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What is the Mechanism of No Injury (MONI)?

Meeuwisse, Willem H MD, PhD

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Clinical Journal of Sport Medicine: January 2009 - Volume 19 - Issue 1 - p 1-2
doi: 10.1097/JSM.0b013e3181979c1d
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When trying to understand sport trauma, whether as a clinician or a researcher, we typically assess the mechanism of injury (MOI). It is important to evaluate the circumstances surrounding an injury and the forces that produce tissue damage. To do so helps a clinician to arrive at the appropriate diagnosis, prescribe treatment and plan for a return to sport. Understanding the MOI also assists a researcher in identifying risk factors and/or specific causes of injury and strategies for the implementation of preventive measures.

However, athletes constantly place their bodies under extreme load, yet rarely suffer an injury. In fact, athletic endeavors are characterized by pushing the personal limits of exertion and loading. So, in watching athletes perform on a daily basis, or even observing a fall or crash, it is equally important to ask: “Why did an injury NOT occur?” What are the normal, often extreme, forces that are placed on the body during typical training and competition that do not have an adverse outcome? If we can measure and understand this “mechanism of no injury” (MONI), then we can begin to understand which component of the apparent MOI is actually responsible for an injury.

Think about this in the context of sport you have witnessed. For example, consider the forces at play in executing a turn at high speed in alpine skiing. There are numerous kinetic and kinematic variables acting through the body and equipment. Clearly, there are motions and forces that are a normal part of executing an injury-free athletic movement. If that is the case, then those forces should not be considered an important part of the MOI. When an injury does occur, there must be a critical factor (or collection of factors) that differs from situations where there is no injury. It is the identification of this critical factor or factors that will permit accurate characterization of the MOI.

Over the past 15 years, researchers have emphasized the need to take a mulitfactorial approach to understanding the cause of injury.1,2 More recently, further attention has been focused on the centrality of the MOI as part of a causal chain.3,4,5 Bahr and Krosshaug specifically advocate that more detailed attention be paid to the MOI as one of multiple factors contributing to sport injury.6 It is clearly important to consider athlete, environmental, situational, and biomechanical factors at the time of any injury; the MOI should be seen as being of special significance, it is argued, in the context of these other risk factors.5,6

Typical biomechanical assessment of injury involves an estimation or measurement of a potentially injurious movement; such an assessment is extremely complex, with an infinite number of possible variables and observations. The challenge of injury prevention research is to find a specific putative factor or factors from among a constellation of possibilities.

It must be recognized, when attempting to evaluate the biomechanical factors surrounding the mechanism of an injury, that a specific difference between those who experience injury and those who do not is often not clearly evident. However, an assessment of the MOI often seems to carry with it an important assumption. That is: Research is often conducted as if all aspects of the potential MOI are important. While this may be true, it is equally plausible that only a small component of the apparent mechanism is actually responsible for an injury.

Perhaps what we need to do is formally study the normal MONI. If we can learn to distinguish between the MONI and the MOI, then we will have uncovered the critical component of the inciting event that ultimately causes an injury. If we can articulate this difference, we will have reduced the set of variables or factors to something that may be simpler to understand, perhaps more feasible to study, and ultimately more practical to modify in planning injury prevention.


1. van Mechelen W, Hlobil H, Kemper H. Incidence, severity, etiology and prevention of sports injuries. A review of concepts. Sports Med. 1992;14 (2):82-99.
2. Meeuwisse W. Assessing causation in sport injury: a multifactorial model. Clin J Sport Med. 1994;4(3):166-70.
3. Gissane C, White J, Kerr K, et al. An operational model to investigate contact sports injuries. Med Sci Sports Exerc. 2001;33(12):1999-2003.
4. McIntosh A. Risk compensation, motivation, injuries and biomechanics in competitive sport. Br J Sports Med. 2005;39:2-3.
5. Meeuwisse W, Tyreman H, Hagel B, et al. A dynamic model of etiology in sport injury: the recursive nature of risk and causation. Clin J Sport Med. 2007;17(3):215-9.
6. Bahr R, Krosshaug T. Understanding injury mechanisms: a key component of preventing injuries in sport. Br J Sports Med. 2005;39:324-9.
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