What is hip adduction during a squat?

It means squeezing your thighs together, in this study by pressing a Swiss ball between the knees while squatting.

Do squats help patellofemoral (kneecap) pain?

In this 30-person trial, both regular squats and ball-squeeze squats reduced pain over 8 weeks, with the ball-squeeze version reducing pain more.

Can I do this exercise at home?

Yes, the program in this study was home-based. A physical therapist can help you set the right depth and form.

Research Summary

Squeezing a Ball Between Your Knees While Squatting Eased Kneecap Pain More in a Small Home-Exercise Trial

By KneePainNews Editorial Team · October 29, 2026 · Editorial Standards

Not medical advice. This is a plain-English summary for general information. Talk to your doctor or physical therapist before changing your care. Read our medical disclaimer.

People with kneecap pain who squeezed a ball between their knees while doing home squats had greater pain relief than those doing regular squats. The randomized trial was published in Medical Science Monitor.

What was studied

Patellofemoral pain syndrome (PFPS) is pain around or behind the kneecap. It is often linked to weak or poorly timed firing of the vastus medialis obliquus (VMO), the inner part of the thigh muscle that helps keep the kneecap tracking smoothly. Squeezing the thighs together (hip adduction) during squats is thought to recruit the VMO more.

In this randomized trial, 30 people with PFPS did an 8-week home program. Fifteen did traditional squats and 15 did squats while squeezing a Swiss ball between their knees. Both groups did the same stretching. Fifteen healthy people served as a comparison group. Researchers measured pain, a kneecap pain severity scale, kneecap alignment and muscle activity.

Key findings

Both squat groups improved in pain and pain severity scores.
The ball-squeeze group had a significantly greater drop in pain.
Kneecap tilt improved within the ball-squeeze group, but the difference between groups was not statistically significant.
Before training, the outer thigh muscle tended to fire before the VMO. After training, the VMO fired first, especially in the ball-squeeze group, whose pattern came to resemble the healthy group.

What it means for people with knee pain

Squats were helpful in both groups, and adding a simple ball squeeze is an easy, low-cost tweak that may add some pain relief for kneecap pain. Check with a physical therapist about depth and form, and stop if squatting sharply worsens your pain.

Limitations

The trial was small, only measured short-term results, and some benefits, like kneecap tilt, did not clearly differ between groups. Larger, longer studies are needed.

Source: Chen CL, Lo SF, Chiu MC, Chang CC, Hong WH. Refining Home-Based Squat Training: The Role of Hip Adduction in Improving Neuromuscular Control for Clinically Diagnosed Patellofemoral Pain Syndrome. Med Sci Monit, 2026 Oct 13;32:e953994. doi:10.12659/MSM.953994. PMID 42864886. Read the original

Frequently asked questions

What is hip adduction during a squat?: It means squeezing your thighs together, in this study by pressing a Swiss ball between the knees while squatting.
Do squats help patellofemoral (kneecap) pain?: In this 30-person trial, both regular squats and ball-squeeze squats reduced pain over 8 weeks, with the ball-squeeze version reducing pain more.
Can I do this exercise at home?: Yes, the program in this study was home-based. A physical therapist can help you set the right depth and form.

Sudden severe pain, swelling, or can't bear weight? Seek medical care promptly. In an emergency call 911.