You need to hear this if you train legs hard.
If you're building big, strong legs and you're not making your hips strong too, you're going to end up with knee pain or back pain. I see it all the time.
Big legs need strong hips
Your hip flexors are the muscles at the front of your hips. They help you lift your legs.
The bigger and heavier your legs get, the more work it takes to lift them. If your hips aren't strong enough for the legs you've built, something else has to do the work. Most of the time, that's your knees or your lower back.
Tight hips cause the same problem. When your hips are tight, your legs can't move the way they should, so the load ends up in the wrong place.
Who this happens to most
I see this most in bodybuilders and bigger athletes, and more often in men. They have big, strong legs. From the outside, they look like the strongest people in the gym.
But their knees hurt, or their back hurts. And that pain holds them back. They can't run, jump or play the way they want to.
How I check if your hips are weak
I test people with a lot of exercises. I start at the feet and check strength all the way up to the hips. That shows me if there's a weak spot below the hips first. (I've written about those lower spots in why your knees hurt and weak tibs.)
Then I check the hips and look at the difference.
A lot of people have strong legs but weak hips. I can tell because they can't hold their hips up. When they sit down and try to lift their legs, like in an L-sit, they can't do it.
Once you know what to look for, it's very easy to see. There's a big gap between how strong their legs are and how strong their hips are.
How I make hips stronger
Strong hips take four things:
- Outer hip strength
- Hip flexor strength
- Hip mobility
- Hip flexibility
Most people need all four. For the hip flexors, I have clients do L-sits, hip flexor lifts and reverse squats. For the outer hips, we use exercises like our outer hip drop set, and cables.
Don't push through it
If your knees or back already hurt when you train legs, don't push through it. You may not be strong enough in the right places yet, and that's okay. Pushing through is how a small problem turns into a big one.
No pain is normal at any age, and it can be rehabbed. That's true even if your legs are the strongest thing about you.
Frequently Asked Questions
Can weak hips cause knee pain? Yes. When your hips are weak, they can't lift and control your legs the way they should. Your knees end up taking load they weren't built to take.
How do I know if my hips are the problem? The pain shows up in your knees or back, so it's hard to tell on your own. I test strength from the feet up to the hips. A common sign of weak hips is not being able to sit and lift your legs, like in an L-sit.
What do I need to fix weak hips? Four things: outer hip strength, hip flexor strength, hip mobility and hip flexibility. Most people need work on all four.
Should I keep training legs if my knee or back hurts? Don't push through pain. Get the weak areas stronger first.
The takeaway
Don't neglect the parts of your body that don't show your strength. They're the ones that make all the difference.