How many reps to do in a set for volume, strength, or endurance. What are sets and reps, supersets and maximum weight What are sets and how to do them
The number of sets and reps per exercise is a fairly common question on various bodybuilding forums. Professionals have long learned to choose the right approaches and repetitions, so beginners are usually interested in this issue. In general, this is a very controversial issue that is dealt with in many books on bodybuilding. Each author has his own opinion on this matter, today we will express our own.
In total, there are two global opinions about approaches and repetitions. One of them is classic, developed over the years of training by many athletes; the other is scientific, more modern. You can read about them at. But for a deeper understanding, we decided to write this article - an examination of the myths created around the choice of the number of approaches and repetitions.
Repetition - the execution of movement along a given trajectory with controlled observance of the phases of the exercise.
Set (approach) - an exercise session in which repetitions are performed.
Myth #1: All exercises should be done 8-12 reps per set.
This amount is ideal in terms of muscle building.
Origin of the myth: In 1954, one of the works of Ian McQueen (a famous MD and bodybuilder) recommended 8-12 repetitions per set for effective muscle building.
Rebuttal: such a number of repetitions keeps the muscles in an average tension, which does not allow them to be developed to the maximum.
Scientific point of view: the highest tension occurs when exercising with heavy weights, it is they that stimulate muscle growth. On the other hand, the total time during which the muscles are tense (a large number of repetitions) stimulates the structures around the muscle fibers - which increases their endurance. Variant with the number of repetitions from 8 to 12, something between tension and weight. But if you constantly work with such a number of repetitions, you will not let the muscles high level tension, which you will get only if you work with large weights.
Outcome: vary the number of repetitions with different weights.
Myth #2: Each exercise should have 3 sets.
With such a load, you will always progress, there is simply no point in doing more.
Origin of the Myth: In 1958, a post by Thomas Delorme stated that 3 sets of 10 reps would be no different in effectiveness from 10 sets of 10 reps.
Rebuttal: This is not true. Believe me, your muscles do not care about the magic of the number "3". You should know only one rule: the more repetitions in the approach, the less approaches. That is, in general, the number of repetitions remains approximately the same, only the number of divisions into sets changes.
Outcome: Average weight? - 3 sets of 8 reps. Are you lifting heavy weights and doing 3 reps? - do 6 sets.
Myth #3. You need to perform 3-4 exercises for each muscle group.
Only in this way you will qualitatively load a specific muscle.
Origin of the Myth: Arnold Schwarzenegger's Postulate (1966).
Rebuttal: the same Arnie said that in each exercise you need to perform 8-12 times in 3 sets. After averaged calculations, almost one and a half hundred repetitions for each muscle group. If you are able to withstand such a load - you are hacking. It is better to make training less voluminous, but more effective. Moreover, working on such advice, your training will take a very long time, not everyone can withstand this.
Outcome: stop at 50 repetitions (maximum) for each muscle group. It is more effective to do 1-2 exercises per muscle group, but with the correct load. You won't want to do more)
In this article, we began to learn such a question about the number of sets and repetitions of exercises. The question is very important when building a training plan. You have already figured out a little what's what, considering popular myths. To specifically find out how many repetitions and sets to do for you, read the continuation of the article.
This is an article on strength sport terminology for beginners.
Sports, like other sciences, have their own terminology. Therefore, many beginners, starting
to training, at first they don’t understand what they want from them For you to talk to athletes
V gym in one language I will explain some initial terms:
sets, reps, rest between sets, superset, maximum strength, basic exercises,
cardio, free weights...
I will also show how the necessary parameters are recorded in the training program.
WHAT ARE SETS AND REPETITIONS
Suppose you did 10 barbell squats, then rested for 2 minutes and did
10 more squats, rested again for 2 minutes and did 10 more squats.
In sports language, this means that you have done THREE sets of 10 repetitions.
In this example, the rest between sets was 2 minutes, but the rest can be different,
it depends on the purpose and on the program being used.
