences of men and women. Buss and colleagues (Buss, Shackleford, Kirkpatrick, & Larsen, 2001) assessed and compared mate preferences in different regions of the United States over a span of several years (1939-1996). Several consistent sex differences were identified, with men, for example, valuing physical attractiveness more than women and women valuing a pleasing disposition and social status more than men. Other preferences (e.g., men's preference for chastity) varied across time or location.
Strength training resistances are often expressed as percentages of maximum strength (1RM). If loads on the muscu-loskeletal system were also expressed as percentages of mechanical strength, what training loads do you think would be safe (acceptable risk) or unsafe (unacceptable risk) 9. Which is most important in selecting weight training resistances training studies or biomechanical tissue tolerances Why
In strength and power sports such as weightlifting, sprinting and bodybuilding, the use of high-protein diets and protein supplements is especially prevalent, and daily intakes in excess of 2-4 g-1 kg-1 are not unusual. Scientific support for such high intakes is generally lacking, but those involved in these sports are adamant that such high levels of intake are necessary, not only to increase muscle mass but also to maintain muscle mass. This apparent inconsistency may be explained by Millward's adaptive metabolic demand model, which proposes that the body adapts to either high or low levels of intake, and that this adjustment to changes in intake occurs only very slowly. This means that individuals such as strength and power athletes who consume a highprotein diet over many years will find that any reduction in protein intake will result in a loss of muscle mass. This is because of an upregulation of the activity of the enzymes involved in protein oxidation to cope with the high...
The training load of athletes varies greatly between individuals, depending on the nature of the sport and the level of competition, and it also varies over time in relation to the competitive season. Training may consist of high-intensity resistance training, brief but intense sprints, prolonged moderate intensity efforts, or technical work. Each places different demands on the muscles, cardiovascular system, and other tissues, and each has different energy requirements. The aim of training is to induce changes in body tissues and organs that will improve exercise performance, but different adaptations are required in different sports. Increasing muscle mass, strength, and power is a key objective in many sports, but in other sports, these changes would hinder, rather than help, performance. The training stimulus, therefore, must be specific to the objectives of the event. Within limits, the greater the training stimulus - consisting of the intensity, duration and
A well-rounded exercise program should include both muscular strength training and joint flexibility exercises in order to improve one's ability to perform tasks and to reduce the potential for injury.3'5 Upper extremity and resistance (strength) training can improve muscle function and evidence suggests that there may be cardiovascular benefit in older patients and those with underlying CVD. This area, however, is rather new and further evidence is needed before recommendations can be made to the public. While these recommendations are especially important for elderly people, persons who have been deconditioned due to recent inactivity or illness may benefit as well. People who are already physically active will benefit even more by increasing intensity or duration of their activity. These recommendations are intended primarily for the healthy sedentary population.5
In the UK, aerobic circuit interval training for group exercise training is commonly used and is an effective method for delivering aerobic exercise (SIGN, 2002). In addition to the aerobic conditioning phase, resistance training is part of CR exercise. Home-based exercise is also prescribed with self-monitoring skills being used by the patients. Typically an exercise class consists of a warm-up, an aerobic conditioning phase, a cool-down period and a conditioning phase. The exercise programme should be tailored to the needs of the patient.The latter is important to encourage adherence to exercise. Details regarding the exercise component of CR are provided in Chapters 3-5.
There is some dispute as to when coronary heart disease patients should commence an RE programme. There is general consensus that patients should complete a period of aerobic exercise prior to initiating resistance training. The ACSM (2001) and SIGN (2002) recommend a period of four to six weeks' aerobic acclimatisation. This period allows for patients' haemodynamic responses to exercise to be assessed and for any complications to be ruled out before progression to RE. Additionally, the patient can use this time to become familiar with self-monitoring and to establish the correct training intensity. Prior to commencing upper limb resistance training CABG patients should have their wound and sternal area assessed, to ensure adequate healing and stability (Pollock, et al., 2000). Caution is advised for patients who demonstrate symptoms of chest clicking or discomfort, as this can signify problems with healing. There is some evidence that an exercise programme should avoid any exercises...
