“It’s just like riding a bike.” You have probably heard the saying before, but do you really know what it means? I saw a video recently that summed it up perfectly.
This video gives new meaning to the phrase, “It’s Just like riding a bike.” What we typically mean when we say this is:
- Something is easy
- Something is easily remembered, even with lack of consistent practice
Things like riding a bike are easy, even if we haven’t done it in years because of something called muscle memory. Contrary to popular belief, muscle memory is not actually happening in your muscles, it’s happening in your brain.
Now for some anatomy!
The primary motor cortex (PMC) is where (the majority of) our movement originates. In other words, you think “bend elbow” and the signal originates in the PMC and goes down the spinal cord to the affected area. However, if you are doing something like walking or riding a bike, there are so many different areas working simultaneously, that you would be unable to perform the task if you had to initiate each movement from the PMC. This is where the supplemental motor area (SMA) comes in. When you think of muscle memory, this is the primary brain area involved. Muscle memory is really just extremely complex motor programs that are stored so that you can easily recall how to do complex tasks such as walking. In these cases, the signal originates in the SMA, the program is loaded to the PMC, and sent down the spinal cord to the affected area(s).
Because there is a need to react to the environment once the program is loaded, a part of the brain called the cerebellum works to correct any errors in movement. This becomes incredibly complex because the newly initiated motor program is now checked against the sensory information it receives from the body. For example, if you use a motor program to serve a tennis ball, the cerebellum checks the movement of your arm against visual information of where the ball is in space, what the joints are feeling, and the weight of you tennis racket. If any discrepancies occur that may cause you to fail in hitting the ball, the cerebellum will issue a correction activating new motor patterns. This all happens in milliseconds, and is literally occurring all day long in every task you perform. Think of the cerebellum like a spell checker that automatically corrects your mistakes before you even perform a task, then rechecks and corrects while performing the task, and updates your programs after you perform the task.
Motor programs contain thousands if not millions of pieces of information, and the more complex the activity, the more complex the program. These programs are constantly updating and becoming more detailed. The more times you perform the given activity, the better you get at it, and the more refined your motor program becomes. Think of a toddler walking vs. an adult walking. Both rely on motor programs to perform the task successfully, but the adult has more detail in the motor program so their walking is smoother and more balanced. In other words, your brain is constantly building new and more complex motor programs to adapt to the physical demands of your life.
The backwards bicycle is a perfect example of muscle memory. Because the motor program is designed for riding a normal bicycle, the brain has difficulty overriding its program to successfully ride the bike. It can be done, but as the video showed, it will probably take A LOT of time. This is similar to a phenomenon we see in individuals who have undergone total joint replacement. Often these individuals will walk with a limp after their surgery, not because of post-surgical pain, but because they have limped for years with joint pain. In other words, their walking motor program has been refined to walk with a limp. Now they have less pain, and can move more normally, but because of motor programming they have difficulty getting back to normal walking. This can be as difficult as riding a backwards bicycle.
Now that you know a little bit about muscle memory, see which of your own programs you can improve. Remember, it’s never too late to learn a few new tricks.