If you didn't know, your butt is important...

"It says here that one of your interests is Dabutt???"

"Oh that's da butt. I also enjoy reading."

~Dialog from the movie Lady's Man

Ground Reaction Forces, Kinematics, and Muscle Activations during the Softball Pitch.

Oliver, G.D. & Plummer, H. (2011). Ground Reaction Forces, Kinematics, and Muscle Activations during the Softball Pitch. Journal of Sport Sciences, 29 (10), 1071-1077.

Oliver and Plummer (2011) took 10 female pitchers with an average age of 17.6 years, height of 1.66 m and weight of 67.4 kg and had them throw into a net, selecting the fastest pitch for the study. The average velocity of their pitches was 54.1 mph.

The study listed a few findings that have been contrary to other studies done with similar models. First, according to the current study, pitchers with longer stride lengths threw the ball slower, than those with short stride lengths. This flies in the face of earlier research by Guido, et al. (2009) and Werner, et al. (2006) who both stated that stride length was positively related to ball velocity. Second, there were huge discrepancies in ground forces when compared with Werner, et al. (2005). This table illustrates the differences in the data:

Forces are all in % BW	Oliver & Plummer, 2011	Werner, et al., 2005
Braking/horizontal force	36% BW	115% BW
Vertical force	179% BW	139% BW
Medial force	12%	42% BW

There are a lot of possible reasons for these discrepancies, including sample size, level of expertise, size and athleticism of the pitcher, etc. As research in softball pitching is in its infancy, there will be studies that contradict one another, and only multiple studies will reveal the truth. However, Oliver and Plummer (2011) had only 10 participants, only one trial per participant, and slow average velocities (54.1 mph) from the pitchers where Werner, et al. (2005) had more participants (53), took 3 trials per participant, and had a higher average velocity (55 mph) making it a little more valid. We can also postulate that the pitchers in 2011 had a more vertical motion, as is evident from the foot strike data, which would lead to shorter strides. This would also explain the findings on stride length vs. velocity.

Oliver and Plummer (2011) did however do muscle EMG ratings for the lower half muscles and found that gluteus maximus activation in the stride leg positively correlated with ball velocity. Also, the glutes seemed to be used to not only extend the hips but also stabilize them close to release. Furthermore, a lack of gluteal activity was evident by the great amount of stride knee abduction at foot contact. They also concluded that training the gluteal muscle group bilaterally is salient in the windmill softball pitch.

To put this in perspective, the gluteal muscles act as the main hip extensors of the body. This is more simply put as the muscles that stand you up when you bend over to pick something up. The straighter the hips are, the harder we can throw. The gluteus medius also helps in hip rotation and stabilization. Excercises such as lunges and step-ups can really target train this area, and also all of their variations. I have found that rotational step-ups and lunges are particularly excellent. As we are putting all of this together, we have noticed that the front side needs to be as straight and as stable as possible at release for optimum ball velocity.