Intracyclic Variation of Force and Swimming Performance
in International Journal of Sports Physiology and PerformanceContext: In front-crawl swimming, the upper limbs perform alternating movements with the aim of achieving a continuous application of force in the water, leading to lower intracyclic velocity variation (dv). This parameter has been identified as a crucial criterion for swimmers’ evaluation. Purpose: To examine the assessment of intracyclic force variation (dF) and to analyze its relationship with dv and swimming performance. Methods: A total of 22 high-level male swimmers performed a maximal-effort 50-m front-crawl time trial and a 30-s maximal-effort fully tethered swimming test, which were randomly assigned. Instantaneous velocity was obtained by a speedometer and force by a strain-gauge system. Results: Similarity was observed between the tests, with dF attaining much higher magnitudes than dv (P < .001; d = 8.89). There were no differences in stroke rate or in physiological responses between tethered and free swimming, with a high level of agreement for the stroke rate and blood lactate increase. Swimming velocity presented a strong negative linear relationship with dF (r = −.826, P < .001) and a moderate negative nonlinear relationship with dv (r = .734, P < .01). With the addition of the maximum impulse to dF, multiple-regression analysis explained 83% of the free-swimming performance. Conclusions: Assessing dF is a promising approach for evaluating a swimmer’s performance. From the experiments, this new parameter showed that swimmers with higher dF also present higher dv, leading to a decrease in performance.
Morouço is with the Center for Rapid and Sustainable Product Development, Polytechnic Inst of Leiria, Leiria, Portugal. Barbosa is with the National Inst of Education, Nanyang Technological University, Singapore, Singapore. Arellano is with the Physical Education and Sport Dept, Faculty of Sports Sciences, University of Granada, Granada, Spain. Vilas-Boas is with the Center of Research, Education, Innovation and Intervention in Sport, Faculty of Sport, and Porto Biomechanics Laboratory (LABIOMEP), University of Porto, Porto, Portugal.
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