Performance Power Of Glutes Part II

Following on from part I; part II will outline the function of the posterior chain, how the glutes are involved in this and again why glute inactivity can lead to an increase risk in injuries.

What is the Posterior Chain?

The term posterior chain refers to a linkage of muscles which involves the lower back, the glutes, hamstrings and the calves. It forms the basis of most strength, speed and explosive movements within the body, whether you’re an athlete or the average Joe. However when sitting for long periods of time (daily) it shortens your hamstrings, tightens your hip flexors, causes your glutes to become inactive and allows your lower back to stiffen.  The creation of this muscle imbalance and loss of flexibility in the posterior chain, dampens its effectiveness and is a road block to better performance.

POstior chain 2

Posterior Chain

Also, like the links in a metal chain, each of these muscle groups are intertwined and work in unison to form part of a stronger and more stable unit. If one muscle forming the posterior chain is underworking, again, similar to the links in a metal chain, it compromises the overall stability and performance. Without a highly functioning posterior chain, it opens you up to injury risks and forms a limitation in your peak performance potential.

#2 Minimise occurrence of acute soft tissue damage

As discussed in Part I, a dysfunction in the glutes, particularly gluteus medius and minimus can cause dynamic valgus within the knee especially during single leg positions. This risk of valgus is heightened when the individual is landing from an elevated position, such as following a jump in basketball or volleyball. This is caused by an increase in ground reaction forces placed on the body, which leads to a greater control required from glute med and min to maintain hip stability to prevent dynamic valgus of the knee.

single leg valgus

Knee Valgus with Landing

What can tend to happen when glute med and min are under performing is the reaction forces acting on the knee following landing can strain the soft tissues around the knee which usually prevent knee valgus. This includes structures such as the medial collateral ligament (MCL), medial patellofemoral ligament (MPFL) and the anterior cruciate ligament (ACL).

 ” A 2008 study by Lawrence et al. demonstrated that the subjects classified within the “weak” hip external rotation group had 146% greater vertical ground reaction forces when landing on a single leg from a 40cm block. The increased ground reaction forces led to increased anterior knee shear forces, external knee adduction and flexor moments causing significantly greater risk of ACL injury. “

Glute strengthening is therefore essential for reducing ground reaction and shear forces on the knee especially if you are involved in sports which involve repetitive jumping and landing, as it significantly reduces the risk of ACL and other ligamentous damage.

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 #3 Decrease the risk of muscular overuse injuries

Hamstring injuries are the most common condition to affect athletes in the AFL. More often than not, these injuries may be attributed to an inhibition of gluteus maximus’s function, as both muscles form part of the posterior chain.

Since glut max is the primary muscle involved in hip extension and deceleration of the swing leg during running and sprinting, a reduction in its activity will lead to secondary synergists, such as hamstrings to compensate and overwork. This usually isn’t a problem, however due to the design of the hamstrings; it is ideally recruited as a helper rather than the primary driver of the movement. What happens over time is an overuse of the hamstrings can lead to feelings of tightness and can cause an increased risk of hamstring injuries.

Hamstring injuries

Knowing this, recurring hamstring injuries can have an underlying component of inactive glutes, which is why glute strengthening should always be implemented into hamstring rehab protocols, especially when previous programs have not involved it.

Stay tuned for Part III where I’ll discuss the recent research on the best glute rehab exercises to help target your bum.

 Part I, Glutes The Powerful Stabiliser 

By William Chin

References:

  • Diagnosis and treatment of movement impairment syndromes – Shirley Sahrmann (2002)
  • Lawrence R K, Kernozek T W, Miller E J, Torry M, Reuteman P (2008) Influences of hip external rotation strength on knee mechanics during single-leg drop landings in females. Clinical Biomechanics 23: 806-813

 

 

Glutes, The Powerful Stabiliser Part I

Desk jobs, cars, lifts; the adversary to stronger gluteal muscles.

