Reliability of time-motion analysis in striking combat sports

Introduction. - Time-motion analysis (TMA) is a noninvasive performance analysis technique used in various sports to provide broad insights into the technical, tactical, and physiological demands of competitions by quantifying the mode, frequency, and duration of discrete activities. Objectives. - This study aimed to assess the intra- and inter-observer reliability of activities in full-contact kickboxing athletes determined using TMA. Equipment and methods. - A total of 29 bouts from the World Association of Kickboxing Organizations World Championships 2019, involving 58 male athletes, were analyzed by two expert analysts in a randomised order to determine the number of actions performed (i.e., punches, kicks, significant punches, significant kicks) and time (in seconds) spent in different activity zones (i.e., high-intensity action, low-intensity action, referee pause). This design was chosen to reflect the common TMA practices in the field. Additionally, one investigator analysed all bouts a second time with a seven-day interval between analyses. Results. - Good to excellent relative reliability was observed for punches, kicks, and total strikes both within and between raters (intraclass correlation coefficients; ICC between 0.88 and 0.99). Good and poor intra- and inter-observer reliability were found for significant punches, significant kicks, and total significant strikes (ICC: 0.76-0.85 and 0.16-0.44, respectively). Intra- and inter-observer reliability was excellent and moderate to high, respectively, for high(HIA) and low-intensity action (LIA) (ICC: 0.91-0.93 and 0.65-0.78, respectively). Conclusion. - TMA in striking combat sports using Hudle SportsCode has been shown to be a reliable method that can provide information of high practical relevance. However, caution should be taken when categorising strikes as 'significant'. Given that the quality of strikes is a key-scoring criterion across a range of combat sports, this outlines serious concerns about the accuracy and reliability of the current judging practices. (c) 2024 The Authors. Published by Elsevier Masson SAS. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).