Optimal race analysis parameters of freestyle swimming events: A case study

Introduction: During the swim meet, race analysis is a common practice to provide insight into each event. This case study explores the variables of swimming performance using the video analysis method. Purpose: To determine the best indicator from a set of swim variables (digitised from video) for competitive swim races by one Malaysian freestyle swimmer in preparation for the Tokyo Olympic Games 2020. Methods: Race video footage was analysed retrospectively to determine the key parameter for each event distance. The following variables were calculated: start time, end time (ET), turn time (TT), stroke count, stroke length, stroke rate, average velocity (AV) and stroke index. Differences were subsequently assessed among the parameters within the same event style. Results: The results from the correlation test between the eight digitised variables and final time (FT) showed that for both 200 and 400 m events the variables AV (respectively, r = −0.96 and r = −0.94) and TT (respectively, r = 0.89 and r = 0.83) were significantly correlated. In addition, for the 200 m events, the ET also significantly correlated (r = −0.94) with FT. Conclusion: This swimmer and over this period of Olympic qualifiers competitions, AV and TT were the best indicators for swim performance. Regarding the 200 m events, the end (sprint) time may also be an indicator.