Motion Capture in Sports

Glenn S. Fleisig, Ph.D. Motion Capture in Sports

Disclosures

• Glenn Fleisig is a paid advisor for Major League Baseball

• Glenn Fleisig is a paid advisor for Dari Motion Motion Capture in Sports

• Sports Biomechanics – Maximize performance (ball velocity, running speed, etc.) – Minimize stress (forces and torques on elbow, shoulder, knee, etc.) History of Motion Capture in Sports

Before 1970’s Most coaching just by eye of former players History of Motion Capture in Sports

1970’s Manual digitization of film History of Motion Capture in Sports

1980’s Manual digitization of film Video camera 2D → 3D Manual digitization Automated digitization Active markers Passive, reflective markers History of Motion Capture in Sports

1990’s Motion Capture expands from biomechanics to entertainment (movies, video games) Today’s Motion Capture in Sports

• 21st Century: Biomechanics Revolution! • Advances in technology • Athletes & teams chasing competitive advance • Example: baseball Baseball Biomechanics

180

160

140

120 Scientific publications 100 per year in baseball 80 biomechanics

60

40

20

0 1985 1990 1995 2000 2005 2010 2015 2020 Baseball Biomechanics

American Sports Medicine Institute (1987 – present) www.ASMI.org

American Baseball Biomechanics Society (2020 – present) www.BaseballBiomechanics.org American Baseball Biomechanics Society

• Mission: Provide valid, valuable biomechanical information to baseball players, coaches, teams, and organizations. To set standards for sports biomechanics evaluations and analyses within a baseball setting. American Baseball Biomechanics Society

• www.BaseballBiomechanics.org • 240 members • 16 corporate sponsors Motion Capture in Sports

Optical Motion Capture In-lab Motion Capture in Sports

Optical Motion Capture In-lab On-site Marker Motion Capture in Sports

• Optical Motion capture • Marker-less motion capture • Full biomechanics systems • Phone app Motion Capture in Sports

Inertial Measurement Units (IMU) Motus elbow sleeve Full-body systems Motion Capture in Sports

Electromagnetic (active transmission and receiver) Motion Capture in Sports

Optical & Inertial Electromagnetic Measurement Unit (IMU) Position (cm) and angle (°) Measured Calculated Linear (m/s) and angular velocities (°/s) Calculated Ang vel measured Linear and angular accelerations Calculated Lin accel measured Force (N, force = mass · acceleration) and Calculated Calculated Torque (N·m, torque = mom inertia · ang accel) Considerations & Recommendations

• Digitization – Manual / Automated – 2D / 3D

• Accuracy – Capture rate (30 Hz → 1000 Hz) – Resolution Considerations & Recommendations

• What it tells you: – Motions (kinematics) – Forces (kinetics)

• Data → Clinical / Practical implementation – Data overload – Collection & computation: Biomechanist / data analyst / video / clinician – Application: Biomechanist, clinician, coach, athlete Considerations & Recommendations

Multi-camera Multi-camera Single-camera Inertial Electromagnetic w/markers marker-less marker-less Measurement Unit (IMU)

$$$ upfront & $ upfront & $ upfront & Cost $$$ upfront $$ upfront monthly monthly monthly

Accurate High (“gold position Accuracy ?? Not high ?? standard”) Limited distance and frequency

Mobility Difficult Difficult Excellent Excellent Difficult

Interpretation Biomechanist Computer savvy Anybody Anybody Biomechanist Thank You!