Examination of the orbits of patients with GO at postmortem reveals marked extraocular muscle hypertrophy with an increase in surrounding fat and connective tissue. Histology of these tissues reveals inflammatory and immune cell infiltrates. The pathogenesis remains as uncertain as the natural history. Are there autoantigens on orbital tissues which share epitopes with autoantigens in the thyroid Data have accumulated to suggest that both antibodies and T lymphocytes may recognize determinants on extraocular muscles or orbital fibroblasts and lead to antibody-dependent or antibody-independent cell-mediated cytotoxicity. The area remains confused and controversial. In all of endocrinology GO remains one of the great enigmas and one of the least well understood and most poorly managed clinical problems. Until we can characterize confidently the autoantigen targets and obtain them in sufficient quantities naturally or through cDNA expression systems, prospects for understanding the...
That participation in an exercise program produced physiological training responses that included increased peak oxygen uptake, resting heart rate, decreased peak exercise heart rate, increased resting blood pressure, and decreased peak systolic blood pressure compared with normal controls. No change was observed in peak systolic blood pressure or pressure rate product. However, these studies were uncontrolled and therefore these changes could be either the result of spontaneous improvement or a treatment effect. While there are few studies in this area and no RCTs, initial observations demonstrate efficacy of this intervention. In addition, it is believed that strength training before the transplantation may help enhance recovery after the operation. However, more research is needed in this area to identify the extent of spontaneous recovery versus the added benefit from exercise intervention.6
W. (Eds.) (2000). Essentials of strength training and conditioning (2nd ed.). Champaign, IL Human Kinetics. Stone, M., Plisk, S., & Collins, D. (2002). Training principles Evaluation of modes and methods of resistance training A coaching perspective. Sports Biomechanics, 1, 79-103. Zatsiorsky, V. N., & Kraemer, W. J. (2006). Science and practice of strength training (2nd ed.). Champaign, IL Human Kinetics.
Strength training is not included in all rehab programs, but recent work suggests that strength training does offer complementary benefits to endurance training. In separate studies, both Ortega and Panton noted that strength training not only improved peripheral muscle strength but walking distance as well, when compared with endurance training alone.7'8 As with upper extremity training, it remains to be proven whether the addition of strength training to endurance training is associated with any improvement in quality of life.
Generates the muscles of the back, and the ventrolateral (hypaxial) domain, which gives rise to the abdominal, intercostal, and limb musculature. Distinct classes of proliferative myoblasts are present during embryonic, fetal, and adult skeletal muscle development.1-3-1 Ultimately, these myoblasts undergo terminal differentiation, which involves both permanent withdrawal from the cell cycle and expression of muscle-specific genes. Differentiation is followed by fusion of myoblasts to form multinucleated myotubes, or immature muscle fibers. Primary myotubes represent the first muscle fibers to form, and provide a scaffolding upon which other myoblasts align and fuse to form secondary myotubes. The process of secondary myotube, or muscle fiber, formation persists for most of the fetal period. Essentially all muscle fiber formation occurs prenatally in domestic animal species. 4 Small muscles will have fewer muscle fibers than large muscles within an animal, but the number of muscle...
Protein metabolism Body nitrogen resides in two main compartments. Approximately half of the body's nitrogen is contained in extracellular tissues such as collagen. The nitrogen present within these tissues is relatively fixed and does not change significantly with starvation. The nitrogen turnover within this compartment can be assessed by the measurement of hydroxyproline excretion. The remaining nitrogen is present in the lean muscle mass, comprising skeletal and visceral muscle. The proteins within these tissues are constantly being broken down and resynthesized at a rate of 3-3.5 g kg day in a young adult. Measurement of urinary 3-methylhistidine excretion and creatinine excretion can be used to estimate the fractional catabolic rate of skeletal muscle.
