What Every Runner Should know about the Hip & Running!
By Tim Waanders, PT, DPT, FAFS
The hip joint is a complex, yet important part of the body when it comes to running. Big, powerful muscles attach to various points and are responsible for providing not only the explosive movement required to run, but also for providing nuanced control of the entire lower body as you run. Over the next few weeks, we’ll look into the anatomy, biomechanics, and injury prevention/recovery strategies every runner should know about the hip – this isn’t meant to be an expert level course but as a general overview to give runners a better understanding of their bodies and what is needed to occur in order to run successfully!
ANATOMY OF THE HIP JOINT
First up, we’ll look into the anatomy of the hip joint itself and the muscles involved in creating motion there.
Put simply, the hip joint is the meeting point of the femur (aka the thigh bone) and the pelvis. It is referred to as a “ball and socket” joint, meaning the head of the femur that is rounded fits into the socket of the pelvis.
→ the socket of the pelvis also contains the labrum
→ the labrum is a layer of cartilage that essentially covers the socket and helps with proper force distribution around the joint.
Labral tears and impingement syndrome can occur when there is decreased space in the joint that causes the ball and socket to rub against each other.
MOVEMENT OF THE HIP JOINT
Based on its positioning, the joint allows for significant ranges of motion in all three planes – it can flex and extend, externally rotate and internally rotate, and abduct and adduct (move side to side). Motion occurs in all three of these planes during both the “loading” and “exploding” phases of gait. Along with the motions at the hip, the pelvis can tilt either forward/backward (known as anterior/posterior tilt) or up/down (lateral tilt), creating relative motion at the hip joint. (Further details will be discussed in the biomechanics blog next week.)
MUSCLES OF THE HIP JOINT
There are a total of 22 muscles that attach at the hip; generally, they can be broken up into three groups based on action and location of attachment. We’ll discuss some of the main muscles you should be aware of as a runner:
HIP FLEXORS (FRONT OF THE HIP)
Hip flexors attach to the front of the hip & pelvis and provide propulsion to the swing leg (aka the leg off the ground when running) by driving the thigh forward when running. The iliopsoas is the main muscle group involved in this action, but is aided by the quad (the rectus femoris to be exact), sartorius, and TFL (tensor fascia lata.)
DID YOU KNOW? The sartorius is the longest muscle in the body.
Hip flexor tendinopathy or strains can be common injuries in runners, especially for those who work a desk job and sit for long hours throughout the day. This constant state of muscle shortening increases the anterior tilt of the pelvis and places the hip flexors in a poor state of length vs. tension that can lead to injury with repetitive motion. This can even lead to low back pain over time.
HIP EXTENSORS (BACK OF THE HIP)
The two main groups of hip extensors include the hamstrings and the gluteus maximus.
All of these hip extensor muscles attach at the back of the hip and pelvis in order to extend the hip during running. Not only that, they also help to control the opposing motion of hip flexion when your leg begins to contact the ground during running. (Again, stay tuned for more on this in the biomechanics blog next week.)
DID YOU KNOW? The hamstrings are actually made up of three muscles: the semitendinosus and the semimembranosus on the inner portion & the biceps femoris on the outer portion.
Other important muscles that attach to the back of the pelvis and hip include the piriformis and the gluteus medius. The piriformis can commonly become irritated in runners due to poor pelvic alignment, leading to a deep hip pain generally surrounding the “butt” region, and may even extend down the back of the leg if the sciatic nerve becomes impinged. This may feel similar to proximal/upper hamstring tendinopathy. The gluteus medius plays an important role in stabilizing the pelvis during single leg stance, which occurs through the entirety of the running gait cycle on the leg that’s on the ground. If the gluteus medius is not functioning properly, it can lead to a “hip drop” which can cause a cascade of issues down the kinetic chain.
ADDUCTORS (INNER THIGH)
The last important group of muscles when looking at runners is the inner thigh/adductor muscles. The adductors are a group of five muscles that attach at the inner thigh and are constantly working during the running cycle. When the hip is flexed in front of you, they help the extensor muscles bring the leg back as your foot lands; meanwhile, when the hip is extended behind you, they help the hip flexors pull the leg back into swing phase. They also play a role in resisting excessive motion at the pelvis and hip joint along with the gluteus medius and TFL on the opposite side of the hip. Adductor strains are not necessarily common in runners compared to other injuries, but can certainly happen if they are being overworked due to compensating for weak hamstrings or hip flexors.
As you can tell, there’s a lot going on at the hip. And we’ve just scratched the surface! If you have any issues going on in and around your hip, give us a call at (212)486-8573 to schedule a proper evaluation with one of our physical therapists.
Again, this isn’t meant to be complete guide, covering all the muscles and potential injuries at the hip but is a general overview to give runners a better understanding of their bodies and what is needed to occur in order to run successfully!