Sometimes, runners can be out even as they are running between bases. If a fielder has the baseball and is near a runner who is in the process of running between two (2) bases, the fielder can simply touch the runner with his glove, and the runner is out. This is called a tag out.
The running lane only exists between home plate and first base and not between any of the other bases. It is a three (3ft) foot wide lane, that batter-runners must stay within when advancing to first base.
A base path is instantly created on the field the moment a fielder tries to tag out a runner. This means that when running the bases, the runner must stay reasonably within three feet (3 ft) of the base path; for example, they cannot veer into right field when running from first base to second base.
Natural Running Arc