How to Build Muscle on GLP-1 Medications When Injuries Limit Exercise

GLP-1 medications such as semaglutide and tirzepatide have helped many people lose weight. You may be seeing real progress on the scale—and still not feel as strong or capable as you expected.

During weight loss, the body can lose some lean tissue along with fat. Strength training can help maintain muscle, but many people cannot simply walk into a gym and start lifting.

Then an old problem gets in the way. Your knee hurts when you squat. Your back flares when you lift. Your shoulder makes upper-body exercises uncomfortable. You know strength training matters, but every attempt seems to remind you why you stopped.

Physical therapy can help bridge the gap between losing weight and becoming stronger.

“I Know I Need to Exercise, but It Hurts”

We hear this all the time: “I know I need to get stronger, but everything I try seems to hurt.”

Avoiding exercise can lead to more weakness. Pushing through pain can cause repeated flare-ups.

The answer is usually not to stop moving—or to force your way through pain. It is to find a starting point your body can handle and build from there.

At Summit Physical Therapy, we use a step-by-step process to move from pain to safe strength training.

Step 1: Calm the Pain and Find What You Can Do

We first figure out what is actually bothering you. Which movements make the pain worse? What helps it settle? What can you already do comfortably?

You may need to change a squat, use less weight, choose a different exercise, or train less often. Hands-on treatment and specific exercises may also help.

These changes are not a step backward. They give you a way to keep moving while the injured area catches up.

Step 2: Restore Comfortable Movement

Stiffness can make exercise harder and place extra stress on other areas.

We focus on the movement that matters to your life. That may mean bending your knee, reaching overhead, squatting, climbing stairs, or getting up from the floor more comfortably.

Step 3: Improve Control

Before adding heavier weights, you need to control the movement comfortably.

This could mean using your hips better during a squat, improving thigh-muscle function after a knee injury, or controlling your shoulder during lifting.

Better control can make exercise feel safer and prepare your body for more resistance.

Step 4: Rebuild Strength

Pain has a way of making the body protect one area and rely too much on another. We rebuild strength in the injured area and the muscles around it.

The exercises should be challenging enough to work, but manageable enough that you are not paying for them for days afterward. As your body adapts, we gradually increase the resistance.

When appropriate, we use VALD strength-testing technology to measure your progress. This helps us identify meaningful weakness, compare one side with the other, and see whether your program is actually working.

The goal is not simply to complete exercises. The goal is to become measurably stronger.

Step 5: Return to Real-Life Strength Training

Once the foundation is in place, therapy should begin to look more like the activities you want to perform.

Depending on your goals, this may include:

• Squats or sitting down and standing up

• Step-ups and stairs

• Lifting objects from the floor

• Rows and pressing exercises

• Carrying groceries or luggage

• Getting up and down from the floor

You do not have to be “in shape” before starting. Each exercise can meet you where you are and progress as you improve.

Step 6: Build Balance, Power, and Endurance

Power is the ability to use strength quickly—such as when catching your balance or standing from a low chair.

We also build endurance so your strength lasts through a workout or busy day. More advanced patients may progress to running or sports. VALD ForceDecks may be used to measure how well they produce and absorb force.

Step 7: Return to the Activities That Matter to You

Maybe you want to feel comfortable in a gym, join a fitness class, travel, hike, play with your children, return to pickleball, or simply trust your body again.

Your rehabilitation should prepare you for that goal—not end as soon as the pain starts feeling a little better.

Weight Loss Is Only Part of the Health Equation

GLP-1 medications can be a powerful tool for weight loss, but the scale only tells part of the story. It cannot tell you whether carrying groceries feels easier, whether stairs are less tiring, or whether your body is becoming stronger.

Strength training provides the challenge your body needs to maintain and build muscle. Nutrition matters too, especially when a medication reduces your appetite. Your prescribing clinician or a registered dietitian can help you determine the right amount of protein and overall nutrition for you.

Physical therapy helps with another essential piece: making exercise feel possible again when pain has been standing in the way.

Build Strength With a Plan Designed Around Your Injury

At Summit Physical Therapy, we help patients reduce pain, return to exercise, and develop the strength needed for an active life. You will work directly with a physical therapist without aides or technicians. We also use objective strength and force-plate testing when appropriate to guide your progress.

We serve patients from Summit, Short Hills, Millburn, Maplewood, Chatham, Florham Park, New Providence, Springfield, South Orange, and surrounding New Jersey communities.

If you are taking a GLP-1 medication and pain is keeping you from strength training, you do not have to figure it out alone. Schedule an evaluation with Summit Physical Therapy. We will help you find the right starting point and build from there.