The term Anterior pelvic tilt is used to describe the orientation of the pelvic bone and refers to when ‘the front end of the pelvis tips forward and the back end hikes up’ causing an increased curvature of our lordotic spine or our low back.
On searching google for pelvic tilt we get a result of some major fear-mongering definitions.
The angle of pelvic tilt in standing describes the orientation of the pelvis in the sagittal plane i.e. seen when the person is standing sideways from the viewer. It is determined by the muscular and ligamentous forces that act between the pelvis and adjacent segments.
A forward rotation of the pelvis, referred to as anterior pelvic tilt, is accompanied by an increase in lumbar lordosis and is ‘believed‘ to be due to tight hip flexors + back extensors, weak core, and gluteal muscles, this phenomenon is termed as the ‘lower cross syndrome’ which is extensively exploited for almost all kinds and areas of pain.
It is also said to be associated with several common musculoskeletal conditions, including low back pain. (note: There is no evidence supporting this belief)
A standard method of assessing the angle of pelvic tilt is measuring the angle between the horizontal (at the highest point of the pelvis) and a line drawn from the anterior superior iliac spine (ASIS) to the posterior superior iliac spine (PSIS) which is usually palpated by the clinicians or is sometimes observed visually.
In a study, where the degree of pelvic tilt within a normal asymptomatic population was examined, 20 healthy subjects (65 males, 55 females) ranging in age from 18 to 44 years were taken. Out of the 65 male subjects tested 55 (85%) presented with an anterior tilt, 4 with a posterior tilt, and 6 presented as neutral. Across the sample of female subjects 41 presented with an anterior tilt (75%), 4 with a posterior tilt, and 10 presented as neutral. The result of the study indicated that 85% of males and 75% of females have an anteriorly rotated pelvis.
Results of the above study emphasize the fact that most people have some degree of anterior pelvic tilt and within normal asymptomatic populations, anterior tilt is common and not unique to pathology.
Moreover, what if anterior pelvic tilt is something you have not developed over time due to incorrect sitting habits but is due to the morphological structure of your bone which cannot be altered either through incorrect posture or exercise?
In a study; Thirty bony pelvises (20 male/10 female) were studied, and the ASIS-PSIS angle was measured on each side of the pelvis. The results showed a range in the ASIS-PSIS angle of 23 degrees across the 30 pelves.
The authors also conclude that “It is possible that differences of up to 23 degrees in the ASIS-PSIS angle could reflect differences in morphology rather than differences in muscular and ligamentous forces acting between the pelvis and adjacent segments.”
The above figure shows two pelves aligned in the standard reference position, with an ASIS-PSIS angle in the first specimen of 0 degrees and in the second of 23 degrees
This raises the question of that is it possible to describe a neutral pelvis when there exists a morphological (bone structure) difference in the angle of the pelvis not only among individuals but also bilaterally in the same individual (i.e. the angles on the right and left of the pelvis can differ in a person.)
It would be safe to say that our posture could be a result of our bone structure which is also seen as a sex-specific difference in the pelvic anatomy among men and women where women tend to have wider pelvis along with slightly increased pelvic angle and not necessarily a result of muscle tightness or weakness.
Variation in pelvic tilt is just one example of how we as humans are full of contrasting attributes. There exist no normal but many deviations from it which are not necessarily defects that need to be corrected.
It is also a common belief that:
1) Anterior pelvic tilt is associated with lengthened/ weak core and gluteal muscles and hence the said low back pain caused by the anterior tilt as well as the pelvic tilt itself can be corrected by the strengthening of the core and glutes.
There is no evidence backing this claim since it is based on the primary concept of ‘lower cross syndrome’ as discussed above which highlights that posture deviation like the anterior tilt occurs as a result of “Muscle imbalances”.
However, it also doesn’t clarify the method of assessing or measuring the muscle imbalance, whether it is in the terms of strength, length, or other factors along with no specific data for the “normal value” to assess the deviation from.
Levine et al found that an 8-week strengthening exercise program for the abdominal muscles increased muscle strength but had no effect on the size of the lumbar lordosis of the subjects.
