Strengthening the psoas requires targeted hip flexion exercises that isolate the deep core, since this muscle sits behind your abdominal organs and is difficult to feel working directly. The psoas runs from your lower spine to your thighbone, making it central to walking, standing upright, and stabilizing your lower back. A weak psoas often shows up as lower back stiffness, hip pain, or a shuffling gait rather than obvious muscle fatigue, which is why many people don’t realize it’s the source of their problems.
What the Psoas Actually Does
The psoas major is one of the deepest muscles in your body. Its upper end attaches along the sides of the lowest thoracic vertebra and the first four lumbar vertebrae, threading through your pelvis before anchoring to a small bony bump on the inside of your upper thighbone called the lesser trochanter. That long diagonal path gives it three jobs at the hip: flexing (lifting your knee toward your chest), slightly rotating your thigh outward, and pulling it toward your midline.
When you’re sitting, the psoas shifts roles. Instead of moving your leg, it acts as a stabilizer for your lumbar spine, helping keep your lower back in a neutral position. This dual role is why problems with the psoas can show up as either hip trouble or back pain depending on what you’re doing at the time. About 60% of people also have a smaller companion muscle called the psoas minor, which runs alongside it and contributes a small amount of trunk flexion and pelvic stability.
How a Weak Psoas Shows Up
Psoas problems rarely announce themselves as “hip flexor weakness.” Instead, you’re more likely to notice a dull ache in the border between the bottom of your spine and your buttocks, stiffness when you first stand up, or groin and pelvic pain that’s hard to pinpoint. The discomfort often radiates down the legs and gets worse when you try to stand fully upright, because extending the hip stretches the irritated muscle.
In more pronounced cases, the pain can be enough to change how you walk. You might find yourself limping, shuffling, or taking shorter steps to avoid fully extending the hip on the affected side. If you spend most of your day sitting, the psoas stays in a shortened position for hours, which can make it both tight and weak at the same time. That combination is common and important to recognize, because a tight psoas needs stretching while a weak one needs strengthening, and many people need both.
Testing Tightness vs. Weakness
A simple clinical test called the Thomas test helps sort out whether your psoas is short and tight, weak, or both. You lie on the edge of a table, pull one knee to your chest, and let the other leg hang down freely. If the hanging leg can’t drop to table level and stays elevated, the psoas on that side is tight. If it drops easily but you struggle to hold the leg up against light resistance, the muscle is weak. Your back and sacrum need to stay flat on the table for the test to be accurate, since arching your back masks tightness by tilting your pelvis forward.
You can approximate this at home on a firm bed. Scoot to the edge so your tailbone is right at the corner, hug one knee, and let the test leg hang. Pay attention to whether the thigh stays above horizontal (tight) and whether lifting it back up feels difficult (weak). This gives you a rough sense of which exercises to prioritize.
Five Exercises That Target the Psoas
Supine Straight-Leg Raise
Lie on your back with both legs extended. Bend one knee and plant that foot flat on the floor to protect your lower back. Tighten the thigh of the straight leg, then lift it about eight inches off the ground. Hold for a few seconds, lower slowly, and repeat. Aim for two sets of 15 on each side. This is one of the most direct ways to load the psoas, because lifting a straight leg from a flat position demands significant hip flexor effort without much help from momentum.
Standing Lunge
Stand with feet hip-width apart, step one foot forward, and lower your back knee toward the floor until both knees form roughly 90-degree angles. Keep your torso upright and don’t let the front knee drift past your toes. Two sets of 10 on each side. Lunges strengthen the psoas of the front leg through the flexion effort while simultaneously stretching the psoas of the back leg. That dual effect makes them especially useful if you’re dealing with both tightness and weakness.
Prone Hip Extension
Lie face down with your arms folded under your forehead. Draw your belly button toward your spine to brace your core, then tighten the glute and thigh of one leg and lift it about eight inches off the floor, keeping the knee straight. Hold for five seconds, lower slowly. Two sets of 15. This exercise strengthens the posterior chain (glutes and hamstrings) that works opposite the psoas. Balanced strength between the hip flexors and extensors is essential for pelvic stability, so this belongs in any psoas-focused program even though it targets the back of the hip.
Side-Lying Leg Lift
Lie on your side with both legs stacked. Keeping the top leg straight, lift it about 12 inches, pause, then lower with control. Two sets of 15 on each side. While this primarily works the outer hip, it also engages the psoas in its role as a hip stabilizer. Strengthening the muscles that surround the psoas prevents it from being overloaded during everyday movements like climbing stairs or getting out of a car.
Psoas March (Standing or Supine)
This exercise isn’t in every rehab handout but is widely used by physical therapists for direct psoas activation. Stand tall with your core braced, then slowly lift one knee above hip height, hold for two to three seconds, and lower it with control. Alternate legs for 10 to 15 repetitions per side. The key is moving slowly enough that momentum doesn’t take over. If standing feels unstable, do the same movement lying on your back: press your lower back into the floor, then lift one bent knee toward your chest against the resistance of your own hand pressing down on the thigh. That manual resistance ensures the psoas is doing the work rather than letting gravity assist.
Programming and Progression
Start with bodyweight only and focus on slow, controlled movement through the full range of motion. The psoas responds better to time under tension than to heavy loading, especially early on. Two to three sessions per week with a day of rest between sessions is enough for most people. If you can comfortably complete two sets of 15 on the straight-leg raise and lunge without hip or back discomfort, you can progress by adding light ankle weights (two to five pounds), increasing hold times, or slowing the lowering phase to four or five seconds.
Pair strengthening with brief psoas stretches on your off days. A half-kneeling hip flexor stretch held for 30 seconds per side helps maintain the length you need for the muscle to contract through its full range. If you sit for long periods, standing up every 45 to 60 minutes and doing a few hip flexor stretches prevents the muscle from adaptively shortening, which would undermine your strengthening work.
Common Mistakes to Avoid
The biggest error is letting your lower back arch during supine exercises. When the psoas fires and your core can’t stabilize the spine, the lumbar vertebrae get pulled into extension. That arching transfers stress to the small joints of the spine and can cause the very back pain you’re trying to fix. Before every rep, press your lower back into the floor or table and keep it there throughout the movement. If you can’t maintain a flat back, the exercise is too advanced. Reduce range of motion or bend the working leg slightly until your core catches up.
Another common issue is substituting with the rectus femoris, the large quad muscle that also flexes the hip. You’ll know this is happening if your thigh burns intensely but your deep hip and lower abdomen feel nothing. Slowing the movement, lifting the leg with the knee bent (which shortens the rectus femoris and reduces its contribution), and focusing on initiating the lift from deep in the hip crease all help shift the demand toward the psoas.
Finally, don’t ignore pain. A dull, deep ache during hip flexion exercises that worsens over days rather than improving could indicate psoas tendinitis or a strain rather than simple weakness. Strengthening an inflamed tendon without addressing the inflammation first tends to make the problem worse. Rest, gentle stretching, and a period of reduced loading usually need to come before progressive strengthening in those cases.