## Body segment parameters of Japanese children

Reference | Body segment parameters of Japanese children |

Journal | Japanese Journal of Phisical Education 31(1986)53-66 |

Author | T.Yokoi, K.Shibukawa,M.Ae |

Item | M COG I |

State | Living |

Sample number | Male:132 Female:123 |

Sex | Male Female |

Age | Male:3-15 Female:3-15 |

Measurement year | n/a |

Race | Japanese |

Measurement place | Japan |

Measurement technique | Photogrammetry |

Raw data accessibility | NG |

#### (1)Definition of body segmentation

14segments: Head, Torso, Upper arm, Forearm, Hand, Thigh, Calf, Foot

a.Head－Torso

Larynx point

b.Torso－Upper arm

Acromion

c.Upper arm－Forearm

Center of the elbow joint

d.Forearm－Hand

Center of the elbow joint

e.Torso－Thigh

Greater trochanteric head

f.Thigh－Calf

Center of the knee joint

g.Calf－Foot

Center of the ankle joint

#### (2)Definition of segment length

a.Head

Tragion to vertex height

b.Torso

Length from suprasternale to mid-point between right and left greater trochanteric head.

c.Foot

Length from acropodion

#### (3)Predictive model

The ratio of the segment mass, COG, and radii of gyration are classified into 18 groups according to age, sex and Kaup's index. The following table shows criteria for classifying subjects.

Body segment parameters of group1-6Body segment parameters of group7-12

Body segment parameters of group13-18

#### (4)Validation

Comparison of determination of the location of the total body center of gravity between photogrammetry and the reaction board method.

-> Error: less than 3%

# Regression coefficients

## The ratio of the segment mass, COG and radii of gyration in groups 1 to 6.

The following table shows the mean value of the ratio of the segment mass, COG and radii of gyration for each group.

Note:

・The ratio of the segment mass is calculated as percentage of the total body mass.

・The ratio of the COG is calculated as percentage of the segment length measured from the proximal end.

・The ratio of the radii of gyration is calculated as percentage of the segment length.

・The origin of the coordinate system for each segment is the center of gravity of that segment. The x-axis is defined as the frontal axis and +x is the direction from origin towards the front of the body. The y-axis is defined as the saggital axis and +y is the dorection from the origin towards the left of the body. The z-axis is defined as the horizontal-axis and +z is direction from the origin towards the head.

## The ratio of the segment mass, COG and radii of gyration in groups 7 to 12.

The following table shows the mean value of the ratio of the segment mass, COG and radii of gyration for each group.

Note:

・The ratio of the segment mass is calculated as percentage of the total body mass.

・The ratio of the COG is calculated as percentage of the segment length measured from the proximal end.

・The ratio of the radii of gyration is calculated as percentage of the segment length.

・The origin of the coordinate system for each segment is the center of gravity of that segment. The x-axis is defined as the frontal axis and +x is the direction from origin towards the front of the body. The y-axis is defined as the saggital axis and +y is the dorection from the origin towards the left of the body. The z-axis is defined as the horizontal-axis and +z is direction from the origin towards the head.

## The ratio of the segment mass, COG and radii of gyration in groups 13 to 18.

The following table shows the mean value of the ratio of the segment mass, COG and radii of gyration for each group.

Note:

・The ratio of the segment mass is calculated as percentage of the total body mass.

・The ratio of the COG is calculated as percentage of the segment length measured from the proximal end.

・The ratio of the radii of gyration is calculated as percentage of the segment length.

・The origin of the coordinate system for each segment is the center of gravity of that segment. The x-axis is defined as the frontal axis and +x is the direction from origin towards the front of the body. The y-axis is defined as the saggital axis and +y is the dorection from the origin towards the left of the body. The z-axis is defined as the horizontal-axis and +z is direction from the origin towards the head.