Introduction: Lower body strength is one of the most important determinants of start performance (McBride et al., 2009). It directly affects the ability to exert force on block during push-off phase which affects the take of velocity and flight distance (Slawson et al., 2013). The aim of this research is to examine the effect of maximal isokinetic knee strength on flight distance for grab, track and kick start techniques. Methods: 17 experienced swimmers (Age; 16.84±1.68 year, Body mass; 72.16±7.16 kg, Height; 179.95±5.80 cm. BMI; 22.28±1.91) participated in this study. Start performance was recorded with two digital video cameras to determine flight distance. I isokinetic peak torque was assessed for the knee extensors and flexors at 60 degree/s and at 180 degree/s (Biodex System 4 Dynamometer). Peak torque value of the best repetition were used for each angular velocities. One way analysis of variance (ANOVA) and Pearson correlation analysis was used to asses the relationship between isokinetic strength variables of the knee and flight distance for three start techniques. Results: There was no relation between flight distance and knee flexion-extension peak torques at 60 degree/s for both front and rear legs in all three starting techniques (p>0,05). However at 180 degree/s, flight distance was related with knee extension peak torques (p<0,05) for front leg in grab start (r=0,539*, p=0,016), track start (r=0,489, p=0,046) and kick start (r=0,663**, p=0,004). Moreover at 180 degree/s positive relationship was found for rear leg in kick start technique between knee extension peak torques and flight distance (r=0,506*, p =0,032). There was no relationship at rear leg in grab and track start techniques (p>0,05). Same as 60 degree/s, knee flexion peak torques were not related with flight distance at 180 degree/s in all three techniques. Discussion: Our results showed that at 180 degree/s isokinetic knee extension strength was positively correlated with flight distance at front leg for all start techniques. Previous studies have also reported significant correlation between the contractile properties of leg extensor muscles and start performance (Ðurovic et al., 2015). Differently from grab and track start techniques, at 180 degree/s positive correlation was found at rear leg between knee extension strength and flight distance in kick start technique. In kick start position swimmer`s back leg is positioned on an incline plate. Therefore, the horizontal component of ground reaction force on the kick plate during push off is bigger, compared to other techniques. It is reported that bigger horizontal force in kick start leads to higher horizontal velocity, thereby longer flight distance (Honda et al., 2011; Garcia-Ramos et al., 2015). This could mean that the contribution of rear leg extensors to the start performance is more significant at kick start.
© Copyright 2016 21st Annual Congress of the European College of Sport Science (ECSS), Vienna, 6. -9. July 2016. Veröffentlicht von University of Vienna. Alle Rechte vorbehalten. / Übersetzt mit https://www.DeepL.com/Translator