When a nerve is pinched or compressed it will commonly lead to pain (or symptoms such as pins and needles or numbness) which radiate down the length of the leg. It may be sharp and short-lived in nature or a lower grade burning type ache. Symptoms may be felt down the front, side, or back of the leg and down into the foot depending on which nerve root is affected.
What causes Sciatica?
Nerve entrapments occur as a result of compression via the surrounding structures (e.g bones, joints, spinal discs, muscles, tendons, ligaments, swelling etc) The most common reason is from a disc bulge or prolapse. This can limit the freedom of movement of the nerve creating excessive stretch on the tissue, which it does not tolerate well.
The riding position places a degree of stress, or load, on the structures along the back of the hip and lumbar spine including the joints, discs, muscles, bones, ligaments. We then often spend long durations riding in this position. If the bike position is beyond the capacity of the riders flexibility or the length of the ride is beyond the riders strength or endurance then it becomes more likely that these structures will become irritated.
The term sciatica is often used as this large peripheral nerve is the most commonly affected. But it is made up from multiple nerve roots in the back meaning the symptoms experienced in terms of location and severity can vary a lot between people.
The most common peripheral compression area is in the buttock where it passes between the gluteal and hip rotator muscles. It is often referred to as ‘piriformis syndrome’ in these cases.
Current or previous disc bulge / prolapse
Facet joint inflammation or arthritis
Muscle weakness in the back and gluteals
A bike fit requiring excessive reach / drop - especially when coupled with inadequate flexibility
What are the symptoms?
The most common feature of nerve-related pain is that the symptoms felt are quite different to those of muscle or joint pain. Pins and needles (tingling), numbness, sharp shooting pain, or burning pain are the most commonly described.
In addition to the above sensory symptoms one must be aware if they note any symptoms of sudden or marked weakness in specific muscle groups.
One of the most common tests employed to assess if there is nerve root related pain or sciatica is the straight leg raise (SLR, pictured below). This is ideally done passively (somebody else lifting your leg up) but can be done actively also. Lying flat on your back with both legs straight, slowly lift one up to the point of any symptoms, then lower. Repeat on the other side and compare. If this range of motion is significantly restricted on one side or strongly reproduces your symptoms down the leg then it indicates the nerve is likely irritated in some way.
In most cases an MRI scan is not necessary to diagnose or treat this condition. There is also mounting evidence to support that early scanning (if unlikely to change the course of treatment) can have longer term detrimental effects.
If you have acute low back pain with pain in both legs then please read about Cauda Equina Syndrome.
How can I manage Sciatica?
In the early stages it is important to try and avoid positions that place excessive stretch or tension forces on the nerve roots / sciatic nerve which runs down the back of the thigh. These include, but are not limited to, bending over with legs straight, hamstring stretches, riding on drops or TT position.
Similarly, positions that place compression around the sciatic nerve, especially through the buttocks and posterior thigh should be reduced. Examples are, sitting on hard surfaces, prolonged sitting without taking a short break to stand up.
Riding may need to be curtailed or split up into shorter session if it is not tolerated. Using an indoor trainer or stationary bike in the gym may be preferable options as they will allow you to adopt a more upright posture, reducing strain on the lower back and sciatic nerve.
As with many other injuries, physiotherapy should include both hands on and hands off treatment as well as education and advice about the condition and timescales for recovery.
Nerve root-related complaints or sciatica will normally improve over a 3 month period provided there is not repeated provocation or aggravation of symptoms.
Encouraging early mobility and restoration of pain free functional range of movement is a primary goal, followed by being able to build strength in the lower back, gluteals, and hamstrings.
To facilitate an exercise and education-based approach, carefully applied mobilisation (image below) and soft tissue work around the lumbar spine and gluteals can be helpful in the early stages.