Lower Back Stiffness? The Hip Mobility Test Every Active Adult Should Try.

You bend down to pick up something off the floor and feel it: that familiar tightness in your lower back. Or maybe your back feels stiff first thing in the morning, especially after a winter of less activity. You stretch it, roll it, maybe even get a massage. It feels better temporarily, but the stiffness keeps coming back.

If this sounds familiar, you might be treating the wrong area. At Nashville Physical Therapy & Performance, we see this pattern constantly: people spend months trying to fix their lower back when the real problem is a few inches away, in their hips.

Let's talk about why hip mobility matters so much for your lower back and how to test whether your hips are contributing to your stiffness. Lower Back Stiffness? The Hip Mobility Test Every Active Adult Should Try:

Why Hip Restrictions Show Up as Back Pain

Your hips and lower back work as a functional unit. When you bend forward to tie your shoes, squat down, or even sit in a chair, motion should come from both areas. Ideally, your hips provide the majority of the movement while your lower back contributes a smaller amount.

But when your hips lose mobility, especially after a sedentary winter, your lower back has to compensate. Every time you need to bend, your spine picks up the slack for motion that should be coming from your hip joints. Over time, this compensation pattern overloads the lower back, leading to stiffness, achiness, and eventually pain.

The technical term for this is the lumbopelvic rhythm. It describes how your hips and lower back coordinate movement. When this rhythm gets disrupted by tight hips, your lower back pays the price.

Research published in the Journal of Orthopaedic & Sports Physical Therapy found that individuals with chronic lower back pain demonstrate significantly reduced hip mobility compared to those without back pain.[^1] The connection is clear and well-established in the research literature.

The Two Hip Mobility Restrictions That Cause the Most Problems

Not all hip tightness affects your back equally. There are two specific restrictions that create the most issues:

1. Hip Flexion (Bringing Your Knee to Your Chest)

Hip flexion is the motion you use every time you bend forward, squat down, climb stairs, or bring your knee up toward your body. When hip flexion is limited, your lower back has to round excessively to make up for the lost motion.

This is why people with tight hips often feel their lower back rounding and straining when they bend forward to pick something up or tie their shoes. The movement has to come from somewhere, and if the hips won't provide it, the spine does.

2. Hip Extension (Moving Your Leg Behind Your Body)

Hip extension is the backward motion of your leg, which happens with every step you take when walking or running. It's also crucial for lunging, climbing, and generating power during athletic movements.

After a winter of sitting more and moving less, hip extension mobility often decreases. Your hip flexors (the muscles at the front of your hip) adapt to a shortened position and resist lengthening. When you try to walk or run in spring, your lower back extends excessively to compensate for the hip extension you've lost.

This compensation is one of the most common reasons active adults develop lower back pain when they ramp up spring training.

The Hip Mobility Tests You Need to Try

Here are three simple tests to assess whether your hips are contributing to your lower back stiffness. These take less than 5 minutes and can be done at home with no equipment.

Test 1: The 90/90 Hip Flexion Test

How to do it: Lie on your back with both knees bent and feet flat on the floor. Bring one knee up toward your chest, holding it with both hands behind your thigh (not on top of your kneecap). Gently pull your knee as close to your chest as comfortable while keeping your other leg relaxed on the ground.

What to look for:

• Can you bring your knee to at least 90 degrees (thigh perpendicular to the ground) without your lower back arching off the floor?

• Does your opposite leg stay flat on the ground, or does it lift up or straighten?

• Do you feel tightness in the back of your hip or buttock?
  

What it means: If you can't reach 90 degrees, if your lower back excessively arches, or if your opposite leg lifts off the ground, you have limited hip flexion mobility. Your lower back is likely compensating for this restriction during bending and squatting movements.

Test 2: The Thomas Test (Hip Flexor Length)

How to do it: Sit on the edge of a bed or sturdy table. Lie back and bring both knees to your chest. Hold one knee with both hands while letting the other leg lower down toward the ground.

What to look for:

• Does your thigh lie flat or parallel to the surface, or does it stay elevated?

• Does your knee naturally bend to about 90 degrees?

• Does your lower back stay relatively flat against the surface?
  

What it means: If your thigh stays elevated and won't lower to horizontal, your hip flexors are tight. This restriction forces your lower back to extend excessively during walking, running, and standing activities. It's one of the most common contributors to lower back stiffness we see in our clinics.

Test 3: The Active Straight Leg Raise

How to do it: Lie on your back with both legs straight. Keeping your knee completely straight, lift one leg up toward the ceiling as high as you can without bending your knee or letting your lower back arch off the ground.

What to look for:

• Can you lift your leg to at least 70-80 degrees (about halfway between horizontal and vertical)?

• Does your lower back stay flat on the ground, or does it arch significantly?

• Do you feel tightness in the back of your thigh (hamstring)?
  

What it means: While this test primarily assesses hamstring flexibility, it also reveals how well your pelvis and lower back can stay stable while your hip moves. If your back arches excessively or you can't reach 70 degrees, your lower back is compensating for hip and hamstring restrictions during forward bending movements.

How Hip Restrictions Create Lower Back Stiffness

Let's connect the dots between what you might have just discovered in those tests and the lower back stiffness you're experiencing.

When your hip flexion is limited, every time you bend forward, your lower back has to round more than it should. This excessive flexion repeatedly loads the structures in your lower back (discs, ligaments, muscles) in a vulnerable position. Over time, this creates stiffness and can lead to pain.

