Muscle Gain & Exercise Research Analysis

Q: Why is exercise and muscle gain important?

Exercise provides a wide variety of health benefits, including improved cognition, mental health, blood-pressure, insulin sensitivity, body-composition, body weight, sleep, bone health, cardiorespiratory fitness, and physical function.[7] Moreover, regular exercise is associated with a reduced risk of all-cause mortality and an assortment of diseases (e.g., type-2-diabetes, cardiovascular-disease, certain cancers, dementia).[7] Similarly, higher levels of muscle mass are associated with improved health outcomes, such as a reduced risk of falls and all-cause mortality.[8]

Q: What type of exercise is best for muscle gain?

Resistance exercise is the most effective type of exercise for muscle gain.[5][9] Performing sets to muscular failure (i.e., the point at which another repetition cannot be completed while maintaining proper form) is just as effective as ending sets a few repetitions away from muscular failure when moderate to heavy loads (60–90% of one-repetition maximum) are used,[10] but sets should be performed to muscular failure when light loads (30–40% of one-repetition maximum) are used.[11] Training frequency doesn’t seem to meaningfully affect muscle gain as long as the amount of volume performed is the same,[12] but a high training frequency (e.g., training a muscle group three times per week) may be particularly advantageous when performing a high-volume training program.[13][14]

Q: What are the different bioenergetic systems that fuel muscle?

Muscles require ATP (the energy currency of cells) to contract and produce movement.[15] Depending on the type, intensity, and duration of exercise, the body will make ATP primarily from one of three energy systems: the creatine-phosphate system (fastest), glycolysis, and fat oxidation (slowest). All three energy systems are always working, but some will work more than others under certain conditions. Through greater activity and training, the efficiency and effectiveness of each of these systems can be increased.

Q: What evidence-based methods are there for decreasing soreness after exercise?

Delayed onset muscle soreness (DOMS) is common after exercise, particularly when starting a program or increasing intensity or frequency of exercise. It is caused by the stress put on muscles and connective tissue when exercising. Contrary to popular belief, it is not caused by lactic acid buildup in the muscles (lactic acid is gone from muscles within 1–2 hours after exercise). Cooling[16], especially cold water immersion, appears to be effective for mitigating DOMS, although the previously mentioned potential to blunt adaptation and delay recovery should be noted. Compression garments[17][18] mitigate decrements in muscle strength and DOMS without overtly impacting measures of muscle damage. Supplements including caffeine,[19] omega-3 fats,[19] tyrosine,[19] whey protein,[20] and BCAAs[21] are potential candidates and often operate through different mechanisms of action. Sodium bicarbonate (baking soda) and magnesium have been studied for DOMS, with some positive results [22]. There are a variety of herbal interventions[23] that could potentially ameliorate DOMS, but the reader is cautioned about the rigor of specific studies and interactions with other supplements and pharmaceuticals. Moreover, there's some evidence in favor of an anti-DOMS effect of massage.[24] One thing to keep in mind, though, is that both "massage" and "antioxidants" are catchall terms for groups of different interventions. Accordingly, we should be wary of unwarranted generalizations of the results of individual studies on specific antioxidants and/or massage techniques to "antioxidants" or "massage therapy" in general.

Q: How do I get a six-pack?

You eat less food to reduce body fat. There will be abdominal muscles under the fat, and adding some muscle to this area (resistance training) can make them appear more aesthetic; fat loss is the main predictor, however.Six-packs; a function of both low body fat and high muscular density The role of low body fat The display of abs is more of a function of low bodyfat than anything else. You cannot reduce the fat around your belly without reducing overall fat.[45][46] Attempts should be made to reduce body fat in general, and fat located on the core will generally be lost in proportion to the rest of the body. At very low body fat levels, a six-pack will almost always be visible. However, without adequate muscle density on the core this six-pack will look somewhat emaciated and reminiscent of skin covering chicken wire. The role of muscular density Like any skeletal muscle, the muscles that comprise the abs (rectus abdominus, serratus anterior, obliques, etc.) respond to stimuli and damage and grow in response to said stimuli; given adequate nutrition and repair is given. The larger the core muscularity, the more likely it is to see the outlines of the highly sought after 'six-pack'. However, until body fat is lost any six-pack at higher body fat levels will appear blurry or otherwise soft.

Q: Will lifting weights convert my fat into muscle?