The number of sets and repetitions in each exercise also depends on the purpose of training.
Additionally, the training program indicates the load for each exercise.
Recording in sports program looks like that:
Shoulder Squats 3x10/50kg Rest 2 minutes between sets
Note #1
IN English language approaches are called "SET"
Therefore, in our country, too, in the English manner, approaches are often called “sets”
They say: three sets of ten repetitions. Repetitions in English would be "reps" short for word
"repetition" which in translation means repetition, repetition.
Note #2
Previously, in Soviet sports, approaches were sometimes called "series"
So the task sounded like this: four series of 12 repetitions
Note #3
Recording format may vary.
In bodybuilding, it is most often written like this:
Bench Press 3x10/50kg Rest between sets 2 minutes
This means that you need to do three sets of 10 repetitions with a load of 50 kg.
In other strength sports, the entry might look like this:
Barbell Shoulder Squats 120/3x5 (or 120x3x5)
This means 120 kg for three times in five approaches, the essence is the same, just the order of recording is slightly different.
In addition, in power sports, the load may not be indicated in kilograms, but as a percentage of the maximum.
For example: Barbell Squat 80%/3x5 (or 80% x3x5)
This means that you need to take the weight 80% of your maximum and do five sets of three repetitions.
For yourself, you can choose any convenient type of recording. If you take a ready-made program, then there should be
it is indicated how sets and repetitions are indicated, what load to use and how much rest between sets
recommended for this program.
WHAT IS A SUPERSET
Superset - performing two different exercises one after the other without rest.
You do the first exercise, then immediately the second, and only after that you rest - this is one set of a superset.
Then again perform the first exercise and immediately the second - this will be the second approach of the superset.
Let's take an example
Superset for arm muscles:
Exercise #1 - Standing Barbell Curl
Exercise #2 - french press with barbell prone
Task: 4x10 Rest 2 minutes
How to perform:
First, do the Barbell Curl – 10 reps.
Then immediately without rest "French bench press" - 10 repetitions.
This will be the first set of the superset!
After that, rest for 2 minutes and do the next approach of the superset and so on.
In fact, there is a short break between exercises in a superset while you change the machine.
or take another barbell or dumbbell. It is desirable to quickly move from one exercise to another,
so that the break does not exceed 10-15 seconds.
MAXIMUM WEIGHT (SINGLE REPETITION MAXIMUM)
The maximum weight (maximum strength, one repetition maximum) is the largest weight that
you can lift in this exercise for 1 repetition. In programs it can be referred to as "1RM"
When in the gym they ask how much you press, they usually mean how much you can squeeze out for 1 time,
that is, they ask about your maximum strength.
Attention- for beginners in the first six months of classes, I recommend not to raise Weight Limit
for one repetition (do not go to the maximum as the athletes say). First, it takes time to prepare
your ligaments and joints maximum loads, secondly, you need to master and consolidate a clear exercise technique,
otherwise, serious injury may result. Take your time, develop your abilities gradually.
To find out the maximum strength, athletes do a “driving”, you also need to be able to do it right!
You can’t immediately take and lift the maximum weight ... I’ll write more about this in another article.
AND A LITTLE TERMINOLOGY...
Free weights- barbells, dumbbells, kettlebells.
Basic exercises- the main developmental exercises for a particular sport.
In bodybuilding, powerlifting and weightlifting, this is a variety of exercises with a barbell.
Additional information in the article - it is also cardio training, it is also aerobic training.
These are the following types of load: light long run, active walking, aerobics, exercise bike,
stepper, etc. Roughly speaking, these are low and moderate power endurance loads.
Basically, these loads are aimed at burning fat, warming up / warming up, training the heart, developing endurance.
TRAINING PROGRAMS FOR REAL RESULTS
Friends, so that you do it right, I developed detailed programs workouts
Each program contains everything necessary instructions and plans for each workout.
