a slider spins more toward the vertical axis and hence tend to move across the horizontal plane with a slight to moderate downward angle (otherwise it’s a fat pitch, not a slider) L to R from the vantage of the mound for a LHP and R to L for RHP. A great R hand slider will look like a fastball inside to a RH batter and wind up moving away and down from him so the catcher catches it on the low outside corner of the plate and the batter is completely fooled and half way back to the dugout by then after whiffing at it. A curve spins toward the horizontal axis so that the rotation produces downward force (bernoulli) and hence it “breaks” or curves more than “slides”. A great curve will break 12 to 6 or down the face of a clock. A great slider is more 2 to 7 for comparison. Both wickedly effective pitches when thrown in the right count and settings.
7. Parallel Feet Drill - Works on upper body mechanics. This drill isolates the upper body. The pitchers face each other chest to chest with the feet at shoulder width. The lower body remains stationary. The ball is held in the glove in the "check-your-pulse" position. The torso twists at a 90 degree angle as the ball is pulled down out of the glove, and in a sweeping arc brought to the power position with the hand always on top, and the elbow at least at shoulder level. The delivery is then made and the proper follow through is checked. The glove elbow finishes pointed toward the sky. The drill emphasizes that the pitcher throws with a "proud chest" that remains closed as long as possible.
Place your index and middle fingers. Grip the baseball with your index and middle fingers placed tightly together across an outer seam of the ball located at the horseshoe or U-shape seam. For right-handers, place your middle finger across the right half of the seam. Left-handers should do the opposite: place your middle finger across the left half of the seam. This should position your fingers towards the outside of the ball (off-center).
In the final phase of this preventative pitching drill the athletes will both face forward. The athlete performing the shoulder portion of the pitching drill will place the KB Powerbands in their outside hand as they laterally lunge and extend their arm away from their body. During this motion it is important athletes use a controlled motion while keeping the arm extended and moving in a straight line. Athletes need to maintain greater control and a slower pace as they bring the hand back toward the body in a controlled motion.
Recommendations: Drills to address “good arm action” should focus on getting both arms working together in concert. What the glove arm does directly affects the throwing arm and there should be a sort of seesaw effect. Establish the positions, but practice moving right through those positions in a fluid, efficient manner. And always remember, every pitcher is different, so let young pitchers find their own natural arm slot – avoid teaching cookie cutter pitching mechanics.