During childhood, the brain creates lasting connections between muscle groups in a process called neuromuscular coupling. This happens when children get attention or praise for physical actions like crawling, learning to walk, or holding hands. The muscles used in those movements become linked, so they contract together even when only one is needed. This reduces coordination and makes movement less smooth and precise.

These connections are the main factor that shapes a person’s physical skill potential. People who are very skilled at an activity have fewer and weaker interfering connections for that specific skill. This allows their movements to be faster and more accurate. People who are less skilled have stronger muscle linkages that get in the way of the movement they are trying to do.

Practice can help improve technique, but it cannot undo the connections formed in childhood. Only the change process can break those links and help restore full coordination.

Here are two ways to experience connected muscles:

1. Finger test: Straighten your fingers and relax your hand. Now, without moving your other fingers, try folding just your little finger into your palm. Most people will find that they cannot keep the ring finger straight while bending the little finger. That’s because the muscles that flex the little finger are neurologically linked to those that flex the ring finger.

2. Tapping test: Place your hand flat on a table with your fingers extended. Repeatedly tap your palm on the table while keeping your arm and shoulder completely relaxed. Most people will notice that the faster or more forcefully they tap, the more their upper arm and shoulder begin to tense. That’s because the muscles that move the wrist are neurologically linked to muscles higher up in the arm and shoulder.