Each program is unique - you will train with pleasure and get excellent results.
Want to know what's new on the Athletic Blog?
– and live with sports!
How to start playing sports and not become disabled
Many people start doing fitness to improve physical form or reset overweight, and end up with injuries and disappointment in sports. Most often this happens due to a lack of understanding in what quantities and with what intensity the exercises should be done. Our freelance trainer explains why to repeat exercises, how to do proper warm-up and calculate the load that is right for you.
IN training programs the number of repetitions is almost always indicated: push up 20 times or do a maximum of squats in 30 seconds. It is clear what to do, but why so? Everyone who begins to engage in self-care needs to understand how many repetitions are needed, in what exercises and for what purpose. Otherwise, there is a risk of training according to a program that will not lead you personally to the desired result. If it is promoted by a fitness businessman breaking into the market, and not by a competent coach, then there is a danger of injury and forgetting for a while about any improvement in the figure.
There is no magic or super complicated calculations in choosing a rep range. Everything is determined by understandable logic related to the reactions of our body to the load. It should be remembered that overall result It also depends on other training parameters: working weight, movement speed, rest between sets, etc. But now let's look at what number of repetitions is better in different exercises and for different purposes.
healthy approach
The main selection criterion, as always, remains health: the right load strengthens it, the wrong one destroys it.
Multi-joint ones are more physiological, movement in them is more natural for the body, so you can perform any number of repetitions in one approach - from one to tens and hundreds. An exception should be made for exercises that strain the spine: back squats and deadlifts. In them, it is better to start with the average range (6-12) even with low weight. Although multi-rep squats and deadlifts are very effective, the lower back must be accustomed to them gradually.
Everything is different with single-joint exercises: since the movement is isolated in one joint and often puts it in a less than optimal position, you need to reduce the load and do more repetitions: 15-20 or more. Never do isolating exercises in a strength style - with a maximum weight of five repetitions, three or even one. Trying to set a record will only lead to damage to the joints, ligaments and tendons.
Warm-up and training
When you first enter the gym, the body is not ready for training and needs to be awakened. To do this, a warm-up is performed, first a general one (jogging on a track, an exercise bike or light gymnastics), then a specific one - in the exercises themselves. Start with minimum weight and a large number repetitions, then gradually increase the load, reducing the number of repetitions. Let's take the barbell squat as an example.
The first warm-up set is 20-30 squats without weights.
The second warm-up set is 10–15 bodybar or empty bar squats.
The third warm-up set is 8–12 squats with a warm-up weight on the bar.
If you have problems with your knee joints or lower back (but the doctor allowed you to squat), then you may need an additional warm-up before squats: extension and flexion of the legs on the simulator or extension of the back (hyperextension). In them, too, do more repetitions - 15–25 with a minimum load to warm everything up, pump blood into the working muscles and lubricate the joints.
After warming up, start working sets of 6-10 repetitions with training weight. The first few months you need to master the technique of the exercise, not thinking about the intensity. If you can’t control the movement in this range, then do fewer repetitions in the approach, for example, three to six. At the same time, do not particularly increase the weight: it should be felt for correct execution, but do not spoil the technique. The better you learn how to do exercises at the very beginning of classes, the more strength, mass or harmony will be in the end.
Reps for Strength
Now fast forward six months: you have learned how to do the exercises correctly, the whole room is going to look at you and bow to the divine technique. What to do next? Let's say your goal is pure strength, you're going to compete in powerlifting, climbing, martial arts or ballet. In cases where you need to become stronger with a minimal increase in your own weight, you should increase the load in a small range of repetitions. In the warm-up, leave everything the same - you still need to warm up the muscles and lubricate the joints, but in working sets, do five to six repetitions. At the same time, do not bring to failure: the last repetition in the approach should be difficult, but clean. When you complete all the planned repetitions, in the next workout, add two 0.5 kg pancakes to the neck and again beat to ensure that each movement is of high quality. Want to do more? Add approaches. Sometimes try the maximum load for five, three and one repetition, but not too often - once every few weeks.
