For a Reactive Virtual Trainer(RVT), subtle timing and lifelikeness\ud
of motion is of primary importance. To allow for reactivity, movement\ud
adaptation, like a change of tempo, is necessary. In this paper we\ud
investigate the relation between movement tempo, its synchronization to\ud
verbal counting, time distribution, amplitude, and left-right symmetry of\ud
a clapping movement. We analyze motion capture data of two subjects\ud
performing a clapping exercise, both freely and timed by a metronome.\ud
Our findings are compared to existing gesture research and existing biomechanical models. We found that, for our subjects, verbal counting adheres\ud
to the phonological synchrony rule. A linear relationship between\ud
the movement path length and the tempo was found. The symmetry between\ud
the left and the right hand can be described by the biomechanical\ud
model of two coupled oscillators
