Most joints either have a primary need for mobility to function well while other joints depend heavily on stability. The hip is unique because its function is greatly influenced by both. The hip joint is similar to your shoulder joint. So it allows for a large range of motion, but also needs to be stable when you stand, walk, and run. During running gait the job of your hips is vital to how you perform and whether you’re at risk for an injury.
Ideally the hip joint acts as a fulcrum as your body moves forward when you run. To take advantage of this forward propulsion you need adequate mobility. This results in a sufficient stride angle during running gait. The stride angle is a measurement of your front and back leg when they at their greatest distance. Muscle and other soft tissue restrictions in the hips are often to blame when it is limited. This can be common for triathletes because the hip flexors become shortened during long periods on the bike. The stride angle can still be short even if the mobility at hip joint is not limited. The glute and hamstring muscles are the main drivers for extending at the hip (moving the leg backwards). Lack or strength here, and other compensation patterns, can limit this. With respect to performance it is clear to see how a lack of mobility will have an impact. Lack of hip movement can also cause compensation that can lead to injury. Hyperextension of the low back is extremely common. Other compensations including excessive bounding or an up and down motion and side-to-side movements or rotation at the hips and pelvis.
We also have to consider what the hip joint is doing in other planes as well. When our foot hits the ground the muscles that support our hips our working hard to keep it stable. If they struggle to do so there is a potential for injury, particularly as the training miles and speed increases. When analyzed this can be seen as a larger angle made up between the pelvis and upper thigh from the hip to the pelvis. The stabilizing muscles are not doing their job to keep the pelvis level and knee more closely under the hip with limited rotation. With this biomechanical fault injury can occur at the hip as well as other tissues above and below as well. This is commonly seen with knee and groin pain as well as hip pain.
Your chance for injuries related to biomechanical faults as well as how well you perform is influenced by both strength and stability along with mobility. The function of the hips is a perfect example why.Social tagging: hip > Mobility > run > soft tissue > stability