If isolation movements are required, such as arm extensions for a lagging triceps, then add them at the end of the workout in a medium-high number of repetitions - 12-20.
Reps for Mass
You can often hear in fitness clubs that for mass you need to do 8-12 repetitions, and for those who are afraid to pump over, this range scares away. The thing is, they don't hear about important nuance: in these repetitions you need to work all the way - 8–12 lifts of a cup of coffee will not add any mass. Muscles in general can grow from different ranges if sufficient training volume is gained and a certain overload occurs. So what do you do when your dream is muscle growth? Choose the most mass-gaining exercises and increase the weights in the middle range, as well as add isolation with a large number of repetitions. In deadlifts, squats and standing presses, taking care of the spine, it is better to stay at 6-10 repetitions. But in lunges, bench presses and pull-ups, you can increase to 12-15 - this will bring more mass. In bench presses and deadlifts on simulators, you can reach up to 20–25 repetitions, reaching muscle failure, and in single-joint exercises, do 30, 40, even 50 repetitions, finally finishing off the muscles so that they no longer have the right not to grow.
How much to do, so as not to pump up?
Now that we have figured out a little about the features of muscle growth, let's move on to workouts that do not increase mass, but vice versa. In order to lose weight, you can do endurance, increasing the time of work of individual muscles and developing cardiovascular and respiratory system. Let's say you need leg endurance for a long run. Marathon every day is not the healthiest solution for knee joints, but some volume of squats will help. Start with light squats and increase the number of repetitions gradually, for example, five or even one per workout. When you hit 100 reps per set, you can continue and get to 200, or you can pick up dumbbells and do sets of 20-50 reps. It’s better not to do so many times with a barbell on your back, the lower back will fail.
Another option is general endurance, developed by circular or interval training. Pick a few multi-joint exercises on the whole body, which you know how to do very well, and perform them one after another without pauses of rest - rest when you finish the whole circle. Work at medium to high reps (8-12 or 15-25), but with half as much weight as you can handle in this range. The meaning of such a scheme is in long-term work with a change of exercises: individual muscles do not get enough load for growth, but the heart and lungs work intensively, and a lot of calories are spent.
Now you know why programs and specific movements have different reps, and you can start meaningful training. First learn how to clearly do the exercises, then take on the technique that leads to your goal. Try not to break the execution technique for the sake of the protocol: if you feel that you do not control the weight and the movement deteriorates, stop the set. It’s better to miss some reps than to finish everything, getting injured and losing the opportunity to train. remember, that healthy body will always look better.
I think one of the most “rhetorical” questions in bodybuilding is how many sets and reps to do in a workout. And it's not for nothing that this question is so popular - specialization and the result in bodybuilding directly depends on the amount of work performed in training.
This is especially important with natural training. However, here, in contrast to athletes on steroids, the principle does not work - the more the better. And these features in natural training will be discussed.
How many sets per muscle group?
Let's first find out how many sets to do for each muscle being trained, namely, how much work to do in training. Based on my training experience, I can advise what works well for me, as well as for the circle of people who train with me. Therefore, all recommendations in this article will come from my personal observations, but I cannot guarantee that this is the ultimate truth for straight people. Perhaps something else will suit you, but I do not think that it will be very different from the basic principles and rules outlined in this article.
A small but very important digression from the topic.
So, first I would like to say that for beginners and more experienced athletes, the amount of work will be very different. Beginners can endure more approaches because they not so much involved in the work of the muscles like experienced bodybuilders. For example (very conditionally), in order to work out the chest muscles approximately equally, a beginner needs to do 8 approaches, and an experienced athlete only 5. At the same time muscles in an experienced athlete will still experience a greater load than in a beginner. Even under the condition that the total tonnage of work is the same for both.
