Common Issues

Neuroplasticity, Habituation and the CPG.

The way in which your body initiates, performs and controls movement of the lower limbs in reciprocal patterns is to use a specialised group of neurons in the lower back called the Central Pattern Generator. Once the body initiates a pattern of movement (for example walking or running) the CPG takes over and sustains that pattern with minimal guidance from your brain. Hence a human being is able to walk and talk on their mobile phone without any concern directed to the complicated act of walking.

The CPG takes care of the movement and adjusts the cyclical patterns of your stride to suit the terrain without you even noticing. Only if a large obstacle occurs to disrupt the movement will you stop walking – for example arriving at your front door, stepping over a log on the path and whatnot. The same structures are responsible for control of the cycling stroke. Hence, you can ride along and talk to your mate about his new $15,000 road bike whilst still enjoying watching him struggle up a slight incline. This is the very definition of multi-tasking! Similarly, this is the reason that a chicken can continue to run around the yard even once its head has been removed – the CPG is continuing to function for a little while until the chicken finally meets its untimely end.

The human brain and nervous system is plastic. That is to say, it can be moulded and shaped to perform different tasks and will refine and adapt the myriad neuronal connections required to perform those tasks through repetition.

Neuroplasticity is responsible for our ever-changing mental states, the ability of our bodies to learn a new task like playing the piano or guitar and to refine and perfect that action over time. The area of the brain devoted to finger and hand control in a concert pianist is hugely greater than that of a soccer player. Similarly, the soccer player will have a larger number of neural connections and brain area devoted to fine control and proprioception (the body’s joint position sense) than the concert pianist. The Central Pattern Generator is also neuroplastic. That is, its timing, sequence and control of your movement patterns can be changed, refined and perfected but this takes time. This time is what I call the “Habituation” phase of the bike fit. Some habituate quickly, in a matter of hours, whilst others with deeply ingrained motor patterns and low neuroplastic tendencies will take many weeks.

So what does all this have to do with cycling?

The basic premise to take from all this is to illustrate that people will change, and, physical changes aside, the way they function on the bike from a neurological control perspective will also change. Hence I will fit you to the bike and attempt to match the fit as closely as possible to the way that you are functioning at this point in time. If the changes have been large, and for some of you they will be, the initial fit will feel unusual, and you will likely be slower on the bike until the new motor patterns embed.

I always advise you to ride SLOWLY at no more than 75% intensity for 2-4 weeks after the fit. The harder you go, the more likely the body is to revert into the “tried and true” motor patterns that you have developed over many years. We want your body to find its new, natural rhythm on the bike, not be forced into old, asymmetrical motor patterns. Cycle gently and, once you are feeling comfortable and “at home” on the bike, begin to re-introduce load and intensity.