The effect of body position and mass centre velocity at toe off on the start performance of elite swimmers and how this differs between gender

Abstract

The start in swimming is a crucial phase of a race, where improvements in performance can be made. Twenty-four elite swimmers race pace starts were recorded from five above and below water 50 Hz video cameras. Body position at toe off was calculated from the recordings and consisted of the two-dimensional mass centre position at toe off, and the arm, trunk, front leg and rear leg angles. Horizontal, vertical and resultant velocity of the mass centre at toe off, time to 5 m, 10 m and 15 m were also determined. Whilst time to 5 m (starting performance) differed by 0.17 s between genders, body position at toe off showed no significant differences. The difference in start performance was mainly due to a difference in horizontal velocity at toe off. The relationship between arm angle and start performance warrants further investigation as there was a range of techniques adopted but no clear link to performance. The trunk angle at toe off was correlated to starting performance for both males and females. This study demonstrates that the body position at toe off is no different between genders but is a critical determinant of starting performance for both males and females.

Foot Placement in the Basic Position on the Start Block OSB12 of Young Competitive Swimmers

“…The advantages provided by OSB starting blocks or their platforms lie in the rear support and its adjustment, which allows displacement in five positions. This change in the start block has led to some research [ 2 , 4 , 6 , 7 , 12 , 13 , 20 ], which have addressed the adjustment of the backrest or the change of the base position on the start block, which affect the kinematic–dynamic parameters in the on-start block phase, the kinematic parameters in the flight and underwater phases, as well as the take-off performance itself. For example, a study by Cicenia et al [ 21 ] looked at the use of shin length as a measure to determine cleat position and its effect on performance.…”

“…The results of the study indicated that shin length is a quick and individualized measure that coaches can use to determine kicking plate position without compromising performance. A study by Shepherd et al [ 7 ] demonstrated that rebounding body position does not differ for the two genders but is a critical factor in determining initial performance for both genders. Barlow et al [ 1 ] and Matúš and Kandráč [ 5 ] reported the best performance when the kick plate is at the third and fourth level, respectively.…”

“…Three positions were monitored—front, neutral, and back. In most studies, shorter times were measured at 5 m, 7.5 m, and 15 m, respectively, at neutral-weighted or rear-weighted positions [ 6 , 7 , 8 , 9 , 10 ]. In the study by Burkhardt et al [ 11 ], the positioning of the lower limbs in the base position on the starting block did not show differences in the base position used between the stronger lower limb on the front edge or on the backrest.…”