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PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) AND ADDRESS(ES)
PERFORMING ORGANIZATION REPORT NUMBER
SPONSORING / MONITORING AGENCY NAME(S) AND ADDRESS(ES) 10. SPONSOR/MONITOR'S ACRONYM(S)U.S. Naval Academy Annapolis, MD 21402
SPONSOR/MONITOR'S REPORT NUMBER(S)Trident Scholar Project Report no. 382 (2009)
DISTRIBUTION / AVAILABILITY STATEMENTThis document has been approved for public release; its distribution is UNLIMITED
SUPPLEMENTARY NOTES
ABSTRACTOur goal was to determine whether expert swing dancers physically optimize their pose for a partnered spin. In a partnered spin, two dancers connect hands and spin around a single vertical axis. We describe the pose of a couple by the angles of their joints in a twodimensional plane. These angles were outputs of an optimization model that gave the ideal pose for a couple. A biomechanical model built in Mathematica allowed comparisons to live dancers with the use of a motion capture system.
SUBJECT TERMS
AbstractOur goal was to determine whether expert swing dancers physically optimize their pose for a partnered spin. In a partnered spin, two dancers connect hands and spin around a single vertical axis. We describe the pose of a couple by the angles of their joints in a two-dimensional plane. These angles were outputs of an optimization model that gave the ideal pose for a couple. A biomechanical model built in Mathematica allowed comparisons to live dancers with the use of a motion capture system.The optimization objective is to maximize angular acceleration, by minimizing the resistance to spin, but still producing torque. The model considers only external forces and neglects internal forces. It consists of equations derived from physical principles such as Newton's laws and moment of inertia calculations that govern how people move. Using numerical non-linear optimization we found the pose for each couple that maximizes their angular acceleration. Different dancers are differently sized, so every couple has a different optimal pose. Each couple's optimal pose was compared to the pose they actually assumed for the spin.Our motion capture system consisted of four video cameras, reflective balls that could be tracked, and software to integrate the different angles of the cameras. The captured data consisted of the three-dimensional location of each of the marked body joints. We used this data to determine the angles of the joints to calculate the couple's actual pose. The couple's actual pose was used to calculate a predicted angular acceleration. Thi...