Muscle Hypertrophy

Only available on StudyMode
  • Download(s) : 203
  • Published : July 9, 2012
Open Document
Text Preview
Strength training typically produces a combination of the two different types of hypertrophy: contraction against 80 to 90% of the one repetition maximum for 2–6 repetitions (reps) causes myofibrillated hypertrophy to dominate (as in powerlifters, olympic lifters and strength athletes), while several repetitions (generally 8 – 12 for bodybuilding or 12 or more for muscular endurance) against a sub-maximal load facilitates mainly sarcoplasmic hypertrophy (professional bodybuilders and endurance athletes).[citation needed] The first measurable effect is an increase in the neural drive stimulating muscle contraction. Within just a few days, an untrained individual can achieve measurable strength gains resulting from "learning" to use the muscle.[citation needed] As the muscle continues to receive increased demands, the synthetic machinery is upregulated. Although all the steps are not yet clear, this upregulation appears to begin with the ubiquitous second messenger system (including phospholipases, protein kinase C, tyrosine kinase, and others).[citation needed] These, in turn, activate the family of immediate-early genes, including c-fos, c-jun and myc. These genes appear to dictate the contractile protein gene response.[citation needed]

Progressive overload is considered the most important principle behind hypertrophy, so increasing the weight, repetitions (reps), and sets will all have a positive impact on growth. Some experts create complicated plans that manipulate weight, reps, and sets, increasing one while decreasing the others to keep the schedule varied and less repetitive. It is generally believed that if more than 15 repetitions per set is possible, the weight is too light to stimulate maximal growth.[1] Anaerobic training

Main article: Anaerobic exercise

Experts and professionals differ widely on the best approaches to specifically achieve muscle growth (as opposed to focusing on gaining strength, power, or endurance); it was generally considered that consistent anaerobic strength training will produce hypertrophy over the long term, in addition to its effects on muscular strength and endurance. As testosterone is one of the body's major growth hormones, on average, men find hypertrophy much easier to achieve than women. Taking additional testosterone, as in anabolic steroids, will increase results. It is also considered a performance-enhancing drug, the use of which can cause competitors to be suspended or banned from competitions. In addition, testosterone is also a medically regulated substance in most countries, making it illegal to possess it without a medical prescription. Factors affecting hypertrophy

Several biological factors such as age and nutrition can affect muscle hypertrophy. During puberty in males, hypertrophy occurs at an increased rate. Natural hypertrophy normally stops at full growth in the late teens. Muscular hypertrophy can be increased through strength training and other short duration, high intensity anaerobic exercises. Lower intensity, longer duration aerobic exercise generally does not result in very effective tissue hypertrophy; instead, endurance athletes enhance storage of fats and carbohydrates within the muscles,[2] as well as neovascularization.[3][4] An adequate supply of amino acids is essential to produce muscle hypertrophy. Changes in Protein synthesis and muscle cell biology associated with stimuli Protein synthesis

Main article: protein biosynthesis

Ultimately the message filters down to alter the pattern of protein expression. The additional contractile proteins appear to be incorporated into existing myofibrils (the chains of sarcomeres within a muscle cell). There appears to be some limit to how large a myofibril can become: at some point, they split. These events appear to occur within each muscle fiber. That is, hypertrophy results primarily from the growth of each muscle cell, rather than an increase in the number of cells. Skeletal muscle cells are...
tracking img