ABSTRACT
The purpose of this study was to examine if aquatic phases of the front crawl stroke could be discriminated by kinematic and kinetic parameters. Nine male subjects swam a 400 yards front crawl at their maximal intensity in a flume. Two underwater cameras filmed the subject, in order to obtain three dimensional data from the DLT method. Velocity and forces of the hand, efficiency index, power output and propelling efficiency were calculated. Discriminant analysis was used in order to study the stroke phases for two conditions: before and after exhaustion. Linear correlation coefficients were calculated between the function discriminant and the swimming velocity, in order to point out a performance effect.. Before exhaustion, the combination of efficiency index, propulsive efficiency and component efficient of the resultant discriminated strongly the three phases. The combination of these parameters was not correlated to the swimming velocity. After exhaustion, two combinations were pointed out. The first included efficiency index, component efficient of the resultant and propulsive efficiency. A significant relationships indicated that the best swimmers had the greater values for these parameters during the insweep phase. The second combination was defined by the hand velocity which was not linked to the swimming velocity.
