Chapter 7: Training for Mobility 162 According to Zatsiorsky & Kraemer (2006), the intervertebral discs are most susceptible to damage when leaning, bending or performing rotational movements. During these movements, the nucleus pulposus (jellylike center of the intervertebral discs) is shifted to the side opposite the lean. Depending on the load used and/or condition of the intervertebral discs, the resulting pressure can exceed the mechanical strength limit of the discs and cause the nucleus pulposus to protrude from annulus fibrous (strong outward wrapping of the discs). If this happens, the disc bulge can press against the spinal cord and cause nerve pain, numbness and/or weakness. Zatsiorsky & Kraemer (2006) provide several recommendations for protecting the lower back while strength training. Recommendations include the use of proper breathing and bracing and weight belts while lifting. The Valsalva maneuver is a particular method of breathing and bracing that increases intraabdominal pressure (IAP) thereby providing additional support to the spine. If done properly, the Valsalva maneuver can reduce the compressive forces on the intervertebral discs by as much as 20-40%. Proper Valsalva performance can be achieved through the training and activation of the muscles comprising the abdominal wall (i.e., erector spinae, rectus abdominis, oblique muscles, intercostals and diaphragm). Zatsiorsky & Kraemer (2006) found that back pain occurs more frequently in individuals with weak or nonproportionally developed abdominal muscles. Similar to the Valsalva maneuver, the use of weight belts can also help increase IAP and decrease the relative spinal load on the intervertebral discs. Other methods that can be used to help restore the dimensions and properties of the intervertebral discs include massage, swimming in warm water (e.g., 30° C / 86° F) and spinal traction (Zatsiorsky & Kraemer, 2006). In terms of treatment, most cases of low back pain resolve on their own within a couple weeks. With that in mind, seeking invasive treatment options (e.g., corticosteroid injections, surgery) immediately upon the onset of low back pain is likely unnecessary. Only when it is determined, through a formal medical evaluation, that the pain is in the same neural pathway as depicted on the MRI, should individuals consider more invasive treatment options (Cady, 2016). Research has shown walking to be an effective treatment option for low back pain (Cole, 2019). Walking as little as 30 minutes per day can help strengthen and increase the blood flow to the muscles that support the spine. Additionally, daily walks have been shown to help improve lumbar spine mobility by increasing the flexibility and elasticity of spinal ligaments and tendons. However, individuals currently suffering from low back pain may not be able to tolerate 30 minutes of continuous walking. Instead, multiple bouts of shorter walks (e.g., 5-10 minutes) throughout the day may be a better initial strategy until a tolerance for longer walks has been established.