Fitness terms can feel like another language. They're mostly simple ideas with shorthand names. This guide translates the essential ones.
#Reps, Sets, and Effort
Rep (Repetition): One complete movement - one squat equals one rep.
Set: A group of reps done without stopping. Written as 3x10 (3 sets of 10 reps).
RIR (Reps in Reserve): How many more reps you could still do. RIR 3 means you stop when you could do 3 more. RIR 0 means muscle failure.
RPE (Rate of Perceived Exertion): How hard it feels on a 1-10 scale. RPE 7-8 is hard effort; you can only speak in short phrases.
1RM: The maximum weight you can lift once - used to calculate training percentages.
#Movement Types
Compound exercises work multiple muscle groups and joints at once - squats, push-ups, deadlifts. Best bang for your buck.
Isolation exercises target one muscle group - bicep curls, leg extensions. Good for targeting weak points.
#Rep Phases
- Eccentric: The lowering/lengthening phase (most muscle damage occurs here)
- Isometric: Holding still under tension
- Concentric: The lifting/shortening phase
#Cardio Terms
LISS: Low Intensity Steady State - easy, sustainable pace you can maintain.
HIIT: High Intensity Interval Training - short bursts of hard work followed by rest.
#Macronutrients
The three macros and their calorie content:
- Protein: 4 calories per gram (builds/repairs muscle)
- Carbs: 4 calories per gram (primary energy)
- Fats: 9 calories per gram (hormone production)
#Recovery Terms
DOMS (Delayed Onset Muscle Soreness): The soreness 24-48 hours after exercise. It is normal and not an injury - it decreases as you adapt.
Active Recovery: Light movement on rest days. Not another workout.
Deload Week: Planned easy week at 50% normal intensity, usually every 4-6 weeks.
#Key Phrases Decoded
- Mind-muscle connection: Focusing on feeling the target muscle work during an exercise
- "What's your split?" = How do you divide your training days? (Upper/Lower, Push/Pull/Legs, Full Body)
- "To failure" = Exercise until you can't do another rep with good form
- AMRAP = As Many Reps (or Rounds) As Possible
- Neutral spine = Natural back position, not arched or rounded
With these terms, you can read programs, talk to trainers, and join gym conversations without feeling lost.