Traditional dry-cured ham may be produced bone-in or boneless, the latter meaning that the aitchbone and shank is removed prior to salting. The next step is to rub a mixture of curing ingredients (sodium chloride and maybe nitrite and or nitrate) onto the lean muscle surface of the ham. The ham is stored at temperatures below 5 C until the curing agents are evenly distributed throughout the ham. This period lasts from a few weeks to a few months. In between, the ham may be washed and resalted if necessary. The ham is then moved to the drying rooms and ripened at temperatures between 15 and 20 C and a relative humidity decreasing from 90 to 70 . In the last part of the ripening period, the ham may be covered with lard or pork fat to prevent excessive drying out. An in-house mold flora will usually grow on the ham surface. Some ham types, for example, country-style ham and German Westphalia ham, are smoked prior to the drying step. The raw material and the length of the ripening period...
Low-fat dairy products provide a solid nutritional base for losing weight. Calcium influences adipocyte metabolism indirectly through calcitrophic hormone levels. Dietary calcium and magnesium can form undigestable complexes that decrease the energy available from fat in food products. Milk minerals may play an important role in bone metabolism and help arrest bone loss during weight loss. This is more important in elderly than young. Protein components in milk provide high branch chain amino acid content and help maintain lean muscle tissue. Several components found in skim Fig. 1.3 The percent lean muscle change approached significance (P 0.08) over the course of a 16-week study that evaluated enriched components from skim milk. Fig. 1.3 The percent lean muscle change approached significance (P 0.08) over the course of a 16-week study that evaluated enriched components from skim milk.
Imagine you are a strength coach at a junior college. You closely watch many of the young men in your preseason conditioning program because they have had little serious weight training in their high schools, and others may be pushing themselves too hard to meet team strength standards to qualify for competition. Suppose you see a player performing the bench press using The biomechanical principles relevant to the bench press are Balance, Coordination Continuum, Force-Time, and Range of Motion. When training for strength, resistance is high, the athlete must have good control of the weight (Balance), and coordination during the lift will be simultaneous. The force-time profile of strength training attempts to maintain large forces applied to the bar through as much of the range of motion as possible. The SSC nature of the movement should be minimized. This keeps the movement slow and force output near the weight of the bar. High initial forces applied to the ball results in lower...
Aerobic activities should be prescribed with the following considerations it is important that all exercises are dynamic, as isometric exercise will increase BP. Isometric activities associated with the valsalva manoeuvre should be avoided. Resistance training should be prescribed using lower resistance and higher repetitions, ensuring the patients are not over-gripping equipment.
Asthma is a chronic disease characterized by increased airway responsiveness to various stimuli. This causes widespread narrowing of the lower airways that reverses either spontaneously or with treatment. Although the exact pathophysiology of asthma is complex and poorly understood, inflammation is thought to play a central role. Pathologic changes that occur in asthma include smooth muscle hypertrophy, mucosal edema, and mucous plugging. Asthma affects 4-5 of adults and 10 of children. Onset usually occurs in children and young adults.
Contrary to popular belief, simply eating more dietary protein, in excess of recommended amounts, will not result in bigger muscles. Our bodies do not store excess protein. If we eat more protein than our bodies need to replenish the amino acids we have used during the day, the excess amino acids are converted to, and stored as, fat. Dietary protein, like carbohydrates, supplies about 4 calories of energy per gram. Because our requirements for protein mainly depend on our body's size, our need for protein increases during times of rapid growth. Therefore, the recommendations for protein are age-dependent and are slightly higher for pregnant and breastfeeding women than for other adults (see the Appendix Dietary Reference Intakes, page 421). The recommended allowances ensure an adequate protein intake by nearly all healthy people. Nevertheless, many Americans typically consume twice this amount, often in the form of meat and dairy products that are high in
Mechanically, the three kinds of actions are based on the balance of the forces and torques present at any given instant (Figure 3.9). If the torque the activated muscles creates is exactly equal to the torque of the resistance, an isometric action results. A bodybuilder's pose is a good example of isometric muscle actions of opposing muscle groups. Recall that isometric literally means same length.
