Understanding Scientific Evidence For The Combat Sports Coach

Dr. James J. Gibson, 1972

Preface: There's a "new" coaching methodology on the scene in the BJJ/combat sports world and it's causing a lot of concern amongst instructors and athletes who are unfamiliar with it.

​This "new" coaching methodology has actually been around for several years in some Jiu-Jitsu/MMA circles and it's called the Constraints Led Approach (CLA). It's based on the multi-discipline theory of Ecological Dynamics, which is a motor learning theory that stems from the psychologist and Cornell professor, James J. Gibson and his ecological perception research.

Currently, Ecological Dynamics Theory and the CLA for skill acquisition are well studied and applied at the highest level in major national and professional sports (major league baseball, NFL American Football, FIFA Soccer, national Judo programs), by the same researchers who are publishing peer reviewed manuscripts on the subject and regularly discussing it on podcasts and social media channels. 

Many BJJ instructors and athletes at the moment have apprehension with this methodology because they are unfamiliar with it. The majority of people who have learned BJJ or any other martial art up to this point have learned it under the other  competing theories of perception and  learning such as Constructivist Theory and/or Information Processing (IP) models (albeit, it's unlikely their coaches were aware of what model they were utilizing). 

Because there is a lot more talk in the BJJ, MMA and combat sport world about CLA and Ecological Dynamics, I've noticed an information gap that exists when those who aren't familiar with these topics attempt to learn more about it or discuss it with a CLA coach.

Understanding of what the CLA is requires an understanding of, or at least an appreciation of the scientific evidence that supports it. More than just that, to understand any other topic of importance, being able to  appreciate the value of strong  scientific evidence will only serve to better inform your decisions. Being more science literate is never a problem. 

As a former molecular biology researcher,  I utilized the scientific method in the course of my research and understood the necessity of having strong evidence supporting my findings as well as being able to publicly present them to the research community under great scrutiny from peer review. I also was required to defend my research when questioned by other experts in the field in a logical and honest manner where I did not utilize logical fallacies or fall victim to cognitive biases. To this day, I always attempt to apply the scientific method when wanting to know more about the world. I also take in scientifically valid findings with a greater deal of weight than any other when forming my opinions.

Hopefully, this article series can both educate and inform others about why coaches such as myself have chosen to adopt the Constraints Led Approach coaching methodology. I begin with "Why Scientific Evidence Should Matter to the Combat Sports Coach." In later articles I want to cover topics such as why coaches should care about research based findings, common cognitive biases and more.

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Why Scientific Evidence Matters and How to Use It Effectively
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In today’s world of instant information and social media debates, people often form strong opinions on complex topics such as health, climate change, and public policy. However, the foundation of a well-informed opinion should be evidence—specifically, scientific evidence that has been rigorously tested and reviewed. This article will explore what science is, the scientific method, different types of evidence, and why peer-reviewed research should be the gold standard when forming opinions. We will also examine why anecdotal evidence and personal observations are unreliable and provide examples of how reliance on weak evidence has led to real-world problems.

A medievall medical procedure.

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What Is Science?

Science is a systematic approach to understanding the natural world. It relies on empirical evidence—data gathered through observation, experimentation, and analysis. Unlike personal beliefs or opinions, scientific knowledge is not static; it evolves as new evidence emerges. The scientific method ensures that claims are rigorously tested before being accepted as valid.

"Zoey and Sassafras", is a book series that teaches critical thinking to children by utilizing the scientific method as a model. There is also a complete science curriculum available for homeschoolers.

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Jane Goodall. English zoologist, primatologist and anthropologist.

The Scientific Method: How Science Works

​The scientific method is a structured approach used to investigate questions and test hypotheses. It consists of the following steps:

1. Observation – Noticing a phenomenon that sparks a question.
2. Question – Forming a specific question about the observation.
3. Hypothesis – Proposing a testable explanation.
4. Experimentation – Conducting controlled experiments to test the hypothesis.
5. Data Collection & Analysis – Gathering and analyzing results.
6. Conclusion – Determining whether the results support or refute the hypothesis.
7. Peer Review & Replication – Other scientists review the findings to ensure validity and reliability.

Scientific knowledge is never absolute. When faced with stronger evidence, an honest scientist will revise their previous conclusions.

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Types of Evidence: What Counts as Reliable Proof?

Not all evidence carries equal weight. Below are the different types of evidence, ranked from most to least reliable:
1. Systematic Reviews and Meta-Analyses

• These studies analyze multiple peer-reviewed studies on a topic to draw broad conclusions.
• Example: A meta-analysis of 100 clinical trials confirming the effectiveness of a drug.

2. Randomized Controlled Trials (RCTs)

• Participants are randomly assigned to groups to eliminate bias.
• Example: A study testing a new cancer treatment by comparing it to a placebo.

3. Cohort and Case-Control Studies

• Observational studies tracking groups over time to identify correlations.
• Example: Research linking smoking to lung cancer.

4. Peer-Reviewed Journal Articles

• Individual research studies published in reputable scientific journals.
• Example: A study on the impact of diet on heart disease published in the Journal of the American Medical Association.

