Would you like to improve your performance in the gym, optimize your strength training and achieve your goals faster and more efficiently? If the answer is yes, then you need to pay attention to a key concept that many beginners ignore: repetition max or RM.
MRI is the maximum weight you can lift in a given exercise by performing a single repetition with correct technique. Knowing your RM allows you to adjust the intensity of your workout, plan your routines in a personalized way, and measure your progress over time.
In this article, we’ll explain everything you need to know about MRI: what it is, how it’s calculated, how often it should be measured, how it’s used to plan strength training, and what benefits it has for your health and aesthetics. In addition, we will answer some frequently asked questions that often arise on this topic.
If you want to get the most out of your strength training, read on and discover the importance of calculating your rep max in the gym.
What is repetition max or RM?
Definition and concept of MR
Maximum repetition or RM is the maximum weight you can lift in a given exercise by performing a single repetition with correct technique. For example, if you can bench press 100 kg once, but you can’t do it twice in a row, your RM in that exercise is 100 kg.
MRI is a measure of the maximum force you can exert on a specific movement. It’s an indicator of your muscle capacity and development potential. MRI varies depending on the type of exercise, the muscle or muscle group involved, the joint or joints involved, and other factors that we’ll look at later.
MRI is usually expressed in kilograms (kg) or pounds (lb), but a relative scale that takes into account your body weight can also be used. For example, if you weigh 80 kg and your RM on the bench press is 100 kg, your relative RM is 1.25 (100/80). This allows you to compare your strength with other people who have different weights.
Types of MRI according to the number of repetitions
Although the strictest definition of MR refers to the maximum weight you can lift at one time, you can also talk about MRI for other rep numbers. For example, your RM for 5 reps is the maximum weight you can lift 5 times in a row without losing form. Your RM for 10 reps is the maximum weight you can lift 10 times in a row, and so on.
These types of MRI are known as submaximal MRIs because they involve a lower load than absolute MRI. However, they are also useful for measuring your strength and planning your workout. In fact, it is often safer and more practical to estimate your submaximal OR than your absolute OR, as we will see later.
The relationship between the number of repetitions and the percentage of RM is inverse: the greater the number of repetitions, the lower the percentage of RM. For example, if your RM for one rep is 100 kg, your RM for 5 reps might be 90 kg (90% RM), and your RM for 10 reps might be 80 kg (80% RM). These values are approximate and depend on each person and each exercise.
Benefits of Knowing Your RM for Strength Training
Knowing your RM has several benefits for your strength training, both physically and psychologically. Some of these benefits are:
- It allows you to adjust the intensity of your workout. Intensity is the degree of effort you put into each set or exercise. It’s measured based on the percentage of your RM you use. For example, if you bench press 80 kg and your RM is 100 kg, your intensity is 80%. Knowing your MRI allows you to choose the right load for each goal, whether it’s gaining strength, hypertrophy, endurance or power.
- It helps you plan your workout in a personalized way. Each person has a different MRI depending on their weight, age, gender, experience, genetics, and other factors. That’s why there’s no point in following a generic routine that doesn’t suit your strength level. Knowing your MRI allows you to design a training plan that fits your individual characteristics and needs.
- It allows you to measure your progress over time. MRI is an objective way to assess your improvement in strength training. If your RM increases, it means that your strength has also increased. Knowing your RM allows you to set concrete, measurable goals, and check whether or not you’re achieving them.
- It motivates you and gives you confidence. Knowing your MRI makes you proud of your muscle capacity and development potential. In addition, it encourages you to surpass yourself and seek new challenges. Knowing your MRI gives you confidence and makes you enjoy your training more.
As you can see, knowing your MRI has many advantages for your strength training. But how can you calculate your RM at the gym? That’s what we’ll look at in the next section.
How to calculate your RM at the gym?
Direct and Indirect Methods for Estimating Your MRI
There are two main ways to calculate your RM at the gym: direct methods and indirect methods. Let’s take a look at what each of them consists of and what their advantages and disadvantages are.
Direct methods are those that involve lifting as much weight as possible in a single repetition with correct technique. For example, if you want to know your RM on the bench press, you should place a barbell with a weight that you think you can lift only once, and do it with the help of a partner or a trainer to secure you. If you succeed, that’s your RM. If you don’t succeed, you should reduce the weight and try again. If you succeed easily, you should increase the weight and try again. And so on until you find the exact weight you can lift just once.
