How Hard Should You Train to Build Muscle? (RIR, RPE, & 1RM)
One of the most common questions in strength training is: "How much weight should I use, and how many reps should I do?"
Doing resistance training effectively is a delicate balance of adding enough challenge to your muscles, but not so much that you sacrifice proper form (or put yourself at risk of injury).
In today’s message, we’ll look in detail at how you can monitor your intensity while doing your resistance training exercises to maximize your gains while staying safe.
Sets & Reps Recommendations
For muscle-building, experts generally recommend performing a weekly total of between 10 and 20 sets for each muscle group. You can do a variety of exercises for each muscle group, as long as the total number of sets comes out to between 10 and 20 each week.
You can split your sets up in several ways, according to your training schedule:
If you’re a beginner and only training between 1 and 3 times per week, you might prefer to split up your sets between your workouts. For example, to work the quads on Day 1, you might do 3 sets of squats, on Day 2 you might do 4 sets of lunges, and on Day 3 you might do 3 sets of leg press. This will prevent you from overly tiring the muscle group past what your body can properly recover from.
If you’re intermediate or advanced and training 3 or more times per week, you might benefit more from doing most of your sets for a muscle group in one or two workouts. For this reason, many intermediate/advanced exercisers split their workouts into muscle-group focus days (Day 1: Legs, Day 2: Back, Day 3: Arms, etc)
Some people prefer to work on different muscle groups according to movement patterns like pushing, pressing, pulling, squatting, hip hinging, and rotation. This is generally best for athletes or exercisers who are interested in moving better. For example, a popular movement-focused split is called Push-Pull-Legs (Day 1: Push, Day 2: Pull, Day 3: Legs).
Regardless of your schedule, for muscle-building sets it’s generally recommended to do 2-3 sets per exercise, working within a high rep range of between 8 and 25 reps per set. Rest should be between 30 seconds and 2 minutes between sets.
Weight Recommendations
Use an amount of weight that gets your target muscles “burning” within the recommended number of reps per set in your program.
For example: If your recommended reps are 10-15 reps, use a weight that has your muscles getting tired and approaching muscle failure on reps 10, 11, 12, 13, 14, or 15 of each set.
If you have tested your 1 rep max (1RM) in an exercise, you can also base your training weight on a percentage of your 1RM. For muscle-building, experts generally recommend using between 60% and 75% of your 1RM.
When to Stop Your Set
It’s important to listen to your body while performing your sets. This will allow you to determine when you should end your set to maximize gains and minimize your risk of injury.
As I mentioned above, the goal in muscle-building sets is to fatigue the target muscle groups and let them “burn” as they approach failure. In general, it’s best to stop just short of muscle failure to avoid injury and overtraining.
But how can you tell if you’re getting close enough to muscle failure?
Reps in Reserve (RiR)
Most of the time for muscle-building, it’s best to leave between 1 and 3 reps in reserve in each training set. This means stopping when you can only do 1, 2, or 3 more reps before your muscles give out. This is usually denoted in training programs as 1RiR, 2RiR, or 3RiR.
Sometimes it’s hard to gauge how close you are to muscle failure. One way to work around that is to perform what’s called an AMRAP set (AMRAP stands for “as many reps as possible”). To do this, perform as many reps as you can until your muscles completely give out, or once you find you can no longer keep good form. Write down how many reps you performed in your AMRAP in your fitness journal or tracking app.
After your AMRAP set, compare the number of reps you performed with the number of reps recommended per set in your program. If you had to stop within your recommended rep range, you are likely using just the right weight for that exercise. In future sets, stop the set at 1, 2, or 3 reps before your AMRAP total.
If, however, you were able to do 5 or more reps above the recommended number of reps in your program, that’s a sign that you should use more weight for that exercise in the future. If, on the other hand, you could barely get the minimum number of recommended reps, then you should use less weight.
Doing AMRAP sets can help you get a sense of what it feels like to approach muscle failure. But paying attention to how fast or slow your reps are can also give you a clue of when to stop your set. You should be able to perform most of the reps of your set at a pace of 2 seconds “up” and two seconds “down” (unless your program recommends a different speed). Once your reps begin to slow down, end your set before your technique breaks down.
Rate of Perceived Exertion (RPE)
Another way to monitor the intensity of your training is to use the Rate of Perceived Exertion (RPE) scale. At the end of every set of an exercise, ask yourself “How hard am I working on a scale of 1 to 10:
RPE 1-4: Light resistance that can be used for mobility, recovery, and form emphasis.
RPE 5: Warmup Resistance Level (5 Reps in Reserve)
RPE 6: 4 Reps in reserve. Resistance level that one can move quickly for speed work (+/- 8 reps pending on speed/training goal).
RPE 7: 3 Reps In Reserve. Able to move quickly, form stays solid, and you could definitely get 3 more reps.⠀
RPE 8: 2 reps in Reserve. Resistance level is challenging but isn’t so heavy that you couldn’t do at least 2 more reps.
RPE 9: 1 rep in reserve. Tough but could squeeze out one more rep if you needed to.⠀
RPE 10: 0 reps in reserve. Max effort, couldn’t do another rep if your life depended on it.
In general, you should work at an RPE between 7 and 8 (sometimes 9) to make muscle gains.
If an exercise is too easy, you can make adjustments (like adding more weight, more reps, or do a more difficult variation of the exercise). If it’s really difficult for you to do the recommended number of reps in each set, then you’ll want to reduce the resistance or weight for that exercise.
When you’re first learning a new exercise, I recommend practicing the movement for 1 or 2 sets at an RPE level 4 or 5. This means that you’re putting in effort but not tiring yourself out in any way.
Once you get familiar with the movement, then you can gradually challenge yourself by adding more resistance (using more weight or a heavier band). Keep it light initially, starting with a low weight/resistance level for 1 or 2 sets. Adjust the weight or resistance until you’re working at an RPE level 6 or 7. At that point, you should start to feel tired in the last few repetitions and you may feel the target muscles beginning to burn.
As you get more comfortable with the technique of the exercise, you can begin to challenge yourself at an RPE level 8 or 9. This means using a weight and doing a number of repetitions that fatigues the muscles and really has them burning by the last repetition, until you feel like you could only do 1 or 2 more reps before your muscles give out.
As you add on more weight to challenge yourself, remember to always prioritize doing your exercises with good technique while keeping your body in alignment. Never sacrifice good form to add more weight or squeeze out another rep–especially as a beginner. Neglecting your technique to do more can lead to injury or muscle strain.
Practice Progressive Overload
Keep in mind that as you get stronger, you will need to do more repetitions and use more weight to fatigue your muscles and keep them challenged. Increase the number of reps that you do in each set over several weeks until you are able to do the maximum number of reps recommended in your program. At that point, you can either add another set of the exercise, or you can increase the weight gradually by about 10-20% at a time (or to a weight that feels more challenging within the recommended rep range for each set).
A good rule of thumb to follow is the rule of two: if you’re able to perform the same amount of weight with the same number of reps two workouts in a row, then progress the exercise by either adding another set or increasing the weight.
Final Thoughts
Choosing the right weight and rep scheme doesn’t have to be complicated. Whether you prefer the intuitive approach of RIR, the subjective feedback of RPE, or the structured guidance of percentage-based training, all three methods can help you optimize your workouts. The key is consistency—track your progress, listen to your body, and adjust as needed.
Which method do you prefer? Let me know in the comments!
