Walk into strength training and you’re hit with a wall of jargon: reps, sets, “3x10,” rest periods, RPE, time under tension, supersets. It sounds like a secret language designed to keep beginners out. It isn’t — it’s just shorthand, and once you know it, every workout instruction suddenly makes sense. Here’s the whole vocabulary in plain English.
Rep (repetition)
One complete performance of an exercise — one squat, one push-up, one curl. Down and back up: that’s one rep. That’s it. When a plan says “10 reps,” it means do the movement 10 times in a row.
Set
A group of reps done back to back without resting. “3 sets of 10 reps” means: do 10 reps, rest, do 10 more, rest, do 10 more. You did 3 sets, 30 total reps. You’ll often see this written as “3x10” — sets first, then reps. “5x5” means five sets of five.
Rest (between sets)
The break you take between sets to recover before the next one. How long depends on what you’re training:
- Strength/heavier sets: 2–3 minutes. You need to recover to lift hard again.
- General fitness/lighter sets: 60–90 seconds is plenty.
Beginners tend to either rush (and lose strength) or scroll their phone for 8 minutes. Aim for the ranges above. Resting isn’t slacking — it’s what lets the next set count.
”Rep range” and why it matters
A rep range is the target window, like “8–12 reps.” You pick a weight where the last couple of reps in that range are genuinely hard. Rough guide:
- Lower reps (3–6) with heavier weight → more raw strength.
- Medium reps (8–12) → great all-around muscle building, ideal for most beginners.
- Higher reps (15+) → muscular endurance.
For a beginner, living mostly in the 8–12 range is a great default. Don’t overthink it.
RPE (how hard it feels)
RPE means “Rate of Perceived Exertion” — a 1–10 scale of how hard a set felt. RPE 10 is all-out, nothing left. RPE 8 means you had about 2 good reps left in the tank. Most of your beginner sets should land around RPE 7–8: hard, challenging, but not grinding to total failure with ugly form. It’s a simple way to autoregulate — push when you’re fresh, ease off when you’re wrecked.
”To failure”
Doing reps until you literally can’t do another with good form. You don’t need to train to failure as a beginner — it’s exhausting, wrecks your recovery, and makes form sloppy. Leaving 1–2 reps in reserve (that RPE 8) gives you almost all the benefit with far less cost.
Time under tension and tempo
How long a muscle is working during a rep. Lowering a weight slowly (say, 3 seconds down) increases time under tension and makes the same weight harder — a handy way to make bodyweight exercises more challenging without adding load. “Tempo” just refers to controlling the speed of each rep. Translation: don’t drop the weight, lower it on purpose.
Superset
Two exercises done back to back with no rest between them, then you rest. Often paired as push + pull (like push-ups then rows) to save time. Useful when you’re busy; not mandatory.
Compound vs. isolation
- Compound exercises work multiple muscles and joints at once: squats, deadlifts, push-ups, rows. Biggest bang for your buck — build your workouts around these.
- Isolation exercises target one muscle: bicep curls, calf raises. Fine as accessories, but they shouldn’t be the main event.
Now go use it
That’s the whole language. “3x10 squats, RPE 8, 90 seconds rest” now reads as: do 10 squats with a weight that leaves ~2 in the tank, rest a minute and a half, repeat twice more. Not a secret code — just instructions.
Knowing the words is step one. Applying them consistently for months is the part that actually builds strength — and the part Gym Bully AI is built to keep you doing. Learn the terms today, then go lift.