Date:
29 Apr 2014
Presenters:
Dr Bruce Mason, Australian Institute of Sport
Biography
Dr Bruce Mason has been a biomechanist at the Australian Institute of Sport over the last 30 years. During the last seven years he has worked primarily with the sport of competitive swimming. Bruce has produced a number of analysis systems to assess elite sports performance.
Synopsis
The Australian Institute of Sport has developed a free swim analysis system called the Assisted Towing Method (ATM) designed to estimate a swimmer’s instantaneous whole body active drag parameter at maximum swim velocity. The computed active drag parameter may then be used to assist in the biomechanical assessment of the swimmer’s free swimming technique. The ATM method involves towing the swimmer at approximately a five per cent greater speed than the swimmer’s maximum swim velocity, using a tow which allows a swimmer’s natural intra stroke velocity fluctuations to occur. The swimmer must apply equal maximum power and use similar swimming technique in both the assisted tow and unassisted swim, as well as maintain a mean constant speed throughout both conditions. The varying drag force and varying velocity profiles are used in the computation of active drag. A cubic function obtained from the maximum swim velocity and the tow velocity is used to compute the swimmer’s active drag parameter by multiplying the drag force profile by this cubic function (Mason et al, 2013). In the first calculation, just the mean swim velocities are used in the cubic function. In the second calculation the instantaneous variable velocities are used. In the third calculation a factor incorporating the acceleration profile is applied to the second calculation.