Rafael F Escamilla's research while affiliated with California State University and other places

... The segmental motion through the kinetic chain is initiated by the ground reaction force (Grf) on the drive (hind) side during the stride phase of the pitching motion. 1,2 propulsive and braking Grfs and impulses on the drive and stride (lead) legs, respectively, have been shown to be associated with the energy flow in and out of the pelvis, trunk, and throwing arm. 1 previous induced acceleration analyses (iaa) 3,4 suggest that the drive and stride legs provide a stable base of support for the movements of the upper body segments after stride foot contact (fc) with the pelvis and trunk generating more than half of the total force and energy required for the delivery. 5-7 a disruption in the functioning of the lower extremities could lead to altered upper extremity kinematics and increased load exerted on the shoulder and elbow. ...

... 9,18,19,37 Additionally, the timing of the kinetic chain is crucial, and temporal variations have significant impacts on both torque and ball velocity. 1,2,23,27,29,30 Professional pitchers with properly sequenced kinetic chains were reported to have faster ball velocity with no difference in elbow varus torque compared with pitchers with discordant kinetic chain sequencing. 23 In the present study, we did not investigate lower extremity, pelvis, and trunk kinematics or the timing of the transfer of energy to the throwing arm, which may be why we found no significant relationships when comparing across different pitchers' arm path and elbow varus torque. ...

... Furthermore, pitchers with an ulnar collateral ligament (UCL) tear had on average 21° of shoulder IR ROM loss compared with 13° of average shoulder IR loss in those without a UCL tear. 23 In the current study, extreme limitations in shoulder IR ROM and GIRD were detected by the reciprocal shoulder mobility screen. There were no high school or college-level players who passed the reciprocal shoulder mobility screen and had <45° of shoulder IR PROM or GIRD >20°. ...

... The ulnar collateral ligament (UCL) is the primary static stabilizer of valgus stress at the elbow. 13,25,29 UCL injuries are often caused by the valgus stress that occurs during the late cocking and early acceleration phases of throwing and are therefore relatively common in baseball pitchers. 14 UCL reconstruction is a well described and frequently performed surgical technique utilized to correct UCL injuries in these athletes. ...

... Pitchers have unique delivery styles, with arm slot (AS) position as a variable that can differ among pitchers. 22 The AS angle is composed of a combination of trunk lateral tilt, shoulder abduction, and elbow flexion ( Figure 1). Before 2018, AS was estimated using either qualitative assessment of video or lateral trunk flexion as a proxy. ...

... Biomechanical studies have investigated the pitching motion starting at the moment of FC, as it has been thought that the impact of movement before FC is negligible because FC is the first moment of energy transference between the ground and the body. [12][13][14]21,42 However, in the time that occurs before FC, or the interval that we have defined as early arm path (from MKH to FC), there is substantial movement of the throwing arm. In the present study, 51% of the total arm path is represented by the distance traveled in the early arm path interval. ...

... BR was calculated as the instant 0.01 sec after the wrist joint center passed the elbow joint center in the positive X-direction. 8,19,11 These time points were used to define the early arm path (MKH to FC), late arm path (FC to BR), and total arm path (MKH to BR). There is potential movement of the throwing arm before MKH and the arm continues to move after BR. ...

... The dummy drag assessment has recruits squat down, wrap their arms around a supine 56-75 kg weighted mannequin, and then drag said mannequin 9-18 m. The dummy drag places a high amount of stress on the spinal erectors like that of traditional hip hinge exercises such as the deadlift [13,[22][23][24]. ...

... 8,20 Data from the markers were filtered by a low-pass filter (fourth-order zero-lag Butterworth filter; 13.4-Hz cutoff frequency). 16 The pitch was divided into 3 time points: maximum knee height (MKH), FC, and BR (Figure 1). MKH was established as the frame where the lead knee reached maximum height in the Y-direction. ...

... Pitching biomechanics/3D motion capture As a secondary outcome measure, 22 athletes (BFR ¼ 12, NoBFR ¼ 10) underwent biomechanical assessments of fast ball pitching during the weeks of pre and post-training measurements (Fig. 2). 23,26,27 Notably, only pitchers who's academic and athletic schedules allowed for biomechanical assessment were able to perform this portion of the investigation. All motion capture measurements took place in a controlled indoor pitching lane off of a standard pitching mound. ...