10 Biofeedback Sword - a new tool for learning

The dynamics of human motion, whilst well understood qualitatively, have been difficult to quantify with inertial sensors due to the complexity of movement of relatively unconstrained limb segments. A study of highly constrained limb motion was undertaken through the development of a novel instrumentation. Results obtained demonstrate that the quantification of subjective measures can be a useful tool in improving athlete performance.

The study of Japanese swordsmanship, in the various traditional martial schools, has developed patterns of movement that are highly repeatable from athlete to athlete within individual schools but have significant difference between schools. Anecdotally traditional masters of these arts take many years to perfect this characteristic shape of movement. The project arose through an interest and study of Aikido in brisbane.

In this paper a method for measuring swing path of a variety of sporting implements is proposed. This method is a refinement of that previously investigated [1] and uses a combination of inertial sensors to track the path of the swing. From this data a graphical visualization of the motion is presented to the athlete using near real time feedback using a wireless link. The visualization is based on the physical movement but abstracted somewhat. As a form of biofeedback it is overlaid with idealised templates of an optimal swing enabling the athlete to learn the swing skill in a novel manner.  

Subject Feedback

Subjects were interviewed at the end of their session for comments on their learning process and on the concept as a learning tool.

I found changing hand positions had an effect and experimented with that and different balance points

I tried different speeds and found in between fast and slow gave the best results, here I found a shape that worked and closely matched the template and was easy to reproduce

After awhile I found the sound of the Bokken to be good feedback

I found power wasn’t helpful and then concentrated on technique

It would be nice to have a history of more than just one swing to look at my progress.

Expert Assessment

The trials were also observed by an expert practitioner who made the following comments:

The subject progressively relaxed through the experiment and whilst the technique wasn’t precise it did improve over the course of the experiment

There were many things I wanted to correct but over the course of the experiment some of them just fixed themselves, it was interesting

Ref: A Biofeedback System for Swing Skill Acquisition in Implement Sports, Japan Society for Mechanical Engineering, Joint Symposium on Sports Engineering and Human Dynamics, Aikita Sept 9-11, 2008