Related Experiment Video
Updated: Aug 5, 2026

Oscillation and Reaction Board Techniques for Estimating Inertial Properties of a Below-knee Prosthesis
Published on: May 8, 2014
Twins and virtual twins: bases of relative body weight revisited
1Department of Psychology and Twin Studies Center, California State University, Fullerton 92834, USA. nsegal@fullerton.edu
Objective:
Application of a new investigative strategy to assess genetic and environmental influences on relative body weight.
Design:
Covariance structure analysis of body mass index (BMI) using genetically informative samples.
Subjects:
One-hundred and fourteen monozygotic (MZ) twin pairs (age 5.04-22.93 y), 81 dizygotic (DZ) twin pairs (age 6.05-16.52 y), and 98 virtual twin (VT) pairs, ie same-age unrelated siblings (3.68-54.75 y).
Measurements:
Height, weight, BMI variously obtained by direct measurement and self-report.
Results:
In contrast with most previous studies, significant common environmental influence on BMI was observed.
Conclusion:
Much past research may have underestimated common environmental effects on BMI because the designs lacked the power or ability to detect them.
Related Concept Videos
Regression Toward the Mean
Mass and Weight
Rigid Body Equilibrium Problems - II
Consider two children sitting on a seesaw, which has negligible mass. The first child has a mass (m1) of 26 kg and sits at point A, which is 1.6 meters (r1) from the pivot point B; the second child has a mass (m2) of 32 kg and sits at point C. How far from the pivot point B should the second child sit (r2) to balance the seesaw?
Virtual Work
In static equilibrium, a body can experience an imaginary or virtual movement, such as displacement or rotation. The virtual work done by a force is equal to the dot product of force and virtual displacement in the direction of the force. When it comes to virtually rotating a...
Virtual Work for a System of Connected Rigid Bodies
Next,...
Mass and Weight

