Cycling is addictive, and when you get the bug it’s easy to quickly ramp up the training and miles. Riding a bike is a repetitive activity and although a spectacular and serious crash is what scares cyclists’ most, it’s actually overuse injuries that are the most common. Australian BMC rider Richie Porte has been suffering one of these overuse injuries – piriformis syndrome, on and off for some time. Richie aggravated the condition in the recent Tour of Oman, which affected his performance on the tour and he subsequently had to take some time off training. So what is piriformis syndrome and why is it common in cyclists?
Let’s tackle some anatomy first. Piriformis is a muscle located deep in the buttock (see Figure 1), and it’s one of a few muscles that helps rotate the hip. The sciatic nerve runs close to piriformis, however in 17% of people the nerve pierces the muscle.
Figure 1: Piriformis & the Sciatic Nerve
Piriformis syndrome is where the sciatic nerves becomes entrapped or irritated by the piriformis muscle. Symptoms are usually described as “sciatic” – pain and/or altered sensation in the buttock and posterior thigh (along the path of the sciatic nerve).
For clinicians, it’s important to distinguish piriformis syndrome from disc-related lower back pain. In piriformis syndrome the symptoms are frequently exacerbated in hip flexion, adduction, and internal rotation (FADIR position) – which tightens the inferior border of piriformis against the sciatic nerve, often compressing or trapping the nerve (1). Nerve conduction studies of piriformis syndrome indicate slowing of nerve signals in the FADIR position (2). There are clear similarities between the FADIR position and the top of the pedal stroke.