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Causes of Lower Back Pain

Lower back pain is usually caused by excessive tensile, compressive, or shear forces, such as such as back/core, glute, hip, and/or ankle strength and mobility deficits.

A. Volume or Intensity Increase

Tissue takes time to adapt and get stronger, so if you persistently push it beyond its limits of recovery then you will get lower back discomfort or injury. This not only occurs from increasing intensity too quickly in training, but also from doing too much too soon after having taken time off, such as for travel, injury, or sickness, during which the tissue has weakened from inactivity.

different-postures-back-pressure-diagram

Flexion Overload:

This kind of injury occurs most commonly with younger, taller people, particularly after activities that involve back flexion (e.g. picking something up from the ground, such as with squats/deadlifts, prolonged sitting in a deep chair, and/or leaning over the kitchen sink while doing dishes). 

Note: Sitting in a slumped position increases lower back stress significantly more than in an upright position. (See graph above.)

Extension Overload:
This kind of injury occurs most commonly with older, shorter people, particularly those who have a history of repeated extensions (e.g. gymnastics). As the disc height decreases, there is more pressure on the posterior aspect of the spine’s facet joints. 

QUESTIONS:

  • Did I recently change my running program?
  • Do I allow adequate rest in my running program?
  • Do I participate in other activities that may be overloading my lower back?
U-Stress Shield (University of Montana Movement Science Lab)

This “U” shape graph indicates Injury Risk (Vertical/ Y-Axis) and Load (Horizontal/ X-Axis). If you don’t train much (low load), your risk of injury is high due to the low resilience of the tissue. If you are training a lot, your risk for injury is also high due to potential overload. The middle zone provides the lowest risk of injury. To increase load capacity, you will have to move toward the higher load zone, but the key is to do so progressively to allow the tissue to adapt. This will be addressed further in the conditioning and training portions of ARC Running.

B. Back & Core Muscles

There are a tremendous amount of forces acting on the spine with each step, therefore having a sound core routine for the back that includes the hip flexors, lumbar multifidi, obliques, transverse, glutes, and rectus muscles can help reduce the risk of lower back pain.

ASSESSMENT TESTS:

Are you able to hold a Side Plank for 90 seconds, Front Plank for 90 seconds, and Back Plank for 3 minutes?

Instructions: For front and sides, with each elbow and/or arm aligned with your shoulder, come up and keep your body straight throughout. For back, using a ball, center your weight from the hips, come up, once balanced place your arms back, and keep your body straight throughout.

C. Glutes

Glute strength helps to support the lumbar spine. If your glute medius is weak, for example, then you may tend to increase shearing forces on your spine due to excessive lateral movement.

Legs - Gluts & Hips (Flickr) - Labeled

ASSESSMENT TESTS:

Trendelenberg Test
If your hip drops over 2 cm on the non-standing leg then that may indicate weakness in the glute medius and/or minimus. 

Instructions: Standing in front of a mirror with your hands on your hips, bring one leg up off the ground, and notice if your hands are able to maintain alignment (i.e. stable pelvis).

Single Leg Glute Bridge
If you can hold for 60 seconds, you are good. Less than 60 seconds indicates weakness in the glutes.

Instructions: On your back, bring your hips up with arms across your chest. Hold your body level throughout the duration of the test. The test is complete when your hips begin to drop, you begin to rotate, or you get too tired to continue. 

Lunge Walk
If your knee caves in as you lunge down or if your knee is unstable then that may indicate weakness in your hip abductors such as the glute medius/minimus.

Instructions: Start with your feet shoulder width apart. Bring one leg forward into a walking lunge, and come back up. Alternate each leg for about 4 steps.

D. Hip Mobility

If you have limited hip flexor length (i.e. limited hip extension), it may increase strain on your lower back and direct more forces to your lumbar spine, driving it to move excessively when compared to a normal, healthy spine. 

ASSESSMENT TEST:

Thomas Hip Flexor Test
If your hip feels tight or your knee doesn’t go past your midline then you may have restrictions in your quadriceps or hip flexors. Furthermore, if your leg shifts or rotates to the side then that could indicate restrictions in your IT Band.

Instructions: Sit at the edge of a raised surface (e.g. bed). Bring one leg up towards your chest, and begin to lie back on the bed, keeping the other leg passively hanging. Your hanging limb should be able to go down past the midline of your body with minimal resistance.

E. Ankle Mobility

If you have restrictions in your ankle motion, it can affect forward motion, particularly causing an inward rotation of the knee or increased stress in the lumbar spine.

ASSESSMENT TEST:

Ankle Dorsiflexion Test
If your knee cannot touch the wall then you have restricted range of motion in the ankle.

Instructions: Kneeling with your toes 4 inches from a wall, bring your knee over your foot, keeping your heel down the entire time.

F. Other Risk Factors

  • Running Form: There can be a combination of factors affecting form (e.g. muscle weakness and/or length issues, or even neuromuscular issues), but habits like lateral shift, unbalanced rotation, heel striking and more can stress the back unnecessarily. Learn More.
  • Training Surface: Harder surfaces like concrete can be more unforgiving than softer surfaces like a track or trail. Changing the surfaces can help offset some of the forces directed to the lumbar spine.
  • Prolonged Sitting, Standing, or Stationary Positions: Your intervertebral discs do not have great blood supply; thus, for it to absorb nutrients and remove undesired elements, movement is essential. Even getting up every 30 minutes for at least a minute to change pressure on the disc can make a significant difference.
  • Past Injury: It is common for those who have experienced lower back pain to avoid putting it “at risk” by limiting their exercise. Yet, if you do not train the structures in a variety of positions then you are more prone to injury because the tissues have not been loaded sufficiently to withstand the forces placed upon them. 

Still Need Help?

You are welcome to meet virtually with our PT for additional feedback and assessment. Otherwise, continue to the next step to learn how best to manage the pain from your injury.