Skydiving Technique Analysis from a Control Engineering Perspective: Developing a Tool for Aiding Motor Learning

Abstract: This study offers an interdisciplinary approach to movement technique analysis, designed to deal with intensive interaction between an environment and a trainee. The free-fall stage of skydiving is investigated, when aerial maneuvers are performed by changing the body posture and thus deflecting the surrounding airflow. The natural learning process of body flight is hard and protracted since the required movements are not similar to our daily movement repertoire, and often counter-intuitive. The proposed method can provide a valuable insight into the subject's learning process and may be used by coaches to identify potentially successful technique changes. The main novelty is that instead of comparing directly the trainee's movements to a template or a movement pattern, extracted from a top-rated athlete in the field, we offer an independent way of technique analysis. We incorporate design tools of automatic control theory to link the trainee's movement patterns to specific performance characteristics. This makes it possible to suggest technique modifications that provide the desired performance improvement, taking into account the individual body parameters and constraints. Representing the performed maneuvers in terms of a dynamic response of closed-loop control system offers an unconventional insight into the motor equivalence problem. The method is demonstrated on three case studies of aerial rotation of skilled, less-skilled, and elite skydivers.