Motion analysis in sports monitoring techniques:Assessment protocols and application to racewalking

Aim. The aim of this study was to propose guidelines for the proper use of data from motion analysis technologies. The field of investigation concerned the monitoring of individual characteristics in sports movements. The objective was to: determine the number of trials needed to attain stability of individual biomechanical parameters and for a robust description of individual peculiarities; implement a feedback process that could provide coaches and physicians with user-friendly information that might help them in the training or clinical context. Racewalking was chosen as the paradigmatic movement for investigation. Methods. Forty racewalking trials were recorded for each of the 7 (inter)national-rank athletes involved in the study. An optoelectronic motion-analysis system, a force platform, and the SAFLo biomechanical model were used to measure the segmental kinematics and kinetics. Indications from expert coaches were used to define and estimate biomechanical parameters for describing the racewalking technique. The "sequential estimation procedure" was used to assess the stability of individual parameters. Results. The minimum number of trials needed to attain stability of individual parameters and a consistent description of individual peculiarities was 15. A set of graphical interfaces was created to visualize the performance-related biomechanical measures and to present the feedback of user-friendly biomechanical information to the end users (coaches, athletes, physicians). Conclusion. This study constitutes a first step toward the application of modern motion-analysis technologies to monitoring an athlete's individual characteristics. As an interdisciplinary methodological contribution, the study demonstrates the potential use of these instruments in the evaluation of performance-related motor factors in sports (training, individual skills, athletic condition, motor learning) and in clinical practice (injury prevention, support to medical intervention, post-injury monitoring).