Direct methods are the most accurate and reliable for calculating your RM, as they are based on your actual performance and not estimates. However, they also have some drawbacks, such as:
- They are dangerous. Lifting as much weight as possible involves a high risk of injury, especially if you don’t have good technique, proper supervision, or safety equipment. In addition, they can lead to fatigue, overtraining, and decreased performance.
- They are difficult to apply. You don’t always have the optimal conditions to perform a direct MRI test, such as a partner or a coach to help you, adequate equipment, enough time, or optimal physical and mental state.
- They are variable. Your MRI may vary depending on the day, time, mood, diet, rest, stress, weather, and other external and internal factors. Therefore, it is not enough to do an MRI test just once, but it must be repeated periodically and the average of the results must be taken into account.
Indirect methods are those that estimate your RM based on your performance with a submaximal weight and a given number of repetitions. For example, if you want to know your RM on the bench press, you should place a barbell with a weight that you think you can lift between 5 and 10 times, and do it until muscle failure (that is, until you can’t do one more repetition with correct technique). Then, you need to apply a mathematical formula that gives you your estimated OR. There are several formulas to do this, but one of the most commonly used is Brzycki’s, which goes like this:RM = peso / (1,0278 - 0,0278 x repeticiones)
For example, if you lift 80 kg 8 times until muscle failure, your estimated RM according to Brzycki’s formula is:RM = 80 / (1,0278 - 0,0278 x 8) = 92,6 kg
Indirect methods are safer and easier to apply than direct methods, as they involve less load and do not require as much help or equipment. However, they also have some drawbacks, such as:
- They are less accurate and reliable. Indirect methods are based on estimates that can have a considerable margin of error, especially if very low or very high weights are used, or if many or few repetitions are made. In addition, mathematical formulas do not take into account individual differences between people, such as weight, age, gender, experience, genetics, etc.
- They are variable. Like direct methods, indirect methods can be affected by external and internal factors that alter your performance at submaximal weight. For this reason, they should also be repeated periodically and the average results should be taken into account.
As you can see, both direct and indirect methods have their pros and cons. Ideally, combine them and use the one that best suits each situation, exercise and goal. But what factors influence your MRI? That’s what we’ll look at in the next section.
Factors influencing your MRI: weight, age, gender, experience, etc.
Your RM is not a fixed and invariable value, but depends on several factors that can modify it upwards or downwards. Some of these factors are:
- Your body weight. In general, the higher the body weight, the higher the RM, as it implies greater muscle mass and a greater ability to generate force. However, this is not always true, especially if the body weight is due to excess fat and not muscle. Therefore, it is more appropriate to use relative MRI than absolute MRI to compare strength between people of different weights.
- Your age. In general, the older you are, the lower the RM, as it implies less muscle mass and a lower ability to generate force. However, this is not always the case, especially if regular and adequate strength training is maintained to prevent the loss of muscle and strength associated with aging. That’s why it’s important to tailor strength training to every stage of life and every fitness level.
- Your gender. In general, men have a higher MRI than women, as they have higher muscle mass and a greater ability to generate force. However, this is mainly due to hormonal and anatomical differences between the sexes, and not a question of gender or ability. In fact, women can improve their RM as much or more than men with appropriate and targeted strength training.
- Your experience. In general, the more experience, the greater the RM, as it implies greater muscular adaptation and a greater ability to generate force. However, this also depends on the quality and frequency of strength training, and the progression of the workload. That’s why it’s essential to follow a training plan that fits your level of experience and allows you to move forward safely and efficiently.
- Your genetics. In general, there are people who have a higher MRI than others, as they have a greater genetic predisposition to build muscle mass and build strength. However, this is not determinative or unchangeable, as genetics can be improved or worsened by strength training and other environmental and lifestyle factors. That’s why you shouldn’t use genetics as an excuse or a limitation, but as a starting point and a challenge.
These are some of the factors that influence your MRI, but not the only ones. There are also other factors that can affect your MRI on a one-off or temporary basis, such as mood, diet, rest, stress, weather, time of day, type of exercise, muscle or muscle group, joint or joints, technique, warm-up, recovery, etc.
As you can see, your MRI is a dynamic and variable value that depends on many factors. That’s why it’s important that you don’t obsess over a number, but use it as a reference and a tool to improve your strength training. But how often should you measure your MRI at the gym? That’s what we’ll look at in the next section.
