Instrumented Holds: Hardware Refinement and Software Development for the Quantitative Study of Sport Climbing

Sports Engineering is a scientific discipline combining knowledge coming from different fields to better design sport equipment and venues and to provide real-time feedback and quantitative performance assessment. Sport climbing has seen an exponential growth in its numbers in the recent years and, after having exploited the technological advancement in terms of materials and equipment, it will benefit a lot from the application of sport engineering methods to its practice. Climbing is a very complex task, involving strength, balance, and dynamic coordination of lower and upper body movements. Despite the evidence that climbing ability depends mostly on trainable parameters, there hasn’t been a comprehensive approach towards the engineering of this discipline. Studies devoted to the evaluation of metabolic parameters have certified the concurrence of both aerobic and anaerobic pathways during the practice. Muscle activity and motor unit activation strategies have been evaluated with EMG and MMG, but only for isometric contractions performed in controlled conditions. What is lacking now is a complete biomechanical analysis conducted on athletes performing an actual climb. Insights could be gained measuring the forces exchanged between the climber and the wall. Although some examples of this are found in literature, a completely instrumented climbing wall hasn’t been realized yet, mainly due to the related cost. Following a previous work which developed a low-cost solution for measuring contact forces during climbing and transmitting the signals, this Master Thesis project aims to give insights into the biomechanical assessment of sport climbing exercises. The first step is the refinement and testing of the existent hardware, in order to ensure a complete and precise 3D force measurement. The following part is the development of the software to analyse the acquired signals, which has been designed for two main purposes: data visualization and data analysis. A script for force visualization has been developed in Python programming language with the help of the library VPython: it enables dynamic 3D rendering of contact forces during the exercise. Data analysis has been performed in Matlab. The developed algorithm extracts peak forces, computes impulses and evaluates the ratio between forces developed by upper and lower limbs. To evaluate the athletes’ centre of mass (COM) trajectory, they are asked to achieve a static position on the wall before starting the exercise. In this condition the COM initial position is retrieved solving the torque equation. During exercises the trajectory is computed solving Newton equation and numerically integrating the acceleration twice. Final aim is to identify meaningful figures of performances to help athletes and trainers by giving a synthetic evaluation of the performance. Three indexes have been proposed: sum of force vectors moduli normalized to body weight, COM effective displacement (i.e. the ratio between the in-plane and the out-of-plane displacement) and force component ratio (i.e. out-of-plane component over the in-plane one). Preliminary results have been obtained, however additional measurements are needed to assess the statistical significance of these parameters and their correlation to climbing performance. Although further studies are required, this work demonstrates the reliability of the system and proposes the possibility for a quantitative evaluation of sport climbing performances.