Sitting in office chairs for long periods of time not only affects your muscles but impacts the disks in your spine. In humans over 5 years of age, there is no direct blood supply to the jelly like nucleus of the intervertebral discs. The intervertebral discs therefore rely upon fluid inflow and outflow for their nutrition: when you lie down, the pressure comes off the discs and they expand, absorbing water and nutrients as they do so (rather like a sponge expanding and sopping up a spill on the floor). Unloaded Disc Filling with nutrient rich liquid When you stand up, the discs are compressed and their watery component is squeezed out, thus removing waste products at the same time. Loaded Discs Being Compressed Similar squeeze/expand cycles are occurring every time that we move, both day and night. This means you must move in order to “feed” your discs and keep them healthy. The disc squeeze/expand cycle is crucial to spinal health.  It is well proven that your degenerative disc "disease" progresses faster over time if your discs can't alternate compression with expansion.  As sitting more than half the time at work is associated with herniated discs (or slipped discs) and sciatic nerve pain in those older than 35, so try to get up and move as much as possible.

One of the most common questions I get asked, by my clients is "is my back pain sciatica?".  So I would like take some time to explain what sciatica or piriformis syndrome is. Sciatica is the irritation of inflammation of the sciatic nerve, which runs from L3 down through your legs and feet to your toes, so its the longest (and widest) nerve in the human body.  The reason sciatica is called piriformis syndrome is that the piriformis muscle (which is in your bum) can compress the sciatic nerve.  Because in most people approximately  87% the sciatic nerve passes below the piriformis muscle, in approximately 13% people the sciatic nerve passes in part or entirely though the piriformis muscle.  So tightness in the piriformis muscle is a major cause of sciatica and this tightness can be exasperated by prolonged sitting.  Other notable causes are trauma to your lower back or your pelvis, a history of herniated disc in your lower back and some systemic diseases e.g. diabetes. So how can you tell if you have sciatica or lower back pain?  Sciatic is characterised by the presence of one or more of the following symptoms:

• Constant pain in one side of the buttock or back of one leg.
• Sharp or burning pain or tingling radiating down the back of your thigh.
• Pain is worse when sitting for long periods of time.
• Pain may be aggravated by sneezing, stooping or straining.
• You feel that you want to slouch away from the effected side.
• Possible pins and needles or parasthesia (numbness) down leg.

Sciatic pain can begin abruptly or can come on gradually and may vary from infrequent and irritating to constant and incapacitating.  While symptoms can be very painful, it is rare that permanent sciatic nerve damage (tissue damage) will result. The vast majority of people who experience sciatica get better within a few weeks or months and find pain relief with non-surgical sciatica treatment including massage. For others, however, sciatica pain from a pinched nerve can be severe and debilitating. There are a few symptoms that may require immediate medical, and possibly surgical, intervention, such as progressive neurological symptoms (e.g. leg weakness) and/or bowel or bladder dysfunction.

While there are many reasons why runner's get injured I want to share with you what I consider the common causes based on what we treat in clinic. Posture I find many clients know they don't have the perfect posture when they sit at their desks but assume their running won't be affected.  This is wrong,  bad posture carries over into your run which can put extra stress on your back and knees.  So its important to focus on good running posture which is upper torso straight with head balanced directly over shoulders and lower back not arched. Training Errors This is the number 1 cause of running injuries.  Training errors basically means your are trying to run too much or too far or too quickly for your body.  The body needs time to adapt from training changes and jumps in mileage, intensity or changes in terrain.  Muscles need recovery time to they can handle more training demands.  If you rush the process you break can down rather than build up.  Running experts recommend the 10% rule, which means the maximum speed or distance (note I didn't say speed and distance) you increase by each week is 10%.  So if you run 10 miles in the first week, you run 11 miles in the second week and so on. RICE - Rest,Ice, Compression and Elevation All of my clients know rice.  However I find too many runners focus on the I (ice), and ignore the RCE.  So they tend to get stuck in a cycle of ice-and-run, ice-and-run etc without giving the muscles time to heal.  Its like dieting every day until 7pm and then pigging out at the all your can eat buffet!  Remember the R in RICE means rest, i.e. don't run until the injury is better.