What Is The Least Amount Of Weight Required To Build Muscle?


Supposing that your maximum in crouch stand is 100 kg. What is more effective to your muscle growth – to crouch to the max with 30 kg. barbells or with 80 kg.? Don’t hurry to give your variant of the answer, scientists have already tested everything.

Sergey Strukov, known fitness expert, gathered and translated into Russian a text, based on 68 scientific studies, where there is an attempt to answer the question “Is there minimal intensity threshold for stimulating adaptative hypertrophy during weight session?” We adapted important and interesting original from almost 35 thousand symbols for your convenience: made text shorter and easier for mass understanding without loss of sense. So let’s dive into the search for answer without hesitation.

60-75% from the rep max gives the best effect

In traditional approach to training sessions load intensity is necessary at the level of 60% of your maximum for apparent increasing of muscle size, which you can do only one time (that approximately corresponds to 10-12 reps). Supposably that it is level, which is necessary for activation of all the spectrum of muscle fibers.

As a part of the study (link #1 below the text) they cleared up the influence of the intensity of the training on the wide spectrum of loading: from 20% to 90% of maximum working weight of persons under test.

They did 3 sets with 27 reps at 20% of load intensity, 3 sets with 14 reps at 40%, 3 sets with 9 reps at 60%, 3 sets with 8 reps at 75% and 6 sets with 3 reps at 90% of load intensity. Thus, the total volume of work (total volume of lifting) in all five cases was the same.

As a result, the increase of muscle protein synthesis was at minimum level after exercises with 20 and 40 percent of intensity, but essentially increased at 60% and hit a rut. In other words, with further increase of load intensity in % of maximum weight, which could lift testees – there was no significant increase of muscle protein synthesis.

The results were fair for young and old people, confirming that stimulating effect of exercises is at maximum level with 60-75% load of maximum weight.


Low intensity is effective, if to train to muscular failure

Nevertheless, there is evidence that low intensity weight session (even with weight in 30% of your maximum) can cause significant muscle growth, in many cases no less than with high intensity exercises.

The authors of the previous study did not indicate whether there was low intensity load (20-40%) to the full, it was not the aim, but it is a very important limitation, as it is shown experimentally that hypertrophy (muscle growth) in reaction to low intensity training happens, if reps are made to the point of arbitrary muscular failure (studies #2, #3).

In study #2 15 young, active persons did 4 sets of knee extension firstly with 30% load and then with 90% of their rep max till arbitrary muscular failure each.

The third time the exercise wad done with 30% intensity with work (reps by load) equal to 90% load (roughly speaking, there was 3 times more sets at 30% load than at 90% load of rep max. As a result, a number of sets were less than doing the same load but to muscular failure).

Four hours later after the finishing of each of three loads, muscle protein synthesis was higher, but levels in third case (30% load with reps 3 times more than at 90% but without muscular failure) were one half as high than after two first loads. In other words, crucial importance in this experiment was the fact of doing exercises with low weight to muscle fatigue, muscular failure.

At the same time, it is noteworthy that the synthesis of muscle proteins myofibrils (muscular fibers) remained increased a day after the exercises only with 30% load from the maximum weight, but with the number of repetitions to muscular failure.


As a conclusion: exercises done with low intensity to muscular failure, cause big urgent muscle response in comparison with exercises with high intensity. Truly it should be noted that the load of training was significantly high at 30% load to muscular failure in comparison with 90% load. Roughly speaking, at 90% load from one-time maximum testees could do, for example, only 3 reps, and at 30% load to muscular failure – much more – 9 reps.

This fact does not allow allocating the intensity influence in this study.


The results are contradicting. More reps — less muscles

During the study #4 32 untrained young men from 17 to 28 years were divided into three groups in a random way:

– in the first group weight in exercises was chosen such that they do 3-5 reps to muscular failure in 4 sets of each exercise with rest of 3 minutes between sets;

– the second group did 3 sets of 9-11 reps and had rest during 2 minutes between sets;

– the third group – did 2 sets of 20-28 reps and 1 minute rest.

