The aims of the present study were to examine quantitatively ground reaction forces, kinematics, and muscle activations during the windmill softball pitch, and to determine relationships between knee valgus and muscle activations, ball velocity and muscle activation as well as ball velocity and ground reaction forces. It was hypothesized that there would be an inverse relationship between degree of knee valgus and muscle activation, a direct relationship between ground reaction forces and ball velocity, and non-stride leg muscle activations and ball velocity. Ten female windmill softball pitchers (age 17.6 ± 3.47 years, stature 1.67 ± 0.07 m, weight 67.4 ± 12.2 kg) participated. Dependent variables were ball velocity, surface electromyographic (sEMG), kinematic, and kinetic data while the participant was the independent variable. Stride foot contact reported peak vertical forces of 179% body weight. There were positive relationships between ball velocity and ground reaction force (r = 0.758, n = 10, P = 0.029) as well as ball velocity and non-stride leg gluteus maximus (r = 0.851, n = 10, P = 0.007) and medius (r = 0.760, n = 10, P = 0.029) muscle activity, while there was no notable relationship between knee valgus and muscle activation. As the windmill softball pitcher increased ball velocity, her vertical ground reaction forces also increased. Proper conditioning of the lumbopelvic–hip complex, including the gluteals, is essential for injury prevention. From the data presented, it is evident that bilateral strength and conditioning of the gluteal muscle group is salient in the windmill softball pitch as an attempt to decrease incidence of injury.

Nd hamstrings have been linked to several lower extremity injuries. The most common protocol used in testing for these deficits is isokinetic strength testing, which is both costly and time consuming. Therefore, the purpose of this study was to employ common vertical and horizontal power field tests to identify those protocols that best predict lower extremity strength deficits. Data describing 22 healthy collegiate graduate students' vertical and horizontal power were collected using standard field tests (i.e., 2 feet vertical jump, single leg vertical jump, 40-, 50-, and 60-yd runs). In addition, data describing each subject's lower extremity strength deficits were collected by using the Biodex 840-000 Multi Joint System Isokinetic Dynamometer (Biodex Medical Systems, Shirley, NY, USA) set to report peak torque at 60°·s−1 of flexion and extension and 180°·s−1 of flexion and extension. Regression analyses indicated that 3 of the 4 strength deficit parameters could be predicted from a linear combination of field test results (p < 0.05). Of the strength deficits measured, hamstring deficits at flexion velocities of both 60°·s−1 and quadriceps strength deficits at 60°·s−1 were those that could be predicted using field test results. The results of this study, by increasing the diagnostic power of the clinician, may make it easier to develop strength training protocols designed specifically to target weak musculature in the lower extremity. This targeting of specific musculature, in an effort to return symmetrical strength to the lower extremity, may ultimately decrease the likelihood of lower extremity injury in college-aged men and women....

Pitch. Seventeen healthy girls who were currently playing competitive fast-pitch softball volunteered for the study. Subjects were instructed to perform 5 successful fastball windmill style deliveries. We selected 1 pitch for analysis based on the velocity, accuracy, and subjects' input. Kwon3D motion analysis package (Visol., Inc., Seoul, Korea), with 6 digital camcorders placed at 60° apart was used for analysis. Raw data were interpolated using a frequency of 60 Hz and then smoothed using Butterworth low-pass second-order filter with a fixed cut-off frequency of 6 Hz. The subjects were divided into groups based on skill level: novice, intermediate, and advanced. Sequential progression of kinematic variables that resulted in increased throwing velocity and the contribution each segment (upper arm, forearm, and hand) possessed toward ball velocity with descriptive statistics and path analysis were assessed. There was evidence of sequentiality among the arm segments in the intermediate and advanced groups. The patterns of the shared positive contributions made by each of the limb segments were similar among the 3 groups of participants. The novice group tended to rely on more of the upper arm and forearm than the other 2 groups. From this study, it is evident that all emphasis should not be placed on the shoulder, but training and conditioning methods should focus on the entire kinetic chain including the torso and the full arm segment, not just the shoulder in an attempt to gain the greatest velocity while performing the 360° arc of the windmill softball pitch....