Differences in kinematics and energy cost between front crawl and backstroke below the anaerobic threshold

Tomohiro Gonjo, Carla McCabe, Ana Sousa, João Ribeiro, Ricardo J. Fernandes , João Paulo Vilas-Boas, Ross H. Sanders

Research output: Contribution to journalArticlepeer-review

21 Citations (Scopus)
43 Downloads (Pure)


Purpose: The purpose of this study was to determine kinematic and energetic differences between front crawl and backstroke performed at the same aerobic speeds.Methods: Ten male competitive swimmers performed front crawl and backstroke at a pre-determined sub-anaerobic threshold speed to assess energy cost (through oxygen uptake measurement) and kinematics (using three-dimensional videography to determine stroke frequency and length, intra-cycle velocity fluctuation, three-dimensional wrist and ankle speeds, and vertical and lateral ankle range of motion). For detailed kinematic analysis, resultant displacement, the duration, and three-dimensional speed of the wrist during the entry, pull, push, and release phases were also investigated.Results: There were no differences in stroke frequency/length and intra-cycle velocity fluctuation between the swimming techniques, however, swimmers had lower energy cost in front crawl than in backstroke (0.77 ± 0.08 vs 0.91 ± 0.12 kJ m−1, p < 0.01). Slower three-dimensional wrist and ankle speeds under the water (1.29 ± 0.10 vs 1.55 ± 0.10 and 0.80 ± 0.16 vs 0.97 ± 0.13 m s−1, both p < 0.01) and smaller ankle vertical range of motion (0.36 ± 0.06 vs 0.47 ± 0.07 m, p < 0.01) in front crawl than in backstroke were also observed, which indirectly suggested higher propulsive efficiency in front crawl. Conclusion: Front crawl is less costly than backstroke, and limbs motion in front crawl is more effective than in backstroke.
Original languageEnglish
Pages (from-to)1107–1118
Number of pages12
JournalEuropean Journal of Applied Physiology
Issue number6
Early online date19 Mar 2018
Publication statusPublished (in print/issue) - Jun 2018


  • Swimming
  • Freestyle
  • Backstroke
  • Kinematics
  • Energy
  • Efficiency


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