The use of multi-gym weight training is widely recommended, but can be an expensive option. Weight machines maintain equilibrium, ensure the movement plane is well controlled and have easily altered resistance. This mode of resistance training may be useful for those with balance difficulties because the machines provide support. Prior to participating in RE patients should have an induction session. This is important to ensure safety. The induction should include advice and demonstration on positioning, moving and handling, and setting the resistance at the prescribed level. During all types of resistance training patients should be advised to avoid excess gripping and breath holding to help prevent valsalva. This advice should also be discussed in relation to heavy household or lifting tasks that are carried out at home or elsewhere.
In addition to increased breast muscle size in selected turkeys and chickens, there are two examples of increased proportions of carcass muscle in cattle and sheep. Generalized muscle hypertrophy in double-muscled cattle results from mutations in the myostatin gene. 8 The increased muscle of purebred animals is associated with so much calving difficulty that delivery by cesarean section is common in countries, such as France, with a high proportion of breeds carrying one of the mutations. An ideal increase in muscle hypertrophy occurs in heterozygous
Assuming other individuals or organizations are not raising them, high-risk children have the unique experience of being reared by a schizophrenic parent (or parents). As a result, family factors have been a source of interest, especially in high-risk studies. In a small retrospective study of adult children (n 9) with a psychotic mother, themes of abuse and neglect, isolation, guilt and loyalty conflicts, dissatisfaction with mental health services, and efforts to seek social supports emerged 72 . Dunn also noted that many of these children were quite resilient ''As children, study participants described consciously overcoming feelings of shyness, feelings of being different from others, and fear of reprisal from their mother in order to put themselves in safe and affirming situations with peers or adults'' 72 . In the New York High-risk Project, Erlenmeyer-Kimling and Cornblatt 40 noted several variables related to resilience, including a good parent-child relationship, good peer...
Increases in skeletal muscle strength after completion of resistance training was reported by all studies. Five of the seven strength training studies demonstrated that submaximal and peak resistance exercise, using a variety of resistance training devices, resulted in significantly lower peak heart rate, pressure rate products, and oxygen consumption responses than did maximal treadmill exercise testing.6 Moreover, angina, ventricular arrhythmias, and ischemic Recommendation for strength training exercises The strength training exercise sessions were typically started 4-6 weeks after MI or coronary artery bypass graft (CABG) and were carried out each week. The intensity ranged from 25 to 80 of the one repetition maximal the most typical format consisted of three 30-60 minute strength training exercise sessions per week for 6-26 weeks. Safety of strength training exercises in coronary patients The lack of cardiovascular and orthopedic complications in the 3 year follow up of strength...
The management of weight loss is a controversial area. At present there is inconclusive evidence regarding the relative effectiveness of physical activity combined with diet, versus diet alone or physical activity alone (Mulvihill and Quigley, 2003). As adipose tissue contains about 7000kcal kg, with physical activity alone it is difficult to lose much weight (BHF, 2004). Therefore, management of obese participants should include advice on diet, physical activity and a behavioural modification component in order to be comprehensive and effective. The most favourable alterations in body composition will occur with low-intensity, long duration aerobic exercise and aerobic exercise combined with high repetition resistance training (Mulvihill and Quigley, 2003).
Endurance training at submaximal levels of VO2 increases the oxidative capacity of muscle without causing muscle hypertrophy. Muscle size does not change but there are increases in the number of mitochondria and enzymes for fatty acid oxidation, the citric acid cycle, and the electron transport chain. Capillary density and
Is still present, neutrophils and a small number of eosinophils may also be found. The calyces and pelvis disclose mononuclear leukocytes, fibrosis, and hypertrophy of the smooth muscle the overlying transitional epithelium may be hyperplastic or display glandular or squamous metaplasia. Renal arteries often have intimal fibrosis and muscular hypertrophy, while glomeruli show ischemic collapse and periglomerular fibrosis. Glomeruli may have Tamm-Horsfall protein in Bowman's space. In severe reflux nephropathy, there is hypertrophy of the glomeruli and tubules in the nonscarred parenchyma there is sharp demarcation between the scarred and preserved parenchyma. Enlarged glomeruli may also demonstrate focal and segmental glomerulosclerosis. Some investigators have reported that in nonscarred areas, glomeruli with elongated capillaries, adhesions, and podocyte detachment were associated with a poorer prognosis (5).