The gluteals act as the powerhouse of the body, providing a base of stability from which power is generated and transferred. Underlying that, the gluteals also play a large role in optimising lower limb function to assist in preventing injuries. Over several posts, I will discuss the roles of the glutes, their effect on lower limb biomechanics, reasons for why they need to be strengthened and exercises to help wake up your booty.

Part I will outline the function of glutes, their influence on biomechanics and their role in preventing overload injuries.

The Gluteal Complex is comprised of gluteus maximus, gluteus medius and gluteus minimis, all which work in unison. Working alone, gluteus maximus acts to create powerful hip extension and hip external rotation. During walking, glute max will help with extension of the hip, deceleration of the swing leg and assist in maintaining an upright trunk. On the other hand, glute medius and minimus have similar actions. Its most important action is to abduct (bring leg to side away from midline) the thigh. It also is able to internally and externally rotate the hip, due to 2 different muscle fibres, anterior and posterior. Functionally, they prevent hip adduction (leg towards midline) and knee valgus, which will be discussed further down. In saying that, the most important function of the gluteals is as a whole. The complex provides stability to the hips, pelvis and trunk and allows for optimal and sound movement. Any disruption to the gluteal stability will result in biomechanical faults and injuries further down the line.

GLUTE!

#1 Gluteal Strength to reduce the susceptibility of overloading injuries

Gluteus medius and minimus are the principle muscles, which provide hip stability to optimise lower limb biomechanics. It is believed that weakness, primarily in these 2 muscles leads to internal rotation of the hip, adduction of the femur and valgus collapse at the knee, particularly in single legged positions, as shown below.

MAX 2                                                                    Dynamic Knee Valgus                                                                    

One of the most commonly caused overload injuries from reduced gluteal strength is Patella femoral pain syndrome (PFPS). It is primarily caused by excessive joint compressive and kneecap mal-tracking from prolonged suboptimal (valgus collapse) loading whilst running.

“ A study by Loyd et al. in 2003 measured the gluteal strength of 15 subjects with patellafemoral pain. On average, all 15 subjects demonstrated a 26% reduction in hip abduction strength and 36% reduction in hip external rotation strength when compared to their control group of subjects without patella femoral pain”

Iliotibial band syndrome (ITBS) is also another common knee injury caused by poor glute medius and minimus function. It is thought that the internal rotation and adduction of the femur results in a valgus position of the knee, leading to lengthening of the iliotibial band during prolonged running, causing it to tighten and irritate.

“A 2014 study by Noehren et al. examined the knee adduction and hip internal rotation angles of 17 ITBS subjects and compared them to subjects with no ITB pain. The study showed that there was a 20%  increase in knee adduction and a 14% increase in hip internal rotation which was attributed to glute deficits”

MAX3

A study regarding the effectiveness of hip and gluteal strengthening on knee joint pain (in particular PFPS), was performed by Ferber et al. in 2011. Following a 3-week hip abduction strengthening program the group with noticeable PFPS pain had a 32.69% improvement in isometric muscle strength and a 43.10% reduction in pain scores.

Part II, Performance Power of the Glutes

By William Chin

References:

  • Ferber R, Kendall KD, Farr L (2011) Changes in Knee Biomechanics After a Hip-Abductor Strengthening Protocol for Runners with Patellofemoral Pain Sydnrome. Journal of Athletic Training 46(2): 142-149
  • Fredericson M, Cookingham C, Chaudhari AM, Dowdell BC, Oestreicher N, Sahrmann SA (2000) Hip Abductor Weakness in Distance Runners with Iliotibial Band Syndrom. Clinical Journal of Sports Medicine 10: 169-175
  • Ireland ML, Wilson JD, Ballantyne BT, Davis IM (2003) Hip Strength in Femails With and Without Patellofemoral Pain. Journal of Orthopaedic & Sports Physical Therapy 33(11): 671-676
  • Noehren B, Schmitz A, Hempel R,Westlake C, Black W (2014) Assessment of Strength, Flexibility, and Running Mechanics in Men With Iliotibial Band Syndrome. Journal of Orthopaedic & Sports Physical Therapy 44(3): 217-222