HPW Biomechanics provides biomechanics & human factors experts that specialize in Personal Injury Accidents that emphasize the interactions between people and their environment including perception response/reaction, expectations, and actions (human performance, human factors)  and the consequences of their actions (biomechanics).  HPW Biomechanics, Inc.'s core expertise is in Personal Injury Accidents / Injury Biomechanics in areas such as motor vehicles / pedestrians, workplace / industry, sports / recreation, slips / trips / falls, and sexual assault / rape.

Human Performance integrates principles from Biomechanics and Human Factors and other related sciences to evaluate the mechanical and behavioral aspects of human movement. Biomechanics is a science/discipline based upon Newton’s three laws of motion (Principia,1684) as elaborated upon within the disciplines of physics and engineering as they apply to the effects of forces on the human body. Human Factors is a science/discipline based upon principles of human capabilities and characteristics as they apply to human/machine/environmental systems and services. Human Performance integrates the laws of physics and working concepts of engineering (Biomechanics) with structural and functional human anatomy, physiology and neuro-muscular function (Human Factors) to describe the effects of forces on the human body and to better understand the mechanical and behavioral interactions between people and their environments. Also of concern are the relationships between body motion, external events and/or objects and forces on tissue structures (Tissue Biomechanics) such as bones, joints, ligaments etc. Human Performance scientists combine this knowledge base with case specific data and relevant research literature to reconstruct accidents and determine the cause and likelihood of behaviors/claimed behaviors. The role of the human performance expert in both civil and criminal litigation (Forensic Biomechanics / Human Factors) is to function as an interdisciplinary integrator to determine the interactive effects between the human body and external forces, events and/or objects in producing behavioral outcomes and/or tissue damage when injury is an outcome. Relevant research in human performance comes from many diverse areas including biomechanics, biophysics, exercise and health sciences, human factors/ergonomics, human performance/movement and behavioral sciences and other sub-disciplines. Considerable overlap exists among many of these diverse areas, especially human performance, biomechanics, and human factors (see Human Performance Model / Analysis).

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Human Performance, Biomechanics, Human Factors

Human Performance integrates principles from Biomechanics and Human Factors and other related sciences to evaluate the mechanical and behavioral aspects of human movement. Biomechanics is a science/discipline based upon Newton’s three laws of motion (Principia,1684) as elaborated upon within the disciplines of physics and engineering as they apply to the effects of forces on the human body. Human Factors is a science/discipline based upon principles of human capabilities and characteristics as they apply to human/machine/environmental systems and services. Human Performance integrates the laws of physics and working concepts of engineering (Biomechanics) with structural and functional human anatomy, physiology and neuro-muscular function (Human Factors) to describe the effects of forces on the human body and to better understand the mechanical and behavioral interactions between people and their environments. Also of concern are the relationships between body motion, external events and/or objects and forces on tissue structures (Tissue Biomechanics) such as bones, joints, ligaments etc. Human Performance scientists combine this knowledge base with case specific data and relevant research literature to reconstruct accidents and determine the cause and likelihood of behaviors/claimed behaviors. The role of the human performance expert in both civil and criminal litigation (Forensic Biomechanics / Human Factors) is to function as an interdisciplinary integrator to determine the interactive effects between the human body and external forces, events and/or objects in producing behavioral outcomes and/or tissue damage when injury is an outcome. Relevant research in human performance comes from many diverse areas including biomechanics, biophysics, exercise and health sciences, biomechanical engineering, human factors/ergonomics, human performance/movement and behavioral sciences and other sub-disciplines. Considerable overlap exists among many of these diverse areas, especially human performance, biomechanics, and human factors (see Human Performance Model / Analysis).

Analytical Procedures: Overview. The analysis and evaluation of many, if not most, human movement problems (with or without injury) is accomplished using a multi-disciplinary approach incorporating principles and methodologies from the academic disciplines of biomechanics, human factors, structural/functional anatomy and physiology, and the behavioral sciences. Technical or specialized knowledge through education, training and/or experience in these areas provides information as a result of analysis and evaluation of case specific facts/information to assist in determining the best explanation for the observed/claimed actions/behaviors.

The disciplines used in the analysis and evaluation of biomechanical and behavioral outcomes are well established and recognized academic disciplines. Each has its own scientific methodology with considerable overlap among areas. These methodologies are recognized as evidenced by published scientific papers in peer reviewed journals. The data results from these studies are typically statistical in nature. These data and the associated principles form the basis for the evaluation of case specific outcomes/behaviors.

Every accident/movement outcome is a unique event (case specific) and therefore is not statistical by definition. Opinions are interpretive based upon best explanation arguments and not probabilities. The best explanation is based upon the correlations/relationships between the facts and evidence and the behavior/claimed behavior which cannot be expressed in probabilities. The methodology for determining the best explanation is based upon gathering all available evidence (observable, empirical and measurable) and subjecting it to principles of unbiased scientific reasoning to determine the best explanation for how the events/behaviors occurred in the particular environment within well recognized biomechanical, anatomical and behavioral constraints (See Figure 1).

