Load bases

Only one runner is allowed on each base at any time this is where the force out rule comes from. However, since there are three bases, up to four runners can be on the field at a time. When all three bases have a runner, the offensive team is said to have the bases loaded, meaning the next fair hit or walk will necessarily result in either a run or an out. Having the bases loaded isnt necessarily the most ideal situation for a team, but its very exciting for the audience.