When the hips are can’t be held level in a horizontal plane while standing on one leg, lateral pelvic tilt occurs, caused by weakness of the Hip abductor muscles, especially the Gluteus Medius. The pelvis tilts down to one side and the head of the Femur is pushed outwards. This is called Trendelenburg sign by physical therapists.
The Gluteus Medius acts a hip abductor but it is also a very important knee stabiliser: if the knee is bent when standing on one leg, it tends to sway inwards, causing pain in the knee. A weak Gluteus Medius also contributes to anterior pelvic tilt, because the Tensor Fascia Latae is substituted in hip abduction movements. The Tensor Fascia Latae is a hip flexor and thus the pelvis tilts forward. Refer also to How Hip Problems Cause Knee Pain
Yoga practitioners with a weak Gluteus Medius may feel
- Pain at the outside of the hip in forward bending, or in lunges like Virabhadrasana or Parsva Konasana
- Hip pain and limited flexibility in wide legged asanas like Baddha Konasana
- Knee-pain in Matsyendrasana.
- In standing asanas, the hip pushes outwards on the weak side, and the pelvis tilts sideways
- Pain at the outside of the knee
- Lower back pain
- Pain turning over in bed when sleeping
People usually have one weak and painful hip, not both. Awareness of habits and a conscious effort to keep the pelvis level and not to allow the hip to push out sideways when practising is essential.
There is another factor in yoga practice that actively contributes to weakness of the Gluteus Medius: strong Adductor muscles weaken hip abductor muscles via reciprocal inhibition. Please refer also to Adductors, the Pelvic floor and Lower Back Pain. The long adductors are strengthened by:
- Excessive use of leg strengthening asanas in yoga sequences: lunge-asanas – Virabhadrasana, etc. and hip extension asanas such as Dighasana. The long Adductor muscles are Synergist muscles for both hip flexion and hip extension and become overactive, inhibiting the Gluteus Medius. Runners often have Gluteus Medius weakness.
- Repeated flexion and extension of the pelvis, especially in Surya Namaskara and Vinyasa. It has been noticed by physical therapists that sports which include large amounts of pelvic flexion and extension tend to have these problems as well, because flexion and extension contributes to tightness in the adductors – which act as stabilisers in these movements
- Keeping the knees together in asanas like Utkatasana shortens adductors and lengthens and weakens abductor muscles
Correcting this is not a matter of stretching adductors, but of strengthening abductors. The hip abductors often feel tight and sore, but stretching them weakens them further. The Gluteus Medius is best strengthened with single leg squatting and upright standing balancing asanas with a strong awareness of horizontal pelvic position and paying attention to pelvic tilt. Avoid asanas that cause hip pain until the hips are stronger. This is a good time to review your yoga practice and change it as necessary
Kendall, Mc Creary, Provance, 1993, Muscles, Testing and Function
De Franca, 1996, Pelvic Locomotor Dysfunction
Ellenbecker, De Carlo, DeRosa, 2009, Effective Functional Progressions in Sport Rehabilitation
Brunnstrom’s clinical Kinesiology, 5th ed, 1996
Neil-Asher, 2005, The Concise Book of Trigger Points
Injury clinic – Adductor magnus | Sports Injury Bulletin
Gluteus Medius: Weak buttocks ruin the runner | Sports Injury Bulletin