Since 2002, the Biomechanics Laboratory in the hospital has used the Qualisys motion capture system and recorded baseball pitching for injury prevention and performance enhancement. The group annually measures 50 to 100 baseball pitchers, including professional, collegiate, high school, and youth, with data on 650+ subjects performing a baseball pitch.
What is the aim at the Nobuhara Hospital Biomechanics Laboratory?
- To determine treatment policy based on motion analysis results and clinical evaluation
- To provide scientific feedback on injury prevention and performance enhancement
- To extract new knowledge from measured data (big data) and its application to clinical use
The motion capture studio at the Nobuhara Hospital Biomechanics Research Laboratory includes an installed regulation-sized pitching mound with a distance of 18.44 m / 60.5 ft between the pitching plate and the home plate. As for system setup, 10 Qualisys 7+ cameras and 2 Qualisys 210C high-speed video cameras are set in an indoor studio.
The studio is 26.5 meters (87 ft) long and 11.6 meters (38ft) wide with a ceiling height of 3.9 meters (12.8ft). The 7+ cameras perform with such high resolution (12 million pixel) for ample coverage of the entire volume, capturing full body movement, even those attached to the fingers.
Nobuhara Hospital Mocap Studio Setup
Pitching Analysis Method at Nobuhara Hospital
The 3D position data of the infrared reflection marker are measured by the Qualisys motion capture system and then kinematic and kinetic analysis are performed using customized scripts in MATLAB created by the Nobuhara Hospital Biomechanics Laboratory.
The 3D position data of the infrared reflection marker are measured by the Qualisys motion capture system and then kinematic and kinetic analysis are performed using customized scripts in MATLAB created by the Nobuhara Hospital Biomechanics Laboratory.
Using a 16-segment rigid body model, kinematic and kinetic variables during baseball pitching are output, such as marker velocity and acceleration, Joint angle and angular velocity-acceleration, the position of the whole-body center of mass, and elbow and shoulder joint reaction force and torque.
The MotionBuilder software is used to animate and graphically visualize baseball pitching and its kinematic and kinetic parameters aiming for easy feedback to pitchers. Pitchers can improve their pitching biomechanics while understanding the magnitude of force and torque exerted on the elbow and shoulder.
The benefit of the 3D motion capture system
- Two-way communication of quantitative results among players, coaches, and PTs
- Feedback on injury prevention and performance enhancement
- Easy comparison between individual players or between players
- Kinetic and Kinematic data collection and reporting
“Using Qualisys motion capture, we have found proper and improper pitching biomechanics for increasing or decreasing the risk of shoulder and elbow pain and injury. To biomechanically prevent pitching-related shoulder and elbow pain and injury for all baseball pitchers, we will continue to research optimal pitching biomechanics.”
We want to thank the team at Nobuhara Hospital and Institute of Biomechanics, for sharing their work, and for using their Qualisys system to its full potential!
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