Rep Ranges & Reps In Reserve

How hard should you actually be training in the gym?

It’s one of the most common questions people ask when they start following a structured program. That’s where tools like rep ranges and reps in reserve (RIR) come in. In this post, we’ll break down how to use rep ranges and RIR to guide your training, help you progress week after week, and ultimately build more muscle.

Rep Ranges

Rep ranges give you a target window for how many reps to complete in a set. For example, a rep range of 8–10 means you should be choosing a weight that challenges you within that window - not too easy at 10 reps, but also not so heavy that you can’t get at least 8. Pairing this with your Reps in Reserve (RIR) target helps guide both intensity and load selection. If you're hitting the top of the rep range with multiple reps left in the tank, it's probably time to increase the weight.

Reps in Reserve (RIR)

Reps in reserve is a way to measure how close you took a set to failure, or how many reps you have "left in the tank". Training with RIR in mind is crucial because we need to train close to failure every week in order to achieve hypertrophy.

Why don't we just train to failure every week then? Well, we also have to consider the stimulus to fatigue ratio. Taking a set to failure is tiring and harder to recover from with little additional muscle growth compared to leaving 1 or 2 reps in reserve. We want to train as hard as we can while still being able to recover in time for our next training session.

Measuring RIR is a skill that takes time to develop. If you've never trained with RIR in mind, that's okay! It will take some time to really understand how close you are to failure and how much harder you can push yourself.

Here's how we will be using RIR during this program:

0 RIR = 0 reps left in the tank, you physically could not perform another rep while maintaining good form

2 RIR = 2 reps left in the tank at the end of your set

During your set, think to yourself, "how many more reps could I do"? If you do a dumbbell bench press for 10 reps and leave 2 reps in the tank, that's training to 2 RIR.

Throughout the training program you will see RIR targets decrease. We want each week to be a little bit harder than the last and our final week within the mesocycle will be our chance to hit PRs and take sets to failure, meaning 0 RIR.

Again, utilizing RIR targets can be tricky if you've never done it before! Focus on pushing yourself a little harder each week - you can do this by increasing the number of reps you do, going up in weight, or just improving form. All of these are ways to make an exercise harder and push yourself further.