Gains in strength and muscle size come quickly when you first start strength training. In fact, you become measurably stronger during the first 8 weeks of training. This happens before your muscles even increase in size. These strength gains, caused by neural adaptations, make up 90% of the gains in strength you experience during the first 8 weeks of strength training.
How do neural strength adaptations come about? When you first start training, your neuromuscular system inhibits your ability to generate force. The purpose of this inhibition is to protect your joints and muscles against injury. Makes sense, doesn’t it? If you’re untrained and lift a super-heavy weight, you’ll likely injure yourself. This low-level inhibition protects you by restricting your strength capacity. But, as you continue to train, your nervous system releases some of this inhibition and you can lift more. Plus, as you train, your motor unit firing becomes more synchronized, making it possible to generate more force when you lift.
Build Muscle: The Law of Diminishing Returns
Due to neural adaptations, you begin to develop strength rather quickly. To a lesser degree, this is true of building muscle size as well. When you start a strength-training program, the stress you place on your muscles is new and your muscles must adapt quickly to this novel stimulus. You’re thrilled to look in the mirror and see new muscle definition!
But as your training progresses, the strength and muscle gains slow. This well-known phenomenon is sometimes called the law of diminishing returns. Due to the dictates of this “law,” you put in the same amount of work but get less return on your investment. You can also think of it as the “newbie effect.” When you start something new, there’s so much to learn that you advance quickly, but as you become more proficient, the gains slow to a crawl.
How much muscle you’re able to build and how much strength you can gain in response to diet and training is partially determined by genetics. Based on the DNA you inherited from your parents, you may have a greater capacity to develop muscle than someone else. But with consistent training, you should be able to achieve YOUR highest potential.
Build Muscle: Reaching Your Genetic Potential To Build Muscle
How long does it take to reach your muscle growth potential? Most men and women achieve about 50% of their genetic potential within the first year of training. This, of course, assumes that you train consistently and use progressive overload. If you train incorrectly, you may only reach a fraction of your genetically determined capabilities.
During the second year of training, your gains will slow even more. Most people reach their full genetic potential after 3 to 4 years of training. However, this is in the setting of optimal training and nutrition. Over a 3 to 4-year period, with the right training, it’s possible for a woman to build as much as 15 pounds of muscle mass and men about twice that much.
Build Muscle: We’re All a Little Different
Research shows that the degree to which training elicits muscle growth varies widely from person to person. That’s genetics in action again. One study showed that muscle gains in response to training varied from no change in a few individuals up to a 60% increase in muscle size. So, response to strength training is highly variable.
What about those super-big guys, and sometimes gals, in weight-lifting magazines? It’s possible to gain muscle mass beyond your genetic potential with the help of anabolic hormones. Don’t forget, not everyone takes the natural route. So, you now have a rough idea of how much muscle gain is possible using natural methods and how quickly you can achieve it. Even then, gains are greatest during the first year of training and fall off each year after that.
Factors that Impact Muscle Strength
Genetic potential for muscle growth also varies with body type. People who have a classic ectomorphic build, long, lean limbs with little muscle or body fat, have a harder time adding lean muscle tissue than a mesomorph, an individual who has natural muscle definition. An ectomorph will have to consume more calories and train hard. The advantage of being an ectomorph is they also don’t gain body fat easily. Endomorphs have an easier time gaining lean body mass than the ectomorph but have a harder time losing body fat.
Other factors that impact the ability to develop strength include age, how your muscles attach to your bones, and the ratio of muscle fiber types you have. Women have more difficulty gaining muscle after menopause due to hormonal changes. How your muscles attach to your bones affects leverage, another factor that impacts muscle strength. You have more leverage if a muscle attaches to the bone further from the joint. Such an insertion allows you to generate more force. Likewise, when a muscle attaches closer to the joint, there’s less leverage and the muscle will be weaker.
Finally, the ratio of fast-twitch to slow-twitch muscle fibers that make up your muscle affects strength. Most of us have roughly 50% slow-twitch and 50% fast-twitch fibers. However, powerlifters often have a strength advantage because they have more fast-twitch fibers than slow-twitch. In contrast, endurance athletes, are at an advantage in their sport due to a higher ratio of slow-twitch to fast-twitch fibers since slow-twitch fibers are built for endurance.
As you can see, it takes time to reach your genetic potential and the gains slow over time. That doesn’t mean you can’t continue to build muscle strength or size after a 3 or 4-year period. However, you’ll have to find ways to challenge your muscles differently by altering training variables and by further optimizing your diet. More advanced training techniques such as drop sets, partials, giant sets, negatives, super setting, pre-exhaust sets, and forced reps can help you break through plateaus and maximize your ability to build muscle.
Now, you also know why it’s important to be patient. Don’t get discouraged if you make slow gains and don’t expect the fast, initial gains to be sustainable. Be ready to change your routine as you plateau to maximize the gains that you do make.
PainScience.com. “Strength Training Frequency”
Med Sci Sports Exerc. 2005 Jun;37(6):964-72.
IDEA Health and Fitness Association. “Beat Training Plateaus”
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