How to Choose the Right Weight
One of the most common questions beginners ask is “how much weight should I use?” Choosing the right weight is crucial—too light and you won’t make progress, too heavy and you risk injury.
The Simple Rule
Choose a weight where you could do 1-3 more reps than prescribed, with good form.
If your program says 3 sets of 10 reps:
- Too light: Could do 15+ reps
- Just right: Could do 11-13 reps
- Too heavy: Can only do 7-8 reps or form breaks down
This is called having “reps in reserve” (RIR). For most training, staying 1-3 RIR is optimal.
Step-by-Step Weight Selection
For a New Exercise:
- Start very light - Maybe even just the bar
- Do 10-12 reps - Assess how it feels
- Rest briefly - 60-90 seconds
- Add weight - Small increment (5-10 lbs)
- Do 8-10 reps - Still too easy?
- Repeat until you find a challenging but controllable weight
- Record this weight - Use it as your starting point next session
For Exercises You Know:
Start with your previous weight and adjust based on how the warm-up sets feel.
Feeling strong? Maybe add 5 lbs. Tired or stressed? Keep weight the same or reduce.
Rep Range Guidelines
Different rep ranges require different weights:
| Rep Range | Weight | RIR | Best For |
|---|---|---|---|
| 1-5 reps | Heavy | 1-2 | Strength |
| 6-8 reps | Moderate-Heavy | 2-3 | Strength + Size |
| 8-12 reps | Moderate | 2-3 | Size (Hypertrophy) |
| 12-15 reps | Moderate-Light | 2-3 | Endurance + Size |
| 15+ reps | Light | 2-3 | Endurance |
Signs the Weight Is Wrong
Too Heavy:
- Form breaks down immediately
- Can’t complete prescribed reps
- Using momentum or “cheating”
- Joints hurt (not muscles)
- Need excessive rest between sets
Too Light:
- Reps feel very easy
- Could do double the prescribed reps
- No muscle fatigue at end of set
- Not breathing harder afterward
- No progressive challenge
Adjusting Weight Between Sets
It’s okay—and often smart—to adjust weight between sets:
First set too easy? Add weight for sets 2 and 3.
First set too hard? Drop weight to maintain form.
Getting weaker each set? This is normal. You can either:
- Keep the same weight and accept fewer reps
- Reduce weight to hit the same reps (called “drop sets”)
Weight Selection by Exercise Type
Compound Exercises (Squat, Deadlift, Bench)
These use multiple muscle groups and allow for heavier weights:
- Can usually go heavy
- Form is critical—never sacrifice it
- Smaller jumps in weight (5 lbs) make big differences
Isolation Exercises (Curls, Lateral Raises)
Single muscle group exercises with typically lighter weights:
- Ego aside—these should feel light
- Focus on the muscle, not the number
- Larger relative jumps okay (2.5-5 lbs)
Machine Exercises
Often the safest to test heavier weights:
- Fixed movement path reduces injury risk
- Good for pushing closer to failure
- Use full range of motion
Progressive Loading Strategy
Week to week, your goal is to gradually increase demands:
Week 1: Find working weight (3 RIR)
Week 2: Try to add 1 rep per set
Week 3: Add another rep per set
Week 4: Add weight, drop back to original reps
This creates sustainable, long-term progress.
Common Weight Selection Mistakes
1. Ego Lifting
Choosing weight to impress others rather than train effectively. Nobody watching cares what you lift—they’re focused on themselves.
2. Using the Same Weight Forever
If you never challenge your muscles with more weight, they won’t grow. Track your lifts and progress them over time.
3. Ignoring Fatigue
Some days you’re tired, stressed, or under-recovered. Using lighter weight on these days is smart, not weak.
4. Going Too Heavy on Isolation Exercises
Bicep curls don’t need to be maximal efforts. Light-moderate weight with perfect form builds more muscle than swinging heavy dumbbells.
5. Not Recording Weights
If you don’t know what you lifted last time, you can’t ensure progressive overload. Track everything.
Let FitnessCoach Choose For You
FitnessCoach tracks all your lifts and suggests appropriate weights based on:
- Your previous performance
- The exercise and rep range
- Your recovery status
- Progressive overload principles
No more guessing—just follow the plan.