How often should you measure your MRI at the gym?
The Importance of Updating Your MRI Regularly
As we’ve seen, your MRI isn’t a static value, but changes based on your strength level and other factors. That’s why it’s important that you don’t just stick with the first value you get, but update it regularly to adapt your strength training to your progress.
Updating your MR regularly has several benefits, such as:
- It allows you to adjust the intensity of your workout. If your RM increases, you should also increase the weight you use in your exercises, to maintain the same percentage of intensity and continue to stimulate your muscle. If your MRI decreases, you should also decrease the weight you use in your exercises, to avoid overtraining and injury.
- It helps you plan your workout in a personalized way. If your RM changes, you should change your training plan as well, to adapt it to your new strength level and new goals. For example, you can vary the number of sets, repetitions, exercises, training days, type of training, etc.
- It allows you to measure your progress over time. If your RM varies, it means your strength also varies. That’s why it’s important to keep track of your MRI every exercise and every date, to see how your performance is progressing and whether you’re improving or getting worse.
- It motivates you and gives you confidence. If your RM improves, it means that your strength training is paying off and that you’re achieving your goals. This makes you proud of your work and encourages you to keep pushing yourself. If your MRI gets worse, it means that something isn’t working and that you need to review your strength training and correct any possible errors. This makes you more aware of your situation and drives you to look for solutions.
As you can see, updating your RM regularly is essential to optimize your strength training. But how often should you do it? That depends on several factors, as we’ll see below.
The variability of your MRI by type of exercise, muscle, and joint
Your MRI is not the same in all exercises, or in all muscles, or in all joints. Therefore, you should not measure your MRI with the same frequency in all cases, but you should take into account the variability of your MRI depending on the type of exercise, the muscle or muscle group, and the joint or joints involved.
In general, it can be said that your MRI varies more in exercises, muscles, and joints than:
- They involve a higher workload. Exercises that use a higher amount of weight, such as basic or compound exercises (bench press, squat, deadlift, etc.), require a higher frequency of MRI measurement, as they involve greater muscle stimulation and adaptation. The same goes for muscles and joints that support a higher workload, such as the large muscles (pectorals, lats, quadriceps, etc.) and major joints (shoulder, elbow, knee, etc.).
- They involve greater technical complexity. Exercises that require greater coordination, balance and precision, such as Olympic or weightlifting exercises (snatch, clean and jerk, etc.), require a higher frequency of MRI measurement, as they involve greater learning and technical improvement. The same goes for the muscles and joints involved in these exercises, such as the stabilizing muscles (core, rotators, etc.) and complex joints (hip, wrist, ankle, etc.).
- They involve greater individual variability. Exercises that are better or worse suited to each person, depending on their morphology, genetics, experience, preference, etc., require a higher frequency of MRI measurement, as they imply a greater difference in performance between individuals. The same is true for muscles and joints that exhibit greater individual variability, such as small muscles (biceps, triceps, calves, etc.) and secondary joints (neck, fingers, etc.).
These are some examples of exercises, muscles, and joints that require a higher frequency of MRI measurements, but they are not the only ones. There are also other factors that can influence the variability of your MRI, such as the type of training, experience level, goal, etc. Therefore, there is no fixed rule that can be applied to all cases, but you must use your judgment and common sense to determine the optimal frequency of measurement of your MRI.
Criteria for determining the optimal measurement frequency of your MRI
While there is no exact formula for determining the optimal frequency of measurement for your MRI, there are some criteria that can help you decide when and how to do it. Some of these criteria are:
- Your goal. Depending on what you want to achieve with your strength training, you should measure your RM more or less frequently. For example, if your goal is to gain maximal strength, you should measure your RM more often, as it is the primary indicator of your progress. If your goal is to gain hypertrophy, you should measure your MRI less frequently, as it’s not the only factor influencing muscle development.
- Your level of experience. Depending on your level of experience, you should measure your MRI more or less frequently. For example, if you’re a beginner, you should measure your MRI more often, as your strength increases quickly and you need to adjust your workload constantly. If you’re advanced, you should measure your MRI less often, as your strength slowly increases and you need to maintain your workload for longer.
- Your training plan. Depending on your training plan, you should measure your RM more or less frequently. For example, if you follow a periodized training plan, you should measure your RM at the beginning and end of each cycle or mesocycle, to see your progress and plan the next one. If you follow a linear training plan, you should measure your RM from time to time, to see whether or not you need to change your plan.
