The system emited a laser light in the execution plane of the propelling movements while the sportsman was swimming against the tide in the ergometric swimming pool designed for the purpose. A high-speed video camera (200 Hz) registered hand and particles lit by laser movement.
The analysis of the records has allowed to observe speed values of the fluid around the hand, identifying in the trail different-sized whirpools and energy according to the propelling efficiency observed in the different subjects. This technique was implemented for the first time in human water displacements under real conditions and had been used to analyse fish trials, but the complexity of applying it in human beings has prevented its development until this recent study. Data are still limited and bidimensional but they will allow to define models that explain how the energy transfer between the swimmer and the fluid around him takes place, a still unknown aspect in which the Research Group Physical and Sports Activity in Water Environment of the University of Granada has been working for years.
Trial visualization systems based on the technique of injected bubbles allowed to identify for the first time whirpools distribution after the swimmer while carrying out the subaquatic ondulating movement, surprisingly similar to that of fishes. This sort of studies, carried out in Granada, opened the door to the present situation where modern tools, which combine recording techniques with computer programs, have allowed to analyse in detail human beings´ movements in water.
Figure1. Surface lit by the laser transmitter while swimming in the ergometric swimming pool.
Further imformation: Prof. Raúl Arellano Colomina. Department of Physical and Sports Education. University of Granada.
Phone number: 958-244388 / 626-976150.
E-mail: arellano@ugr.es
