Date of Award

2017

Degree Type

Thesis

Degree Name

Master of Science (Sports Science)

School

School of Medical and Health Sciences

First Advisor

Professor Robert U Newton

Second Advisor

Associate Professor G. Gregory Haff

Field of Research Code

110601, 110602, 110699

Abstract

Undertaking dry-land strength and power training to increase leg extensor power output is believed to increase a swimmer’s ability to start and turn during a swim race. Swimmers generally undertake dry-land strength and power training as part of their overall training regime to increase lower body force output and impulse, in order to improve both swim start and turning performance. Elite swimmers demonstrate faster swimming turn times that are potentially a result of having better strength-power characteristics than sub-elite swimmers. The aim of this research was to quantify differences in dry-land and swimming turn leg extensor force-time characteristics between elite and sub-elite swimmers, and investigate whether short-term ballistic training or maximal strength training is more effective in enhancing leg extensor force-time characteristics during the swim turn in elite and sub-elite swimmers.

To quantify the differences in dry-land and swim turn leg extensor force-time characteristics sub-elite (11 males: 17.4 ± 0.6 y; 10 females: 17.1 ± 0.6 y; mean ± SD) and elite swimmers (15 male: 23.2 ± 2.3 y; 7 female: 21.6 ± 2.5 y) were tested in a cross-sectional design. All swimmers performed a bodyweight and loaded (20 kg females, 30 kg males) squat jump (SJ) on a portable force platform. On the same day, all swimmers completed swimming turn analyses using a force platform fixed within the pool wall. The magnitude of difference between sub-elite and elite groups was estimated using a standardised mean difference (effect size statistic). Elite male and female swimmers had superior swim turn and dry-land force-time characteristics than sub-elite swimmers in all tests. The standardised mean differences between groups ranged from small to very large. The largest differences being unloaded SJ peak velocity (male: 3.07 ± 1.0 m.s-1; female: 3.49 ± 2.29 m.s-1; standardised mean difference ± 90% confidence limits) and unloaded SJ peak power (male: 2.59 ± 0.79 W; female: 2.80 ± 1.64 W) with elite male and female swimmers demonstrating ~25-50% higher performance than the sub-elites.

To investigate whether short-term ballistic or maximal strength training is more effective at enhancing leg extensor force-time characteristics during the swim turn, twelve elite swimmers (10 males and 2 females 19.4 ± 1.0 y) were assigned to either strength (n=6) or ballistic leg extensor (n=6) training based on their coaching group for a six-week period. All testing was conducted during the final training cycle leading into the 2013 World Championships selection trials. There was only one substantial difference between the strength and ballisticgroups after the six-week intervention. Loaded SJ peak velocity was substantially lower (-0.71 ± 0.42 m.s-1; mean ± 90% confidence limits) after six weeks in the strength-trained group. Relative peak power (4.0 ± 2.1 W.kg-1), loaded and unloaded SJ peak force (loaded: 195.0 ±122.8 N, unloaded: 155.0 ±152.3 N) and unloaded SJ impulse (2.9 ± 2.1 N.s) all showed small but clear improvements with ballistic training over the six-week intervention.

Elite male and female swimmers, exhibit superior leg extensor force time curve characteristics in both dry-land and in pool measures than younger and less experienced swimmers. The greatest differences were in squat jump relative peak power and peak velocity. A 6-week training intervention focused on either strength or ballistic dry-land training yielded small improvements in aspects of the push off stage of the swim turn for elite swimmers. Swimming and strength and conditioning (S&C) coaches should include programming options for both strength and ballistic dry-land training to enhance swim turn performance of their athletes

Comments

The Appendix is not included in this version of the thesis.

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