During full tethered swimming no hydrodynamic resistance is generated (since v = 0) and all the swimmer’s propulsive force (FP) is utilized to exert force on the tether (FT = FP). During semi-tethered swimming FP can be made useful to one of two ends: exerting force on the tether (FST) or overcoming drag in the water (active drag: Da). At constant stroke rate, the mean propulsive force (FP) is constant and the quantity FP - FST (the “residual thrust”) corresponds to Da. In this study we explored the possibility to estimate Da based on this method (“residual thrust method”) and we compared these values with passive drag values (Dp) and with values of active drag estimated by means of the “planimetric method”. Based on data obtained from resisted swimming (full and semi-tethered tests at 100% and 35, 50, 60, 75, 85% of the individual FT), active drag was calculated as: DaST = kaST .vST2 = FP - FST (“residual thrust method”). Passive drag (Dp) was calculated based on data obtained from passive towing tests and active drag (“planimetric method”) was estimated as: DaPL = Dp.1.5. Speed-specific drag (k = D/v2) in passive conditions (kp) was )25 kg.m-1 and in active conditions (ka) )38 kg.m-1 (with either method); thus, DaST &gt; Dp and DaST &gt; DaPL. In human swimming active drag is, thus, about 1.5 times larger than passive drag. These experiments can be conducted in an ecological setting (in the swimming pool) by using basic instrumentation and a simple set of calculations.

Matteo Cortesi

Giorgio Gatta

Rémi Carmigniani

Paola Zamparo

Journal of Sports Science and Medicine

JOURNAL OF SPORTS SCIENCE AND MEDICINE (JSSM) 是一本非盈利性科学电子期刊，发表运动医学和运动科学领域的研究和评论文章以及案例研究。 JSSM 每季在 3 月、6 月、9 月和 12 月发布。 JSSM 还出版社论、“致编辑的信”部分、国际和国家代表大会、小组会议、会议和专题讨论会的摘要，并可作为当前关注的重大问题的公开讨论论坛。

The Journal of Sports Science and Medicine (JSSM) is a non-profit scientific electronic journal that publishes research articles, review articles, and case studies in the fields of sports medicine and sports science. JSSM is published quarterly in March, June, September, and December. The journal also includes editorials, letters to the editor, abstracts from international and national conferences, panel meetings, and symposiums, serving as a public forum for discussing significant current issues.

《Journal of Sports Science and Medicine》（JSSM）是一份非盈利性的科学电子期刊，专注于运动医学和运动科学领域的研究、评论文章以及案例研究。JSSM 每年发布四期，分别在 3 月、6 月、9 月和 12 月。期刊还包括论文、致编辑的信件、国际和国家代表大会、小组会议、会议和专题讨论会的摘要，并为当前重大问题提供公开讨论的论坛。

Category	Quartile
医学	2
医学, 运动科学	2

Estimating Active Drag Based on Full and Semi-Tethered Swimming Tests

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Journal Info

Category	Quartile
SPORT SCIENCES	2