Saturday, 24 February 2018

The Evolution of Biomechanics: A Review

The Evolution of Biomechanics: Stephen Braybrook. Published by DM Press 2016

The subtitle of the book is: Bringing movement theory back to life, and the book goes on to detail the fundamentals of current biomechanics with respect to their origins in the various theories of mechanics and mathematics that underpin mechanics and engineering in general. Throughout the book the author raises questions about the continuing validity of these historical understandings of geometry and maths to human movement.

Perhaps the best way to describe the book is that it seeks to start a conversation about how we understand human movement. It does this by presenting the past and present of biomechanics and in so doing points out the flaws in our current thinking. The author declares his intention  to be:

to evolve the theory of human movement to a level where it accurately reflects reality so the way we understand, describe and experience what is happening in the body is in alignment, allowing us to connect with the physicality of the body rather than the theory of movement being an abstract, mathematical pattern. (216)

Each chapter concludes with a "Pit Stop Summary" and a series of questions for reflection. Of course the questions, while intended to be fairly open and not designed as an examination of whether you have fully understood the theories and argument presented, inevitably reflect the authors position that the fundamental principles upon which much current biomechanical thinking is based is flawed and needs to change. That's okay, because he might just be right and a rethink might be what is needed.

Anyone in sport (I'm an active tennis player and have played rugby and cricket amongst others for many years) knows that the body doesn't move in simple straight lines of movement, that it certainly deforms under impact or pressure and is therefore far from a  traditional "rigid body" when it comes to the mechanics of movement. But do these simple models assist our understanding or hinder it? Is there a better way to think about movement? That's a question the book seeks to unpick and a question that the biomechanics community needs to address.

The principle that deeply affects our traditional approach to understanding human movement is the presumption that we are fundamentally mechanistic. In other words you can treat the body as a machine, or a series of interconnected machines. Link this with other things like the principles behind levers and how they do or do not fit with the mechanism of a joint (a lever can't have a joint in it in the way the arm has the elbow, so is the arm a lever in the traditional sense of the word?), and the rigid body, lever based, mechanistic model for human movement seems to come up quite a long way short of a perfect fit. But then that's the author's point.

The book overall is divided into three main sections:

The Past:

This section deals with the historic basis for biomechanics, it's roots in Euclidean geometry, Descartian mathematics, Newton's theories and a few other notaries of engineering and mathematics history. It is this foundation in history that has shaped the representation of movement in terms of levers, points, straight lines and rigid bodies. You don't need to understand all the intricacies of these various theories and models to get the picture that these models are limited. The question that remains to be answered through the rest of the book is how limited are they and are they doing a disservice to our understanding of how the human body moves.

The Present:

This section deals with current thinking in the field of biomechanics. It covers concepts that are applied to human movement such as degrees of freedom, kinetics and kinematics and continues to address the authors concerns about the fit, or lack of it, that human movement has with traditional maths and geometry.

The final chapter introduces the more recent concept of tensegrity. Is this a move in the right direction, ie away from a mechanical view and towards something new? You might hope so, but apparently nit because it too is based around Cartesian coordinates, Newtonian maths and Euclidian geometry. In other words, it's just a new way of "beating down the same path with outdated ideologies" (p159)

The Future:

The last three chapters make up the final section of the book. This is where we get the author's perspective on a new way to think about human movement. Here we come across ideas like holism, complex and non-linear systems, synergistics, self-organisation and sub-optimisation.

In the final chapter we get to the heart of the search for a new paradigm for understanding human movement. Dispensing with maths, the root of the problem as far as the author is concerned, he looks for a new model. It is his hope:

that by rewriting the theory and rules of human movement that we can gain a deeper scientific understanding of the real nature of movement and provide credibility to a whole host of principles, methods and movement practices. p169

The new paradigm is christened "biokinesis-ontology", and is broken down as:

Biology: the study of living organisms
Kinesis: movement or motion
Ontology: the philosophical study of the nature of reality.

This is not to say we must abandon all physical laws as they are currently applied, but rather to move beyond an understanding of human movement based solely upon those laws.

The downside to the book is that someone needed to proof read it properly. In the first few pages there are too many errors that make reading the book more of a challenge than it needs to be. The problem is that these early mistakes mean that some of the arguments lose their clarity because you end up trying to work out if there is another grammatical or syntactical error or whether the author actually meant what was written. Someone with a better grasp of the principles being discussed and described might well be able to discern and correct minor errors as they go, but if you are unfamiliar with some of the ideas then you might just struggle.

The book wasn't what I was expecting, but then that's not a big problem. I guess I was looking for something that outlined the development of biomechanics rather than raising questions concerning the validity of current theories. It was certainly a challenge to read and stimulating to think about how I think of movement from a soft tissue therapist's point of view.

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