While much attention is given to the negative impact of sitting as it relates to posture through the upper back, neck and head, the posture of the low back and pelvis can also be greatly affected by prolonged sitting. This can cause muscle imbalances that greatly influence both pain and athletic performance.
Postural problems at the hip and pelvis most commonly present as an anterior pelvic tilt (APT). As the name suggests, this posture involves a forward rotation of the pelvis which results in tightening and loosening in select muscle groups surrounding the hips.

The compressed position of the hip while sitting causes the hip flexors (mainly iliopsoas) to become tight and overactive. This causes the pelvis to rotate forward, resulting in the increased curve through the lumbar spine and “pushing” of the belly seen in the above diagram.
Forward rotation of the pelvis changes the mechanics of muscle contraction around the hip, resulting in certain muscles becoming overactive and some becoming underactive, or inhibited.
                  Tight and overactive muscles
·       Paraspinal lumbar back extensors
·        Hip Flexors

Weakened and inhibited muscles

·       Abdominals and core
·       Glutes and hamstrings

This arrangement increases the curve in the low back (known as lordosis), placing increased strain on the low back structures. Conversely, our core muscles which should be tight and strong, become lengthened and weak.
The effects of this change in muscle tone and activity are two-fold:
1)     The increased strain on the lumbar spine and weakening of the core muscles is a major contributor to back pain. Additionally, weakening of the glutes along with overactive hip flexors can contribute to a number of overuse injuries like IT band syndrome and runner’s knee.
2)     The weakening of the glutes and core muscles can greatly decrease the quality and performance of functional movements like squats, deadlifts, and lunges.
APT can be addressed during both workouts and day-to-day activities.
Workouts should focus on movements and exercises that strengthen the glutes and core muscle while minimizing strain on the hip flexors. Of most importance is any variation of squat, lunge, and plank exercises. Additionally, adding a warm-up routine of “lunge and holds”, where you perform a regular walking lunge while pausing for 5 seconds at the bottom of the lunge, can help open up the hips.
Caution should be used while performing ab exercises on your back when the legs are up in the air. Unless the core muscles are strong enough to stabilize the spine (this should be assessed by a professional) these exercises engage mainly the hip flexors and place excessive load on the lumbar spine while pulling the pelvis into APT.
Given how much time we spend sitting throughout a given day, one 30 or 60 minute workout is not enough to reverse the negative effects of sitting. Making an effort to open up the hips throughout the day through light stretching and lunging can greatly complement an effective workout routine. You might get a few looks while stretching in the office, but your hips and low back will thank you!

Written by: Andrew Courchene, Msc. PT


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