What coaches can learn from Frans Bosch’s Anatomy of Agility

Frans Bosch’s upcoming book Anatomy of Agility: Movement Analysis in Sport is the most comprehensive text I have seen on human movement and the underlying biological systems that regulate it. It expands on Bosch’s previous book Strength Training and Coordination: An Integrative Approach and goes into a huge amount of detail to explain how complex dynamical systems theory applies to the regulation of change of direction in field sports. Below I hope to explain the key takeaways in the book, where I struggled, and how it will impact my own approach as a strength and conditioning coach.

» Related content: learn more from Bosch himself in our exclusive two-part interview on agility.

The disclaimer

I have been critical of how people use Bosch’s work in the past. Having spent more time learning from his work and spending a fair bit of time with John Pryor and Leigh Egger I have more of an appreciation of how it can fit into a holistic S&C program. We incorporate a lot of the principles at Edinburgh, particularly around hip lock and strengthening our running postures. My concern is the trend of coaches who have a very limited understanding and apply his principles off an Instagram video without understanding context and how that movement or constraint applies to a bigger picture. I certainly think there will be a lot of scope for this to occur again with the content of this book.

The book can be a challenging read, and it is easy to copy what you see without exploring why. But for anyone wanting to learn more about human movement you need to put in the time and you will find it a brilliant resource. The book skews towards theory rather than practice and leaves it up to the coach to see how to fit the concepts and methods into a training plan. The preview copy I received had no diagrams, which might have made it more difficult, and I am looking forward to seeing coaches who have read this book link the theory and practice, not just one or the other. This is where the work of John Pryor and Leigh Egger has been brilliant for me in translating the concepts of the first book into ideas I use every day in training. I’m sure more of the same is to come.


To start off the book, Bosch focuses on two “flows” of information: top down and bottom up. To put it another way, centrally governed control from the brain/CNS (top down) and peripheral self organization utilizing attractors to form self stabilizing units that are able to correct errors (bottom up). Depending on the environment, Frans argues that some movement can be top down and other movement bottom up.

» Learn more: read the full book introduction and table of contents to Frans Bosch’s Anatomy of Agility.

After a thorough discussion of how these flows work, Bosch dives deeper into what attractors help form the bottom up self organization in agility to form the stable base to which the two flows link together. Like the running examples in his last book, Frans highlights a multitude of attractors that underpin agility and his knowledge of anatomy and biomechanics is very impressive, but also hard to follow in places.

With these fundamentals established, the book finishes with an explanation of how attractors combine to create intentional movement patterns which are likely more familiar to most coaches reading this book. Acceleration and deceleration technique is described in detail with some simple take home points (e.g. the interaction of body posture when decelerating on a bent vs a straight leg), the “option posture”/ready position and the concept of transitional steps. Stop and go, sidesteps, curved running and spinning are all included in the latter parts of the book.

The final chapter on motor learning was very interesting and the concept of applying constraints with “overlap”, i.e. a successful outcome can be achieved that fulfils all the constraints. There is some good advice on how to use this to maximize motor learning and for me goes beyond the realm of S&C and as much into the realm of technical sports coaches. For example in my sport, I’m sure Frans would have lots of ideas on how to teach rugby players to kick goals and how constraints could be applied to develop the techniques involved.

Easily overlooked, the book ends with a glossary of key terms. I would actually recommend that this is a starting point for readers as it can familiarize them with basic terms used throughout the book and makes the rest of it a lot easier. Even after reading it serves as a great reference guide.

Key takeaways for coaches

There’s a few basic messages that Frans explains in a lot of detail which I’ll do my best to highlight.

Slow movement and fast movement are fundamentally different – The top down vs. bottom up topic can be complex, but it relies on a fundamental principles that seem so simple yet are often overlooked. Firstly, the regulation of the same movement done at low intensity vs high intensity is completely different as it shifts from top down to bottom up. The pressure of time and increased forces at high intensity reduce the options available creating a reliance on co-contractions, attractors, peripheral corrections and reflex actions which are critical to a successful outcome. At lower intensities, without these pressures there are plenty of options to execute a task and so the argument could be made that this type of practice becomes of little use to an athlete.

Context is king – Agility performance assessed by a traditional test like a 505 agility test is worthless in Frans’ opinion. Agility is so determined by the context in which it is performed with relation to external stimuli, time pressure, forces involved etc that assessing performance using a video camera or measuring the time to complete a pre planned task is irrelevant. Without understanding the sensory dimension, any assessment of whether agility performance is effective is futile. Having read the previous book, the biggest thing I took from this book was an understanding of the role of sensory information (body postures, changes in force vectors, various sources of environmental information) on the execution of movement in sports and how this regulates what effective movement might entail.

Learn what drives different attractors – For an S&C coach, I’d say the most relevant novel concept lies in understanding action-perception is relevant and how the identification of common attractors across the different patterns can improve the quality of information. Based on this, the development of a few attractors could improve the efficiency of movement and give the athlete better skills in which to deal with the sensory information they will be subjected to on the field of play.

Knowing key attractors is important, but what is more helpful is how Bosch helps categorize them. It almost creates a checklist for what to look for in attractors. For example, creating movements around muscles operating at optimum length is a necessity with large forces involved and there are several examples of attractors that ensure this. The other common theme for developing attractors is those that support reflex actions. The relevance of the upper body and the reliance on trunk stiffness also gets a lot of mention and how these four components of agility fit together make a lot more sense to me having read the book.


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Putting the book in context

The debate about coordination training is often framed as either/or. Either you lift heavy or you do hip lock exercises. It doesn’t have to be this way.

I still feel coordination training is best used to ensure the optimum transfer of forces which are developed with traditional strength based training. Agility requires large forces to be produced by the neuromuscular system and the magnitude of force (with respect to time) that an athlete can produce is likely to be a limiting factor in performance. Improving the amount of force available or the speed at which it is generated cannot be ignored, in essence being stronger and more powerful.

Frans would likely argue that context is king. Developing force through centrally governed simple movements like a squat or a jump won’t transfer to the complex interaction of bottom up self-organization with central control. But we’re still applying force, right? Regardless of the neural pathway, I would think having more force to apply can only be a good. Working with high-level athletes who are well trained, strong, and powerful presents a unique challenge. Frans even states this in the book: as you improve you are able to place more demands on the sensory system as the other systems become more stable. In the elite population, I can see these methods being a very valuable way to maximize the expression of their underlying qualities on the field of play. But I would urge coaches to look at their athletes and consider whether the athletes they are working with fall into this category? Or do they lack the basic force production in the first place.

I may be biased or missing the point, but I know that making most athletes stronger and more explosive in traditional, simple movements like weightlifting, jumping and sprinting translates to the field of play in many cases. Therefore it is still hard for me to move away from this entirely. The point I have reached with my athletes is that coordination training is non invasive, and induces very little fatigue and so it doesn’t have to be one or the other. We use both methods with our players at Edinburgh Rugby and this book has raised some new ideas which we will undoubtedly look to incorporate in due course.