Subjective Assessment of Impact Quantity and Magnitude in Rugby: A Comparative Analysis with >8G Impact Values from MEMS Technology

Purpose: The main objective of this research was to develop a questionnaire for the subjective evaluation of the quantity and magnitude of impacts experienced by rugby players. Methods: Thirty-six male rugby union players (mean ± SD, age; 23.5 ± 3.6 years, height; 179 ± 10.0 cm, body mass; 89.58 ± 13.6 kg) participated in this study, comprising eighteen forwards and fourteen backs. Participants were tasked with completing self-reported questionnaires assessing their perception of the quantity and magnitude of impacts after thirteen consecutive matches. Objective data were concurrently collected using Micro-Electrical Mechanical Systems (MEMS) integrated with a GPS device (WIMU, Realtrack Systems, Almeria, Spain). Results: The statistical analysis revealed that 49.7% of players overestimated and 39.8% underestimated the number of impacts above 8G, with a mean team error of 0.017 impacts. Bayesian methods indicated a 95% high-density interval for the mean error between −0.46 and 0.45, with 95.8% within the region of practical equivalence, signifying negligible bias at the team level. Positional variations were notable, with Halfbacks overestimating and Fullbacks and Second Row underestimating impacts. The errors and number of impacts displayed a non-linear relationship, better described by an exponential model. Additionally, the study identified significant correlations between the number of impacts players estimated and the actual impacts received, further underlined by position-specific trends, suggesting that players’ estimation abilities are influenced by the actual exposure to impacts and their playing positions. Conclusions: The utilization of a subjective impact questionnaire is a valid tool to assess rugby players level of impacts during a match. This approach proves particularly valuable in situations where technology is unavailable, showcasing its adaptability as a practical tool in diverse sporting contexts.