Developing a methodology for estimating the drag in front-crawl swimming at various velocities

Abstract

We aimed to develop a new method for evaluating the drag in front-crawl swimming at various velocities and at full stroke. In this study, we introduce the basic principle and apparatus for the new method, which estimates the drag in swimming using measured values of residual thrust (MRT). Furthermore, we applied the MRT to evaluate the active drag (Da) and compared it with the passive drag (Dp) measured for the same swimmers. Da was estimated in five-stages for velocities ranging from 1.0 to 1.4ms; Dp was measured at flow velocities ranging from 0.9 to 1.5ms at intervals of 0.1ms. The variability in the values of Da at MRT was also investigated for two swimmers. According to the results, Da (Da=32.3 v, N=30, R=0.90) was larger than Dp (Dp=23.5 v, N=42, R=0.89) and the variability in Da for the two swimmers was 6.5% and 3.0%. MRT can be used to evaluate Da at various velocities and is special in that it can be applied to various swimming styles. Therefore, the evaluation of drag in swimming using MRT is expected to play a role in establishing the fundamental data for swimming.

Effect of leg kick on active drag in front-crawl swimming: Comparison of whole stroke and arms-only stroke during front-crawl and the streamlined position

“…Similar results were reported in studies using an energetics approach (Di Prampero et al, 1974;Zamparo et al, 2005). Narita et al (2017) estimated drag during swimming using measured values of residual thrust (MRT) and found similar results. From data reported in previous studies, it is evident that the active drag in front-crawl swimming is larger than that in passive conditions, except when the data were obtained using the MAD approach.…”

“…To evaluate active drag, we used the MRT method developed by Narita et al (2017). Prior to measuring the value of residual thrust, which is the difference between the propulsive force and the resistance force, to evaluate the active drag at the targeted swimming velocity V Si , each swimmer self-propelled in the flume with the flow velocity U set to i m s 1 (i indicates an arbitrary velocity at which to evaluate active drag).…”

Comparison of Active Drag Using the MRT-Method and the MAD-System in Front Crawl Swimming

“…We measured the residual thrust at eight points within the range of 0.2 m/s around VSi, changing U by 0.05 m/s each time. Thereafter, we derived best-fit regression curves for the measured values of residual thrust and U and used them to calculate the active drag (for further details, see Narita et al [6]). The drag was estimated in six-staged velocities from 0.9 to 1.4 m/s.…”

“…A methodology for estimating the drag in swimming using measured values of residual thrust (MRT-method) has recently been developed by Narita et al [6]. The MRT-method has no restriction on swimming style and velocity, therefore, the method can evaluate active drag at any velocities as with MAD-system.…”

A comparison between active drag in front-crawl and passive drag on the body with a streamlined position at various velocities

“…Narita et al(2017)による MRT 法を用いて評価された．速度に関しては， 回帰曲線により導出された速度(U Tre0 )を分析に 用いた．なお，U Tre0 は評価対象となる速度(V Si )Top view of the measurement process. To measure only the horizontal component forces, the angles of inclination of each wire, θ 1 and θ 2, were considered.…”