Posted by: Shawn (mariner0324@yahoo.com) on Tue Feb 20 18:29:17 2007

> Are there any studies that show the actual muscle groups and the sequence of firing in the swing. I could imagine as some of the major league players report that is is a thighs to chest sensation with the arms and hands on loose to transfer the energy generated by the big muscle groups. One would think hooking someone worth studying up with the monitor that registers muscle firing has been done. What result?'

Clin Orthop. 1993 Jul;(292):285-93.

Baseball batting. An electromyographic study.

Shaffer B, Jobe FW, Pink M, Perry J.

Department of Orthopaedics, Georgetown Medical Center, Washington, D.C.

The muscle firing pattern in 12 muscles throughout the lower extremity, trunk, and upper extremity during the batting swing is described in this study. The two hamstring muscles studied and the gluteal muscle had a similar pattern of high muscle activity during pre-swing and early swing, and then rapidly diminished. The vastus medialis demonstrated peak activity between 95 and 110% maximum muscle test (MMT) throughout the swing phases and follow-through. The erector spinae demonstrated activity from 85 to 185% MMT during the swing phases. The abdominal obliques showed greater than 100% MMT during the swing phases and follow-through. The supraspinatus and serratus anterior showed relatively low muscle activity (less than 40% MMT). These results show that batting is a sequence of coordinated muscle activity, beginning with the hip, followed by the trunk, and terminating with the arms. Power in the swing is initiated in the hip, and therefore exercises that emphasize such strength development are indicated. The maintained, high muscle activity in the trunk muscles indicates a need for back and abdominal stabilization and rotation exercises. The relatively low level of activity in the four scapulohumeral muscles tested indicated that emphasis should be placed on the trunk and hip muscles for a batter's strengthening program.