When your hip extension is limited (tight hip flexors), your lower back extends excessively to compensate during walking and standing. This compression on the back side of your spine can create stiffness, particularly in the morning or after periods of inactivity.

A 2019 study in Clinical Biomechanics demonstrated that restricted hip mobility directly alters lumbar spine motion patterns, increasing mechanical stress on the lower back during daily activities.[^2] Your body will always find a way to accomplish a movement, but when the hips can't contribute their share, the lower back pays the price.

Fixing Hip Mobility to Fix Your Back

The good news is that hip mobility often responds quickly to targeted stretching and movement. Unlike some areas that take weeks to change, many people notice improvement in hip range of motion within days of consistent work.

Here are three exercises that address the most common hip restrictions contributing to lower back stiffness:

1. 90/90 Hip Stretch (2 minutes per side)

Sit on the floor with one leg in front of you, knee bent at 90 degrees with your shin roughly perpendicular to your body. Position your back leg behind you, also bent at 90 degrees. Sit tall and gently lean your chest forward over your front leg. Hold this position and breathe deeply.

Key point: This targets hip external rotation and hip flexion simultaneously. If this position is too challenging, sit on a yoga block or cushion to elevate your hips.

2. Kneeling Hip Flexor Stretch with Posterior Pelvic Tilt (90 seconds per side)

Kneel with one knee down and the other foot forward in a lunge position. Before stretching, tuck your pelvis under (imagine pulling your tailbone between your legs) and squeeze the glute on your back leg side. Maintain this pelvic position while you gently shift your weight forward.

Key point: The posterior pelvic tilt is critical. Without it, you'll stretch your lower back instead of your hip flexor, which defeats the purpose. The stretch should be felt at the very front of your hip on the kneeling leg.

3. Supine Hip Flexion Mobilization (10 reps per side)

Lie on your back with both knees bent, feet flat on the floor. Slowly bring one knee up toward your chest, using your hands behind your thigh to gently pull it closer. Focus on keeping your lower back flat against the ground (don't let it arch) and keeping your opposite leg relaxed on the floor. Lower back down and repeat.

Key point: This actively works your hip flexion range of motion while teaching your body to maintain lower back stability. It's mobility and motor control training combined.

Perform these three movements daily for one week. Most people notice their lower back feels less stiff within 3-5 days as their hips begin moving better.

The Movement Pattern That Ties It Together

Improving hip mobility is important, but you also need to retrain movement patterns so your body actually uses that new mobility instead of defaulting back to compensating with your lower back.

The Hip Hinge: This is the foundational movement pattern for protecting your back during bending activities.

Stand with your feet hip-width apart. Place your hands on the front of your hips (where your thigh meets your pelvis). Push your hips backward as if you're trying to close a car door with your buttocks. Your knees will bend slightly, but the majority of the motion should come from your hips moving backward, not your knees bending forward. Keep your back relatively neutral (not excessively rounded or arched). Return to standing by squeezing your glutes and driving your hips forward.

Practice this pattern daily. Use it when picking things up off the floor, loading the dishwasher, or any time you need to bend forward. The more you reinforce proper hip-dominant movement, the less your lower back will default to compensation patterns.

When Lower Back Stiffness Needs More Than Hip Mobility

Most lower back stiffness related to hip restrictions improves significantly within 1-2 weeks of consistent mobility work and movement retraining. However, some symptoms warrant evaluation by a physical therapist:

• Stiffness accompanied by sharp, shooting pain down your leg

• Morning stiffness so severe it takes more than 30 minutes to loosen up

• Stiffness that progressively worsens over days or weeks despite stretching

• Pain that's worse with certain movements and doesn't improve with position changes

• Stiffness on one side of your back only
  

At Nashville Physical Therapy & Performance, we specialize in identifying the specific movement restrictions contributing to your lower back pain. A comprehensive movement assessment can pinpoint exactly where your limitations are (hips, thoracic spine, core control, or a combination) and give you a targeted plan to address them.

Lower Back Stiffness? The Hip Mobility Test Every Active Adult Should Try: The Bottom Line on Hips and Lower Back Health

Your lower back and hips are biomechanical partners. When one loses mobility, the other compensates. After a winter of reduced activity, hip mobility restrictions are incredibly common and often show up as lower back stiffness as you become more active in spring.

Before you spend weeks or months trying to stretch, strengthen, or treat your lower back directly, take five minutes to test your hip mobility. If you discovered restrictions in any of the three tests above, you now have a clear starting point.

Start with the three hip mobility exercises above. Do them daily for one week. Pay attention to how your lower back responds. Many people are surprised to find that addressing their hips resolves stiffness they've been attributing to their back for months.

And if you've been dealing with persistent lower back stiffness without a clear answer, a movement assessment can give you the clarity you need. Sometimes the solution is simpler than you think, but you need the right evaluation to find it.

Ready to figure out what's really causing your lower back stiffness? Schedule a physical therapy evaluation at Nashville Physical Therapy & Performance. We'll test your hip mobility, identify compensation patterns, and create a personalized plan to get you moving better this spring. Call us at 615-428-9213 or book online at nashvillept.com.

References

[^1]: Van Dillen LR, Bloom NJ, Gombatto SP, Susco TM. Hip rotation range of motion in people with and without low back pain who participate in rotation-related sports. Journal of Orthopaedic & Sports Physical Therapy. 2008;38(12):705-711.

[^2]: Roach SM, San Juan JG, Suprak DN, Lyda M. Passive hip range of motion is reduced in active subjects with chronic low back pain compared to controls. Clinical Biomechanics. 2019;62:42-47.