Speed up to slow down

Lower-Extremity Ground Reaction Forces in Youth Windmill Softball Pitchers.

Guido, J.A., Werner, S.L., & Meister, K. (2009). Lower-Extremity Ground Reaction Forces in Youth Windmill Softball Pitchers. Journal of Strength and Conditioning Research, 23(6), 1873-1876.

In Werner, Et al. (2005), ground reaction forces were presented but not really discussed in their relationship to the rest of the pitch. The researchers here took that data from the 53 pitchers ages 12-18 (mean 14 years old), average height of 1.65 m and weight of 59 kg, and compared it to the baseball pitch (MacWilliams, et al., 1998). Each threw 10 fastballs and the three fastest were chosen for analysis. The average velocity was 55 mph, average knee angle at stride foot contact (SFC) was 30˚ and average stride length was 1.03 m (62% height).

Braking force peaked at 115 %BW just after SFC and was 0 %BW at release (REL). Medial forces peaked at 42 %BW at .061 s after SFC and vertical forces peaked at 139 %BW also .061 s after SFC. Stride length correlated (r=.765,  p<.05) with ball velocity. Also, time from SFC to peak braking force (r=.764, p<.05) and time to peak vertical force (r=.710, p<.05) correlated with ball velocity. Furthermore, the time from the top of the backswing to release also correlated with time from SFC to peak braking force (r=.788, p<.05) and SFC to peak vertical force (r=.808, p<.05).

In their comparison with MacWilliams’, et al. (1998) data with baseball pitchers, very few similarities were noted. The authors attributed much of the difference to the angle of the baseball mound, which is downhill versus the flat softball mound. They also noted, as did MacWilliams, et al. (1998) that the stride leg serves as an anchor in transferring momentum from the vertical and horizontal components of the leg drive to the arm. Therefore, the more force to stabilize the body against it’s forward energy derived from the leg drive, the better. And they noted that the more leg drive that the pitcher can produce, the more velocity the pitcher will be capable of producing. Research to this point has not touched upon the leg drive component at all.

Studies have shown that the longer force is applied, the higher the performance in other areas of research as well, such as jumping research (Dowling & Vamos, 1993). Pitchers who can reach SFC with their body more “loaded” or with more time to apply force can generate a lot more force. There are a lot of ways to apply these data, one of which I see is in the arm circle. If the pitcher hits SFC with the ball still extended in front of their face vs. over their head, they will have more time around the arm circle to generate force. Although it is difficult to teach, this might be a secret to increasing velocity.

However, there are still gaps to be filled. Without knowing anything about the leg drive component, we cannot apply proper mechanical analyses to any of the end components. Pitchers may be weak because they are recovering from poor leg drive, or they may be braking twice as much from the speed they developed. As always, we need more research.