Whether you're new to strength training or looking to push your limits, figuring out the right amount of weight to lift is critical. Lift too little, and you won’t see the gains you’re working for. Lift too much, and you risk injury or burnout.
At O2 Fitness, we believe fitness should be both effective and safe. That’s why we’ve put together three straightforward, science-backed methods to help you find your ideal weight (without the guesswork.)
Why Knowing Your “Max” Matters
Before we dive in, let’s talk about why finding your strength baseline is so valuable:
- Progress Tracking: You can’t improve what you don’t measure.
- Workout Efficiency: Lifting the right weight saves time and energy.
- Injury Prevention: Understanding your limits keeps your joints and muscles safe.
- Confidence Building: There’s nothing like seeing real, measurable strength gains.
Now, let’s get into the methods you can use.
Method 1: The Repetition Maximum (RM) Test
This is the most common way to gauge strength. Instead of trying a dangerous one-rep max right away, you’ll work in a rep range to estimate your capacity.
How to do it safely:
- Warm up thoroughly for 10–15 minutes (light cardio + dynamic stretches).
- Pick an exercise you’re familiar with, like the barbell bench press or squat.
- Start light. Choose a weight you can lift for 8–10 reps with moderate effort.
- Rest 2–3 minutes, then increase the weight slightly.
- Aim for 3–5 reps with good form. If it feels manageable, rest again and go slightly heavier.
- Stop when you reach a weight that feels challenging but still allows perfect form for 3–5 reps.
Pro Tip: Use an online 1RM calculator like this one from NASM to estimate your max based on these sub-maximal lifts. This keeps you safe while still giving you a clear number to work from.
Method 2: The Rate of Perceived Exertion (RPE) Scale
Sometimes the best gauge is your own body. The RPE scale ranges from 1 (extremely light) to 10 (maximum effort or nothing left in the tank).
How to use it:
- Choose a weight you can lift for 6–8 reps.
- Pay attention to how it feels.
- If it’s a 6–7 on the RPE scale (challenging but you could do several more reps), that’s your ideal weight for building muscle safely.
- If it’s a 9 (feeling like you might have one rep left in you), that’s close to your current max for that rep range.
Why it works: This method trains you to listen to your body. It’s especially useful on days when you’re fatigued or not feeling 100% to help you adjust your lifts without risking injury.
Method 3: The Form-First Approach
Form never lies. If your technique breaks down, then the weight is too heavy.
Steps to follow:
- Film yourself or work with an O2 Fitness trainer to observe your lift.
- Select a weight you believe you can lift 8 times.
- Perform the set, focusing entirely on slow, controlled technique.
- Check for signs that the weight is too heavy:
- Arching your back on the presses
- Knees caving in on squats
- Jerky, momentum-based movements
- If your form worsens before rep 8, reduce the weight by 10–20% and try again.
Remember: Perfect form with lighter weight builds more strength long-term than hazardous lifts with heavier loads.
How to Use This Information
Once you’ve found your baseline:
- For Strength: Lift at 80–90% of your estimated max for 3–6 reps.
- For Muscle Growth: Work at 70–80% of your max for 8–12 reps.
- For Endurance: Stay around 50–70% for 15–20 reps.
Always allow at least 48 hours of recovery for the same muscle groups, and never test your max more than once every 4–6 weeks.
Your Next Steps at O2 Fitness
Still unsure where to start? We’re here to help.
- Book a session with one of our certified trainers for personalized guidance.
- Join a strength-focused group fitness class to start learning weight-lifting techniques in a supportive group setting.
- Track your progress using our PRSNL app and log your lifts so you can watch your strength grow.
Finding your strength isn’t about lifting as heavy as possible; it’s about building a foundation for lasting fitness. Lift smart, stay safe, and let’s grow stronger together!
Ready to discover your strength? Visit any O2 Fitness club today for a complimentary fitness assessment with our expert PRSNL Coaches. Let’s find your starting point, safely and confidently.