The Biomechanics and Motor Control of Tap Dancing

Although tap dancing is a popular dance genre, little is known about the biomechanics and motor control of this complex motor skill. We conducted a detailed 3D kinematic analysis of movement timing, amplitude, and symmetry in three experienced female tap dancers. Kinematic analyzes of three basic tap dance steps (nerve beats, brush brush stamps, and heel ball walks) were undertaken. A 10-camera Vicon motion analysis system was used to collect the data. The results showed the feet and knees to play a major role in movement execution. Each step required at least 10° of ankle motion (range: 10° to 66.8°). Knee range of motion varied from 1.3° to 147.4°. For each of the dance steps the hips showed the smallest amplitude of movement, which was not greater than 21° in two out of the three dance steps. Analyzes of movement timing showed that each of the dance steps was fast, accurate, and well synchronized. The nerve beats took on average 0.50 seconds, the brush brush stamps 1.36 seconds, and the heel ball walks 4.03 seconds. A high degree of symmetry in total movement amplitude was evident at the ankles,knees, and hips for the nerve beats and heel ball walks. There was a mild degree of asymmetry at the hip for the brush brush stamp steps (symmetry index 90%). The results showed that experienced dancers had very high levels of proficiency in controlling movement amplitude, timing, and inter-limb coordination across the ankles, knees, and hips. This resulted in skilled, fast, and well executed dance steps.