Sets, Reps and Load: the Minimum Vocabulary
Introduction
You open any training plan and find "4×8 at 70 % with 2 RIR, rest 2'". If nobody explained that language to you, the plan is useless however good it is — and the feeling of not belonging in the training world gets reinforced again.
The good news is that the entire vocabulary fits on one page. You don't need to understand physiology: you need to be able to read a routine and execute it.
Almost every program says the same thing. What changes is the notation.
The four terms that solve nearly everything
Repetition (rep). One complete execution of the movement: you lower and raise once. Eight reps are eight in a row, without putting the weight down.
Set. A block of consecutive reps. You finish the set, rest, and the next one comes.
Load. The weight you use. It can be a dumbbell, a barbell, a band or your own bodyweight.
Rest. The time between sets.
With that you can already read the standard notation: 4×8 means four sets of eight reps. Some countries write 8×4 instead, which causes confusion; when in doubt, the larger number is usually the reps, except in maximal strength work.
How much of each
Reps: the range matters less than you'd think
There's an idea that magic ranges exist: low reps for strength, medium for muscle, high for "toning". Reality is considerably simpler.
For building muscle, the evidence shows similar results across a wide range — roughly 6 to 30 reps — as long as sets are taken close to failure. What governs is the effort, not the number.
For maximal strength, heavy loads with few reps do have an advantage.
And "toning" doesn't exist as a physiological process: it's gaining some muscle and losing some fat. High reps with light weight don't produce a different kind of muscle.
To start, the 8 to 12 range is comfortable: the load isn't intimidating, technique can be corrected, and the margin for error is wide.
Sets: fewer than you think
Between 2 and 4 sets per exercise covers almost any beginner. There is a dose-response relationship — more weekly sets per muscle group produce somewhat more muscle, up to a point — but when starting out, the limiting factor is recovery and consistency, not volume.
Load: the last-two-reps rule
This is the most useful concept in the whole article. It's called reps in reserve (RIR): how many more you could have done when the set ended.
- 2 RIR means you could have done two more.
- 0 RIR is failure: not one more with good technique.
For a beginner, leaving 2 or 3 in reserve is the right zone: enough effort to adapt, enough margin not to wreck technique or recovery.
In practice: if you finish eight reps feeling you could have done another eight, the weight is far too light. If by rep six you can't hold form, it's too heavy.
One honest caveat: beginners systematically underestimate how much they have left in reserve — believing they're near failure when five reps remain. The estimate improves over months.
Rest: longer than people think
It's the parameter most often cut short out of impatience, and the one that costs the most performance.
- Large exercises (squat, deadlift, press): 2 to 3 minutes.
- Small exercises (biceps, lateral raises): 1 to 2 minutes.
Schoenfeld's research compared 1- and 3-minute rests and found more muscle gain with the longer rests, contrary to the popular belief that short rests "burn more". If time is your constraint, the solution isn't shortening rest but alternating two exercises for different areas while one recovers.
Other terms you'll encounter
RM (repetition maximum). The weight you can lift once. "70 % of 1RM" is 70 % of that weight. As a beginner you don't need to measure it: it's uncomfortable and unreliable without experience.
RPE. A perceived-exertion scale, usually 1 to 10. RPE 8 corresponds roughly to 2 RIR.
Tempo. The speed of each phase, written as 3-1-1-0 (down, pause at the bottom, up, pause at the top). An advanced detail; ignore it at first.
Superset. Two exercises back to back with no rest between. Useful for saving time.
AMRAP. "As many reps as possible".
Progression. The principle underpinning everything: to keep improving you have to increase something over time — weight, reps, sets or difficulty. Without that, the body has no reason to adapt.
Common mistakes
Changing the weight every session without recording anything. Without a notebook or app you can't tell whether you progressed; you only remember how it felt, which is terrible data.
Chasing the number instead of the effort. Eight reps with a trivial weight aren't a stimulus, however much the sheet says 4×8.
Going to failure on every set. Very tiring, degrades technique, and adds little. Save it, if at all, for the last set of small exercises.
Cutting rest short to "get cardio in". You end up doing both worse.
Changing routine every two weeks. Without repetition there's no measurable progression and no technical learning.
Conclusion
The language of training is short: sets, reps, load, rest and a way to measure effort. With that you can read and execute virtually any beginner plan.
Apply it today in its simplest form: pick one exercise, do three sets of ten leaving two or three reps in reserve, rest two minutes between sets, and write down the weight and reps. That record is what turns a loose session into training, because it's the only thing that will tell you next week what you need to beat.
References
- Schoenfeld, B. J., Grgic, J., Ogborn, D., & Krieger, J. W. (2017). Strength and hypertrophy adaptations between low- vs. high-load resistance training. Journal of Strength and Conditioning Research, 31(12).
- Schoenfeld, B. J., et al. (2016). Longer interset rest periods enhance muscle strength and hypertrophy in resistance-trained men. Journal of Strength and Conditioning Research, 30(7).
- Zourdos, M. C., et al. (2016). Novel resistance training-specific rating of perceived exertion scale measuring repetitions in reserve. Journal of Strength and Conditioning Research, 30(1).
- Halperin, I., et al. (2022). Accuracy in predicting repetitions to task failure in resistance exercise: A scoping review. Sports Medicine, 52(2).
- Schoenfeld, B. J., et al. (2017). Dose-response relationship between weekly resistance training volume and increases in muscle mass. Journal of Sports Sciences, 35(11).