By Tom Wigginton
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October 3, 2025
Every time you pick up a dumbbell or load a barbell, you’re faced with making a decision: How heavy should I go? Too light, and you’re just passing the time and your body never gets the signal to adapt. Too heavy, and you risk poor form or injury. Somewhere in the middle is the “sweet spot” where strength, muscle, bone, and metabolic improvements are stimulated. The question is: how do you find that sweet spot without risking over-doing it or under-doing it. Choosing the right weight can be a tricky process that involves your experience, training history, daily energy levels, focus, goals, hopes, and dreams. That’s where Reps in Reserve (RIR) comes in. If you finish a set of squats and you know, deep down, you could have squeezed out three more reps before you collapsed, that’s 3 RIR.