Pitching Biomechanics FA 24 PDF

PT 512 “Bad officials are the ones elected Overhead by good citizens Pitching who do not vote.” Analysis George Jean Nathan Eric Folkins, PT, DPT, DHSc...

PT 512 “Bad officials are the ones elected Overhead by good citizens Pitching who do not vote.” Analysis George Jean Nathan Eric Folkins, PT, DPT, DHSc Fall 2024  Describe phases of overhead pitching. Objectives Identify normal pitching ROM and sequencing for: Shoulder Elbow Trunk Identify normal concentric and eccentric shoulder muscle activity and sequencing during pitching Describe function of shoulder muscles during each pitching phase Pitching Phases (1) Pitching Phases(1) Wind-up phase - Start of movement to highest knee lift Stride phase - Highest knee lift to foot contacts ground Cocking phase - Foot contacts ground to maximum shoulder ER Acceleration - Maximum shoulder ER to release of ball Deceleration phase - Release of ball to maximum shoulder IR Follow-through - Body resumes fielding position What Students Care About Decides their Future Wind-up Phase(1) Very low shoulder muscle activity Upper Trap, serratus anterior and anterior deltoid most activity ○ Concentric to upwardly rotate and abduct shoulder ○ Eccentric to downarly rotate and adduct shoulder to ready position Low torque and therefore few injuries Stride Phase(1) Supraspinatus ○ Highest activity to abduct and stabilize GH joint Deltoid ○ High activity to abduct and hold abducted GH joint Upper trapezius and serratus anterior ○ Moderate/high activity to upwardly rotate and position scapula What type of contraction? (Muscles in bold peak activity for that muscle during pitching) Arm Cocking (1) Pec major and anterior deltoid ○ Concentric to horizontally adduct humerus Serratus anterior ○ Early - Eccentrically controls retraction ○ Late - Concentrically to protract scapula RTC ○ High activity to stabilize and compress GH joint Infraspinatus, Teres minor ○ Prevent anterior translation of humeral head in GH joint ○ ER rotates humerus Lats ○ Prevent anterior translation of humeral head in GH joint Arm Cocking (1) Pecs and subscapularis ○ High activity to slow ER ○ Also concentric to horizontally adduct shoulder Triceps ○ Eccentrically controls elbow flexion ○ Helps stabilize GH joint ○ Concentrically to start elbow extension Biceps ○ Helps stabilize GH joint anteriorly Acceleration Phase (1) Deltoid Moderate activity to abduct shoulder to 100 degrees Pec major, subscapularis and lats Concentric to rapidly IR shoulder Subscapularis also helps stabilize GH joint Teres minor, infraspinatus and supraspinatus Stabilize GH joint Scapular muscles Moderate to high activity to position scapula properly Tricep Minimal to no activity Biceps Stabilize GH joint anteriorly Deceleration Phase (1) Posterior muscles (Infraspinatus, teres minor and major, posterior deltoid and lats Eccentric to control horizontal adduction and IR Stabilize GH joint Scapular musculature Eccentrically control depression, retraction and upward rotation Upper trap max contraction Bicep Brachi Eccentric to decelerate elbow extension Stabilizes GH joint UE Throwing ROM(2) Max Shoulder ER - 169 + 15 degrees Elbow flexion at peak elbow valgus - 43 + 22 degrees Elbow flexion at ball release 41 + 24 degrees LE Throwing ROM (3,4) Knee flexion at foot contact - 38.5 (age < 20), 43.8 (age > 27) Youth (Article reported similar to adults) Hip ROM Foot contact Stance leg - 5.8 IR Stride Leg -.5 ER Hip ROM Max shoulder ER Stance leg - 8.2 ER Stride leg - 6.44 IR Hip Ball release Stance leg - 7.8 ER Stride leg - 7 IR Kinematic Factors leading to injury(3,4) Increase Torque at Elbow and shoulder related to injury. Increased Elbow and Shoulder Torque 1. Increased elbow flexion 2. Increased shoulder ER 3. Early trunk rotation prior to foot contact 4. Decreased knee flexion at foot contact Muscle forces and Shoulder Injury(1) Anterior instability and RTC Posterior RTC muscles (infraspinatus and teres minor) ○ Controls anterior translation of humeral head during cocking Pec major, lats and subscapularis ○ Controls ER at end of cocking Decreased pec major, subscapularis and serratus anterior muscle activity which leads to increased bicep and supraspinatus activity during cocking phase ○ Decreased serratus may lead to limited scapular upward rotation Decreased infraspinatus activity Muscle forces and Shoulder Injury(1) SLAP (superior labral anterior posterior) lesions Anterior instability leads to increase bicep activity during cocking Weak biceps during deceleration phase Impingement Decreased strength/coordination of scapular muscles All types of shoulder injuries Decreased LE Force/power Increased stress on the upper extremities References 1. Escamilla, & Andrews, J. R. (2009). Shoulder Muscle Recruitment Patterns and Related Biomechanics during Upper Extremity Sports. Sports Medicine (Auckland), 39(7), 569–590. https://doi.org/10.2165/00007256- 200939070-00004 2. Aguinaldo, & Chambers, H. (2009). Correlation of Throwing Mechanics With Elbow Valgus Load in Adult Baseball Pitchers. The American Journal of Sports Medicine, 37(10), 2043–2048. https://doi.org/10.1177/0363546509336721 3. Chalmers, Wimmer, M. A., Verma, N. N., Cole, B. J., Romeo, A. A., Cvetanovich, G. L., & Pearl, M. L. (2017). The Relationship Between Pitching Mechanics and Injury: A Review of Current Concepts. Sports Health, 9(3), 216–221. https://doi.org/10.1177/1941738116686545 4. Holt, & Oliver, G. D. (2016). Hip and upper extremity kinematics in youth baseball pitchers. Journal of Sports Sciences, 34(9), 856–861. https://doi.org/10.1080/02640414.2015.1076163