The thing is that an experienced athlete was able to squeeze a huge load in just 5 approaches, while for a beginner, the load stretched over time for 8 sets. It is to such a progression of the load that one should strive natural athletes – work the muscle as hard as possible in more than a short time . This is the basic postulate of natural bodybuilding.
The most popular and easiest progression is to increase the weight on the bar. Yes, it works well in the first years of training, but gradually stagnation sets in and the working weight increases very slowly, if not completely stands still. Moreover, further progress in weight is fraught with injury. Therefore, willy-nilly, over time, it will be necessary to look for another principle of load progression. And this principle is the maximum contraction of the muscle in the approach so that it experiences a lot of stress in a very short amount of time.
And do it (perhaps surprising to many) can only using a weight of approximately 70% of the maximum. Then tendons do not experience overload And the brain does not inhibit nerve signals muscle contraction . Those. in this way we deceive our body - we force the muscles to contract more strongly (without obstacles in the form of inhibition of nerve impulses).
Thus, the conclusion is the following - in the first years of training, you can progress with weights and make a base. But then when the weights stop for a long time (and the weights themselves will be large, which is fraught with injury) you will need to move on to the next principle of load progression, which I just described in the article (working with 70% of the one-time maximum with the maximum mental contraction of the muscle).
This is why top bodybuilding pros train with relatively light weights. Yes they have days strength training, but still the main type of training is working with a weight of about 60-70% of a one-time maximum. However, they have another type of training (with which the previous one is very often confused)- pumping. Here they work with a similar weight, maybe a little less. (50-60% of times. max.), BUT at the same time they do not strongly contract the muscles - in order not to deplete the nervous system. With this training, you can train very volume (do dozens of sets per workout) and not get overtrained.
In general, it was such a digression from the main theme. But this is necessary in order to be able to show the two most effective principles of training in naturals, and also to separate beginners. (or more correctly, athletes who have been training for less than two years) from more experienced (trained for 3 years or more).
So, the first version of the progression is an increase in working weights.
For all athletes who on this moment progress with an increase in working weights, you need to do for training no more 14 working approaches (it doesn't matter if you train one muscle group or combine two or more). That is training should not last more than an hour. And this roughly equals 14 working approaches. However, this figure is not accurate, this is an approximate guideline, it may differ by a couple of approaches. The main thing is to train no more than 1 hour.
On large groups muscles must be performed in a range 7-10 working approaches, for small 3-6 . For example, when I train in a strength style, I do 8 sets for the back, and 4 sets for the biceps. In total, 12 working approaches were obtained for the training. I do 7 working sets for chest and 5 for triceps - a total of 11 sets per workout.
Rep Range i keep in the area 8-9 . However, it happens that I do both a little more and a little less number of repetitions. But I don't usually go lower. 6 and I don't get higher 11 . The scheme is something like this: at the beginning of the workout I do in the region of 10-11 (first sets), then by the 5-6th set I go down to 7-6 reps, and again I do the last sets in the range of 9-10 reps. Failure is present, approximately in the middle of the workout (when rep range drops to 6-7), in other cases, i.e. at the beginning and end of the workout - there is no failure, I stop 1-2 sets before failure. Or more precisely - when the execution technique begins to be violated, I stop the approach. Rest between sets 2-3 minutes.
The second option is the progression of maximum muscle contraction.
With this variant of the progress of the load, the number of approaches can be quite different. It all depends how strongly do you feel the trained muscle group.
The directions are something like this: 10 to 20 working sets per workout. Personally, I now do the number of approaches closer to 20 (usually 16-18) than 10. However, it all depends on how you feel, if there is a surge of strength, I do more, if not, less.
Of which number working approaches on large muscle groups 11-14 , into small 8-10 .
But with number of repetitions everything is much more interesting. It is in the region 5-8 . There is no failure in any approach. Those. the approach ends when the first signs of lactic acid acidification begin to appear.
