To Tuck the Pelvis or Extend the Spine - That is the Question

Whether you are sitting in a chair all day long, lifting weights or pregnant, the position of your spine matters. In fact, in all three instances we want the same thing - a neutral spine. To tuck the pelvis or extend the spine - that is the question, but really, the answer is neither...we want a happy medium of both and here is why:

What is a neutral spine?

A neutral spine is when the position of the diaphragm is aligned with the pelvic floor. The spine is not flexed, extended, tilted or twisted.

Benefits of a neutral spine

The following is a list explaining why a neutral spine is beneficial:

• Maintains good posture
• Prevents or decreases muscular imbalances and strain on joints ⁽³⁾
• Supports and protects the spine
• Improved lung capacity
• Increased strength and mobility ⁽⁴⁾
• Maintains integrity of stabilizing complex (diaphragm, abdominal muscles, pelvic floor)
  • Antagonistic trunk flexor‐extensor muscle coactivation was present around the neutral spine posture in healthy individuals. ⁽¹⁾
• Decreases risk of pregnancy-related pain, including sciatica and low back pain ⁽³⁾
• Distributes load evenly through discs ⁽³⁾
• Relieves pelvic floor dysfunction including urinary incontinence ⁽³⁾

The Mechanics of Tucking the Pelvis vs. Lumbar Extension

Tilting the pelvis too far forward or tucking it too far backward can exaggerate or minimize the natural curve of the spine and cause pain, discomfort, or instability through the following mechanics:

Tucking:

Pelvic tucking is called a posterior pelvic tilt and is created when the pelvis rotates backwards (posteriorly). When this happens the coccyx (aka tailbone) moves down and forward. At the same time the pubic symphysis which is in the front of the pelvis moves forward and up towards the navel. By tucking, the lumbar spine actually moves into flexion and can pull the ribs down in a shearing motion that puts the abdominals almost into a crunch position by shortening the musculature. This movement also shortens the hamstrings while lengthening the quadriceps and back musculature. One reason people will tuck the spine is to activate the glutes, but this movement actually causes chronic tightening of the gluteal muscles and external hip rotators but this movement can pull the femur head back and externally rotate it causing widening of the pelvic floor and weakening the pelvic floor muscles.

Lumbar Flexion:

Lumbar flexion creates an anterior pelvic tilt and is created when the pelvis rotates forward (anteriorly). When this happens, the lumbar spine (low back) goes into hyper lordosis and the hamstrings and abdominals are lengthened while the quadriceps and back musculature are shortened causing the psoas and spinal erectors to be hyperactive. This position can also elevate the ribs and create a concentric abdominal wall while creating an oblique position of the diaphragm and pelvic floor, causing pelvic floor instability and an inability to optimally use the diaphragm.

How do I get to neutral?

Here are a few tips to help you achieve a neutral spine:

• Toes/feet are pointed straight ahead or at a slightly outward direction (11 o’clock & 1 o’clock position) and feet are hip-width apart
  • You should feel equal pressure on the three points of your foot (see diagram) creating a tripod
• Stacking is the key to stability: your head should be above your shoulders, your shoulders should be above your pelvis, your pelvis should be above your knees and your knees should be above your feet
• Make sure your diaphragm and pelvic floor are on top of each other
  • Avoid “rib flare” by gently lowering your ribs down until the lower ribs move into the abdominal skin and musculature
  • Don’t tilt the pelvis forwards or backwards: the pelvis should be neutral and not tilted forward or tucked. To do this, think of a cup, you don’t want the pelvis tilted forward or backwards causing water to drip out of the cup
• Make sure your chin isn’t jutted out and your head is squarely on your shoulders
  • To do this you tuck the chin straight back while also elongating the neck
  • Sure, you may feel like you have a double chin but we almost all do and that’s ok because it helps maintain that neutral, stacked spine

What does a neutral spine look like?

A neutral spine/ pelvis is when the ASIS (aka the hip bones) is in line with the pubic crest and the lumbar spine is balanced atop the sacrum, the rib cage will be lifted and supported by both the abdominal and back musculature and the pelvic floor and the diaphragm should be stacked upon one another.

To Tuck or Extend: Is it black-and-white?

Nope. First off, not everyone is created equal so there will naturally be some variance in what is best for each person. Constantly arching the spine is not healthy just as constantly tucking the spine is not healthy. The key is to systematically move the spine through its full range of motion with load. Therefore, we need to focus on a neutral spine for both weight-bearing and non-weight-bearing movements to help build strength and create a strong stabilizing system.

 

Resources:

1. Cholewicki J, Panjabi MM, Khachatryan A. Stabilizing function of trunk flexor-extensor muscles around a neutral spine posture. Spine. 1997;22(19):2207–2212.
2. Wallden, Matt. The neutral spine principle. Journal of Bodywork and Movement Therapies, Volume 13 , Issue 4 , 350 - 361
3. Panjabi, Manohar. (1993). The Stabilizing System of the Spine. Part II. Neutral Zone and Instability Hypothesis. Journal of spinal disorders. 5. 390-6; discussion 397. 10.1097/00002517-199212000-00002.
4. Jagarinec, Tomi. (2017). Core Training in Football: Improve Your Players’ Posture and Unlock Their Play Potential.
5. Bendix, T & Biering-Sørensen, F. (1983). Posture of the trunk when sitting on forward inclined seals. Scandinavian journal of rehabilitation medicine. 15. 197-203.
6. Richardson, C, Jull, G, Hodges, P, Hides, J. Therapeutic exercises for spinal segmental stabilization in low back pain. Churchill Livingstone, Toronto; 1999.
7. Elia, DS, Bohannon, RW, Cameron, D, Albro, RC. Dynamic pelvic stabilization during hip flexion: a comparative study. J Orthop Sports Phys Ther. 1996;24:30–36.
8. Robinson, R. The new back school prescription: stabilization training part 1. Occup Med. 1992;7:17–31.
9. Dumas, GA, Reid, JG, Wolfe, LA, Griffin, MP, McGrath, MJ. Exercise posture and back pain during pregnancy: part 1. Exercise and posture. Clin Biomech. 1995;10:98–103.