For comparison a control group didn’t do any load exercises.

Training included leg press, knee bends and knee extension with approximately equal total volume of training. Trainings were 2 times a week during first four weeks and 3 times a week during last four weeks. Weights were increased progressively, focusing on the required quantity of reps in all sets, and all sets were done to concentric muscular failure.

As a result, muscle cross sectional area was measured (its strength and volume directly depend on this). Biopsy of lateral vastus muscle was used for assessment.

Eight weeks later, groups with small and average number of reps had substantial increase in cross sectional area of the fiber type I, IIA and IIX to 12.5%, 19.5% and 26%, respectively. Increasing the fibers in the group with a large number of reps (and correspondingly low intensity) did not reach statistical significance for any types of fibers, and then low intensity exercises (with 20-28 reps to muscular failure) are not suitable for hypertrophy stimulating.

Number of reps is inessential if they are done till muscular failure

Other specialists applied similar basic training program (study #5). Twenty five healthy people aged 34-44 with experience of weight sessions at least one year were divided only into two groups: with small and large number of reps, the group with average number of reps was excluded.

As a result, after 8 weeks of training there was 10% increase of cross sectional area of quadriceps muscle of thigh in both groups with no significant difference.

In the other work of this laboratory (#6) with the similar characteristics of testes, there was 10% increase in quadriceps volume with no significant difference between groups, which used similar training formula.


Specialists think that results differ from facts, described by us in previous example, because of untrained people of older age, hereupon any type of weight session of this population is able to give substantial stimulus for muscle growth. It is noteworthy that next studies, where a similar formulary was used for healthy young people, showed 18% increase in the number of satellite cells, connected to low-intensity training (with a large number of reps).

So exercises with small weight and a large number of reps to muscle failure may produce a positive impact on early stages of the process of muscle tissue formation.

Three sets with small weights give greater effect than one set with heavy weights

In Stuart Phillips laboratories there was an experiment with similar conditions for testees in order to check the hypothesis of long-term muscle increase (#7).

18 untrained people aged 20-22 were randomly divided into groups. They did different weight sessions, including knee extension of one leg to muscular failure:

– the first group did 3 sets of low intensity exercises with 30% from one rep maximum;

– the second – 3 sets of high intensity exercises of 80% from maximum;

– the third – only one set with 80% from rep max.

Trainings were 3 times a week during 10 weeks.


At the end of the study there was significant increase of muscle volume in first two groups with low and high intensity (in first group +6,8% at an average, in second +7,2%).

There was insignificant muscle increase in the third group, which did only one set, less than half a result of previous groups: 3,2%.

It means that exercises with low intensity in three sets to muscular failure are more effective than exercises closer to max weight but in one set.

It means that at your max with 100 kg. crouch stand, if you crouch with 30 kg. barbell to muscular failure, it is equal to crouches with 80 kg. barbell according to effect of muscle growth.



Studies show that average range of reps (6-12) with the use of controlled tempo in lifting weights is probably optimum for max muscle growth. This so called “hypertrophy range” possibly provides optimum combination of mechanical stress, metabolic stress, and muscle damage, thereby forming stable muscle growth.

However there are strong evidence for including different intensity loads in training programs for muscle growth. Training with small number of reps (1-5) improves neuromuscular adaptation, which is necessary for the development of max strength. Such adaptation allows using heavy weights and therefore more mechanical stress at low intensity.

And vice versa, training with a large number of reps (more than 15) can decrease lactate formation at doing exercises, delaying onset of fatigue and therefore can lead to great changes of muscle fibres.

This variative approach is of prime importance for people with considerable experience of trainings, when higher level of overwork is necessary for continuance of adaptative changes.

There is also the information that low intensity training with a large number of reps can increase muscle mass of untrained people. Trainings with low intensity to muscular failure are optimum decision for muscle mass increase of novices.

This can be useful for elderly people or those who cannot do load exercises closer to maximum.

Source: fitness-pro.ru

Author: Sergey Strukov


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