Technical bulletins
August 2012

Biomechanics and forensic engineering

By Érica Beaucage-Gauvreau EIT, M.A.Sc.,

Accidents happen so easily! In fact, results from a study by the Canadian Public Health Agency show that 226,436 individuals were admitted to a hospital due to bodily injuries between April 2002 and March 2003 and that 13,906 Canadians died as a result of their injuries in 2003 (1) . Motor vehicle accidents and slip/trip and falls are the main causes for hospitalizations and fatalities (2). Accidents in the workplace are also responsible for a large number of bodily injuries as demonstrated by the numbers reported by the Workplace Safety and Insurance Board of Ontario (WSIB). These numbers indicate that 489 fatalities and 240,220 claims for injuries and illnesses occurred in the workplace in 2010 (3).

Figure 1: Bicycle accident injuries

These accidents and their consequences can generate large costs for rehabilitation or long-term care, depending on the severity of the injuries. Furthermore, these injuries can prevent a worker from performing certain tasks at work, and thus delay his/her return to work. As a result, it is not uncommon to see victims of accidents or their relatives file a lawsuit against the party found responsible of negligence in order to receive monetary compensation for their loss.

Several Canadian provinces such as Ontario, Alberta, and British Columbia allow victims of bodily injuries from a motor vehicle accident to file a lawsuit against the driver of the vehicle responsible for their injuries. However, these lawsuits are not permitted in the province of Quebec. Instead, the Société de l'Assurance Automobile du Québec (SAAQ) offers monetary compensations for victims of bodily injuries, regardless of who committed the fault.

However, in Québec as well as in other provinces, lawsuits can be filed when accidents involving all terrain vehicles and/or farming vehicles occur, or when accidents take place during recreational activities or other daily activities.

When lawsuits are filed, the party accused of negligence must:

  1. show that they acted with care and diligence;
  2. show that the claimant or another party is entirely or partly responsible for the accident and the injuries caused;
  3. show that the injuries claimed are exaggerated, amplified, or even not related to the accident itself.

In the latter category, it is possible to speculate if the injuries claimed have a causal link with the accident. This is precisely where the expert in biomechanics comes into play. But what is an expert in biomechanics and what is his/her role?

Biomechanics is a discipline that studies the behaviour of human tissues when forces are been applied to it. Much like a mechanical engineer studies the components and mechanisms of purely mechanical devices or structures, a biomechanical engineer studies the components and mechanisms of the human body. Education in the field of biomechanics will combine the principles of mechanical engineering to human anatomy and physiology. Biomechanics is a large field that encompasses numerous aspects such as research in orthopaedics, ergonomics, sport performance, and many others.

Figure 2: Staircase fall accident

In particular cases where lawsuits are filed, the legal aspect of biomechanics interests us where a biomechanical expert will be recognized as an expert in Court. The role of the biomechanical expert is to determine if the reported injuries are related to the accident and if their severity matches the accident. The expert will have to demonstrate the causal link between the claimed bodily injuries and the accident, and if needed, determine if they could have been avoided with the use of proper safety equipment.

The services of a biomechanical expert might be required in various cases where bodily
injuries occurred following an accident. The following situations are only a few examples where the services of a biomechanical expert might be required:

  • bicycle fall,
  • sports injuries,
  • fall in staircase,
  • accidents in the workplace,
  • pedestrian accidents,
  • sport safety equipment,
  • motor vehicle accidents.

The presence of a biomechanical expert in Court is relatively new. This role was traditionally filled by doctors or experts in accident reconstruction for specific situations where motor vehicle accidents were involved. However, their opinions are less and less recognized in Courts. In fact, the Ontario Superior Court (4) and the Supreme Court of British Columbia (5) do not necessarily admit experts from these two professions. Their reasoning is quite simple: they typically do not have the required knowledge to establish the causal link between the accident and the injuries.

In fact, doctors have an educational background that allows them to diagnose and treat bodily injuries. However, they do not have formal training in mechanical engineering or the behaviour of human tissues when forces are applied to them.

On the other hand, experts in accident reconstruction can quantify forces experienced by an individual involved in a collision, but they do not have formal training in anatomy or physiology.

The biomechanical expert fills the gap between traditional medicine and mechanical engineering, therefore linking these two professions. As such, Courts are increasingly recognizing the need for an expert specia­lized in the field of biomechanical injuries. The future appears bright for the biomechanical engineer in the field of forensic engineering.

(1) Canadian Public Health Agency. (2006). Facts on Injury. Visited on March 10, 2011.

(2) SMARTRISK. The Economic Burden of Injury in Ontario. Toronto: SMARTRISK, 2006.

(3) Commission de la santé et de la sécurité du travail du Québec. (2010). La CSST en bref. Visited on March 10, 2011.

(4) Garrat v. Orillia Power, 13 April 2006, Ontario Superior Court, Barrie Court 03B5833 (2006 CanLII 11911 OnSC).

(5) Hugues v. Haberlin, 15 December 1997, Supreme Court of British Columbia, Vancouver Registry B950232 (1997 CanLII 2186 BCSC).