Posted by: Jack Mankin (Batspeed@verizon.net) on Mon Mar 24 11:38:56 2014

Most batting instructors would agree that there is a correlation between bat speed at contact and how far a hit ball will travel. However, I have also talked with coaches that believe bat speed at contact is overrated. They contend that gaining speed after contact is important because of the "driving through the ball" effect. They further contend that the "grip" and "speed of the incoming pitch" is also important factors.

Here are links to two scientific studies that address ball exit speed and flight. The first link (ESPN Science Study - Ball Flight) is to a science study that explains why bat speed is far more important to ball flight than pitch speed.

The second link (Drussell - Bat/Ball Collision Study) is to a Bat/Ball Collision Study that explains why forces applied at the handle after contact has no effect on ball exit speed or flight. The study concludes that the ball is in contact with the bat for about 1/2000 of a sec. During this time the bat moves less than 1 in. (about 5/8 to 3/4 in.). It further concludes that the ball will have left the bat before any force at the handle reaches the impact point.

Therefore, the bat speed that really counts is that attained at (or by) contact. Swing mechanics of a great hitter allows him to generate higher bat speed much earlier in the swing than average hitters. Players with a lot of "pop" in their bat expend all of the bodies rotational and torque energies before and at contact. After contact their limbs and torso are how in a relaxed and coast mode. The follow through portion of the swing is from the momentum of the bat pulling the arms up and through.

Average hitters are still expending energy to gain bat speed for 20 to 40 degrees (poor hitters past 60 degrees) of bat travel after the bat passes the optimum contact point. Their hardest hit balls are pulled and they have little power to the opposite field. Practicing drills that have the batter "swing through two balls" or "Hit deflated basketballs" can only add to their problem.

Jack Mankin