DOI: 10.5061/dryad.dncjsxm8v
title: Temporal relationship between dancer’s body movements and music beats in classical ballet

description: Musicality is one of the most essential aspects of dance performance:
 Dancers control their bodies to the music, and audiences appreciate dances
 beautifully harmonized with music. The present study explores this problem
 from the perspective of synchronization between music beats and body
 movements. Specifically, we investigated the temporal relationship between
 dancer’s body movements and metronome beats when a dancer performed four
 basic classical ballet movements (i.e., changement, passé, jeté, and
 tendu) to the metronome. We measured body movements of 10 ballet dancers
 using an optical motion capture system and force plates, and analyzed what
 movement reference points of dancer’s body motion (e.g., movement
 endpoints and ground reaction force peaks) occurred on or close to the
 beat and backbeat. Specific reference points coincided with the beat
 timing common to most dancers, but the different reference points were
 synchronized with the beat depending on the movements. These reference
 points were consistent with those reported in previous studies of the
 temporal relationship between music and body movements. Therefore, the
 present result suggests that humans have a set of common movement features
 that can serve as reference points for music-motion synchronization, and
 dancers select appropriate ones according to the target movements.
description: Appratus and signal processing We measured
 the dancer’s body movement using an optical motion capture system (Vicon
 Nexus) at a frame rate of 250 Hz. Retroreflective markers were attached to
 35 body sites using a plug-in full-body gait model. Ground reaction force
 (GRF) was measured using a force plate (Kistler Instruments) at a sampling
 rate of 1 KHz via external analog inputs to the Vicon system. Motion data
 were filtered with a 4th-order zero-phase low-pass filter (cutoff
 frequency: 50 Hz), and velocity and acceleration were calculated using
 numerical derivatives. GRF data were filtered with a 4th-order zero-phase
 low-pass filter (cutoff frequency: 400 Hz). Positional data are expressed
 in xyz coordinates, where the x-axis represents the front-back direction
 (positive towards the back), the y-axis represents the left-right
 direction (positive towards the right), and the z-axis represents the
 up-down direction (positive upwards).  Task and
 procedure The participant’s task was to perform the
 specified ballet movements in sync with the metronome’s rhythm. The target
 movements were <em>changement</em>,
 <em>passé</em>, <em>jeté</em> (outward), and
 <em>tendu</em> (outward). The metronome's tempo was set
 to 60 beat per minute (bpm) for passé, jetés, and tendus, and 80 bpm for
 changements. Participants repeated the movements at least 16 times for
 changements and 24 times for the other movements. We discarded the first
 several cycles of motion data and used the subsequent 10 cycles of data
 for further analysis because the body movements were unstable at the
 beginning of a trial. Data analysis
 We defined several “movement reference points” (i.e., distinctive
 perceptual events that can be used to synchronize body movements with the
 metronome beats) for each movement. We analyzed the temporal relationship
 between these reference points and the beats for every cycle. The table
 below summarizes the reference points used in the following
 analysis. These reference points were calculated from
 the movements of markers attached to the participants’ C7, ankles and
 toes. Thus, the experimental data stored in this database are the
 trajectories of these markers and the GRF data. In addition, we registered
 the timing of the extracted reference points for each movement.
   <strong>Table: Movement Reference Points for
 Four Target Movements</strong> 
 
 <strong>Symbol</strong> 
 <strong>Objective
 Criterion</strong> 
 <strong>Physical Event</strong>
   
 <strong>Changement</strong>
 <strong> </strong>
     
 GC GP1
 BB GP2 GL
 BT GRF onset
 GRF’s first peak C7’s bottom point
 GRF’s second peak GRF offset
 C7’s top point Feet
 contact the ground. Feet kick the ground to support the
 body. Body is at the bottom. Feet
 kick the ground to jump up. Feet leave the
 ground. Body is at the top. 
   
 <strong>Passé</strong> 
      
 BB
 VBU BR VFU
 FT VFD BF
 VBD C7’s bottom
 point C7’s peak upward velocity
 Offset of C7’s upward velocity Ankle’s peak
 upward velocity. Ankle’s highest point
 Ankle’s peak downward velocity Onset of C7’s
 downward velocity C7’s peak downward
 velocity. Body is at the
 bottom. Body moves up the fastest.
 Body has ridden on tiptoe. Working toot goes
 up fastest. Working foot is at the top.
 Working foot goes down fastest. Body starts to
 come down from the tiptoe. Body moves down the
 fastest.   
 <strong>Jeté</strong>
    
   
 FLS VR FR
 VL FLE 
 Onset of ankle’s velocity Ankle’s peak
 rightward velocity Ankle’s rightmost point
 Ankle’s peak leftward velocity Offset of
 ankle’s velocity Working foot
 starts to move rightward (outwards). Working foot moves
 rightward (outwards) fastest. Working foot reaches the
 rightmost position. Working foot moves leftward
 (inwards) fastest. Working foot returns to the starting
 position.   
 
