When you learn how walk, ride a bicycle, or any physical activity, you are learning how to control your muscles in a specific way. This is called motor control. Our bodies have a lot of muscles in them. It is likely that you have not learned to control all of your muscles. There is the coordination between these muscles to learn as well.
I have learned about muscles I can control as recently as a few weeks ago. I learned that you can control the muscles in the arch of your foot while standing. Also, I learned how to individually activate muscles in my quadriceps and back muscles.
With good motor control, you can smoothly and strongly contract a muscle without engaging the muscles around it. This can be hard at first, because your brain has not necessarily figured out the exact signals to send that create the motion you desire. An example of this is your toes. If you are standing up, you should be able to independently lift up your big toe from your small toes. Alternatively, you should be able to lift up your small toes while keeping your big toe on the floor. These are tricky to do if you have not practiced them before, but with practice, you can develop the control to do it. Another example is Spock's Vulcan Salute, which also requires some practice to learn.
As a newborn, we barely know how to use any of our muscles, but as we get older we begin to learn how to use more and more of them. These obscure muscles and movement patterns above are examples of muscle control that you might not get as you go through life. Learning how to control the muscles in your body and activate them with strength, speed, and precision lets you use your body optimally. You will have more dexterity and strength if your brain has the ability recruit your muscles at the right time.
I often talk about mobility and strength being important, but without motor control, you cannot really have either. If you do not know how to activate a muscle or do a particular pattern, how can you know if you have the flexibility or strength to do it? Motor control is the first step in any plan to improve functioning of an area of your body.
This is why people do air squats (squats with no weight) before they load up the bar. This is one of the reasons people focus on going smoothly and slowly through a motion. You can only go smoothly and slowly if you have the necessary motor control to activate all the fibers in your muscle in the right order. When I started doing calf raises regularly, I noticed that my muscles would twitch at certain points in the motion. I could not go smoothly from flat-footed to toes pointed. By working on it every day for a minute, I have been able to smooth out the motion greatly. It is not a question of strength in my muscle fibers it is a question of being able to sequence them correctly to smoothly go through the motion.
Improving motor control
Motor control improvements start by trying to do a particular motion or activating a particular muscle. Even if you cannot make it move, trying helps build up the neurological pathways. When you get motion, focus on repeating it continuously and making it bigger and more pronounced over time. Another trick that sometimes works is to help hold back the muscles that you do not want to activate. For example, you can hold down your little toes while trying to lift your big toe. Eventually you decrease how much you are holding the muscles back, until you are able to activate the muscle individually without restraining the other ones.
It is important to have a mindset of persistence when improving motor control. It can take multiple sessions to see changes and improvements. But continually working on it can lead to great gains. This is the principle used to help people that have serious neuromuscular problems, like losing the ability to move a finger, hand, or arm. But the techniques work for healthy people too.
More motor control is, of course, something you want to have, and you can achieve it without lengthy sessions, but you need to work on it over multiple days to build up your control. The good part is once you have control, it is difficult to lose it. It is not like we forget how to ride a bike even after taking a break for a long time. Motor control that you develop now, is likely to keep paying you back for a long time.