Comparison of Kinematic Sequences During Curveball and Fastball Baseball Pitches

Abstract

Performance of a sequential proximal-to-distal transfer of segmental angular velocity (or Kinematic Sequence) is reported to reduce stress on musculoskeletal structures and thus the probability of injury while also maximizing ball velocity. However, there is limited investigation regarding the Kinematic Sequence of the five body segments (Pelvis, Trunk, Arm, Forearm, and Hand) among baseball pitchers. Some biomechanical and epidemiology studies have reported an association of the curveball with increased risk for elbow injury among youth pitchers. Kinematic Sequences with altered distal upper extremity (forearm and hand) sequences have been associated with greater elbow valgus and shoulder external rotation torques compared to other Kinematic Sequences. Identifying Kinematic Sequence patterns during curveball pitches may lead to improved understanding of injury susceptibility. This study investigated the Kinematic Sequence patterns (and their variability) during curveball pitching and compared them to the sequences identified during fastball pitches. Using 3D motion analyses, 14 baseball pitchers (four high school, eight college, and two professional) performed 5–6 curveball pitches and 12 pitchers also threw fastball pitches in a simulated bullpen session. Eleven different curveball Kinematic Sequences were identified and 8 fastball Kinematic Sequences. There was no significant variability in the number of Kinematic Sequences performed between the two pitch types, (Z = −0.431, p = 0.67). The median number of KSs performed by each group was 2.5. The most frequently used Kinematic Sequences for both pitch types were due to alteration in the sequence of the distal segments. The total percentage of Kinematic Sequences with altered distal segment sequencing for the curveball pitches was 49% and 43% for fastball pitches. Identifying the frequency of Kinematic Sequences with altered timing of hand and forearm peak velocities across pitch types may lead to a better understanding of the stresses that individual pitchers incur.

Neuromechanical Integration of Pelvic-Thoracic Rotation among Youth Baseball Throwers

“…The kinetic chain model of throwing suggests that the safest, most optimal method of throwing requires a highly orchestrated series of segmental movements throughout the body 4 5 6 7 8 9 . A summary of this kinetic chain model of throwing states, “…the utilization of the kinetic chain to generate and transfer energy from the larger body parts to the smaller, more injury-prone upper extremity.…”

“…The order in which each segment reaches its maximum angular velocity is described as the kinematic sequence and has been the subject of investigation. The presumed optimal kinematic sequence is, pelvis - trunk - arm - forearm - hand 7 . This optimal kinematic sequencing facilitates the distal arm acceleration to be driven primarily by the forces generated within the thorax and shoulder 10 .…”

“…Previous research has documented that the kinematic sequencing between the pelvis and thorax commonly conforms to the expected. In one study it was determined that of the three most performed kinematic sequences for both curveball and fastball pitches, the pelvis was the first and the trunk the second segment to reach maximum angular velocity 7 . In another study the pelvis was the first segment to reach maximum angular velocity in 96% of the trials whereas the thorax was the second segment to do so in 91% of trials 8 .…”

“…In another study the pelvis was the first segment to reach maximum angular velocity in 96% of the trials whereas the thorax was the second segment to do so in 91% of trials 8 . The exception to this involves either the thorax reaching maximum angular velocity before the pelvis or at the same time as the pelvis 7 8 . This exception to the expected pelvis–trunk, kinematic sequence was revealed to occur in 60% of the trials and was associated with greater maximum shoulder external rotation and greater force at the shoulder 9 .…”

“…Results suggest that youth baseball participants may not adequately utilize the core of the body to fully benefit from the optimal kinetic sequencing postulated within the literature. series of segmental movements throughout the body [4][5][6][7][8][9]. A summary of this kinetic chain model of throwing states, "…the utilization of the kinetic chain to generate and transfer energy from the larger body parts to the smaller, more injury-prone upper extremity.…”