- Your feeling. Depending on how you feel, you should measure your MRI more or less frequently. For example, if you feel stronger, you should measure your MRI to confirm your improvement and increase your weight. If you feel weaker, you should measure your MRI to detect your problem and decrease your weight. If you’re feeling the same, you should measure your RM to check your plateau and vary your training.
These are some criteria that can help you determine the optimal frequency of measurement of your MRI, but they are not the only ones. You should also take into account other aspects, such as your availability, your motivation, your health, etc. The important thing is that you are consistent and consistent with your MRI measurement, and that you use it as a tool to improve your strength training and not as an obsession or a competition.
Now that you know how and how often to measure your RM at the gym, you may be wondering how to use it to plan your strength training. That’s what we’ll look at in the next section.
How to use your MRI to plan your strength training?
The RM Percentage Table to Adjust Your Workload
To find out what percentage of your RM you’re using at any given time, you can use an RM percentage chart that tells you the weight you should use based on your RM and the number of reps you want to do. There are several tables of this type, but one of the most widely used is Lombardi’s, which reads as follows:Peso = RM x (repeticiones)^0,1
For example, if your RM on the bench press is 100 kg and you want to do 8 repetitions, the weight you should use according to the Lombardi chart is:Peso = 100 x (8)^0,1 = 84,4 kg
This means that if you lift 84.4 kg 8 times, your intensity is 84.4% of your RM. If you want to know the weight you should use for another number of repetitions, just change the value of the formula. For example, if you want to do 5 reps, the weight you should use is:Peso = 100 x (5)^0,1 = 89,4 kg
This means that if you lift 89.4 kg 5 times, your intensity is 89.4% of your OR. This way you can calculate the weight you should use for any number of repetitions, based on your MRI and the Lombardi chart.
The Lombardi chart is a useful tool for adjusting your workload based on your RM and the intensity you want to use. However, it also has some limitations, such as:
- It’s not accurate. The Lombardi table is based on an estimate that may have a margin of error, especially if very low or very high weights are used, or if many or few repetitions are done. Also, it doesn’t take into account individual differences between people, such as weight, age, gender, experience, genetics, etc.
- It’s not universal. The Lombardi chart cannot be applied to all exercises, nor to all muscles, nor to all joints. Therefore, you should use it with caution and adapt it to each situation, exercise and goal.
As you can see, the Lombardi table is a practical tool, but not infallible. Therefore, you should use it as a reference and not as a standard, and combine it with your criteria and your feeling. The important thing is that you know how to adjust your workload according to your RM and the intensity you want to use, to optimize your strength training. But how can you design a workout routine based on your RM? That’s what we’ll look at in the next section.
Examples of workout routines based on your RM
Once you know your RM in each exercise and the intensity you want to use, you can design a workout routine based on your RM. To do this, you need to take into account other aspects, such as the number of sets, rest time, training frequency, exercise selection, exercise order, workout variation, etc.
There is no single way to design a training routine based on your RM, but it depends on your goal, your level of experience, your availability, your preference, etc. However, here are some examples of workout routines based on your RM for different goals:
- Routine to gain maximum strength. If your goal is to gain maximum strength, you can follow a workout routine that is based on the following principles:
- It uses a very high intensity (>90% of RM) and a very low number of repetitions (1-3).
- Perform a high number of sets (4-6) and a long rest time (3-5 minutes).
- Train moderately (2-4 times a week) and respect rest days.
- Select basic or compound exercises that involve multiple muscles and joints (bench press, squat, deadlift, etc.).
- Arrange the exercises from highest to lowest intensity, and from highest to lowest technical complexity.
- Vary the workout from time to time, changing the weight, the number of sets, the number of repetitions, the rest time, the selection of exercises, the order of the exercises, etc.
- Routine to win Muscle hypertrophy. If your goal is to gain muscle hypertrophy, you can follow a training routine that is based on the following principles:
- Use a medium intensity (70-80% RM) and a medium number of repetitions (7-10).
- Perform a moderate number of sets (3-4) and a short rest time (1-2 minutes).
- Train at a high frequency (4-6 times a week) and work each muscle at least twice a week.
- Select a variety of exercises that involve different muscles and joints, both basic or compound and isolated or specific (bench press, biceps curl, quadriceps extension, etc.).
