Background
Issue 1.
The gayageum is a Korean traditional string instrument. The gayageum is generally fitted for adults,
which creates several problems for elementary-school-aged students.
Postures issues for players of small stature:
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Excessive upper body bending
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Uncomfortable/Unnatural sitting positions
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Awkwardness in reaching for the farthest part of the instrument while playing
Issues 2.
There are little literatures to scientifically resize Korean instruments in order to better accommodate
children even though there are some resizing gayageums in market.
So scientific methodology of resizing Korean Instruments are needed more.
Research Goal
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Develop a resizing methodology for the gayageum
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Prototyping resized gayageums for elementary school students
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Verify the redesigned gayageum for desired properties
Method
Research Flow
Field Trip
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Record expert and child musicians while playing and interview them
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Measure the body dimensions of adult and child musicians
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Observe the bent-trunk angles of adult and child
Selection of target age group
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Search percentile of arm length at all ages
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Divide age group between child and adult group by box plot
Calculation resizing ratio for children
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Calculate resizing ratio by trigonometric functions
Prototype of resized gayageum
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Develop the resized gayageum
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Prototype the gayageum according to the calculated size
Verification of prototype
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Make a comparison of physical compatibility
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Verify the difference of the bent-trunk angle
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Verify variance of bent-trunk angles between adult and children
Comparison of playing postures between adult and child
A: Bending angle of trunk (𝜽1) and distance between maximum reach point of right and left hand (d1) of an adult player
B: Bending angle of trunk ( 𝜽2) and distance between maximum reach point of right and left hand (d2) of a child player
Scaling process of the Gayageum for children
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Search percentile of body dimensions at all ages
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Divide age group between child and adult group by box plot
Calculation of resizing ratio for children
A and A’: Adult’s and child’s the entire arm’s length including the out-stretched hand, B and B’: Adult-sized and child-sized Gayageum’s length from the center of the trunk to the farthest-reaching point
Result
As a result, the reduction ratio is 0.76. From this, the size of the shrinkage gayageum was decided.
Summary
Research significance
This research is an example of ergonomic design for Korean traditional instrument, especially biomechanical technique can reduce the musculoskeletal workload for children playing instruments.
It would encourage children to easily learn traditional music.
Resizing Methodology Process
Hypothesis
The more similar the bent-trunk angles of children is to that of adults while playing the instrument, the more effective their playing posture will be.
Method
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Search percentile of arm length at all ages
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Divide age group between child and adult group by box plot
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Calculate the resizing ratio by trigonometric functions
Result
The proposed gagyageum based on the assumption from the hypothesis was effective at reducing the trunk bending angle for every child group.