An article out of Mayo Clinic and LaTrobe University outlines the key reasons behind such a recommendation. The authors determined that an R-squared of 0.2 is our designated threshold level for clinically meaningful correlation. R-squared (R2) represents the variance for a dependent variable that’s explained by an independent variable. So an R2 of 0.2 indicates 20% of the variation can be explained by the model, or a maximum of 5 variables.
The authors went on to highlight the 5 areas to provide such insights:
Anthropometrics: size/proportion of the body (i.e. a deeper notch of the femur reduces ACL risk).
Strength: the ability to produce force.
Biomechanics: how structures work together to produce movement, basically the sequencing of movement.
Proprioception: sense of body position in space, best measures here usually involve balance.
Psychological: often ignored, but scientifically exists as a kinesiophobia which has validated screens like this.
A common litmus test we use with colleagues internally & externally is what you focus on for injury rehabilitation or prevention. If the answer is prolonged and/or overtly academic in nature (i.e. “it depends”), then your big 5 have not been solidified yet.
Rather than a deeper dive into more tests/variables, focus on educating the individual to also allow more frequent data collection. After all, our life is a journey and other than anthropometrics, none of these factors are concretely set, unless you quit already.
Hewett, Timothy E et al. “Systematic Selection of Key Logistic Regression Variables for Risk Prediction Analyses: A Five-Factor Maximum Model.” Clinical journal of sport medicine : official journal of the Canadian Academy of Sport Medicine vol. 29,1 (2019): 78-85. doi:10.1097/JSM.0000000000000486