I often see people using the terms knowledge and information interchangeably, but it's important to understand they are not the same thing. Information is simply opinions or data (or access to such), and it comes with no implied level of accuracy. Access is an important consideration because information is easier to get hold of now than at any point in human history. But many people often mistake ease of access with validity. How easy some datum or statistic is to obtain has no bearing on its accuracy. In fact, it is precisely the lack of any peer-review process on the Internet that means we must be especially mindful of the information that we find online, for the simple reason that anyone can post anything they like on a webpage.
Knowledge, on the other hand, has a much higher chance of being correct than information. This is because it incorporates information to support or oppose theories within a specific context to provide the most accurate explanation currently available. The 'currently available' bit is significant because knowledge, particularly within the scientific domains, is a structured set of principles based upon experimental evidence that constantly changes and adapts as new information is discovered and shared, mainly because of improved technologies and refined methodologies.
The issue is made more difficult by two facets of human nature: 1) people like to think they are correct, and 2) people don't like change. As a result, it can be tough to let go of information that supports our beliefs (also known as confirmation bias) and even harder to change our beliefs to align with the current knowledge structure.
A common folly in the health and fitness industry is that some individuals claim to have all the answers to human movement problems, often professing to base their solution(s) on biomechanical knowledge. But this is an absurd position to adopt because the current biomechanical knowledge structure can, at best, provide only partial answers, since the research that is specific to the context of the individual, the task, and the environment is limited. Most biomechanical knowledge isn't perfect and can only be arranged into a few general principles, so it's hard to modify human movements based on biomechanical knowledge because movement is a multifaceted phenomenon and involves so many different factors that no one system, method, or approach will ever have all the answers.
Perhaps even more absurd than people claiming to have all the answers are those who use the word biomechanics to refer to some ideal archetype of movement. In blog 030, I explained how we have known for more than a century that one person never moves the same way twice, let alone it being impossible for two people to move the same way once. So, having an ideal standard of movement for everyone to achieve is exceedingly myopic, especially when that standard is often arbitrary and not evidence-based. But calling that standard "biomechanics" is just plain dumb because biomechanics is not a way of moving; it is a way of understanding how forces change the body's motion, and it can guide our professional practice as coaches. It can help us to make movement more efficient and less injurious, but it is not a universal approach, so the biomechanical principles that apply to one person will be vastly different to any other person. Therefore, anyone who says "this movement is proper biomechanics" or uses words to that effect does not fully understand biomechanics.