This is an excerpt from Baseball Skills & Drills by American Baseball Coaches Association.
Little has been written concerning the headfirst slide. Its increased use in modern baseball may be due to the aggressive playing style of Pete Rose. Or perhaps players use it more today because of the widespread belief that it is the quickest approach to the bag. Whatever the reason, the headfirst slide is becoming a bigger part of today's game.
Although few studies have been made, experience and observation would lead one to believe that an aggressive headfirst slide will get the runner to the base more quickly than other slides because the runner does not have to move his center of gravity back (as he does in the leg-first approach). Instead, he moves it forward in the direction he is going.
The headfirst slide is not advantageous in the following situations:
The runner begins by lowering his upper body and placing his center of gravity farther in front of his legs. As his body lowers and his weight shifts forward, he makes his final thrust forward with only one leg. On the final thrust forward, the body must be low to the ground as if the player were running and then gliding on top of the water. The arms stretch forward with only a slight bend in the elbows. The player keeps his head up so that he can see the base. His chest, legs, and arms should all be in one plane, parallel to the ground. The forearms, chest, and thighs make simultaneous contact with the ground. The hands catch the base to avoid jamming the fingers.
Problem areas to watch for are players using their elbows or hands to break the fall, players not keeping their chests up, and players using their knees to break the fall. Remind players to keep their bodies straight but not rigid.
To practice the technique, use dives back to first base on pick-off attempts. You can also use short runs with good aggressive explosion on the final thrust. Once the players can feel the slide, they will become faster, more aggressive, and better able to perform it.
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