Liz Jones – https://flic.kr/p/s7S2M
In the classic book Hitchhiker’s Guide to the Galaxy by Douglass Adams the number “42” was given as the answer to a question that wasn’t well defined. When those asking the question complained about the answer they were told that the problem was they didn’t actually understand what they were asking. “Once you understand the question the answer will make sense” is the main thrust of this story. This is a humorous example of a problem that is commonly seen within sports medicine. Having answers is of little use without a comprehensive understanding of the question they apply to.
Since the FMS has recently made waves with a video they released it should serve as a good example. A large push has been made by the organization to revise the interpretation of the test. The original research was done looking at the total score and the core tests were considered to be things like the overhead squat and the hurdle step. As time progressed and data indicated that this wasn’t predictive the narrative has changed to a discussion around the identification of a movement baseline. A comparison to blood pressure has often been made in the attempt to demonstrate how the FMS fits in. The video that was released has been defended by the organization as a call for researchers to move away from looking at a composite score. How the video failed to do that is a different discussion. The point that is relevant here is what exactly the scores are identifying.
The conceptualization of a movement baseline is fascinating. The emergence of movement itself is enormously complex. A goal is set and the movement solution used organizes out of the interaction of the constraints of the individual, the environment and the task. The solution that is used is often “sloptimal” with many other options being sufficient to also achieve the same goal. 1 Since there is often a time constraint the option that is settled on will rarely be perfect and it will vary over repeated performances. This results in a scattering of solutions to the same problem that fall within a zone of acceptable options i.e. what Latash called the “uncontrolled manifold” 2
So if movement solutions are fluid and context dependent then the idea of some baseline becomes harder to pin down. Without a definition it is impossible to begin to test this idea. Therefor a test that offers an answer (whether it is a composite score or individual scores) to a question that hasn’t been defined poses a problem. Until the question is understood the ability to walk away with an 18, or a 2 or even a 42 offers very little. Since answers matter in context it is probably a good idea to pause and ask what the answer provided actually means. Once the question is understood it becomes possible to begin determining whether some particular test is reliable and valid. Until this occurs arguments around the answer become a bit meaningless.
Reference:
- Ting LH, Chiel HJ, Trumbower RD, et al. Neuromechanical Principles Underlying Movement Modularity and Their Implications for Rehabilitation. Neuron. 2015;86(1):38–54.
- Latash ML, Scholz JP, Schöner G. Motor control strategies revealed in the structure of motor variability. Exerc Sport Sci Rev. 2002;30(1):26–31.