Biomechanical Influence of Start Technique Preference for Elite Track Starters in Front Crawl~!2009-07-05~!2009-11-10~!2010-08-13~!

Abstract

The aim of this study was to analyse the differences between preferential and non preferential start technique, and the inter-trial variability. Seven elite swimmers, who used track start as preferential technique, realised three trials in track and grab start. The kinematical analysis assessed the durations of the block, flight, entry, glide, leg kicking and full swimming phases to the 15-m mark. Aerial (sum of block and flight phase with head mark) and underwater (from entry to the head reach the water surface) phases, number of underwater leg undulations and arm stroke to 15m were also measured. The kinetic analysis assessed reaction and impulse time and total impulses in vertical and horizontal axis. Track start, as preferential technique, had shorter block and entry phases but similar flight phase. In grab start, swimmers spend more time in the impulse and obtained higher vertical impulse values; moreover higher inter-trial variability was found for non-preferential technique suggesting lower efficiency. Differences of kinematics and kinetics observed tended to explain that the preferential technique is highly stabilised and reproducible by the swimmers. However, no differences on the 15m start time performance are observed between the two techniques, confirming the high skill level of the swimmers, and notably their capability to compensate lower block efficiency by effective underwater phases. Indeed, the relative duration of the underwater phases, the number of leg undulations and arm strokes are very similar in both techniques.

Does the Back Plate Position Influence Swimming Start Temporal Characteristics?

“…It has been noted that a starting technique specialized throughout the training of a swimmer ensured a better mastery [ 28 ]. The most practiced technique often guarantees the best starting performance [ 22 , 23 ]. In a study evaluating the differences in the preferred back plate position with the consideration of anthropometrical characteristics, only one-third of the participants displayed a decline in the 15 m start time as a result of changes to their preferred position [ 18 ].…”

“…Thus, swimmers may tend to follow their usual movement patterns, particularly by adjusting their body position to the provided starting block features [ 21 ]. Despite the availability of findings exposing positions other than a preferential one as equal to or even more advantageous [ 18 ], the most frequently practiced technique has been very often qualified as the best to be used [ 22 , 23 ]. Therefore, the decisions involved in the swimming start training process optimization should be supported by multidirectional research and findings implied by reliable sources of information.…”

Key Parameters Affecting Kick Start Performance in Competitive Swimming

“…This study dealt with all the phases of the swim start, although some studies [5,25] have highlighted the importance of the underwater phase. The analysis of the block phase of the start showed that the front ankle angle, rear knee angle, and block time were significantly correlated with the time to 5 m. The highest degree of correlation was found between block time (p < 0.01) and the time to 5 m. Other authors, who also used correlation analysis, reported similar findings [9,17,[26][27][28][29][30], reporting high correlations with the times to 5, 10, and 15 m. There was a specific type of correlation between block time and leg position, which affects the movement on the OSB12 starting block. The strongest relationship was found for the front ankle angle.…”

Leg Dominance and OSB12 Kick Start Performance in Young Competitive Swimmers

“…Most recent studies have shown that the addition of a kick plate to the block may allow swimmers to more effectively apply force during the start. Improved start performance was determined in particular by a shorter block time and higher take-off velocity [ 1 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 ]. When comparing start techniques such as track start, grab start, and kick start, multiple authors found shorter times to 2, 5, 7.5, 10, and 15 m when the swimmers used the kick start.…”

“…When comparing start techniques such as track start, grab start, and kick start, multiple authors found shorter times to 2, 5, 7.5, 10, and 15 m when the swimmers used the kick start. Therefore, swimmers should learn to perform the correct kick-start technique [ 1 , 3 , 4 , 9 , 11 , 12 ]. Swimmers need to realize that a change in the foot placement on the kick plate may change their swim start performance [ 13 ].…”