Journal of Sports Science and Medicine
Journal of Sports Science and Medicine
ISSN: 1303 - 2968   
Ios-APP Journal of Sports Science and Medicine
Androit-APP Journal of Sports Science and Medicine
©Journal of Sports Science and Medicine (2021) 20, 94 - 100   DOI:

Research article
The Association of Baseball Pitch Delivery and Kinematic Sequence on Stresses at the Shoulder and Elbow Joints
Donna Moxley Scarborough1,2, , Nicholas K. Leonard1, Lucas W. Mayer1, Luke S. Oh1, Eric M. Berkson1
Author Information
1 Sports Medicine Service, Department of Orthopaedic Surgery, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
2 MGH Institute of Health Professions, Boston, MA, USA

Donna Moxley Scarborough
✉ PT, PhD MGH Sports Medicine Service Department of Orthopaedic Surgery Massachusetts General Hospital 175 Cambridge St. Floor 4, USA
Publish Date
Received: 23-07-2020
Accepted: 04-12-2020
Published (online): 01-03-2021
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Although there is a commonly held belief within the baseball community that delivery from the stretch confers more stress at the elbow and shoulder joints than delivery from the windup, there remains little evidence in the literature investigating this hypothesis. This study aimed to help address this gap in the literature by studying both intra-pitcher kinematic sequence variability, and intra-pitcher joint torque variability when throwing from the windup vs. the stretch. We hypothesized that 1) each pitchers’ kinematic sequence would remain similar whether throwing from the windup or stretch, and 2) Kinematic sequence would influence peak arm torque more than delivery method. This cross-sectional 3D biomechanical study included 88 pitches thrown by ten (6 collegiate, 4 high school) pitchers with a mean age of 17.60 ± 2.63 years. Pitch velocity, throwing shoulder/elbow torques and the kinematic sequence of each pitch utilizing segmental peak angular velocities were captured. No statistically significant differences in ball velocity (p = 0.17), peak shoulder external rotation torque (p = 0.80), shoulder extension torque (p = 0.97), or elbow valgus torque (p = 0.83) were found between delivery approaches. Three primary kinematic sequences were identified. Shoulder external rotation torque [F(53,2) = 10.992, ɳ2 = .293, p < 0.00], shoulder extension torque [F(53,2) = 15.517, ɳ2 = .369, p < 0.00] and elbow valgus torque [F(53,2) = 9.994, ɳ2 = .274, p < 0.00] did vary significantly across these three kinematic sequence patterns. Our data suggest that the kinematic sequence influences shoulder and elbow torque more than the delivery approach. Instructing ideal kinematic sequence may be more influential for injury avoidance than delivery method.

Key words: Windup, stretch, pitching biomechanics, shoulder torque, elbow torque

           Key Points
  • Our findings demonstrate that baseball pitchers utilize a similar kinematic sequence whether throwing from the windup or the stretch.
  • The specific kinematic sequence pattern employed during pitch delivery is more influential to the torques on the shoulder and elbow than the pitch delivery approach.
  • Instructing ideal kinematic sequence may do more to avoid injury than avoiding a particular delivery method.
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