If you’ve ever stared at a dumbbell and wondered, “Is this too heavy? Too light?”, you’re not alone.

Choosing the right weight can feel like guesswork - but there’s a simple technique that can take the stress out of it: Reps in Reserve (RIR).

So, what is RIR?

Reps in Reserve is just a fancy way of saying, “How many more times could I lift this weight before I absolutely couldn’t do another rep?”

For example, if you do 10 reps and could’ve done 2 more, your RIR is 2.

Why it matters ...

You don’t need to push to your max every set.

In fact, leaving a few reps in the tank can:

Reduce injury risk

Help you recover faster between workouts

Make your sessions more consistent and enjoyable

How to use it at the gym:

Pick a weight that feels challenging but doable.

Do your set, and notice how many reps you could’ve done with good form if you really pushed.

Adjust next time:

If you had plenty of reps left, go slightly heavier.

If you couldn’t finish the set with the number of reps on the programme, drop the weight a bit.

Think of it like a gas tank - you don’t need to hit empty every time.

Stopping a couple of reps before fatigue helps you build strength steadily, safely, and keeps you moving well for the long term.

Bottom line ...

Reps in Reserve is a simple way to take the guesswork out of your workouts.

It lets you challenge yourself just enough to get results, without overdoing it.

Next time you pick up a dumbbell, ask yourself: “How many reps do I have left in the tank?”