Kinematic Analysis of the Underwater Undulatory Swimming Cycle: A Systematic and Synthetic Review

Abstract

The increase of low-cost technology for underwater filming has made quantitative analysis an affordable resource for swimming coaches on a frequent basis. In this context, a synthesis of the kinematic determinants of underwater undulatory swimming (UUS) seems to be lacking. The aim of the present study was to synthesise the scientific evidence on the kinematic characteristics of competitive swimmers during UUS and the main kinematic determinants of UUS performance, as well as to summarise the main methodological considerations for UUS kinematic analysis. A systematic literature search was performed through four electronic databases following the PRISMA guidelines and STROBE for evaluating the quality of the included studies. Twenty-three research studies from the first search and two from the second search were finally considered. In total, 412 competitive swimmers (321 males and 91 females) with a performance standard of international B (11%), national (51%), or regional (35%) level were analysed. Most studies focused on a two-dimensional analysis of the ventral UUS performed from a push start and filmed 6-12 m from the starting wall. Kinematic analysis of UUS included kicking parameters (kicking length, frequency, and amplitude) as well as selected segmental kinematics in 76% of studies and the analysis of UUS performance determinants in 36%. Information about the determinants of UUS performance was inconsistent due in part to inconsistencies in the definition of kinematic parameters. Further research studies where automatic motion capture systems are applied to the analysis of UUS on the aforementioned conditions should be conducted.

Keywords: angular kinematics; competition; dolphin kick; performance; segmental kinematics; swimming start; swimming turn; underwater filming.

Figure 1

Flow diagram for screening and selection of studies according to Preferred Reporting Item for Systematic Reviews and Analysis (PRISMA). Notes: The brackets refer to the first search process (until December 2021) and the square brackets to the second process (from January to April 2022).

Figure 2

Evolution of kicking parameters during UUS according to distance from the starting wall. Note: data from a dive start are denoted with *.

Figure 3

UUS kicking parameters in relation to the kicking velocity. Note: data from a dive start are denoted with *.

Figure 4

UUS parameters in relation to the swimmers’ level of skill. Note: data from a dive start are denoted with *.

Figure 4

UUS parameters in relation to the swimmers’ level of skill. Note: data from a dive start are denoted with *.

Figure 5

Correlation matrix between kinematic parameters and UUS performance [9,12,13,16,31,33,36,41,43]. Note: Blue colour indicate positive correlation coefficient, whereas red indicate increasing negative correlation coefficient. Color intensity and the size of the circle are proportional to the correlation coefficients.