Validation of an integrated experimental set-up for kinetic and kinematic three-dimensional analyses in a training environment

Biomechanical analyses using synchronized tools [electromyography (EMG), motion capture, force sensors, force platform, and digital camera] are classically performed in a laboratory environment that could influence the performance. We present a system for studying the running sprint start that synchronizes motion capture, EMG, and ground reaction force data. To maximize motion capture (Vicon 612 with six cameras), a special dim environment was created in the stadium. "Classical" tools were combined with "purpose-built" tools intended to analyse the different aspects of movement. For example, a synchronization system was built to create a common time-base for all data recordings and a portable EMG system was synchronized by a cable that was "disconnected" by the athlete's movement out of the blocks. This disconnection represented an independent event recorded by different tools. A "gap" was measured for some sprint start events between kinetic and kinematic (motion capture) data. Calibration results, measurements of time "gap", and duration of the independent event were used to validate the accuracy of motion capture and the synchronization system. The results validate the entire experimental set-up and suggest adjustment values for motion capture data. This environment can be used to study other movements and can easily be applied to several sports.     

The law of one price,noise and “irrational exuberance”: the auction market for Picasso prints

We use prices realized for Picasso prints at auctions worldwide, as well as the 100 prints that comprise his Vollard Suite, to test the law of one price: the proposition that identical art objects sold contemporaneously should command the same price regardless of the auction house or geographic region where the sale takes place. Picasso is the most prolific printmaker of the twentieth century and, from 1977 to 2004, his prints appreciated in price significantly faster than the prints of modern masters as a whole. We find that Picasso prints sold in the United States command higher prices than in Europe. However, prices realized at Sotheby’s in New York are no longer higher than at Christie’s in New York, nor at Kornfeld than at other auction houses. We find evidence of “irrational exuberance” in the transitory nature of the extraordinary prices realized for the Picasso prints included in the 1997 sale of the collection of Victor and Sally Ganz at Christie’s in New York. More generally, we find substantial noise in auction outcomes, a result well known to savvy auction goers.

Stressors in elite sport: a coach perspective

We examined the varying performance and organizational stressors experienced by coaches who operate with elite athletes. Following interviews with eleven coaches, content analysis of the data revealed coaches to experience comparable numbers of performance and organizational stressors. Performance stressors were divided between their own performance and that of their athletes, while organizational stressors included environmental, leadership, personal, and team factors. The findings provide evidence that coaches experience a variety of stressors that adds weight to the argument that they should be labelled as "performers" in their own right. A variety of future research topics and applied issues are also discussed.