Department of Health and Sport Sciences

Biomechanics and Motor Control

Improve performance and prevent exercise-related injuries
  • Biomechanics and motor control of baseball pitching
  • Pathomechanics of throwing injuries and improvement of performance
  • Physics, statistics, and cognitive science of ACL tears
  • Risk management based on the individually-specific signal of ground reaction force
  • Motor learning for chopsticks

Understanding and prediction of exercise-related injuries, and improvement of performance


Professional baseball pitchers can throw a baseball that reaches the catcher in a blink of eyes. To do this with extraordinarily precision, an error in the projection angle at the instant of ball release should not exceed 0.5°. This combination of speed and precision performed with a remarkable physical feat, especially when one considers all the body segments involved. A slight aberration in one joint will require others to compensate. Overall, even though a pitcher can throw the ball at the same speed in the same place consistently, his movement is not the same. We are interested in how the different joints coordinate. This research uses high-speed cameras and motion analysis to quantitatively describe the movements.

Image 1. Motion analysis of a baseball pitcher using the musculoskeletal and link segment models


Sports injuries are very common for athletes. One of the most debilitating knee injury is the anterior cruciate ligament (ACL) rupture. Injury to the ACL can occur without body contact, reflecting the athlete’s own dynamic postural control skill. We are conducting quantitative analysis of athletes who have suffered torn ACLs to see if there are any commonalities. Our data have suggested that high-risk and low-risk ACL injury individuals could be identified by observing the dynamic postural stability while landings. These data are to be used for the development of predicting high risk population and enhancement of performance.

Image 2. Prediction of anterior cruciate ligament injury based on ground reaction force


In Japan, chopsticks are the common utensils for eating. There is a socially accepted form of chopstick usage that all children should learn. We are studying how infants (1-2 years old) control their chopsticks from the viewpoint of motor dynamics and hand dexterity, to identify key learning bifurcation which accelerates children’s proper chopstick etiquette.