Svientific Method. The scientific method is the formal process used by scientists within their disciplines to generate data, principles and theories. The method of inquiry is based upon the gathering of observable, measurable and empirical data using specific and recognized methods. Each discipline has its own scientific methodologies that are typically well established and recognized within the field. It is the process repeated over time that scientists use to construct the most accurate, reliable and representative scientific knowledge (data, principles and theories) within their specific areas of inquiry. Although every discipline has its own scientific method, considerable overlap exists among areas with identifiable features common to all established methodologies. The first step in the process is to identify relevant questions of inquiry to be addressed based upon observations of natural phenomena in the real world. These questions are used to formulate hypotheses to evaluate the phenomena of interest. The scientist then designs an experiment to systematically control and/or observe the variables of interest to evaluate the hypothesis. This is followed by data collection and data observation. The final step in the process is to accept, modify or discard the hypothesis which subsequently leads to new questions/hypotheses and the process is then repeated. It is important to note, however that scientific methods and the complexity of the research questions evolved over time. During the early stages of inquiry the process often takes a simple form of data collection and/or observation before meaningful questions can be generated. Independent of the stage of inquiry it is essential that the process be repeatable and as objective and unbiased as possible. Although scientific methodology is an attempt to minimize/eliminate bias it is unlikely that all bias can be eliminated as is discussed later in this document.

Scientific Reasoning. Scientific methodology is an essential part of the scientific process. It is the means for generating valid and reliable data and formulating principles and theories that can be used to evaluate and predict outcomes. The process requires systematic experimentation and is based upon statistical procedures. Adherence to the process is essential to providing valid and reliable data for subsequent data processing using the method of scientific reasoning. Scientific reasoning/critical reasoning on the other hand is a cognitive process used to draw a conclusion(s) (form an opinion) from a set of premises. It can be used to evaluate unique case specific events that are not statistical by definition and are not subject to replication. The reasoning process is founded in the entire structure of all past logic making up scientific research/methodology and involves gathering, assessing and interpreting relevant information to determine its meaning and significance relative to some event or observation. The outcome of this process is a conclusion/opinion based upon best explanation arguments and not probabilities. The best explanation is based upon the correlations/relationships among 1) case specific facts and evidence, 2) scientific data and principles that provide relevant and accepted standards and criteria and 3) anatomical, biomechanical and behavioral constraints and observed/claimed outcomes (behaviors, tissue damage, etc.) and cannot be expressed as a probability. The process is diagramed in Figure 1. The Figure clearly summarizes the various inputs to the scientific reasoning process that enable an expert with the appropriate education, training and experience to provide case specific opinions as shown.

Bias. As previously stated, it is impossible for scientific methodology or any methodology to eliminate bias although some outcomes are less prone to bias than others. Every observation (scientific or nonscientific) is biased by the education, background, knowledge and experiences of the individual making the observation. Since no two individuals are identical in these qualities every individual has his/her own perspective, i.e. biases. It is these differences that often lead individuals to different conclusions/opinions. In the absence of these differences/biases far fewer disagreements would be apparent, however, given this fact it is important if not essential to have multiple perspectives for people to evaluated. A common example of this occurs when a patient seeks a second medical opinion for an injury or illness diagnoses. Another example occurs in injury litigation where doctors and scientists view/evaluate phenomena (tissue damage) from different perspectives (biases) and often differ in their conclusions/opinions. Of course this is also often the case among scientists and doctors for opposing parties and therefore makes multiple perspectives and possibly different opinions even more important.

Tissue Biomechanics/Injury Reconstruction

Tissue Damage verses Injury. Trauma or tissue damage is simply the result of applying stress to a tissue via an external load. The application of force to the system results in stress that can cause tissue damage, i.e., injury. The problem can be viewed from two perspectives as stated by Nahum and Melvin in the preface of their book Accidental Injury, Biomechanics and Prevention (1993). One perspective is that of the professionals involved in injury diagnosis and treatment while the other is that of engineers and scientists interested in the mechanics of injury. Both perspectives are well documented/represented in the professional and scientific literature.

Biomechanics examines the forces and motions required to damage tissue structures (cause injury). Biomechanics also focuses on the causes and/or mechanisms of tissue damage based upon mechanical properties and tissue tolerance values published in the scientific/research literature. Biomechanics evaluates the mechanical factors leading up to tissue damage whereas other practitioners, such as physicians, are generally involved with diagnosis, management and treatment of injuries. Biomechanists use a knowledge of anatomical structure and function, physiology and relevant research literature in conjunction with scientific and engineering principles and case specific data to reconstruct accidents and determine the cause and likelihood of events including subsequent tissue damage.

Tissue damage/injury results when the tissue is stressed beyond some critical value/tolerance level. The stress is a result of the magnitude of an applied force and the type or direction of the force. Tissue damage can be acute (a single traumatic event) or chronic (developing/progressing over time). For many types of tissue, critical values/tolerance levels have been established through research in conjunction with statistical procedures. In addition, the mechanisms (types of required forces) for many types of tissue damage/injuries are also well established. Since no two individuals are identical, these results are always statistical in nature but more so for critical values than mechanisms of injury. In addition, injuries to individuals are not replicable, i.e., we cannot break a given individual’s leg to see how much force is required, so all results apply to a "typical" or similar individual and not specifically to the person in question. Certain factors, however such as height, weight, gender, anthropometry, age effects etc. can be incorporated into the analysis.