All player safety is of paramount importance. With that in mind:
Pinch runners may be used as needed. When used from home plate, a pinch runner can only get a single or double.
The same pinch runner should not be allowed to run more than once per inning.
When there is a play at any base, it is the base runner's responsibility to do everything possible to avoid colliding with a fielder. If the runner does not avoid colliding with a fielder, the umpire will call the runner out regardless whether the runner or the ball arrived first, the play will be called dead, and all runners will return to the last occupied base. If it happens a second time in a game, the player may be ejected. (This does not include minor, incidental contact.)
When there is no play at a base, it is the responsibility of the fielder to avoid contact - to avoid interfering with a runners path. If a fielder interferes with a runners path, runner shall be awarded the next base.
Home plate to first base: If a play is contested at first base, the batter must use the safety base located in foul territory next to the regular first base. If there is no play at first base, the batter may use the regular first base. Violation of this rule is an out unless the batter did so to avoid colliding with the first baseman (for example, the first baseman is off first base fielding a ball and blocks the batter’s path to first base.)
First base to second base to third base: The runner may overrun second or third base in a straight line and return to the overrun base. The runner does not have to touch second or third base when overrunning the base - especially to avoid contact. Put-outs at second and third base are determined by whether the fielder catches the ball before the runner reaches the base. Runners must run to the non-fielder side of the base to avoid interfering with the fielder. When overrunning second or third base, the runner must return to the overrun base before advancing to the next base. If the runner does not return, the runner is in play and may be called out. The runner cannot be called for interfering with a fielder’s throw as long as the runner is in the three foot wide base lane and does not raise hands to make contact with the ball.
All bases: With the intent to avoid injuries, plays at all bases are treated similar to a put-out at first base - they are determined by whether the fielder catches the ball before the runner reaches the base; a runner can be tagged out between bases. For safety, there is a second home plate adjacent to the regular home plate. Runners step on the second base to run through the base at first base and run wide at second and third. A runner scores by stepping on the second home plate. The strike zone mat is for the catcher, who may step on any part of the strike zone mat to force out the runner. If a runner steps on any part of the strike zone mat, he is out.
A marker placed perpendicular to the third base line and twenty feet from home plate is the commitment line. Once a runner crosses this line, he must continue to home plate. Violation of this rule is an out.
Run downs are not allowed. A runner may make a usual turn past a base and may consider advancing to the next base. He can proceed any distance (10, 20, 30 feet, etc) toward the next base and still stop. If he stops and changes directions back to previous base he must return to that base - he cannot change direction a second time.
Sliding and diving are not allowed. A runner who slides or dives will be called out - an exception is allowed if the slide or dive is made solely to avoid injury/contact.
If a runner continues to play on after making a turn toward or taking a few steps toward the next base, he may be tagged out. When returning to a base, a runner may not overrun the base.
A base runner cannot leave his base until the batter makes contact with the ball. Leaving a base early is an out. There is no rule violation if a runner leaves the base when the ball crosses home plate and is not hit.