Throwing Biomechanics
*Throwing arm will be considered I/L
Phases
Wind Up
- Initial Movement to Maximum Knee Lift
- Necessary:
- I/L rotation
- Relative I/L Hip IR
- I/L SLB
- Lead HF (end range)
- I/L Hip ext
- Stance (I/L) leg ext/IR
- stride leg max HF
- Upright trunk with I/L rot
- Eccentric trunk/shoulder load
- Critical events and considerations:
- SLB and stance stability (lumbopelvic)
- Load hip, min shoulder mm activity
Early Cocking
Defined as Maximum Knee Lift to Lead Foot Contact
- Stance leg EXT/ER/ABD with pelvic Rot
- Stride leg drives trunk and UE eccentric load
- This powerful stride before front foot strike is important
Increased hip/pelvic Rotation
- Increased GHJ HorABD stress (Laudner 2019)
- Increased Elbow valgus (Laudner 2019)
Decreased hip/pelvic Rotation
- Increased GHJ HorADD (Laudner 2019)
Late Cocking
Characterized by Lead Foot Contact to Maximal Shoulder ER
- Trunk begins C/L rotation (following the pelvis)
- Trunk is moving faster than the shoulder (relative HorABD)
- C/L arm: Remains closed
- I/L arm
- GHJ Max ER & Max ABD
- Scapula: Retracts to create stable base
- Foot placement
- Angled 15° from 180°
Note
A focus of a clinician during this phase should be foot placement
Acceleration
Maximal Shoulder ER to Ball Release
- Hips & Trunk rotate the shoulder to “ball release point” of 90° rotation
- Muscle function transition
- Internal rotaters are eccentrically working as the shoulder moves to max ER then transition to concentric activity during this phase
Deceleration
- Ball Release to Maximum Shoulder IR
- Arm crosses body (hor-add)
Follow Through
- Maximum Shoulder IR to Body Stops Moving
Stride Length
- Professional: Stride length = 85% of height
- Youth: Stride length = 65% of height
Citation
For attribution, please cite this work as:
Yomogida N, Kerstein C. Throwing Biomechanics.
https://yomokerst.com/The
Archive/Biomechanics/Throwing/throwing_biomechanic.html