To discuss the importance of the gluteal muscles we must first understand the how the gluteal muscles coordinate movement of our hip and thigh bone.
For the purpose of our discussion, we will cover the primary movements that the three gluteal muscles engage in; however, it is important to know that different portions of the gluteal muscle fibers can assist with secondary movements which will not be covered in this discussion.
The main action of the gluteus minimus and gluteus medius is to bring the leg away from the midline of our body. Furthermore, they also work to stabilize our pelvis, for example, when standing on one leg.
The gluteus maximus acts to extend and outwardly rotate the hip. Additionally, when the feet are fixed to the ground as in a squatting position, the gluteus maximus can help to extend or straighten the knee through the illiotibial tract.
How does this apply to functional movements?
We can learn about the importance of the gluteal muscles by analyzing what happens when they are not working properly.
Let’s start by analyzing how dysfunctions in the gluteal muscles can affect how we walk. If, for example, the gluteus medius and minimus were impaired, we may see someone walking with an uneven or dropped pelvis.
If the left gluteus medius and minimus were not contracting properly, the pelvis would drop towards the right, while the trunk will lean towards the left. The body may compensate for the weak gluteus medius and minimus, by shifting the weight of our trunk over the affected leg so we can maintain our balance. Therefore, it can be seen that the gluteus medius and minimus act to stabilize the pelvis in single leg stance, which accounts for 30% of our normal walking cycle.
The gluteus maximus contracts when our heel strikes the ground during walking to slow the forward motion of our trunk and decelerate the swinging leg (which becomes more pronounced during running). If our gluteus maximus was impaired during walking, we would likely compensate by extending our trunk backward to counteract the forward motion of our trunk.
Furthermore, the gluteus maximus is utilized when walking up steps as it is a powerful extensor of our hip which helps propel us forward.
What issues can weak gluteal muscles lead to?
Weak gluteal muscles have been associated with a variety of lower limb issues. If the gluteal muscles contractile ability is impaired, this may result in other muscles and tissues compensating and as a result they may be placed under greater strain.
For an example, Illiotibial Band Syndrome, also commonly known as runner’s knee, is often associated with weak gluteal muscles.
It is theorised that if our gluteal medius and minimus muscle are unable to support our pelvis in single leg stance we may experience increased strain through our IT band, which may result in pain and inflammation over time.
Patellofemoral joint pain, which can be described as irritation of the knee cap, is another common knee issue where weak gluteal muscles may be a contributing factor.
As discussed earlier, weak gluteal muscles can cause the opposite pelvis to drop, which can lead to a cascade of events in the lower limb, including inward rotation of our thigh (femur) and shin (tibia) bone, possibly leading to a dropped arch on the side where the gluteal muscles are impaired.
Thus, small alternations in our lower limb biomechanics can upset normal knee cap mechanics and lead to pain and irritation over time.
It’s important to emphasize that there are numerous factors that are associated with patellofemoral joint pain and weak gluteals are just one factor your physiotherapy may consider when diagnosing this condition.
To summarize, if the gluteal muscles are weak, it may cause other muscles or tissues to become overloaded through a cascade of events as described in the above examples.
To use one last example with runners and sprinters, it is necessary for them to achieve adequate hip extension in order to propel themselves forwards. If the gluteal muscles are not completing their role effectively, muscles like the hamstrings (which can extend the hip to a lesser degree than the gluteals) may be required to increase their contractile output to achieve proper hip extension. Over time this may contribute to overloaded hamstring muscles.
As you can appreciate, the orchestration of movement is generated by the various muscles in our lower limb and if some muscle's contractile ability is impaired, this can lead to an issue over time with other tissues becoming overloaded in order to compensate.