In a study, the authors conclude, “Abdominal muscle strengthening exercises are routinely recommended by physical therapists to correct faulty standing posture in patients with CLBP. These recommendations are often based on an assessment of standing posture. We urge physical therapists to avoid prescribing therapeutic exercise programs of muscle strengthening of abdominal muscles in patients with CLBP based solely on the assessment of relaxed standing posture.”
2) Anterior pelvic tilt is due to tight hip flexors.
Someone with anterior pelvic tilt due to tight hip flexors would have decreased hip extension range of motion since the hip flexors present in the front of the thigh would restrict the hip extensors present at the back of the thigh due to their shortening or tightness. However, in a paper by Heino et al it was concluded that no such relationship exists between hip extension range of motion and pelvic tilt.
By virtue of iliopsoas attachment to the pelvis and lumbar spine, some investigators have assumed that tightness of this muscle affects the size of the lumbar lordosis and causes LBP. Biomechanical analysis has revealed that the iliopsoas muscle, which generates significant compressive forces, exerts very small rotatory movement on the vertebrae and has no substantial action on the lumbar spine.
Furthermore, in this study, no significant difference was found in the length of the hip flexor muscles between subjects with and without LBP, and no association was found between the length of these muscles and LBP.
3) The third area of concern is that anterior pelvic tilt, if present, is the cause of current low back pain, hip pain, knee pain, and various other pains almost everywhere in the body, and if not then can eventually lead to pain in the coming years (well, if only pain was that easy to predict and prevent). There are several studies that challenge this belief.
Youdas et al & Walker et al concluded that patients with CLBP had no more standing lumbar lordosis or pelvic inclination than their counterparts with healthy backs.
A multifactorial cross-sectional study with a total of 600 participants which were divided into 4 groups asymptomatic men, asymptomatic women, men with LBP, and women with LBP concludes that muscle endurance and weakness are associated with LBP and that structural factors such as the size of the lumbar lordosis, pelvic tilt, leg length discrepancy, and the length of abdominal, hamstring, and iliopsoas muscles are not associated with the occurrence of LBP.
So what can we conclude from this?
Anterior pelvic tilt is not an abnormality, neither a diagnosis nor a cause of low back pain and it is very ignorant as well as reductionist to blame variations in posture for almost every pain anywhere in the body.
Any posture can be painful depending on multiple factors like the duration of the posture held, duration of the pain, sensitization of the tissue to the specific posture. For eg. People sometimes find forward bending painfully in cases of low back pain or when their knees go over their toes while squatting, this doesn’t mean these postures are inherently faulty and the cause of their pain considering how both of these movements are required to fulfill so many tasks of our daily living.
A problem of posture can in fact be a problem of movement, most likely a lack of movement rather than an “incorrect” movement.
Not so surprisingly, rehab programs designed to change posture can help people out of pain without changing their posture as we see with resting scapular position! emphasizing the fact that posture isn’t really the culprit.
In fact, anterior pelvic tilt can be beneficial if we look at most high-level athletes, we observe some degree of anterior pelvic tilt. Some studies suggest that for activities like running and weightlifting, it can be an advantage since it might act as a mechanical advantage for the hip extensors producing more force.
And well, I have an anterior pelvic tilt for as long as I can remember, from people telling me constantly that I need to fix it by stretching my hip flexors and training my core, to warning me that it will eventually lead to back pain (and all of these advice mostly came from physical therapist themselves, physical therapy students and of course Instagram) I can well assure you I’ve almost never had low back pain but yes these advice used to bother me significantly till I discovered a whole body of evidence which says otherwise. Also in my experiences working doing exercises with the goal of posture correction is extremely boring and mundane!
In conclusion:
Science does not really support a link between anterior pelvic tilt and pain as well as tightness and weakness of other associated muscles and it's important to downplay the importance of postural variations to health.
Your posture doesn’t need constant fixing. The best posture is the one that is the most comfortable for us. Like none of us have the same face size, shape, and features likewise we differ in our bone morphology, orientations, etc our bodies are adaptable, adapt to the posture we spend the most time in. It is very impractical to assume that there exists a perfect posture we should all aim for.
A better goal is to be active, and strong and love our bodies the way they are even if that means having larger guts!
There is no reliable evidence to suggest we can change posture anyway!
~Embrace the asymmetries~
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