How to Know If You’re Lifting Heavy Enough: A PT + Strength Coach’s Guide

Most women come to us saying the same thing:

“I lift weights… but I’m not seeing the changes I expected.”

And most of the time, it’s not because they aren’t working hard — it’s because their weights simply aren’t heavy enough to stimulate real strength or body composition changes.

Today, I’m breaking down exactly how to know if your weights are heavy enough, how to adjust them, and what “challenging but safe” truly feels like.

Why Lifting Heavy Matters (Especially for Women)

Strength training is one of the most powerful tools you have for:

• Improving metabolism

• Building lean muscle and definition

• Supporting fat loss

• Enhancing posture and joint health

• Improving bone density and longevity

• Reducing injury risk

• Boosting confidence and mental health

But these benefits only happen when the muscle is adequately challenged.

Light weights with endless reps feel productive — but physiologically, they work more like cardio, not strength training.

If your goal includes fat loss or improving metabolism, you need enough intensity to create muscular change and improve body composition.

What is body composition? Body composition is the breakdown of what your body is made of — mainly muscle, fat, bone, and water. Instead of just looking at your weight on a scale, body composition tells you how much of your body is muscle vs. fat, which gives a much clearer picture of your health and fitness.

3 Signs Your Weight Is Too Light

Here’s how to know if the weight you’re using isn’t doing much for you:

1. You can talk easily during the set

If you can carry on a full conversation while lifting, you’re not close to the intensity you need for strength.

2. You finish the set thinking, “That wasn’t bad at all.”

The last few reps should feel like work — not a warm-up.

3. You could keep going for 10–15 more reps

This is the clearest sign the stimulus is too low.
If your goal is strength or muscle tone, you want to be far closer to fatigue.

The “2 Reps in Reserve” Rule (Simple & Evidence-Based)

This is my favorite way to teach clients how to self-assess intensity:

After your set, ask yourself:
“If I absolutely had to, could I do 2 more reps with good form?”

• Yes, I could do 2 more → Perfect weight

• I could do 5–10 more → Too light

• I couldn’t do even 1 more → Too heavy for that rep range

This method is widely used in strength and conditioning because it’s safe, effective, and easy for beginners to understand.

What the Right Weight Should Feel Like

When your weight is “just right,” you’ll notice:

• The last 2–3 reps feel challenging but controlled

• You need to focus to complete the set

• Your breathing increases

• Your form stays clean (you’re not flinging or rocking the weight)

• You feel muscle fatigue, not pain or joint pressure

Remember: Discomfort from effort is normal. Pain in a joint is not.

*This is when training with a Physical Therapist can be incredibly beneficial…we can easily adjust your program to reduce injury risk and pain*

Whether Your Goal Is Strength, Fat Loss, or Better Health

Aim for:

• Heavier weight, but still maintaining proper control and form

• You finish the set thinking, “I may have 1 or 2 reps left only.”

• You follow a progressive program that allows for improvement and increase in weight for certain movements each week

• Improved diet: Nutrition is KEY for muscle gain and fat loss!!!

  • You MUST consume enough protein in order to build muscle. You MUST reduce your sugar and processed food intake for fat loss. You MUST drink enough water to properly hydrate and recover from workouts.

Lower reps + higher intensity = more strength adaptation. AKA, 6 very difficult reps at a heavy weight will produce better strength gains than 12 easy reps at a lighter weight

When to Increase Your Weight

Progressively increasing load is the secret behind every successful program.

You should increase weight when:

• Your last reps no longer feel challenging

• You can easily hit all reps for 2–3 workouts in a row

• Your form stays perfect the entire time

• Your heart rate doesn’t increase as much during your workouts and you don’t need rest breaks between sets

• You find yourself talking or zoning out during the set

• You don’t feel any fatigue in the muscle afterward

Your body adapts quickly — and if you don’t adjust, your progress plateaus.

A Final Note — Women Are Stronger Than They Think

Most women are lifting below their capability.

Not because they’re weak — but because they’ve been conditioned to fear heavy weights or to believe “toning” requires light dumbbells.

But challenging yourself is the key to:

✨ Faster results/Improved body composition
✨ A healthier metabolism
✨ Stronger bones
✨ Long-term, sustainable fitness
✨ Better confidence

Strength is empowering — and you deserve to train in a way that reflects your goals.

Want Help Choosing the Right Weights or Building a Program?

If you’re unsure where to start or you want a personalized plan designed by a DPT + Strength Coach, we’d love to help you.

At Plus Forte, we create customized strength, mobility, and wellness programs that help women build strength safely and effectively.

📍 North Chelmsford, MA
💪 Physical Therapy • Strength Coaching • Nutrition
📞 978-590-6951
🌐 plusforte.co
📸 @plusfortept