Development of a new resisted technique in active drag estimation

Biography

Pendar Hazrati is a PhD student at the University of Sydney and PhD scholar of the Australian Institute of Sport. She works with Aquatic, Testing, Training and Research Unit (ATTRU) team at AIS.

Synopsis

A swimmer produces propulsive forces to propel the body forward, however the water creates a resistance or drag force on the swimmer’s body in the opposite direction; opposing forward movement. The Velocity Perturbation Method (VPM) (Kolmogorov & Duplishchea 1992) estimated active drag by comparing two conditions: free swim velocity and the velocity of swimming with an additional hydrodynamic body attached to a swimmer’s waist which produced a known extra drag. The calculation of active drag was based upon two assumptions: first, the swimmer was able to generate an equal mechanical power output in both conditions; and second, the swimmer maintained a constant average velocity during each trial. Xin-Feng et al. (2007) estimated active drag using similar calculations and assumptions to the VPM technique, but with a new device that enabled a drag force that could be varied for different swimmers.
Mason et al. (2011) assessed active drag by using the Assisted Towing Method (ATM) at the Australian Institute of Sport (AIS). This technique utilised the same equal power assumption as the VPM technique except that the swimmer was assisted by a motor driven cable. The purpose of the present study was to implement a new technique to estimate active drag using an electrically braked resisted force rather than an assisted tow, whilst fluctuations in intra-stroke velocity were still allowed. This technique is similar to the method of Kolmogorov & Duplishcheva (1992) and Xin-Feng et al. (2007).