The effects of leg kick on swimming speed and arm-stroke efficiency in the front crawl

Ricardo Peterson Silveira, Flávio Antônio de Souza Castro, Pedro Figueiredo, João Paulo Vilas-Boas, Paola Zamparo

Research output: Contribution to journalArticlepeer-review

27 Citations (Scopus)


Purpose: To analyze the effects of swimming pace on the relative contribution of leg kick to swimming speed and to compare arm-stroke efficiency (ηF) assessed when swimming with the arms only (SAO) and while swimming front crawl (FCS) using individual and fixed adjustments to arm-stroke and leg-kick contribution to forward speed. Methods: Twenty-nine master swimmers (21 men, 8 women) performed SAO and FCS at 6 self-selected speeds from very slow to maximal. The average swimming speed (v), stroke frequency (SF), and stroke length (SL) were assessed in the central 10 m of the swimming pool. Then, a 2nd-order polynomial regression was used to obtain values of v at paired SF. The percentage difference in v between FCS and SAO, for each paired SF, was used to calculate the relative contributions of the arm stroke (AC) and leg kick (LC) to FCS. Then ηF was calculated using the indirect “paddle-wheel” approach in 3 different ways: using general, individual, and no adjustments to AC. Results: The LC increased with SF (and speed) from –1% ± 4% to 11% ± 1% (P < .05). At the lower FCS speeds, ηF calculated using general adjustments was lower than ηF calculated using individual adjustments (P < .05), but differences disappear at the fastest speeds. Finally, ηF calculated using individual adjustments to LC in the FCS condition did not differ with ηF assessed in the SAO condition at all the investigated speeds. Conclusions: The relative contributions of the arm stroke and leg kick should be individually estimated to reduce errors when calculating arm-stroke efficiency at different speeds and in different swimmers.

Original languageEnglish
Pages (from-to)728-735
Number of pages8
JournalInternational Journal of Sports Physiology and Performance
Issue number6
Publication statusPublished - Jul 2017
Externally publishedYes


  • Froude efficiency
  • Lower-limb contribution
  • Upper-limb contribution

ASJC Scopus subject areas

  • Orthopedics and Sports Medicine
  • Physical Therapy, Sports Therapy and Rehabilitation


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