 <strong>Tendu</strong> 
      
 FRS
 VL FL VR
 FRE Onset of toe’s
 velocity Toe’s peak leftward velocity
 Toe’s leftmost point Toe’s peak rightward
 velocity Offset of toe’s velocity 
 Working foot starts to move leftward
 (inwards). Working foot moves leftward
 fastest. Working foot is in the leftmost
 position. Working foot moves rightward
 fastest. Working foot returned to the rightmost
 position.   
  
description: # Temporal Relationship between Dancer’s Body Movements and Music Beats in
 Classical Ballet
 [https://doi.org/10.5061/dryad.dncjsxm8v](https://doi.org/10.5061/dryad.dncjsxm8v) ## Summary of experiment The purpose of this experiment is to analyze the temporal relationship between the dancer's body movement and musical beats when a dancer dance to music. To this end, we measured the body movement of classical ballet dancers using an optical motion capture system (Vicon Nexus) and a force plate (Kistler Instruments). The participant’s task was to perform the specified ballet movements in sync with the metronome’s rhythm. The target movements were *changement*, *passé*, *jeté* (outward), and *tendu* (outward). In order to examine the temporal relation between body movement and metronome beats, we defined several “movement reference points” (i.e., distinctive perceptual events that can be used to synchronize body movements with the metronome beats) for each movement. We analyzed the time difference between these reference points and the beats for every cycle. The reference points were calculated from the movements of markers attached to the participants’ C7, ankles and toes. Thus, the experimental data stored in this database are the trajectories of these markers and the GRF data, as well as the timing of the extracted reference points relative to the metronome beat.　 ## Files and variables #### Motion Capture data: (filename: Mocap\_X\_Y.csv, X: movement type, Y: participant ID) **Description:** Motion capture data give the temporal sequence of the position and velocity of several marker's attached to the dancer's body. Data are presented in xyz coordinates, where x, y and z values represent the fore-aft, right-left and vertical components of the position (or velocity), respectively. The units of position and velocity are mm and mm/s, respectively. ##### Variables * trial: Trial number (1-10) * time: Relative time from the metronome beat (unit: ms) * C7_z: z coordinate of the position of the marker at C7 (7th cervical vertebra) * C7_vz: z coordinate of the velocity of the marker at C7 (7th cervical vertebra) * RAnkle_x: x coordinate of the position of the marker on the right ankle * RAnkle_vx: x coordinate of the velocity of the marker on the right ankle * RAnkle_y: y coordinate of the position of the marker on the right ankle * RAnkle_vy: y coordinate of the velocity of the marker on the right ankle * RAnkle_z: z coordinate of the position of the marker on the right ankle * RAnkle_vz: z coordinate of the velocity of the marker on the right ankle * LAnkle_x: x coordinate of the position of the marker on the left ankle * LAnkle_vx: x coordinate of the velocity of the marker on the left ankle * LAnkle_y: y coordinate of the position of the marker on the left ankle * LAnkle_vy: y coordinate of the velocity of the marker on the left ankle * LAnkle_z: z coordinate of the position of the marker on the left ankle * LAnkle_vz: z coordinate of the velocity of the marker on the left ankle * RToe_x: x coordinate of the position of the marker on the right toe * RToe_vx: x coordinate of the position of the marker on the right toe * RToe_y: y coordinate of the position of the marker on the right toe * RToe_vy: y coordinate of the position of the marker on the right toe * RToe_z: z coordinate of the position of the marker on the right toe * RToe_vz: z coordinate of the position of the marker on the right toe * LToe_x: x coordinate of the position of the marker on the left toe * LToe_vx: x coordinate of the position of the marker on the left toe * LToe_y: y coordinate of the position of the marker on the left toe * LToe_vy: y coordinate of the position of the marker on the left toe * LToe_z: z coordinate of the position of the marker on the left toe * LToe_vz: z coordinate of the position of the marker on the left toe #### **Ground Reaction Force Data (filename**: GRF\_X\_Y.csv, X: movement type, Y: participant ID) **Description:** Ground reaction force (GRF) data give the temporal sequence of the three dimensional force applied on to the force plate. ##### Variables * trial: Trial number (1-10) * time: Relative time from the metronome beat (unit: ms) * GRF_x: x component of GRF (unit: N) * GRF_y: y component of GRF (unit: N) * GRF_z: z component of GRF (unit: N) #### Movement Reference Point Data (filename: MovRef\_X.csv, X: movement type) **Description:**  ##### Variables * ID: participant ID (1-10). * Trial: Trial Number (1-10). Note that some rows include median and IQR (interquartile range) of 10 trials. * (Reference point): Relative timing of movement reference point from the metronome beat (unit: ms). Reference points are dependent on movement type. The list of reference point is shown below. ##### List of Movement Reference Points | **Symbol** | **Meaning** | | :------------- | :------------------------------ | | **Changement** | | | GC | GRF onset | | GP1 | GRF's first peak | | BB | C7's bottom point | | GP2 | GRF's second peak | | GL | GRF offset | | BT | C7's top point | | **Passé** |   | | BB | C7’s bottom point | | VBU | C7's peak upward velocity | | BR | Offset of C7's upward velocity | | VFU | Ankle's peak upward velocity | | FT | Ankle's highest point | | VFD | Ankle's peak downward velocity | | BF | Onset of C7's downward velocity | | VBD | C7's peak downward velocity | | **Jeté** |   | | FLS | Onset of ankle’s velocity | | VR | Ankle's peak rightward velocity | | FR | Ankle's rightmost point | | VL | Ankle's peak leftward velocity | | FLE | Offset of ankle's velocity | | **Tendu** |   | | FRS | Onset of toe’s velocity | | VL | Toe's peak leftward velocity | | FL | Toe's leftmost point | | VR | Toe's peak rightward velocity | | FRE | Offset of toe's velocity | ## Code/software No special software is required to view the data. ## Access information NA.