Rest between approaches For large muscle groups(back, chest) in the area 1.5-2minutes. For the little ones - 1-1.5 minutes.
Thus, you need to choose the load progression option and focus on this basis, which is given above.
I will not describe about pumping, because. there you can take a meager purely symbolic weight and perform from 10-12 and up to 20-30 repetitions with a short rest at your discretion, i.e. as the pulse drops - immediately into battle for the next approach. But here we do not contract the muscles much, here the main task is to increase blood flow and blood flow to the muscles. With the right organization training process we can use pumping in light workouts, and it is needed not for muscle destruction, but for faster recovery and maintenance of creatine phosphate (energy in muscles) in the supercompensation phase.
In conclusion, I would like to note that, first of all, you should focus on your well-being. If you feel that some type of training is not suitable for you, feel free to change it and adjust it to suit you. Because everyone has a different daily routine, someone does not get enough sleep, someone is malnourished, etc. (although, of course, you need to strive to establish a daily routine) Therefore, everyone's recovery ability is different. Someone can train 5 times a week and do 15 sets per workout, and someone 2-3 times and 10 sets. Therefore, your well-being is the most important thing in training, and especially in natural bodybuilding, where there is no additional recovery support in the form of artificial hormones.
Your personal trainer online
Important! If you are determined to achieve the result and want to achieve your goal in the shortest possible time (gain muscle mass by correctly compiling a diet / nutrition plan, training program and daily routine), then use the services of a personal fitness trainer online ==>
Absolutely in any gym you will see people making a lot of mistakes during training - the guy on the bench beats the barbell from the chest, someone does leg curls, and at the same time his pelvis is more mobile than the hamstrings, while the other tries to press in the simulator "butterfly". These visible shortcomings can significantly slow down your progress in training, however, this is not the only thing you should worry about. What about errors you don't see?
None of these mistakes will harm your training efforts as much as choosing hard training over training smart. Many people can train hard, but it is training smartly that will help you get closer to your goal. For example, let's say you want to build muscle. You can choose light weights and do 50-60 reps, or take big weight and pick it up 10 times. In both cases, you will work hard, but one of the methods is more effective in building muscle.
Efforts are important, but they must be used wisely! In order to optimize your efforts in the gym, you need to understand what rep range is best for reaching your goal. Fortunately, research has already been done on this topic. And today we will talk about how to choose the right rep range for your goals.
Three Goals - Three Rep Ranges
Training to increase muscle volume (Hypertrophy)
If you are training to increase muscle volume, then you should select the weight in such a way that muscle failure occurs after 8-12 repetitions. In other words, after you've completed your warm-up sets - which will help you prevent injury - you should pick up a weight that you can do at least 8 and no more than 12 reps with.
This means that if you only did 6-7 reps, then that weight is too heavy and you should reduce it on the next set. On the other hand, the option when you can do more than 12 repetitions is also wrong. The correct set is when you hit failure - the point where you can't do another set on your own - in the 8-12 rep range. If you can easily do more than 12 reps, add weight to the next set to reach muscle failure in the range we need.
Of course, the guy who hits the barbell off the chest and the guy who lifts the pelvis off the bench to do the barbell press are grossly violating technique. If your technique breaks down when performing an exercise, the weight of the projectile may be too large for you. Learn and practice techniques from books.
By choosing the right load for building muscle mass, you can effectively load fast muscle fibers, which are more likely to increase volume and strength, in combination with weight training, and this will be enough to stimulate growth. However, these muscle fibers tire very quickly, so you shouldn't lift very heavy weights for high reps.
Train like a bodybuilder: if you want to increase muscle mass, aim for 8-12 reps per set and choose multi-joint movements such as bench press, squat, overhead press, bent over row and deadlift. These exercises engage more muscles than single-joint movements, allowing you to lift more weight.
Target the right muscle group different exercises with high reps and sets to stimulate growth. In general, the rest period between sets should be 1-2 minutes.
