How Tight Hamstrings Can Affect Your Lumbar Spine in Yoga

Here’s a quick update from the science literature on your hamstrings…

Biomechanically speaking, tight hamstrings can affect the position of your pelvis, especially in forward bends. This can, in turn, affect your lumbar spine because tight hamstrings produce a pull on the ischial tuberosities and tilt your pelvis back (as shown below in figure 2).
 

Tight Hamstrings in Your Yoga Practice

Adjacent joints move in what is known as a “coupled” fashion. When the pelvis tilts back, the lumbar vertebrae flex forward. This means that if the hamstrings are tight and we bend forward in Uttanasana, more of the flexion comes from the lumbar spine. Conversely, when the hamstrings are flexible, the pelvis can tilt forward, allowing the forward bend to come from the hip joint, rather than the lumbar spine.

This interaction is known as spino-pelvic rhythm and is how the pelvis and lumbar spine move in relation to each other. Ideally, we want to have have a forward bend come predominantly from pelvic movement (pelvic dominance) rather than from the lumbar (lumbar dominance).

Scientific Literature on Tight Hamstrings, the Pelvis and the Lumbar Spine 

To this end, I wanted to share a couple of articles from the recent science literature relating to how tight hamstrings affect your pelvis and lumbar spine. The first one discusses spino-pelvic rhythm in relation to the hamstrings. These researchers investigated forward bends (essentially Uttanasana) in subjects with tight hamstrings vs flexible hams.

What they found was…

“The lumbo-pelvic-rhythm comprises 2 patterns—lumbar dominant and pelvis dominant. In flexible subjects, pelvis movement was dominant. In conclusion, improving tight hamstrings may reduce lumbar loading thereby reducing low back pain.”

And in a subsequent article they concluded that:

“Dynamic stretching could change the spino-pelvic to a pelvis-dominant motion, indicating that flexible hamstrings are important for preventing low back pain.”

Yet another article reported that:

“Hamstring stretching exercises performed in the working place are effective for increasing hamstring muscle extensibility. This increase generates a more aligned thoracic curve and more anterior pelvic inclination when maximal trunk flexion is performed.”

(references cited below)

Figure 1 below shows what happens with flexible hamstrings…

Figure 1: This illustrates how stretching the hamstrings releases the pull on the ischial tuberosities, permitting the pelvis to tilt forward into anteversion. This is known as femoral pelvic rhythm.

Figure 2 below illustrates what happens when your hamstrings are short or tight…

Figure 2: Uttanasana: tight hamstring drawing pelvis into retroversion and coupled movement of lumbar spine into flexion. This is lumbar pelvic rhythm.

As the research demonstrates, stretching your hamstrings can help take the strain off of the ligaments and disks of the lumbar spine. Click here to read more on this subject. Click here to read about the role of the thoracolumbar fascia and the core muscles in protecting the lumbar. Click here for some cool information on gaining flexibility in your hamstrings as well as the myofascial connections between your hammies and your feet. (This shows how everything is connected…)

Figure 3  illustrates the pressure on the intervertebral discs in seated poses during lumbar flexion.
 

Anatomy of the Hamstrings

Here’s a quick review of the anatomy of your hamstrings…

The hamstrings comprise three separate muscles—the semimembranosus, semitendinosis, and biceps femoris. The biceps has a long and short head. The semimembranosus, semitendinosis, and long head of the biceps originate from the ischial tuberosities (sitting bones). The short head of the biceps originates from the back of the femur (thigh bone). The semimembranosus and semitendinosus insert on the inside of the tibia (lower leg). The two heads of the biceps join into one tendon that inserts onto the head of the fibula at the outside of the knee. The main action of the hamstrings is to flex the knee. Secondary actions include extending the hip and rotating the knee.

Reprinted with permission of thedailybandha.com

3d Graphic Designer / Illustrator Chris Macivor has been involved in the field of digital content creation for well over ten years. He is a graduate of Etobicoke School of the Arts, Sheridan College and Seneca College. Chris considers himself to be equally artististic and technical in nature. As such his work has spanned many genres from film and television to videogames and underwater imagery.         

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