Lifting weights can increase muscle mass and induce fat loss, but these are two separate processes.Sort of, kind of, maybe; not really. What weight lifting will do Weight lifting can increase muscle mass, primarily through becoming damaged (via weight lifting) and then sending out signals to the body to turn ingested proteins into new muscle tissue as a repair mechanism. Carbohydrates and fats are used as energy to fuel this process. Weight lifting can also decrease fat mass, by using up body fat stores to fuel both this muscle building process and also using fat stores directly as fuel for the exercise that is needed to damage the muscle. What weight lifting will not do The technical, literal, direct conversion of fat into muscle. Fat is comprised of triglycerides, which are molecules shaped like a capital E comprising a backbone and three chains of fatty acids (shown below). These chains are made up of carbon, hydrogen, and oxygen almost exclusively. Muscle mass is made up of muscle tissue, glycogen, water, and some intra-muscular fat.[47][48] The muscle tissue (the only tissue able to contract) is made up of chains of amino acids, which can be quite various in their structure. These chains contain nitrogen, and nitrogen is almost exclusively stored in the body as muscle (with some amino acids floating around). It is impossible for fat to directly turn into muscle, since fat lacks the nitrogen and no mechanism exists in the body to reconstruct fat into amino acids. No evidence has surfaced implying that amino acids can be made in the body from anything other than other amino acids, a process known as transamination.[49][50] The vast majority of muscle built is from dietary nitrogen intake; dietary protein is the only significant source of nitrogen in the human diet.[51][52] So although lifting weights can both build muscle and induce fat loss, these should be viewed as two separate results and not one being the result of another.

Q: Does exercising in the fasted vs. fed state matter for improving glycemic control and insulin sensitivity?

It is generally accepted that exercise can improve blood glucose control and enhance insulin sensitivity. Several physiological processes may be responsible for these improvements, including the following: Adaptations in muscle insulin signaling[53] Glucose transporter type four (GLUT-4)[54] protein expression, content, and action Enhanced intramyocellular oxidative enzyme capacity[55] Increased muscle capillary density.[56] However, it is not entirely clear whether exercising in the fasted state may be better than exercising in the fed state. Based on the available scientific evidence, it seems that being physically active and losing weight (through a hypocaloric diet) are the most important factors[57] for improving glycemic control and insulin sensitivity, while performing exercise in a fasted vs. fed state plays a minor role at most. However, the research comparing the effects of fed vs. fasted exercise on glycemic control and insulin sensitivity is still in its infancy, so it’s probably best to wait until there is more research before drawing definitive conclusions.

Mike Murray, RDN

Muscle Gain & Exercise

•Last Updated: August 16 2022

Exercise is planned, structured, and repetitive physical activity that aims to maintain or improve physical fitness. Muscle gain is a consequence of muscle protein synthesis exceeding muscle protein breakdown and is provoked by exercise and diet.

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Mike Murray, RDN

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Nick Milazzo, MSc, MPH • Rob Stenstrom, MD, PhD

Last Updated: August 16 2022

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Frequently asked questions

How does muscle gain work?

Muscle tissue is constantly turning over, with the rates of muscle protein synthesis (MPS) and muscle protein breakdown (MPB) fluctuating throughout the day. Net protein balance is the difference between MPS and MPB. For an increase in muscle mass to occur, MPS must exceed MPB, resulting in a positive net protein balance.^[1] MPS is very sensitive to exercise and diet (namely, essential amino acid intake).

Why is exercise and muscle gain important?

What type of exercise is best for muscle gain?

What are the different bioenergetic systems that fuel muscle?

What evidence-based methods are there for decreasing soreness after exercise?

Why do my muscles get sore?

How do I get a six-pack?

Will lifting weights convert my fat into muscle?

How could diet affect exercise and muscle gain?

An adequate energy intake is essential to optimize exercise performance and adaptations — if one maintains an energy-deficient diet during training, muscle loss, impaired recovery, illness, decreased bone mineral density, poor mood, and menstrual dysfunction can occur.^[2] Consuming a hypercaloric diet augments resistance-training-induced increases in muscle mass.^[3]

Beyond general energy intake, carbohydrate intake is important because it serves as a primary fuel source over a wide range of exercise intensities, and a robust body of evidence demonstrates that matching carbohydrate availability to exercise demands enhances both prolonged endurance exercise and intermittent high-intensity exercise performance.^[4] Additionally, dietary protein intake is essential for the synthesis and repair of muscle tissue and is required after exercise to elicit a positive net protein balance.^[5]

Does exercising in the fasted vs. fed state matter for improving glycemic control and insulin sensitivity?

Are bodybuilding diets healthy?

Which supplements are of most interest for exercise and muscle gain?

Supplements may benefit exercise performance and muscle gain by providing a convenient form of energy and nutrients (e.g., powdered proteins such as whey protein or vegetable protein sources, carbohydrate drinks and gels), correcting or preventing nutrient deficiencies, improving recovery from exercise, or enhancing exercise performance directly.^[6] The supplements of most interest for enhancing exercise performance directly are creatine, caffeine, nitrate, citrulline, beta-alanine, and sodium bicarbonate.^[6]

Should I take BCAAs before exercise if I work out while fasted?

Will supplementing with BCAAs and arginine increase exercise performance?

Creatine doesn’t seem to work for me. What should I do?

Does the menstrual cycle affect caffeine’s performance-enhancing properties?

Does creatine benefit elite athletes?

Fact check: does glutamine build muscle?

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