Human Motion Modeling & Simulation

Exponent has extensive expertise, capabilities, and publication history in human motion modeling and simulation. Simulations are used to evaluate human motion and injury potential in a wide variety of cases, including motor vehicle collisions, pedestrian accidents, bicycle accidents, falls, industrial accidents, and other types of incidents.

Our biomechanical engineers use state-of-the-art computer simulation programs, such as MADYMO® (TASS International), to analyze dynamics of the human body under varying impact/crash conditions. MADYMO®, an acronym for MAthematical DYnamic MOdels, is a sophisticated computer program that has been used for many years to simulate human motion during dynamic events, especially occupant kinematics during motor vehicle collisions. Our biomechanical engineers also have experience with Articulated Total Body (ATB), 3D Static Strength Prediction Program (3DSSP), OpenSim, LS-DYNA, Abaqus, and other modeling software to simulate human motion, analyze static and dynamic loads applied to the musculoskeletal system, evaluate injury potential, and perform complex biomechanical finite element (FE) analyses. Our engineers continue to perform and publish ongoing research using human motion modeling and simulation.

Occupant Kinematics

Exponent’s biomechanics professionals simulate occupant kinematics resulting from a wide array of vehicle motions. We frequently use complex accident histories obtained from crash tests, collision simulations, and accident reconstructions, to determine the kinematics of single and multiple occupants, and to evaluate injury mechanisms. Our team has extensive experience in simulating occupant kinematics in frontal impacts, rear impacts, side impacts, multiple rollovers, and combinations thereof. We have created numerical models using MADYMO® to simulate these test conditions, and are knowledgeable regarding Federal Motor Vehicle Safety Standards (FMVSS), United Nations Economic Commission for Europe (UNECE) vehicle regulations, and the Federal Aviation Administration (FAA) airworthiness standards. 

Occupant Restraint Performance

Our experience includes modeling and evaluating the effectiveness of occupant restraint systems such as seatbelts, frontal airbags, side airbags, side-curtain airbags, pretensioners, energy management systems, and child restraint systems. We have experience with modeling inflators and have evaluated inflator/airbag performance to optimize the protection offered by the airbag systems. Our team has the ability to capture the complex interactions between the occupants and the restraint systems with a high degree of accuracy. We have created validated MADYMO® models to evaluate restraint-system performance for automotive and aerospace applications. Our expertise also includes modeling restraint systems for other specialized applications.

Other Vehicle Accidents

Our team has the experience reconstructing motorcycle accidents, vehicle-to-pedestrian accidents, Go-Kart accidents, bicycle accidents, and vehicle-to-bicycle accidents using various types of software. We have evaluated injury claims related to incidents involving amusement park rides, including analysis of human motion, loading, and injury potential. We also assist clients in designing cabin structures, seats, and restraint systems for rides involving high speeds and g-forces, such as roller coasters and Go-Karts.

Other Incident

Exponent’s modeling and simulation experience also includes the analysis of human motion during a wide variety of incidents not involving motor vehicles, including trips, slips, falls, diving injuries, and human/machine interactions. For instance, we have also simulated falls down stairs, falls from height, falls on mass transit vehicles, and human motion and injuries resulting from agricultural and industrial accidents.

Human Body Modeling

Exponent has expertise in using modeling and simulation to compute the loads applied to the human body during various activities. We model and evaluate injury risk various regions and organs of the human body, including the head, spine, shoulders, knees, and chest, among others. In addition to injury assessment, Exponent has expertise in using human body models to evaluate and predict human performance during occupational, recreational, and athletic activities.  

Finite Element 

Exponent’s biomechanical professionals have experience in using finite element (FE) software (for example, LS-DYNA and Abaqus) to evaluate potential injury to the human body from dynamic events such as motor vehicle collisions. FE models of Anthropomorphic Test Devices (ATDs), commonly referred to as crash test dummies, can be used to simulate complex occupant kinematics in a variety of impact scenarios. Highly detailed human body FE models not only accurately simulate occupant kinematics, but also tissue and organ deformation during loading from seatbelts, airbags, and other contacts with the vehicle interior.

For example, Exponent has developed a number of tools useful in understanding the complex biomechanics of the human eye. Our experts have used experiments coupled with computational simulations to evaluate the injury tolerance of the eye to blunt impact and penetrating objects. In addition, Exponent has developed techniques and processes to evaluate the interaction of eye tissue with surgical instruments and implanted devices.

Analysis of Simulation

Accurately simulating real-world scenarios requires not only expertise in computational modeling, but also extensive knowledge and experience in real-world vehicle crash dynamics and occupant kinematics. Our team has decades of experience with both, and we are therefore able to examine vehicle dynamics and occupant kinematics in existing simulations for accuracy and validity across numerous software platforms.


Figure 1. This series of figures depicts a MADYMO® model of a lateral collision involving a seatbelted child occupant. Our analysis included validation of the simulated vehicle dynamics using a crash test, as well as validation of the occupant-to-vehicle interaction using sled testing. This analysis allowed for determination of the occupant kinematics in the subject collision, which provided additional insight into occupant injury mechanics.

Software Capability Overview

3D Static Strength Prediction Program (3DSSP)

University of Michigan’s 3D Static Strength Prediction Program (3DSSPP) is a lumbar spine biomechanical model used for determining lower-back loads during daily activities and occupational tasks.


LS-DYNA and Abaqus are general-purpose finite element software packages capable of simulating complex real world mechanics including occupant kinematics in automotive, aerospace, and military environments. For instance, we have experience with the Global Human Body Models Consortium (GHBMC)  50th percentile male model, as well as the Humanetics Hybrid III 50th percentile anthropomorphic test device.


MADYMO, an acronym for MAthematical DYnamic MOdel, is a sophisticated computer modeling software that has been used for many years to simulate human motion during dynamic events, especially occupant kinematics during motor vehicle collisions. 


Software capable of performing multibody force/motion simulations; vector geometry and analysis; symbolic and numeric computations; analysis involving kinematics, energy, mass, and inertia properties; and many other powerful functions.


OpenSim is an open source musculoskeletal modeling platform which enables dynamic simulations of human movement and the determination of loads applied to the musculoskeletal system.

Diving Kinematics Software

We have developed software based on models in the peer-reviewed literature to analyze airborne and underwater human diving kinematics. We use these models to reconstruct accidents in and around swimming pools and other bodies of water.

MATLAB® and GNU Octave

General purpose mathematics software for numerical analysis, linear algebra, differential equation solution, visualization, image processing, signal processing, and optimization.