The research for motion capture analysis of snare drumming technique (IRB #2016-02-0031) applies aspects of linguistic theory to the displacement data derived from the motion trackers found on the subjects. The Vicon Motus system allows for an analysis of snare drumming technique via a 3D coordinate plane. This 3D data gives insight into the movement patterns of the snare drummers analyzed under the IRB project. Unless stated otherwise, all data will contain only the Right Shoulder, Elbow, Ulna, and Radius anatomical markers. Additionally, the data used in the analysis is transformed where the median value of each vector is set as approaching zero.
Rudimentary snare drumming can be organized in sets from positions to rudiments. Positions can be viewed as a super set of all snare drumming; for a snare drummer must pass through each positions in order to create a sound on the snare drum.
As stated in the last blog, different arrangement of positions create the basic strokes; and different arrangement of the basic strokes create the rudiments. In terms of set theory, the rudiments are a subset of the basic strokes; and the basic strokes are a subset of the positions. In other words, the positions are a superset of the basic strokes; and the basic strokes are a superset of the rudiments. This organization can aid in the approach to mastery of the snare drum via traditional rudimentary drumming, or military drumming.
Based on the data, the positions are not a specific data point, but a range of values in all vectors; meaning, the positions are not a specific point in space, but a approximated range of values based on the five number summary found in statistics. To review, here are as follows: minimum value, maximum value, mode, median, and mean with standard deviation. For more information on the five number summary, consult Wikipedia for five number summary and central tendency.
An example of elements of the five number summary and central tendency for the Full Stroke can be found on ResearchGate.
Below is a graph of the entire trial for the Full Stroke on experiment date April 23, 2016.
NOTE: sh-r refers to the shoulder anatomical marker in the resultant vector, el-r refers to the elbow anatomical marker in the resultant vector, ul-r refers to the ulna anatomical marker in the resultant vector, and ra-r refers to the radius anatomical marker in the resultant vector.
As seen in the graph, the right arm is constantly in motion; even when the right arm is at rest. For the tap position, the corresponding statistcal value is the minimum value from the perspective of the wrist, ulna or radius, in the resultant vector. The displacement value for the Radius anatomical marker in the resultant vector is -8.2658105 cm. This number is an average of the two points in time where the right hand strikes the drum. The maximum value refers to the point in time where the radius anatomical marker approaches its greatest value; the average of the two relative maximum values is 3.627726167 cm. For the rest position, the statistical phenomenon related to this position is the mode. For the mode, a range of values were included. This range is between the tap and beginning of the up position. While this range is not precise, the approach gives insight to where the body is most still. The average for the rest position is -7.179821167 cm. Notice that the average of the rest position is about 1.08 cm greater than the average for the tap position. It can be concluded that the wrist is slightly lower when the drummer is striking the drum than in rest position.
The data set can be found here on ResearchGate for this specific trial of the Full Stroke on the April 23, 2016 date.