Your backside plays an important role when we run. It’s a powerful piston into the ground when we run fast, slows down our leg to contact the ground, and is a supporting actor to keeping our leg on course. Today we are going through what it does, how it works as a coordinated unit, and what we can do to keep it ready to run.
Key Concept: Dynamic Motion of the Spine, Pelvis, and Hips
The main role of our posterior hip is to bring our leg behind us when we walk or run. This motion is known as hip extension and is shown in the above picture. This runner is at max hip extension on his right leg. Max hip extension occurs as our toe starts to come off the ground. This motion occurs through coordinated movements of the hips, pelvis, and lumbar spine.
Notice how I said…Hips…Pelvis…Spine.
Those three motions are normal and occur together to allow our leg behind our body. Their ratios will be different from person to person.
To get their leg behind them, Schache and colleagues found some runners will use more anterior tilt and others more hip extension. They also found that runners with shorter legs use more hip extension. Our preferred way to extend our leg will depend on our anatomy, previous injuries, training history, and other factors.
It’s like answering the question, “What’s your favorite episode of the Office?” Everyone has a preference with no wrong answers.
*Obviously the best answer is Dinner Party*
“That’s a $200 plasma screen TV that you just killed!”
Ok. Ok. but how MUCH hip extension do I need to run?
For distance running, we need about 10 degrees of hip extension.
This is about the same amount we need to walk.
As we run faster, we actually FLEX our hip more while our max extension remains the same. We talked about this in the first blog of the series HERE. Our hip extensors have to work HARDER as we run faster, but they don’t necessarily go through more motion.
Changing Your Running Form Makes You Less Efficient
Running mechanics are important.
BUT…..they can be overblown and overcomplicated.
Our anatomy, training history, and past injuries play a big role in how we move. This is why we see runners with different foot strikes, pronation strategies, and arm swings. It’s important to mention this first because I want to take a different approach than most to hip extension.
When we change our “preferred” way of running we use more energy. We become LESS efficient. I think of our limbs having desired motion paths like water moving through a riverbed. It’s grooved a specific path in the earth. It’ll gonna take extra effort to get the water to flow in a different direction. Consciously thinking of activating, tightening, or squeezing a certain muscle makes you less efficient as a runner.
You’re changing the route of the river.
When we start to have an internal focus (focusing on a specific joint/muscle) versus an external focus (ex. “explode off the ground”) we become less efficient.
I talk more about the specifics of anatomy and running form in this video.
Key Concept: Primary Hip Extensors
We normally assign one job to a specific muscle. That’s the muscle’s primary action.
Our primary hip extensors are:
*Adductor Magnus (we’ll cover these in Part IV)
This group helps us push off during a sprint, stand up out of a squat position, and drive up steep inclines. Depending on the positions of paintball splatter, our muscles can perform secondary actions. Our glute max extends our hip and secondarily adducts and externally rotates our leg.
Key Concept: Hip Muscle Function
We’ve covered the biomechanics of hip extension.
Let’s dive into how the posterior hip helps us run.
Our hip extensors are a bit overrated when we run at slower speeds. They don’t do much. The muscles that have to work the hardest at slower speeds are farther down our leg at our knee and ankle. When we run slower we bias our calf muscles and quadriceps. When we run faster we start to use our glutes and hamstrings more.
I highlight that a bit in this video.
Your glutes see a big increase in their work as we run faster.
Check out this graphic below from Mann et al depicting running at a slow jog versus a max sprint. The biggest increase in activity is in the glute max and hamstrings.
Your Hammies Job
Our hamstrings help extend our hip, bend our knee, and slow our leg swing down when running.
They do a lot and their particular job puts them in a tough position from an injury standpoint. We broke down hip extension when talking about the glute max. Let’s focus on slowing knee flexion down for the hamstrings. The eccentrically control knee flexion as our leg drives forward.
Developing a Strong Backside
Now that we’ve covered the biomechanics of hip extension, and what the posterior thigh does, let’s go over my favorite drills for these specific tasks. Remember, his area has to work more as we run faster so we want them strong and powerful in the weight room. These can all be progressed by adding more weight or speed to the movements.
Thanks for taking the time to read!
Part III will cover the lateral hip. Check for it next week!
Nathan Carlson PT, DPT, USATF
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