- Sort the exercises from highest to lowest intensity, and from highest to lowest muscle involvement.
- Vary the workout from time to time, changing the weight, the number of sets, the number of repetitions, the rest time, the selection of exercises, the order of the exercises, etc.
- Routine to gain muscular endurance. If your goal is to gain muscular endurance, you can follow a workout routine that is based on the following principles:
- Use a low intensity (60-70% RM) and a high number of repetitions (11-15).
- Perform a low number of sets (2-3) and a very short rest time (30-60 seconds).
- Train at a moderate frequency (3-5 times a week) and work each muscle at least once a week.
- Select simple exercises that involve few muscles and joints, both isolated or specific and basic or compound (biceps curls, bench presses, quadriceps extensions, etc.).
- Rank the exercises from lowest to highest intensity, and from lowest to highest muscle involvement.
- Vary the workout from time to time, changing the weight, the number of sets, the number of repetitions, the rest time, the selection of exercises, the order of the exercises, etc.
Here are some examples of workout routines based on your RM for different goals, but not the only ones. You can also create your own workout routines based on your RM, following the principles we’ve explained and adapting them to your situation, exercise, and goal.
Conclusion
In this article, we’ve explained everything you need to know about MRI: what it is, how it’s calculated, how often it should be measured, how it’s used to plan strength training, and what benefits it has for your health and aesthetics. In addition, we have given you some examples of training routines based on your RM for different goals.
We hope you found this article helpful and that it encourages you to calculate your RM in the gym and use it to improve your strength training. Remember that MRI is a tool that allows you to adjust the intensity of your training, plan your training in a personalized way, measure your progress over time, and motivate and give you confidence.
If you want to know more about MRI or strength training, do not hesitate to consult our other articles or contact us. We will be happy to help you and answer your questions. See you next time!
Frequently asked questions
Which is better: doing more reps with less weight or fewer reps with more weight?
There is no one-size-fits-all answer to this question as it depends on your goal, your level of experience, your preference, etc. In general, it can be said that doing more repetitions with less weight is better for gaining muscular endurance and power, while doing fewer repetitions with more weight is better for gaining maximal strength and muscle hypertrophy. However, the ideal is to combine both types of training, varying the weight, number of repetitions, intensity and volume of work, to achieve balanced muscle development and avoid stagnation or overtraining.
What is the difference between MR and 1RM?
MRI is the maximum weight you can lift in a given exercise by performing a single repetition with correct technique. The 1RM is the same concept, but specifying that it is a single repetition. Therefore, there is no difference between RM and 1RM, they are two ways of expressing the same thing. However, you can also talk about RM for other rep numbers, such as 5RM, 10RM, etc. In that case, MRI refers to the maximum weight you can lift in a given exercise by performing that number of repetitions with correct technique.
What are the risks of doing an unsupervised 1RM test?
Doing an unsupervised 1RM test has several risks, such as:
- Getting injured. Lifting as much weight as possible involves a high risk of injury, especially if you don’t have good technique, proper preparation, or safety equipment. In addition, if there is no one to help or help you in the event of an accident, the consequences can be serious.
- Overtraining. Lifting as much weight as possible involves a high level of effort, which can lead to fatigue, exhaustion, decreased performance, hormonal, immunological and psychological alterations, etc. If there is no one to monitor or advise you, you can fall into overtraining and harm your health and aesthetics.
- Getting the wrong result. Lifting as much weight as possible involves high precision and reliability, which can be affected by external and internal factors that alter your performance. If there’s no one to supervise or correct you, you can get the wrong result and plan your training inappropriately.
As you can see, doing an unsupervised 1RM test has many risks and few advantages. For this reason, we recommend that whenever you can, you take a 1RM test with the help of a partner, a coach or a qualified professional, who will secure, guide and evaluate you correctly.
What can I do if I don’t have access to a gym to measure my MRI?
If you don’t have access to a gym to measure your RM, you can use other alternative methods that allow you to estimate your RM from your performance with a submaximal weight and a given number of repetitions. For example, you can use dumbbells, elastic bands, your own body weight, or any other element that offers resistance, and apply a mathematical formula that gives you your estimated OR. However, you should keep in mind that these methods are less accurate and reliable than the direct methods performed in the gym, and that they can have a considerable margin of error. Therefore, we advise you to use them only as a reference and not as a rule, and to combine them with your criteria and your feeling.