Once the patient can move smoothly through the range of motion it is time to further strengthen the affected muscles. Restoring strength to the hip-stabilizing muscles should begin in their shortened range. The gluteus medius functions primarily eccentrically in the initial contact to the midstance phase of gait to stabilize the pelvis on the femur in the frontal plane. Before developing eccentric strength, the gluteus medius must achieve isometric and concentric strength. Isometric contractions can be elicited in the hips during a lateral-push wall exercise. (Figure 17.9.) Isometric exercise duration should begin at 5-10 seconds. Isotonic strength can be attained through a side-lying leg lift. This exercise is often done incorrectly with the patient rotating the hip externally to substitute for the weak gluteus medius with the tensor fascia lata and hip flexor muscles. (Figure 17.10.) Leg lifts can also be performed into hip extension and hip adduction. Active hip extension in the...
Elderly patients constitute a high percentage of those with MI, CABG, and PTCA and are also at high risk of disability following a coronary event. Seven studies - one nonrandomized study and six observational studies - provide the evidence for this review.6 Also, the Surgeon General's report5 concludes that physical activity, including strength training (resistance) exercise, appears to be protective against falling and fractures among elderly people, probably by increasing muscle strength and balance. Elderly coronary patients have exercise trainability comparable to younger patients participating in similar exercise rehabilitation. Elderly female and male patients show comparable improvement, but referral to and participation in exercise rehabilitation is less frequent for elderly patients,5 especially females. Physical activity need not be strenuous to achieve health
Blood flow is redistributed during exercise away from vegetative organs and toward actively exercising muscles by both intrinsic (local) and extrinsic (reflex) mechanisms. In isometric exercise, muscle blood flow may actually decrease with compression of arteries and veins in contracted muscles. In contrast, active hyperemia, or an increase in blood flow, occurs in muscles during dynamic exercise. Arterioles dilate in exercising muscles in direct response to local metabolic changes (decreased O2, increased CO2 and H+ ion), adenonsine, and nitric oxide (NO). This local control of muscle blood flow overrides the effect of sympathetic stimulation to
Equipment can have quite a marked influence on the training effect of an exercise. Exercise machines, preacher benches, and Smith machines are all examples how equipment modifies the training stimulus of weight-training exercises. Strength and conditioning catalogues are full of specialized equipment and training aids unfortunately, most of these devices have not been biomechanically studied to determine their safety and effectiveness. Garhammer (1989) provides a good summary of the major kinds of resistance exercise machines in his review of the biomechanics of weight training.
Arterial blood pressure increases during exercise, but the increase is much greater in isometric than in dynamic exercise. During isometric exercise, the blood vessels are clamped shut by sustained contractions, and resistance increases. This leads to anaerobic metabolism and strong stimulation of the muscle chemoreflex. Without the benefits of local vasodilation in isometric muscle contraction, the net effect is an increase total peripheral resistance and arterial pressure.
Suppose a high school track coach has shot put athletes in the weight room throwing medicine balls. As you discuss the program with the coach you find that they are using loads (inertia) substantially lower than the shot in order to enhance the speed of upper extremity extension. How might you apply the principle of inertia in this situation Are the athletes fully using their lower extremities in a similar motion to shot putting Can the athletes build up large enough forces before acceleration of the medicine ball, or will the force-velocity relationship limit muscle forces How much lower is the mass of the medicine ball than that of the shot All these questions, as well as technique, athlete reaction, and actual performance, can help you decide if training is appropriate. The biomechanical research on power output in multi-segment movements suggests that training loads should be higher than the 30 to 40 of 1RM seen in individual muscles and muscle groups (see the following section on...
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