5. Expert Opinions and Consensus Statements

• Views of multiple scientists based on available evidence.
• Example: Climate change statements from the Intergovernmental Panel on Climate Change (IPCC).

6. Anecdotal Evidence and Personal Observations (Least Reliable)

• Stories or personal experiences.
• Example: “My grandfather smoked every day and lived to 90, so smoking isn’t bad for you.”

Raw scientific research/data can be complex and difficult to interpret for those not familiar or immersed in it. However, there are some sources that bridge the gaps from published research to interested people without a science background.

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What Doesn't Constitute Strong/Stronger Evidence?

Many people mistakenly believe that merely adding more personal experiences or opinions to an argument strengthens its validity. However, weak arguments often rely on logical fallacies, cognitive biases, or poor methodologies that do not align with rigorous scientific standards. Here are a few common examples:

• Appeal to Authority – Citing a single expert’s opinion, especially when it contradicts broader scientific consensus.
• Cherry-Picking Data – Selecting only favorable results while ignoring the broader body of evidence.
• Confirmation Bias – Giving more weight to evidence that aligns with preexisting beliefs while dismissing contradictory data.
• Misinterpretation of Correlation as Causation – Assuming that because two things occur together, one must cause the other.
• Anecdotal Evidence – Using personal stories or small, unverified case studies instead of large, controlled studies.

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Why Anecdotal Evidence Is Not Sufficient

​Anecdotal evidence is misleading because it lacks the rigorous testing of the scientific method. Here’s why:

• Bias – People tend to remember examples that confirm their beliefs (confirmation bias).
• Small Sample Size – A single case does not represent a whole population.
• No Controls – No way to rule out other factors influencing the outcome.

​Example: Unsupported Diet Fads
​Many people base their dietary choices on personal stories of miraculous weight loss or health improvements from specific diets. However, large-scale studies (systematic reviews and meta-analyses) have repeatedly shown that balanced diets supported by scientific research, such as the Mediterranean diet, lead to the best long-term health outcomes (Willett et al., 2019). Despite overwhelming evidence, anecdotal claims continue to influence public perception, leading to widespread misinformation about nutrition.

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What Constitutes "Stronger Evidence" than Already Strong Evidence?

Stronger evidence is determined by factors that enhance reliability, validity, and reproducibility. When evaluating competing scientific claims, the following aspects indicate even stronger evidence:

• Larger Sample Size – Studies with a greater number of participants are more representative and less likely to be skewed by anomalies.
• Better Controls – Eliminating variables that could introduce bias ensures the results are due to the factor being tested.
• Double-Blind Methodology – Ensuring neither the participants nor the researchers know who is receiving treatment versus placebo prevents bias in data collection and interpretation.
• More Independent Replication – Findings that have been replicated by multiple independent researchers, across different populations and settings, increase credibility.
• Meta-Analyses and Systematic Reviews – Combining multiple high-quality studies to assess overall trends and findings strengthens the reliability of conclusions.
• Longitudinal Data – Studies conducted over extended periods provide insight into long-term effects and rule out temporary or coincidental findings.

By prioritizing these elements, scientists and informed individuals can distinguish between evidence that is simply compelling and evidence that is truly conclusive.

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Changing Opinions in Light of Stronger Evidence

​A hallmark of scientific integrity is the willingness to revise conclusions when faced with stronger evidence. For example:

• Ulcers and Bacteria: For decades, scientists believed stress caused ulcers. In 1982, researchers Barry Marshall and Robin Warren discovered that Helicobacter pylori bacteria were the real cause (Marshall & Warren, 1984). Despite initial skepticism, overwhelming evidence led the medical community to change its stance.
• The Earth’s Age: Early religious and scientific beliefs estimated the Earth to be a few thousand years old. As geological and radiometric dating methods developed, evidence overwhelmingly supported an age of about 4.5 billion years.
• The cause of scurvy: early theories about the cause of scurvy were largely anecdotal, but once controlled experiments confirmed that vitamin C deficiency was responsible, the medical community universally accepted citrus fruits as an effective treatment.
• Relativity: Einstein’s theory of relativity replaced Newtonian mechanics in certain contexts after multiple experiments and astronomical observations confirmed its predictions.

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Conclusion

The Importance of Peer-Reviewed Research
To develop well-informed opinions, individuals should prioritize peer-reviewed, scientifically validated evidence over anecdotes and personal observations. While personal experiences are valuable, they should not outweigh large-scale, controlled studies that have undergone rigorous scrutiny. Being open to changing one’s position in light of new evidence is not a weakness—it is the foundation of intellectual honesty and scientific progress.

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References

• Willett, W. C., Sacks, F., Trichopoulou, A., Drescher, G., Ferro-Luzzi, A., Helsing, E., & Trichopoulos, D. (2019). Mediterranean diet pyramid: a cultural model for healthy eating. The American Journal of Clinical Nutrition, 61(6), 1402S-1406S.
• Marshall, B. J., & Warren, J. R. (1984). Unidentified curved bacilli in the stomach of patients with gastritis and peptic ulceration. The Lancet, 323(8390), 1311-1315.

This article is the first in a series exploring scientific literacy and utilizing it as a combat sports coach. Stay tuned for the next installment.

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