Dr Delanghe, Waterloo Chiropractor

Category

Injuries

TFL

What is it?!

Overuse injury associated with pain on the outside (lateral) part of the knee

Anatomy

The ITB is a band or sheath of fibrous connective tissue that surrounds the muscles on the outside of the thigh and crosses both the hip and knee joint. It originates from the tensor fascia latae (TFL) and gluteus maximus muscles and then continues down the femur (thigh bone) where it attaches to both the femur and tibia (shin bone) on several bony landmarks.

The function of the IT band is to stabilize the hip and knee as well as limit hip adduction (leg moving towards the midline) and internal rotation of the knee.

Epidemiology and Risk Factors

The knee is the most commonly injured area in runners – accounting for 25-42% of all running injuries. ITBs is the second most common knee injury for runners with patellofemoral pain syndrome being first.

ITBSigns/Symptoms

Runners usually have no exact history of trauma and find that the pain comes on gradually over the outside of the knee during a run. The pain usually appears within a few km of a run and increases in intensity. That same area can also be tender to touch.

Pathophysiology/Etiology

There are a couple theories on the pathophysiology of ITBs.

Some researchers believe that ITB inflammation is a result of excessive friction between the ITB and the boney prominences which occur when the ITB slides over the boney structure and causing inflammation during repetitive movements such as running. Others have argued that rather than the ITB band causing excessive friction, the inflammation is caused by the ITB compressing an area of highly innervated fatty tissue between the IT band and boney prominence

Contributing Factors to Developing ITB Syndrome

The most common factor in developing ITBs is an increase in exercise intensity through mileage, hill training or speed work.

Other reported possible causes which may increase tension in the ITB by altering hip and knee angles include:

  • Downhill running
  • Wearing old shoes
  • Always running on same side of road
  • Leg length discrepancies
  • Excessive pronation of the foot (foot rolling inward)
  • Tight ITB
  • Weakness of glute medius muscle

ITBs and Running Biomechanics

It has been suggested that injuries can manifest as a result of an increase in exercise intensity beyond a threshold level, combined with certain intrinsic factors in athletes.

A recent systematic review looked at biomechanical variables and investigated whether distance runners who suffer from or develop ITBs have different biomechanics than runners who do not develop ITBs.

The evidence shows that it is unlikely that abnormal biomechanics at the foot or shin bone can contribute to increasing tension of the ITB.

The results suggest more is happening at the hip and knee. Runners who eventually develop ITBs have more internal rotation at the knee and greater glut medhip adduction angles during the stance phase of running (when the foot is in contact with the ground) compared to healthy controls.

Some researchers have found that this internal rotation of the knee is due more to an externally rotated femur (thigh bone rotated outside) and suggests this may be due to insufficient activity in the medial rotators of the hip (gluteus medius, gluteus minimus, TFL).

As for muscle strength and endurance, there is currently no evidence to suggest that reduced muscle strength plays a role in ITBs. However, the research is limited because many of the trials give inaccurate impressions of a muscle’s functional strength. Future research is needed to look at the timing of muscle action rather than the magnitude of strength.

Research also suggests that runners with current ITBs tend to have more trunk flexion than healthy controls. It is uncertain whether the increased trunk flexion is due to a tight ITB or if the ITB becomes tight as a consequence of the flexed trunk (aka: the torso leaning forward)

How do we treat it!?

Stay tuned to my next article on the latest evidence for treating and managing ITBs!

References:

Foch et la. Associations b/n IT band injury status and running biomechanics in women. Gait & Posture. 2014.

Louw & Deary. The biomechanical variables involved in the aetiology of iliotibial band syndrome in distance runners – a SR. Physical Therapy in Sport. 2014

glut med

Let’s target the hip abductor muscles! In my last article I discussed the importance of core strength and control to stabilize our trunk when we run – specifically the importance of the hip abductor muscles.

To refresh, the hip abductors help to bring the leg to the outside of our midline to counteract the moment of force where our leg naturally wants to move toward the midline each time our foot hits the ground.

We have several hip abductor muscles in our body, the majority of them are in our butt muscles! Gluteus medius (Gmglut meded), gluteus maximus (GMax), gluteus minimus (GMin) and TFL (tensor fascia latae). The focus of this article is going to be on the gluteus medius because of its important role in stabilizing the pelvis.

Why do the gluteal muscles become weak? Most of us spend our days sitting and therefore develop weak gluteal muscles making it harder to recruit them during exercise. This can lead to improper use and poor muscle patterning of other muscles to try to compensate for a weak GMed which may increase risk of injury somewhere down the road.

Using techniques to help isolate these muscles can increase their activation and ultimately improve performance. So, how do we target these muscles? A few electromyographic (EMG) studies can help us out!

Study #1: One leg vs. two legs for Gmed activation 

This study used EMG signal amplitude to measure GMed activation in 5 different weight-bearing exercises; double leg stance, single leg (SL) stance, single leg squat, single leg stance on a cushion, and single leg squat on a cushion, where the cushion was an unstable surface underneath the foot to make the exercise more difficult.

To no surprise, the results showed that a SL stance placed higher demands on the GMed than double leg stance and SL squats are more demanding than SL stance. As for the SL exercises on the cushion; the GMed muscle was activated more, but not significantly more than on flat ground.

Study #2: How do we activate Gmed even more?

This study used EMG signals to measure muscle activation patterns of the GMed (among 3 other hip muscles) during 5 unilateral weight-bearing exercises as shown here:
picss

They compared the level of activation to the subject’s maximal voluntary contraction. The EMG signal amplitude had to be between 40-60% of the maximal voluntary contraction to have sufficient intensity for strengthening.

Of the 5 exercises, the results for the GMed showed the highest amount of activation during the wall squat! The next exercises for activation were as follows: forward step-up, lateral step-up, backward step-up and then mini squat. The authors suggested that these exercises may be used as progression exercises towards the wall squat.

TFLStudy #3: What happens when the gluts are weak?

The last article looked at hip abductor muscle activity during resisted side-stepping exercises in either a squatted or standing position. They found that both the GMax and GMed had greater muscle activity during the squatted position than the upright posture. By being in this squatted position, the TFL muscle is less active which means the gluteal muscles should, in theory, be more active. This is important because if the gluteal muscles are weak, the
TFL will compensate which may lead to further underuse and weakening of the gluteal muscles.

Practical Applications

Here are a few key take home points for activating the Gmed to help enhance our running:

  • The GMed plays an important role in stabilizing the pelvis/hip joint during weight-bearing
  • GMed activation is greater when the base of support is less ie: during a side bridge, unilateral squat and lateral step up
  • Some key exercises to get the most activation from the GMed:
    • Single Leg Stance
    • Single Leg Wall Squats
    • Forward Step Ups
    • Lateral Step Ups
    • Side Steps with a resistance band around the knees/ankle (aka: Monster Walks)

And does strengthening GMed actually help to prevent injuries?  As always, the answer is that it depends, but check out this article  from Dr. Delanghe exploring how GMed strength work can decrease injury-causing variability of motion at the knee.

Happy strengthening!

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