Muscle Growth: Hypertrophy

Muscle fiber increases its size in response to training. These little changes accumulate over time, which gives us a great way for remodeling our bodies and, in addition, increases our performance. 

Hypertrophy means the increase in muscle fiber size. Strength training causes an increase in muscle protein synthesis that lasts 36–48 hours. Simply put, during this time frame, more muscle protein is synthesized than broken down and the end result is more muscle mass. The size increase in muscle fiber can be substantial. Studies have shown that bodybuilders have up to 58% larger muscle fibers compared to untrained individuals. Size increase can also be rapid. Training studies lasting only a couple of months can lead up to 30% increase in muscle fiber size. Muscle hyperplasia, the increase of the amount of muscle fibers, either does not occur in humans or has only a really marginal role in hypertrophy.

How fast can you gain muscle?

I bet you have heard different opinions about maximal rate of muscle hypertrophy. Some people claim you can only grow 2–4 lbs (1–2 kg) of muscle mass in one year. Others insist they have gained 60 pounds during one year. Is the growth rate purely an individual thing? It is, but only to a degree. After all, most of us have average genetics for muscle growth, so research findings give us reasonable guidelines of expected gains. Evidence shows that the rate of muscle growth during the first couple of training months is approximately 60 grams of muscle per one training session. Bigger, more talented people gain more. Smaller, less talented people little less. So if you train three times per week, you can expect up to two lbs or 1 kg of muscle mass per month during first few training months.

Women and muscle growth

We often hear claims that women can’t really gain muscle. This is a fallacy that has its roots in myths surrounding women’s strength training. Because of various “toning” myths, women tend to use too low training intensity for optimal muscle growth. The fact is that women gain muscle practically as fast as men during the first month of training – if they train with sufficient frequency and intensity. After that men start to have an advantage over women, mostly because of ten times more testosterone in their blood. This is not to say that women can’t gain muscle after the beginner level. They absolutely can; the progress is just a little bit slower compared to men.

Progress slows down

If we could sustain this growth rate, most of us would look like Arnold during his heyday in a couple of years. Yep, the growth rate slows down and experienced trainees can be lucky to gain 1–2 kilos per year after several years of hard training.

Bust through the muscle gain plateau!

So we all will hit the plateau sooner or later. But this is not the end of story. With help of intelligent, more effective training and proper nutrition you can break the plateau! Here’s where RecoApp Muscle Recovery comes in handy. Hypertrophy is largely a response to increased mechanical and/or metabolic load and growth happens during rest periods between workout bouts. Thus, optimizing the total workload of workout (by adjusting the workload bar in the app) and following proper recovery times are even more important. Optimal gains will not be realized if you train a muscle group too early, during the repair progress. Over the time, improper recovery times will cause you to work out with too low training volume or intensity during training sessions, leading to sub-optimal hormonal milieu for muscle growth and, in the worst case scenario, to overtraining.

Want to go deeper?

Different individuals have different responses to a training stimulus. Others benefit more from high loads and short sets, high mechanical load. Others benefit from high metabolic load, using long sets and less load. If hypertrophy is your goal, you absolutely need to get stronger. Bigger weights equal bigger muscles. So once again, you need progression in your training. By using RecoApp you can clearly see how you respond to a certain training stimulus and you’ll soon find out what is the optimal rest period for each muscle group. Of course, the training stimulus needs to be changed every now and then, but you can mainly stick to those set and rep schemes that bring you optimal results. But if you want to grow even bigger and learn tacit expert knowledge about splitting your workout routines into 2–6 weeks’ periods (known as mesocycles), read my forthcoming blog article about them. 

Summary: Basics for hypertrophy training

-          If you are a beginner, train one muscle group 2 to 3 times per week. Whole body program, upper body/lower body split or push-pull split are all good choices.

-          If you’re more advanced, train one  group every 5 to 7 days using more advance splits. Discover your optimal split by using RecoApp. You may do best by training biceps two times per week but chest only every 6 days.

-          Mainly use a rep range between 6–12 reps. Maximum strength training using low reps (1–5) or strength endurance using 12–20 reps is sometimes a good stimulus change

-          With a solid training program, good nutrition and proper rest, you can expect gains up to 2 lbs or 1 kg per month during the first few training months.

Remember progressive overload! Lift bigger weights, do more sets, do more reps. There are many different ways to do this. Click here to check out nutritional guidelines for optimal muscle growth.


Jabekk, PT et all. 2010. Resistance training in overweight women on a ketogenic diet conserved lean body mass while reducing body fat. Nutrition and Metabolism. 7:17.

Fleck SJ, Kraemer WJ. Designing resistance training programs. Champign, IL. Human Kinetics. 2004.

MacDougall JD et all. 1984. Muscle fiber number in biceps brachii in bodybuilders and control subjects. J Appl Physiol Respir. Evinrol. Exerc. Phyiol. 57: 1399-1403. 

Data analysis for your smart clothing

To achieve optimal muscle growth it is important to avoid over- and undertraining. RecoApp's methodology aims for the supercompensation by evaluating input data. Taking advantage of this methodology and RecoApp’s way of the data interpretation in smart clothing would give impressive results.

RecoApp’s efficient, visually pleasant and quickly readable way of the data interpretation is a user-friendly experience. Smart clothing is a rapidly growing business and manufacturers need more efficient ways to interpret the data. RecoApp’s patent covers using an image of a human figure in a form of traffic light color coding for receiving and displaying optimal training information regarding muscle recovery times. Therefore it is a significant asset for smart clothing manufacturers to protect their smart clothing portfolio.

RecoApp has demonstrated the function of the patent through MVP mobile application. RecoApp's MVP has over 10 000 users.

Learn to listen to your body - and discover your ideal supercompensation times with the help of RecoApp. The U.S Patent Pending. Global PCT Patent Pending.

 Download RecoApp on the App Store



Timo Haikarainen, MSc, Finnish personal trainer and strength and conditioning coach.

Markus Mäntynen, the CEO and founder of RecoApp Oy.


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