## The Mass and Inertia Characteristics of the Main Segments of the Human Body

Reference | The Mass and Inertia Characteristics of the Main Segments of the Human Body |

Journal | Biomechanics V-IIIB(1983)1152-1159 |

Author | V.Zatsiorsky |

Item | M COG I |

State | living |

Sample number | 100 |

Sex | Male |

Age | 45-65 |

Measurement year | n/a |

Race | Caucasian |

Measurement place | Russia |

Measurement technique | γ-ray scanner |

Raw data accessibility | NG |

#### (1)Definition of Body segmentation

16segments:Head, Upper part of torso, Middle part of torso, Lower part of torso, Thigh, Foot, Calf, Upper arm, Forearm, Hand

a.Head －Upper part of torso

Vertebra prominens

b.Upper part of torso －Middle part of torso

Xyphion

c.Middle part of torso－Lower part of torso

Omphalion

d.Upper part of torso －Upper arm

Akromion

e.Upper arm－Fore arm

Radiale

f.Fore arm－Hand

Stylion

g.lower part of torso－Thigh

The plane passes through iliospinale anterious and leans to 37° with respect to midline

h.Thigh－Calf

Tibiale

i.Calf－Foot

Sphyrion

#### (2)Predictive Model

- Dependent variables : the ratio of the center of gravity, segment mass、moment of inertia
- Independent Variables : Body weight and stature

#### (3)Validation

- Not performed

## The ratio of the center of gravity

The following table shows regression coefficients.

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

**Ex.) **

**The ratio of the COG of head (%)=8.35700-0.00250×body weight(kg)+0.02300×stature(cm)**

## Segment mass

The following table shows regression coefficients.

Note:Weight in kg, stature in cm.

**Ex.)**

**Head mass(kg)=1.29600+0.01710×body weight(kg)+0.01430×stature(cm)**

# Regression coefficients

## Moment of inertia

The following table shows regression coefficients.

Note:

・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.

・Weight in kg, moment of inertia in kg・cm^{2}, stature in cm.

**Ex.) **

**Moment of inertia of the head around x-axis(kg・cm ^{2})=-78+1.171×body weight(kg)+1.519×stature(cm)**