COMPARISON OF VIDEO AND IMU DATA FOR ANALYZING THE UNDERWATER DOLPHIN KICK
DOI:
https://doi.org/10.12922/jshp.v8i1.165Keywords:
Dolphin-kick, IMU, Video Analysis, Underwater, BiomechanicsAbstract
Inertial Measurement Units (IMUs) increasingly gain scientific interest because they are less time consuming and priceless than traditional methods, i.e. video analysis to analyze performance-related parameters. Only few studies in swimming have addressed the underwater dolphin kick (UDK), known to have an important influence on overall swimming performance. The investigations of the UDK were limited to video analysis. Various factors were identified which have an influence on the UDK performance, such as the identical duration of up- and downbeat and constant frequency, resulting in a high toe speed and a large angular velocity of the hip.
The present study compares IMU data with video data of a kick cycle and the up and downbeat phase of the feet and hips. 11 national and international top athletes participated during regular diagonstic in the Olympic Training Center Hamburg. Kick cycles (110) were measured via video (50-100 Hz) and IMU (400 Hz, +/- 16g, +/- 2000°/s) and both measuring methods compared using the Bland-Altman Plot. The results of the hip-foot comparison within one method showed no significant difference, while the comparison of both methods showed a significant difference. We explain this by the inherent error in the detection of key positions from the video. From a practical viewpoint, the absolute difference (max. 0.07 s) is negligible. Future efforts is on software development, which automatically analyses the UDK and supports daily work from coaches and scientists.
References
Mooney R, Corley G, Godfrey A. Inertial sensor technology for elite swimming performance analysis: A systematic review. Sensors 2015; 16(1):18.
Magalhaes FAD, Vannozzi G, Gatta G. Wearable inertial sensors in swimming motion analysis: a systematic review. Journal of Sports Sciences 2015; 33(7):732-745.
Cossor J, Mason B. Swim start performances at the Sydney 2000 Olympic Games. ISBS-Conference Proceedings Archive (ed. RH Sanders), San Francisco, USA, 2001; 70-74.
Cossor J, Mason B. Swim turn performances at the Sydney 2000 Olympic Games. ISBS-Conference Proceedings Archive (ed. RH Sanders), San Francisco, USA, 2001; 65-69.
FINA, http://www.fina.org/sites/default/files/2017_2021_swimming_16032018.pdf (last time accessed: 22 January 2020).
Gavilán A, Arellano R, Sanders R. Underwater undulatory swimming: Study of frequency, amplitude and phase characteristics of the ‘body wave’. Biomechanics and Medicine in Swimming X 2006; 35-37.
Sanders RH, Cappaert JM, Devlin Wave characteristics of butterfly swimming. Journal of Biomechanics 1995; 28(1):9-16.
Ungerechts BE. A comparison of the movements of the rear parts of dolphins and butterfly swimmers. Biomechanics and Medicine in Swimming 1983; 215-221.
Maglischo EW. Swimming even faster. McGraw-Hill Humanities: Social Sciences & World Languages; 1993.
Schramm E. Sportschwimmen: [Hochschullehrbuch]. Sportverlag; 1987.
Counsilman, JE, Counsilman BE. The new science of swimming. Benjamin-Cummings Publishing Company; 1994.
Madsen Ö, Reischle K, Rudolph K. Wege zum Topschwimmer Band 1 -3. Hofmann; 2014.
Arellano R, Pardillo S, Gavilán A. Underwater undulatory swimming: Kinematic characteristics, vortex generation and application during the start, turn and swimming strokes. In Proceedings of the XXth international symposium on biomechanics in sports 2002; 29-41.
Ungerechts B, Persyn U, Colman V. Analysis of swimming techniques using vortex traces. In ISBS-conference proceedings archive. 2000
Callaway AJ, Cobb JE, Jones I. A comparison of video and accelerometer based approaches applied to performance monitoring in swimming. International Journal of Sports Science & Coaching 2009; 4(1):139-153.
Shimojo H, Sengoku Y, Miyoshi T, Tsubakimoto S, Takagi H. Effect of imposing changes in kick frequency on kinematics during undulatory underwater swimming at maximal effort in male swimmers. Human Movement Science 2014; 38:94-105.
Yamakawa KK, Shimojo H, Takagi H, Tsubakimoto S, Sengoku Y. Effect of increased kick frequency on propelling efficiency and muscular co-activation during underwater dolphin kick. Human Movement Science 2017; 54:276-286.
Atkison RR, Dickey JP, Dragunas A. Importance of sagittal kick symmetry for underwater dolphin kick performance. Human Movement Science 2014; 33:298-311.
Higgs AJ, Pease DL, Sanders RH. Relationships between kinematics and undulatory underwater swimming performance. Journal of Sports Sciences 2017; 35(10):995-1003.
jBeam, https://www.amsonline.de/de/produkte/jbeam/ (last time accessed: 22 January 2020).
Bland JM, Altman DG. Measuring agreement in method comparison studies. Statistical Methods in Medical Research 1999; 8(2):135-160.
Cohen J, A power primer. Psychological Bulletin 1992; 112(1):155.
Downloads
Published
Issue
Section
License
Authors who publish with this journal agree to the following terms:- Authors retain copyright and grant the journal right of first publication with the work simultaneously licensed under a Creative Commons Attribution License that allows others to share the work with an acknowledgement of the work's authorship and initial publication in this journal.
- Authors are able to enter into separate, additional contractual arrangements for the non-exclusive distribution of the journal's published version of the work (e.g., post it to an institutional repository or publish it in a book), with an acknowledgement of its initial publication in this journal.
- Authors are permitted and encouraged to post their work online (e.g., in institutional repositories or on their website) prior to and during the submission process, as it can lead to productive exchanges, as well as earlier and greater citation of published work (See The Effect of Open Access).