Strength training
When you pick up the weight to do 8-12 muscle-building reps, you are also building strength, no question. But this weight is not optimal for increasing strength. When your goal is to maximize strength, you should train with a weight that you can lift for only 1-6 reps. Very heavy weight makes you stronger.
This is exactly the approach to training used by the strongest men and women on the planet, especially powerlifters. They lift inhuman weights in competition and you can be sure they use a similar approach in training.
Of course, many of these athletes don't train hard all the time. They alternate high intensity workouts (heavy weights) and low-intensity periods, which helps them reduce their risk of injury, keep their joints healthy, and peak their strength for competition. They usually use a 12 or 16 week periodization program to help them progress well. First they do a set of 5 reps, then 3, and finally 2 or 1 reps. Strength training also recruits fast muscle fibers. But it is aimed not only at increasing the volume and strength of muscles, but also at training the nervous system.
Train like a powerlifter: The training of athletes for strength differs from the training of bodybuilders in that they avoid sets in failure because they can negatively affect nervous system. The rest period between sets on working weights is quite long - 3-5 minutes - in order to fully recover before the next set. After the main multi-joint exercises, auxiliary exercises are performed, which help to strengthen the weak points in the execution of the main movement.
Muscle Endurance Workouts
You may be focused on getting as big or strong as possible, but not everyone is chasing those goals. Classic example of a runner on long distances(marathon runner), who needs to run 42 kilometers at one pace, for this he develops muscle endurance. In the gym, this will mean that you need to take less weight and do 15 reps or more.
Low-intensity training usually involves aerobic exercise because oxygen plays a key role in metabolic processes. This allows you to keep you active for a longer period of time. These energy processes take place predominantly in slow muscle fibers, so by doing low-intensity, high-rep training, you create mechanisms within the muscle cell that make it more aerobic.
This type of training increases muscle endurance without necessarily increasing their volume. Well-trained athletes can perform high reps for long periods of time without feeling tired, but you are unlikely to see a marathon runner with a sprint body.
Train for endurance: The basis of training for athletes whose sports require good endurance is most often not related to the gym, so it is quite difficult to repeat their movements with weights. Multi-joint exercises performed with light weights for high reps or even weightlifting exercises can build muscle endurance, of course, as long as you can maintain proper form during the execution.
The rest period should be short enough, because. oxygen consumption and lactic acid removal process are not limiting factors in endurance training.
Relationship between reps and weight
By understanding how many reps you should be doing, you will also understand how much weight you should be lifting. These things are inseparable. If you draw a graph, you will get a linear relationship: the more weight you add, the fewer repetitions you can do; with lighter weights, you will be able to do more reps.
I'm always surprised when I'm training with a new partner who is stuck on a specific weight and rep scheme—say, 36kg dumbbell bench press for 8 reps. I tell him to take 40kg, to which he replies, "I can't do it!". In fact, he can, just not 8 times. Inevitably, after working with 40kg dumbbells and feeling this new sense of strength, he will be able to lift 42kg, and even try 45kg.
We have touched a lot important point A: You don't have to train in the same rep range all the time. You can start your workout with heavy multi-joint exercises for 5 sets of 5 reps. In order to focus on building muscle mass, you can add some exercises in the 8-12 rep range. At the end of the workout, you can work out slow muscle fibers and finish the session with isolation exercises for 15-20 repetitions.
Over time, you will understand your personal strength curve and weight-to-rep ratio in every exercise you do. It will help you a lot if you write down the weights and repetitions that you have done in a notebook. This is important because as you get stronger, you will want to lift more weight in the same rep range. When building muscle, once you can do more than 12 reps on a core exercise, it's time to increase the weights by 5-10 percent.
The weight you pick up on your strength curve should match the number of reps you need to do according to your training goal. In that sense, your workouts shouldn't be random where you just lift the same weight every session; there are more suitable weights and the optimal number of repetitions that you should do. It all depends on the goal you set for yourself!
